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The conductance of electrolytes in high electric fields Birnboim, Meyer Harold 1956

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THE CONDUCTANCE OF ELECTROLYTES IN HIGH ELECTRIC FIELDS by MEYER H. BIRNBOIM A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF We accept t h i s t h e s i s as conforming t o the standard r e q u i r e d from candidates f o r the degree of MASTER OF ARTS. MASTER OF ARTS IN THE DEPARTMENT of PHYSICS Members of the Department of THE UNIVERSITY OF BRITISH COLUMBIA January, 1956. THE CONDUCTANCE OF ELECTROLYTES IN HIGH ELECTRIC FIELDS by MEYER H. BIRNBOIM A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS IN THE DEPARTMENT of PHYSICS THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1956. i ABSTRACT An apparatus was developed to measure the conductance change of electrolytes i n the presence of high electric f i e l d s to a high degree of accuracy, end i s described herein. The apparatus employs square wave pulse excitation to a special conductivity bridge, and permits direct observation of pulse shape on a high-speed oscilloscope, as well as separate compensation of resistive and capacitive unbalance. With this apparatus, the high-field electric conductances of several solutions of biologically interesting substances were investigated and classified. The substances investigated, together with the observed increment i n electric conductance at a f i e l d strength of 105 volts per cm., are li s t e d : 1. glutamine (1.25 x 10"%), 0.56% 2. 1 (+) arginine monhydrochloride (2.0 x 10-4M), 0.48% 3. acetic acid (3.75 x 10-*M), 4.6% 4. p-amino benzoic acid (5 x 10-5M), 5.5% 5. sulfanilic acid (6.55 X 10-5M), 1.4-^  6. 1 (+) glutamic acid (1.22 x 10-5ll), 2.6% 7. glycine (0.6l M), 1.9% 8. protamine sulfate (7 .9 x 10-5 g/cc.) 40% 9. agar (3 x 10-* g/cc), ' 37% Some of the observed results have been compared with those obtained by other methods, while the remaining substances have not been previously reported. The results were discussed i n the light of available theoretical information on the high-field conductance effect i n various types of electrolytes. i i Acknowledgement The present work was c a r r i e d out under a IT.R.C. research grant t o Dr. Otto B l u h . I g r a t e f u l l y acknowledge f i n a n c i a l support i n form of an a s s i s t a n t s h i p from t h i s grant during the sessions 1953/51*- and 1951+/55> and Dr. B l i i h ' s continuous i n t e r e s t i n the progress of the i n v e s t i g a t i o n . i i i I l l u s t r a t i o n s F i g u r e Subject Page 1. Schematic diagram of the Bridge C i r c u i t 5 2. Block Diagram of the Apparatus 10 3. Schematic diagram of the Pulse Generator 11 h. Photograph of the Apparatus 12 5. Photograph of the Apparatus 13 6. Balance Patterns f o r Simple Impedances at Low F i e l d Strengths 17 7. Balance Patterns f o r Complex Impedances at Low F i e l d Strengths 18 8. Balance P a t t e r n s f o r Complex Impedances at High F i e l d Strengths 20 9 . V e r t i c a l D e f l e c t i o n C a l i b r a t i o n Curve f o r O s c i l l o s c o p e 2h 10. Pulse Amplitude C a l i b r a t i o n Curve 27 11. Glutamine 33 12. 1(+) A r g i n i n e Monohydrochloride 33 13. p - Amino Benzoic A c i d 36 lh. A c e t i c Acid 36 15. G l y c i n e 38 16. S u l f a n i l i c A c i d hi 17. 1(+) Glutamic A c i d hi 18. Protamine S u l f a t e hk 19. Agar hk CONTENTS > Page A b s t r a c t i Acknowledgement i i I l l u s t r a t i o n s i i i I . INTRODUCTION 1 I I . DESCRIPTION OF APPARATUS 3 1. Bridge C i r c u i t h 2. C o n d u c t i v i t y C e l l s 6 3. Pulse Generator 7 I I I . EXPERIMENTAL PROCEDURE lh 1. Balancing of the Bridge lh 2. (a) Determination of Pulse Amplitude 16 (b) C a l c u l a t i o n of F i e l d Strength 22 3. Determination of R e l a t i v e Conductance 25 h. P r e p a r a t i o n of Water and of S o l u t i o n s 28 5. Temperature F l u c t u a t i o n and P o l a r i z a t i o n E f f e c t s 29 IV. EXPERIMENTAL RESULTS 30 Tables I I I t o XI Graphs f i g s . 7 t o 15. 7. DISCUSSION OF RESULTS h$ 1. Theories of Wien E f f e c t (a) I n t e r i o n i c A t t r a c t i o n Theory f o r Strong E l e c t r o l y t e s *+5 CONTENTS (Continued) (b) Ion A s s o c i a t i o n Theory f o r Weak E l e c t r o l y t e s ^7 (c) Wien E f f e c t i n P o l y e l e c t r o l y t e s *+9 (d) Wien E f f e c t i n C o l l o i d a l E l e c t r o l y t e s 50 2. I n t e r p r e t a t i o n of Experimental R e s u l t s 51 3 . Other E f f e c t s 56 (a) D i e l e c t r i c E f f e c t 56 (b) E f f e c t of I m p u r i t i e s 57 (c) Pulse Duration 57 (d) E f f e c t of Temperature on R e l a t i v e Conductance 58 (e) H y d r o c h l o r i c A c i d as a Reference E l e c t r o l y t e 58 V I . SUMMARY AND CONCLUSIONS 59 BIBLIOGRAPHY 6 l •I. INTRODUCTION In 1927 Wien (21,22) discovered t h a t the c o n d u c t i v i t y of an e l e c t r o l y t i c s o l u t i o n i n c r e a s e s w i t h i n c r e a s i n g f i e l d s t r e n g t h when ve r y h i g h e l e c t r i c f i e l d s are a p p l i e d , i n other words, under these extreme c o n d i t i o n s Ohm's Law i s no longer v a l i d . This d e v i a t i o n from Ohm's Law i s r e f e r r e d t o as the Wien e f f e c t . Wien f u r t h e r showed th a t f o r ex-tremely high f i e l d s the conductance of e l e c t r o l y t i c s o l u t -i o n s , w i t h c e r t a i n exceptions, tended towards a l i m i t i n g v alue which corresponds n e a r l y t o the l i m i t i n g conductance at i n f i n i t e d i l u t i o n as measured at low f i e l d s . ' Wien observed t h a t the magnitude of the e f f e c t was much l a r g e r f o r weak e l e c t r o l y t e s than f o r the corresponding strong e l e c t r o l y t e s i n s i m i l a r s o l v e n t s . He a l s o found the magnitude of the e f f e c t t o be i n v e r s e l y p r o p o r t i o n a l t o the d i e l e c t r i c constant of the s o l u t i o n . These e f f e c t s were afterwards accounted f o r by the t h e o r i e s of i n t e r i o n i c a t t r a c t i o n and of i o n i c a s s o c i a t i o n as developed by Debeye, Huckel, Onsager, Wilson and others. This work has been summarized by Eckstrom and Schmelzer (8). P a r t i c u l a r l y l a r g e Wien e f f e c t s were subsequently observed by Malsch and H a r t l e y (18), Adcock and Cole (1), Bluh and Terentiuk (7) and B a i l e y et a l (2,7) f o r aqueous macromolecular and c o l l o i d a l s o l u t i o n s . Determination of the e f f e c t f o r some ampholytes was c a r r i e d out by Bluh and Terentiuk (7), and Berg and P a t t e r s o n (5)6). - 1 -- 2 -The purpose of t h i s i n v e s t i g a t i o n has been (1) t o develop an apparatus which would be capable of measuring the Wien e f f e c t t o a h i g h degree of accuracy, and (2) t o continue the measurements of Bluh and Terentiuk (7) on b i o l o g i c a l l y important substances. An apparatus has been constructed which i s capable of measuring the Wien e f f e c t a c c u r a t e l y over a wide range of f i e l d s t r e n g t h , pulse d u r a t i o n , and i n i t i a l c o n c e n t r a t i o n of s o l u t i o n s ; and the d e t a i l s are reported h e r e i n . This apparatus was used to measure the Wien e f f e c t i n a v a r i e t y of b i o l o g i c a l substances, many of which have not been p r e v i o u s l y r e -ported. High f i e l d strengths must be a p p l i e d i n order t o o b t a i n a p p r e c i a b l e conductance changes i n aqueous s o l u t -i ons of most e l e c t r o l y t e s . This places a number of r e s t r i c t -i o n s on the method of measurement not encountered i n measurements at low f i e l d s . The a p p r e c i a b l e temperature r i s e i n the conductance c e l l s d i c t a t e s t h a t the h i g h f i e l d be a p p l i e d f o r l e s s than 10 microseconds, i n form of a p u l s e , and the requirement of a c c u r a t e l y knowing the f i e l d s t r e n g t h i m p l i e s the use of techniques f o r producing a square p u l s e . Wien and Malsch solved these d i f f i c u l t i e s by developing a b a r r e t t e r b ridge method i n which a c r i t i c a l l y damped sin e wave was a p p l i e d t o a double Wheatstone b r i d g e network, where the temperature s e n s i t i v e b a r r e t t e r elements i n the a u x i l i a r y bridge permit the determination of the main b r i d g e balance. The p r i n c i p a l drawbacks of the method are t h a t i t does not - 3 -permit observation of pulse shape or behavior, and t h a t i t s o p e r a t i o n i s t e d i o u s . Later Fucks (10) and Huter (17) developed o s c i l l o g r a p h i c methods of o b s e r v a t i o n which were l e s s time consuming, but a l s o l e s s p r e c i s e . Adcock and Cole (1) have reported a method of measurement which employs square pulse e x c i t a t i o n and o s c i l l o g r a p h i c p r e s e n t a t i o n of bridge balance. Bluh and Terentuik (7) have reporte d an o s c i l l o g r a p h i c scanning method f o r r a p i d i n v e s t i g a t i o n . A method developed by G l e d h i l l and P a t t e r s o n (1^ , 15) employs a " d i f f e r e n t i a l pulse transformer" as the b a s i s of a bridge c i r c u i t , square wave e x c i t a t i o n , and o s c i l l o g r a p h i c obser-v a t i o n . This apparatus seems capable of more accurate r e s u l t s than those obtained by the previous methods, and i t i s on these l i n e s t h a t the apparatus described below has been designed. Experimental data are presented f o r some b i o l o g i c a l l y i n t e r e s t i n g substances which can be s a i d to be r e p r e s e n t a t i v e of the v a r i o u s c l a s s e s of aqueous s o l u t i o n s of e l e c t r o l y t e s , which i n c l u d e strong and weak e l e c t r o l y t e s , ampholytes, and p o l y e l e c t r o l y t e s such as p r o t e i n s and p o l y s a c c h a r i d e s . I I DESCRIPTION OF APPARATUS In d e s c r i b i n g the apparatus developed f o r the measure-ment of the Wien e f f e c t we s h a l l d e s c r i b e f i r s t the bridge c i r c u i t and c o n d u c t i v i t y c e l l s , and secondly the pulse generator. - If -1. The Bridge C i r c u i t A schematic diagiam of the bridge c i r c u i t i s shown i n f i g . 1. The c o n d u c t i v i t y c e l l s I and I I c o n t a i n the e l e c t r o -l y t e t o be measured and the r e f e r e n c e o e l e c t r o l y t e s o l u t i o n s . The bridge c i r c u i t employs a d i f f e r e n t i a l pulse t r a n s -former (DPT), which i s used t o e s t a b l i s h the n u l l c o n d i t i o n of the brid g e . The two i d e n t i c a l t w i n primary windings connected i n o p p o s i t i o n are i n s e r i e s w i t h the impedances composed of the two c e l l s and the balancing r e s i s t o r s (Rl,R2) and eondensors (Ci,C2). A h i g h speed o s c i l l o s c o p e i s used t o observe the wave form of the v o l t a g e developed across the t h i r d winding of the DPT. I f c u r r e n t s , equal both i n amplitude and phase, f l o w through the two opposed primary windings, no net magnetic f l u x w i l l r e s u l t i n the core of the transformer, and no v o l t a g e w i l l be induced i n the t h i r d winding. I f the impedances connected i n s e r i e s w i t h the pulse generator and transformer windings, are unequal, unequal currents w i l l f l o w i n the two windings, and a net magnetic f l u x p r o p o r t i o n a l t o the degree of unbalance w i l l r e s u l t , so t h a t the s i g n a l across the t h i r d winding of the transformer w i l l be observed on the o s c i l l o s c o p e screen. Balance i n the bridge c i r c u i t i s thus shown by a n u l l i n vo l t a g e from winding 3» Phase unbalance due t o c a p a c i t i v e unbalance i n the two c e l l s w i l l appear as a s l o p i n g or d i f f e r e n t i a t e d i n s t e a d of a f l a t - t o p p e d p u l s e ; balance can be r e s t o r e d by means of the h i g h v o l t a g e v a r i a b l e vacuum eondensors C i and C 2 (15-75 p f . ) . R e s i s t i v e unbalance which i s p r o p o r t i o n a l t o the height of the pulse appearing D i f f e r e n t i a l Pulse Transformer O s c i l l o s c o p e (a) F i g u r e 1 0 (a) Schematic diagram of bridge c i r c u i t , (b) Equi v a l e n t c i r c u i t f o r an i d e a l c e l l , (c) Equivalent c i r c u i t f o r a r e a l c e l l . on the o s c i l l o s c o p e can be compensated by means of the v a r i a b l e r e s i s t a n c e s R i and R2 (each c o n s i s t i n g of a group of f i v e General Radio decade-resistances type 668 each group t o t a l l i n g 311 ohms.). Any sm a l l d i f f e r e n c e s between windings 1 and 2 of the D.P.T. can be c o r r e c t e d by tr a n s p o s i n g the windings w i t h the r e v e r s i n g s w i t c h , and t a k i n g the a r i t h m e t i c mean of the balance p o i n t s . The D.C. r e s i s t a n c e of each winding i s only of the order of 1 ohm., and t h e r e f o r e , p r a c t i c a l l y a l l the pulse v o l t a g e appears across the c e l l s and r e s i s t a n c e s . The t h i r d winding of the transformer i s w e l l s h i e l d e d t o prevent pickup of the r a d i a t i o n from the pulse generator and prevent c a p a c i t i v e c o u p l i n g t o primary windings. A T e k t r o n i x 517 A o s c i l l o s c o p e was used f o r pulse observation and amplitude measurements. The b u i l t - i n c a l i -b r a t o r of t h i s scope provided a standard pulse amplitude. A 35 mm. camera attachment permitted the photographing of s i n g l e p u l s e s . 2. C o n d u c t i v i t y C e l l s The e l e c t r o d e s of the c o n d u c t i v i t y c e l l s were h i g h l y p o l i s h e d platinum d i s c s of 1.6 cm. diameter and spaced 0.090 cm. apa r t . The e l e c t r o d e s were sealed i n t o a support-i n g frame of g l a s s t u b i n g , which i n t u r n was sealed i n t o a gl a s s v e s s e l , c l o s e d except f o r the ground g l a s s j o i n t . The c e l l constant was 0.050. The two i d e n t i c a l c e l l s were suspended i n a constant temperature bath of h i g h q u a l i t y transformer o i l from a p l a s t i c rod beam support r e s t i n g on top of the bath. C i r -c u l a t i o n and mixing of the s o l u t i o n s was achieved by a g i t a t i n g - 7 -the s o l u t i o n s through a gentle r o t a t i o n a l motion of the c e l l s about t h e i r support. An a l t e r n a t i v e method of c i r c u l a t i o n had been used i n the p r e l i m i n a r y experiments. The c o n d u c t i v i t y c e l l e l e c t r o d e s were e c c e n t r i c a l l y suspended i n the beaker c o n t a i n i n g the s o l u t i o n . Continuous r o t a t i o n of the beaker by a motor provided automatic c i r c u l a t i o n of the s o l u t i o n through the e l e c t r o d e s . I n order t o provide i s o l a t i o n from the atmos-phere, a system of c o n c e n t r i c beakers w i t h a l i q u i d s e a l was used. The e l e c t r o d e s were 1.6 cm. diameter and spaced 0.90 mm. The method of c i r c u l a t i o n can be seen i n the photograph of f i g . 5« Neither of these methods of c i r c u l a t i o n were found t o be e n t i r e l y s a t i s f a c t o r y but the f i r s t mentioned method had a b e t t e r degree of c o n t r o l . Since the s o l u t i o n s were nit r o g e n a t e d before the measurements were taken t o remove d i s s o l v e d carbon d i o x i d e , the a g i t a t i o n of the s o l u t i o n tended t o f r e e some of the d i s s o l v e d n i t r o g e n and t o cause formation of minute gas bubbles about the e l e c t r o d e s . This changes the e f f e c t i v e area of the e l e c t r o d e s and thus the r e s i s t a n c e of the s o l u t i o n , and at h i g h f i e l d s caused a r c i n g . I t was found t h a t removal of excess d i s s o l v e d n i t r o g e n before measurements, by s l i g h t h e a t i n g , and s t i r r i n g was of advantage. 3. The Pulse Generator A General Radio pulse generator provided low v o l t a g e r e c t a n g u l a r pulses of 26 v o l t amplitude, which were used t o determine the balance c o n d i t i o n s a t low f i e l d s ("zero f i e l d " ) . - 8 -High v o l t a g e pulses are obtained from a h i g h - v o l t a g e p u l s e r ( f i g . 2 , 3 , a n d could be v a r i e d i n amplitude from one t o s i x t e e n k i l o v o l t s by changing the power supply output w i t h a v a r i a c . transformer. Photographs of the apparatus i s shown i n f i g s , h and 5, a block diagram i n f i g . 2, and a schematic diagram i n f i g . 3* In the c o n s t r u c t i o n of the pulse generator r e f e r -ence was made t o the pulse technigues d e s c r i b e d i n the books of Glascoe and Lebacqz; (13) and of V a l l e y and wallmann (20). The h i g h v o l t a g e p u l s e r i s d r i v e n by a low v o l t a g e pulse generator, which i s i n t u r n d r i v e n by the t r i g g e r generator. The t r i g g e r generator which t r i g g e r s both pulse and o s c i l l o -scope, i s a t h y r a t r o n r e l a x a t i o n o s c i l l a t o r (2050), i n which the frequency can be v a r i e d from manual oper a t i o n t o 10 pulses per second. These pulses are f e d i n t o a second p u l s e -shaping t h y r a t r o n (2050) i n c l u d e d i n the t r i g g e r generator. The output pulses are f e d simultaneously i n t o a f i x e d t r i g g e r delay u n i t and a v a r i a b l e t r i g g e r delay u n i t , whieh both c o n s i s t of a r e s i s t a n c e - c a p a c i t y network i n the g r i d c i r c u i t s of the thyr a t r o n s (2050). The g r i d t o ground c a p a c i t y i n the t r a i l i n g edge t h y r a t r o n can be v a r i e d , thus v a r y i n g the time r e q u i r e d . f o r grid-cathode capacity- t o reach the t h y r a t r o n t r i g g e r i n g v o l t a g e ; i n t h i s way the delay between f i r i n g of the l e a d i n g and the t r a i l i n g edge th y r a t r o n s can be v a r i e d . When the l e a d i n g edge t h y r a t r o n f i r e s , the energy storage condenser discharges some of i t s energy t o the g r i d s of the hard tube p u l s e r , w h i l e the f i r i n g of the t r a i l i n g edge t h y r a t r o n s h o r t - c i r c u i t s the g r i d s of the p u l s e r tubes, and cuts o f f the f i r s t t h y r a t r o n . The pulse generated by the thy r a t r o n s i n e f f e c t switches on and o f f the g r i d s of the hard tube p u l s e r (two 5021»s i n p a r a l l e l ) . The pulse reaching the g r i d s of the 5021's has an amplitude of 600 v o l t s . A 1 mf, 16 kv paper condenser i s used as the energy storage u n i t i n the hi g h v o l t a g e p u l s e r c i r c u i t , and i s charged through an i s o l a t i n g r e s i s t o r by the h i g h v o l t a g e power supply. When the p u l s e r tubes are switched on and o f f by the 600 v o l t pulse on the g r i d s , the condenser p a r t i a l l y discharges through the bridge c i r c u i t . At the end of the pu l s e , the energy storage condenser must recharge through the bridge c i r c u i t , thus a u t o m a t i c a l l y p r o v i d i n g a pulse of opposite p o l a r i t y f o r the d e p o l a r i z a t i o n of the e l e c t r o d e s . The pulse l e n g t h can be v a r i e d between 0.5 and 5° m i c r o s e c , and amplitude up t o 16 kv, and the current up t o 30 amps. The r e p e t i t i o n frequency i s up t o 10 per second, but t o minimize h e a t i n g and p o l a r i z a t i o n e f f e c t s , the r e p e t i t i o n frequency i s kept t o 2 per minute, w h i l e a pulse l e n g t h of 10 microseconds has been used. The high v o l t a g e pulse amplitude can be measured w i t h a c a p a c i t i v e v o l t a g e d i v i d e r (Jenning's h i g h - v o l t a g e vacuum type) of r a t i o 110:1, and a c a l i b r a t e d o s c i l l o s c o p e (Tektronix 5 l?A). TRIGGER GENERATOR Manual to 10/second - 150 7 500 V + 1000 7 1 ENERGY STORAGE CONDENSER FIXED TRIGGER DELAY LEADING EDGE TflYRATRON SWITCH VARIABLE! TRIGGER DELAY JL TRAILING EDGE THYRATRON SWITCH law Voltage Pulse Generator H.V. POWER SUPPLY 0-16 K.V. (Variable) < ISOL RES IS brim rANCE PULSER SWITCH TUBES 1 ENERGY STORAGE CONDENSER High Voltage Pulse Generator OSCILLOSCOPE D.P.T. BRIDGE CAPAcrrrvE VOLTAGE DIVIDER r: Bridge Circuit Fig. 2 . Block diagram of pulse generator and bridge c i r c u i t . Trigger Rate Generator Low Voltage Pulse Shaper ' High Voltage Pulser 5Q0V 1000 V •200K 0-I6KV I0K. 200K> IK COARSE RATE rWv j 20 1 1 i i 350 50 r<§l < l M -200<4K <5K Ki_L 0.5 EXT 3RNAL TR1GGBR 0.2J 0J[* T .01 r 20 20 1 . 11 Bib T < l|MFf 50 50 5 I K i 35*0 I0( 11 5JK 1001 I •Jo 20 I 5 K •AAr-5 0 COARSE F0lj3E W3DJH '36K OK f ? Mi i 47 K60T600T I 0p300T 6pOO 150 IMF ' HI— oj -400V o O o o 5J to Hr—> I JlOOK W2"50K A/w—' FINE RATE FINS PULSE WIDTH 390K 680K -150 V 6 1000 V F i g . J. Schematic diagram of pulse generator - 12 -F i g . h. Photograph of the Apparatus F i g . 5. Photograph of the Apparatus - 1U, -I I I EXPERIMENTAL PROCEDURE 1. Balancing of the Bridge A schematic diagram of the bridge c i r c u i t i s shown i n f i g . 1 ( a ) . F i g . 1(b) i l l u s t r a t e s the eq u i v a l e n t c i r c u i t & r the impedance of an i d e a l c o n d u c t i v i t y c e l l where the r e s i s t a n c e I s due t o the c o n d u c t i v i t y of the e l e c t r o l y t i c s o l u t i o n and the p a r a l l e l c a p a c i t y i s due t o the two e l e c t -rodes separated by a s o l u t i o n of high d i e l e c t r i c constant. F i g . 1(c) i l l u s t r a t e s the proposed eq u i v a l e n t c i r c u i t f o r the impedance of a r e a l c e l l composed of ( i ) the r e s i s t a n c e due t o the c o n d u c t i v i t y of the s o l u t i o n , ( i i ) a s e r i e s c a p a c i t y , which has been introduced t o account f o r the p o l a r i z a t i o n at the e l e c t r o d e s and ( i i i ) a p a r a l l e l c a p a c i t y due t o presence of two conducting e l e c t r o d e s separated by a s o l u t i o n of h i g h d i e l e c t r i c constant. There i s no p r o v i s i o n made f o r balancing the s e r i e s c a p a c i t y ( f i g . 1(c)) i n the two arms of the b r i d g e , except by j u d i c i o u s choice of reference e l e c t r o l y t e , such t h a t the amount and r a t e of p o l a r i z a t i o n i n the two s o l u t i o n s w i l l be the same. The t r a c e s on the o s c i l l o s c o p e screen were photographed under v a r i o u s c o n d i t i o n s of balance and unbalance of the bridge c i r c u i t . A c t u a l photographs of the t r a c e s are shown i n f i g s . 6, 7» and 8. F i g . 6 i l l u s t r a t e s the case of bala n c i n g a simple impedance of form of f i g . 1 ( b ) . The c o n d u c t i v i t y c e l l s are replaced each by a ch a i n of carbon r e s i s t o r s of 3000 ohms t o t a l r e s i s t a n c e . Photograph 1 shows the form of the input pulse t o the bridge from the General Radio low v o l t a g e pulse - 15 -generator. For pure r e s i s t i v e unbalance the form of the i n p u t pulse i s reproduced at the bridge output, where the height of the f l a t top i s p r o p o r t i o n a l t o the degree of r e s i s t i v e unbalance (photograph 3)» I f c a p a c i t i v e unbalance i s introduced as w e l l , then the output pulse a l s o appears d i f f e r e n t i a t e d (photograph 2 ) . A r e c t a n g u l a r pulse of zero amplitude i s obtained when both r e s i s t a n c e and c a p a c i t y are balanced (photograph h) by means of R^, R2 and C^, C2. I t i s of i n t e r e s t t o note here t h a t since the amplitude of,the f l a t top of the pulse i s p r o p o r t i o n a l t o the degree of r e s i s t i v e unbalance, i t i s p o s s i b l e from the measurement of pulse amplitudes f o r two s e t t i n g s of the compensating r e s i s t a n c e s , t o e x t r a p o l a t e an estimate of the r e s i s t a n c e r e q u i r e d f o r b a l a n c i n g . This i s of p a r t i c u l a r importance at h i g h f i e l d s t r e n g t h measurements, where economy of pulses t o minimize h e a t i n g and p o l a r i z a t i o n i s important. The photographs of f i g . 7 i l l u s t r a t e the r e s u l t of the presence i n the bridge of complex impedances ( f i g . 1 ( c ) ) represented by the e l e c t r o l y t i c c e l l s , c o n t a i n i n g agar and HC1 i n t h i s i n s t a n c e . The f i r s t photograph again shows the low v o l t a g e i n p u t pulse, w h i l e the second shows the best compromise a t c a p a c i t i v e and r e s i s t i v e balance. The net c a p a c i t y unbalance seems t o give r i s e t o two p a i r s of s p i k e s . The spikes of each p a i r are o p p o s i t e l y d i r e c t e d , and the two p a i r s are a l s o o p p o s i t e l y d i r e c t e d . Any attempt t o reduce the height of one p a i r of spikes by a d j u s t i n g C]_ or C2 i n c r e a s e s the height of the second p a i r of spikes , t h e r e f o r e the a r b i t r a r y compromise f o r c a p a c i t i v e - 16 -balance was adopted making a l l spikes of about equal h e i g h t . The t h i r d photograph i l l u s t r a t e s the d e v i a t i o n from c a p a c i t i v e balance by i n c r e a s i n g the .capacity of the agar s i d e of the b r i d g e , w h i l e i n the f o u r t h case c a p a c i t y i s greater on the HC1 s i d e . M a i n t a i n i n g excess c a p a c i t y on the HC1 s i d e of the b r i d g e , the r e s i s t a n c e i s brought above and below balance on the HC1 s i d e of the bridge (photographs 7 and 8 r e s p . ) , r e s u l t i n g i n the displacement of the f l a t top of the p u l s e . F i g . 8 shows another example of b a l a n c i n g a complex impedance. I n t h i s case one c o n d u c t i v i t y c e l l c ontains 0.61 M g l y c i n e s o l u t i o n and the other a HC1 r e f e r e n c e s o l u t i o n . Photograph 1 shows the t y p i c a l balance p a t t e r n of a complex impedance a t low f i e l d s . I f however a h i g h f i e l d pulse of 130 K.V./cm. i s a p p l i e d t o the bridge (photograph 2), then the b r i d g e output pulse appears as i n photographs 3 and being e x t e r n a l l y attenuated i n the l a t t e r i n s t a n c e by a f a c t o r of 10. whether the unusual shape of t h i s pulse i s due t o change i n c a p a c i t i v e balance w i t h f i e l d ( c l o s e l y r e l a t e d t o p o l a r i z a t i o n ) or due t o r e l a x a t i o n phenomenon could not be decided, however, i n a l l cases the c o n d i t i o n f o r r e s i s t i v e balance was somewhat a r b i t r a r i l y taken as zero amplitude f o r the end of the non-d i f f e r e n t i a t e d p a r t of the p u l s e . 2 . (a) Determination of Pulse Amplitude and F i e l d Strength The h i g h v o l t a g e pulse a p p l i e d t o the bridge c i r c u i t a l s o appears at a c a p a c i t i v e v o l t a g e d i v i d e r , which, t o -gether w i t h a d d i t i o n a l e x t e r n a l a t t e n u a t o r s , reduce the - 17 -If F i g . 6. O s c i l l o g r a p h i c Traces i n the Balanc i n g of a Simple Impedance i n the D.P.T. Bridge at Low E l e c t r i c F i e l d s . The c o n d u c t i v i t y c e l l s were re p l a c e d by carbon r e s i s t a n c e s , each of 3000 ohms t o t a l r e s i s t a n c e . 1. Low v o l t a g e (26 v o l t ) input pulse i s shown. 2. Output pulse when both r e s i s t a n c e and c a p a c i t y are unbalanced. 3. Output pulse when c a p a c i t y i s balanced and r e s i s t a n c e remains unbalanced. h. Output pulse when r e s i s t a n c e and c a p a c i t y are both balanced. - 18 -\ i r V F i g . 7. O s c i l l o g r a p h i c Traces i n the Balancing of a Complex Impedance i n the D.P.T. Bridge a t Low E l e c t r i c F i e l d s . The c o n d u c t i v i t y c e l l s form the complex impedance, and c o n t a i n 3 x IO"*4" grams/cc. agar s o l u t i o n and the reference s o l u t i o n of HC1, r e s p e c t i v e l y . 1. Low v o l t a g e (26 v o l t ) i n p u t pulse. .2. Output pulse w i t h the best r e s i s t i v e and c a p a c i t i v e balance t h a t could be obtained. 3. Output pulse when c a p a c i t y i s unbalanced. The c a p a c i t y i s greater i n the agar arm of the br i d g e . k-. Output pulse when c a p a c i t y i s unbalanced. The c a p a c i t y i s now greater i n the HC1 arm of the b r i d g e . - 19 -vara t F i g . 7 (Continued). O s c i l l o g r a p h i c Traces i n the Balancing of a Impedance i n the D.P.T. Bridge at Low E l e c t r i c F i e l d s . -5. Output pulse when c a p a c i t y and r e s i s t a n c e are both unbalanced. C and R are both greater i n the HC1 arm of the b r i d g e . 6. Output pulse when c a p a c i t y and r e s i s t a n c e are both unbalanced. C remains greater i n the HC1 arm of the b r i d g e , w h i l e R i s now greater i n the agar arm. - 20 -T V " 7 F i g . 8. O s c i l l o g r a p h i c Traces i n the Bal a n c i n g of a Complex Impedance i n the D.P.T. Bridge a t High E l e c t r i c F i e l d s . The c o n d u c t i v i t y c e l l s form the complex impedance, and co n t a i n 0.6l M g l y c i n e and the refer e n c e s o l u t i o n of H C 1 . 1. Output pulse w i t h the best r e s i s t i v e and c a p a c i t i v e balance at low f i e l d (26 v o l t p u l s e ) . 2. High v o l t a g e i n p u t pulse ( f i e l d 130 K.V./cm.) i s shown. 3. Output pulse at h i g h f i e l d s t r e n g t h when r e s i s t a n c e i s s l i g h t l y unbalanced but best c a p a c i t i v e balance o b t a i n a b l e . h. This i s i d e n t i c a l t o 3 above except attenuated x 10, - 21 -amplitude of the pulse t o a i e v e l p e r m i t t i n g d i s p l a y on the o s c i l l o s c o p e . I f the pulse height (h) i s measured and the t o t a l a t t e n u a t i o n r a t i o (A) i s known, and the s e n s i t i v i t y (S) of the o s c i l l o s c o p e d e f l e c t i o n i s known i n volts/cm., then the pulse amplitude V i n v o l t s i s V = h.S.A. In order t o avoid unnecessary r e p e t i t i o n of the pulse ( t o minimize heating e f f e c t s ) , i t was f e l t convenient t o have a secondary standard f o r p r e - s e t t i n g t o any pulse h e i g h t . Measurement of the primary a.c. v o l t a g e a p p l i e d t o the h i g h v o l t a g e power supply seemed t o provide a convenient secondary standard, s i n c e the pulse amplitude v a r i e s l i n e a r l y w i t h primary v o l t a g e . The v a r i a t i o n of the primary v o l t a g e by means of a v a r i a c , was used t o change the pulse amplitude. The a t t e n u a t i o n A, mentioned above, i s provided by ( i ) the c a p a c i t i v e vacuum v o l t a g e d i v i d e r of r a t i o : A]_, and ( i i ) the b u i l t - i n c a p a c i t i v e attenuator of the cathode f o l l o w e r probe of ratio:- A2» and ( i i i ) an e x t e r n a l c a l i -brated T e k t r o n i x step attenuator of r a t i o : A3. Thus the t o t a l a t t e n u a t i o n between the h i g h v o l t a g e pulse and the o s c i l l o s c o p e i s A = A~L.A2.A3. The T e k t r o n i x 517A o s c i l l o s c o p e i s equipped w i t h a pulse type amplitude c a l i b r a t o r w i t h v a r i a b l e output from 0.01 v o l t t o 5° v o l t p o s i t i v e p u l s e s , which was used as the standard of pulse h e i g h t . By feeding the c a l i b r a t o r output d i r e c t l y t o the o s c i l l o s c o p e , i t s s e n s i t i v i t y i n volts/cm. i s d i r e c t l y determined (see t a b l e I and f i g . 9 ) . Having - 22 -c a l i b r a t e d the o s c i l l o s c o p e s e n s i t i v i t y ( f i g . 9) i n t h i s way, the r a t i o A 2 can be adjusted t o any d e s i r e d value by fee d i n g the c a l i b r a t o r output i n t o the cathode f o l l o w e r and through the attenuator A3 i n t o the o s c i l l o s c o p e . Thus i t remains only t o determine the r a t i o A^. To do t h i s , the amplitude of a low v o l t a g e pulse a p p l i e d t o the bridge was measured f i r s t as i t appeared across the bridge d i r e c t l y and secondly through the c a p a c i t i v e v o l t a g e d i v i d e r . I n each case A 2 and A^ were adjusted t o convenient r a t i o s , bearing i n mind not t o overload the cathode f o l l o w e r . The pulses appearing on the o s c i l l o s c o p e were photographed f o r more accurate measurement. The r e s u l t s appear i n Table I I , w h i l e the c a l i b r a t i o n curve, primary a.c. v o l t s i n terms of pulse height appears i n f i g . 10. 2. (b) The F i e l d Strength End e f f e c t s being n e g l e c t e d , the f i e l d s t r e n g t h i n the p a r a l l e l d i s k c o n d u c t i v i t y c e l l i s given by • X = V d where V i s the v o l t a g e across the c e l l and d i s the spacing between the p a r a l l e l e l e c t r o d e s . The pulse height V Q appearing across the bridge as determined from the c a l i b r a t -i o n curve ffig.ld) i s d i v i d e d i n t o two p a r t s : t h a t appearing across the s e r i e s compensating r e s i s t o r (Rj. o r ^2 a s ^ h e case may be) and t h a t p a r t across the c e l l . Thus i f R i s the c e l l r e s i s t a n c e - t h e n where g e n e r a l l y R » R i . \ - 23 -Table I C a l i b r a t i o n data f o r v e r t i c a l d e f l e c t i o n of T e k t r o n i x 517A o s c i l l o s c o p e Input P u l s e * V e r t i c a l D e f l e c t i o n v o l t s cms. 0.03*f 0.60 0.052 O.87 0.061 1.00 0.068 1.13 o.iou, 1.66 O.I36 2.13 0.266 2.35 •The s i g n a l source was the pulse type c a l i b r a t o r of the Tek t r o n i x 517A o s c i l l o s c o p e . F i g u r e 9. V e r t i c a l d e f l e c t i o n c a l i b r a t i o n curve f o r the T e k t r o n i x 517A O s c i l l o s c o p e , (data from Table I ) - 25 -3. Determination of the R e l a t i v e Conductance / A f t The t h i r d and f o u r t h columns of the t a b l e s of e x p e r i -mental r e s u l t s (Tables I I I t o XI) show the r e s i s t a n c e r e q u i r e d i n s e r i e s w i t h each c o n d u c t i v i t y c e l l t o o b t a i n r e s i s t i v e balance at v a r i o u s f i e l d s t r e n g t h s . The d i f f e r e n c e between these two f i g u r e s gives the d i f f e r e n c e i n r e s i s t a n c e of the e l e c t r o l y t e under i n v e s t i g a t i o n and the h y d r o c h l o r i c a c i d at the p a r t i c u l a r f i e l d s t r e n g t h . We note t h i s d i f f e r e n c e by ( i R ) x = ( R H c i - R e l e c t r o l y t e ^ X at a f i e l d strength.X. The change i n r e s i s t a n c e of the e l e c t r o l y t e r e l a t i v e t o HC1 at f i e l d strengths X and at X = 0, i s given by (•R) x - ( S R ) X = o =AR wh i l e the r e l a t i v e change i n r e s i s t a n c e i s *X F 0 + <*R>X where Rx=o ( * h e ze*° f i e l d r e s i s t a n c e of the e l e c t r o l y t e ) has been determined by independant measurements and i s given i n the footnotes of each t a b l e . I t i s o f t e n more convenient t o w r i t e the l a s t expression i n terms of the conductance ( A ) of the s o l u t i o n where A = 1 > so tha t the r e l a t i v e change i n conductance R i s A A - 26 -Table II Pulse amplitude c a l i b r a t i o n data 1. S e n s i t i v i t y of Tektronix 517 oscilloscope. Refer to f i g . 1 f o r c a l i b r a t i o n curve. 2. Determination of r a t i o A^ of capacitance vacuum voltage d i v i d e r . A 2 A^ Amplitude at Scope Pulse Amplitude Output taken d i r e c t l y from source: 2000 10 0.04-8 v o l t s 960 v o l t s Output taken through voltage d i v i d e r Aq_i 96 2 0.052 v o l t s 10.0 v o l t s Therefore voltage d i v i d e r ratio: A]_ = 960 • 10.0 = 96 3. C a l i b r a t i o n curve Pulser Primary Scope Amplitude A 2 A 3 Pulse ac. v o l t s v o l t s K.V. 13.8 .05*f 96 96 h 2.0 lh.6 .057 96 96 h 2.1 19.7 .037 96 96 8 2.7 25.2 .0^7 96 96 8 3.5 36.5 .054- 96 96 10 5.0 60.0 .ohh 96 96 20 8.1 95.0 .070 96 96 20 12.9 100 .038 96 96 4-0 lh.0 104- .04-1 96 96 ho 15.1 - 27 -20 60 100 PULSER PRIMARY - A.C. VOLTS F i g u r e 10. Pulse Amplitude C a l i b r a t i o n Curve, (data from Table II). - 28 -P r e p a r a t i o n of C o n d u c t i v i t y Water and of S o l u t i o n s The c o n d u c t i v i t y water was prepared i n a three stage d i s t i l l a t i o n apparatus; the steam being condensed i n a b l o c k - t i n condenser. Nit r o g e n was bubbled through t h i s water t o remove d i s s o l v e d carbon d i o x i d e . The water was then heated t o about 80°C. t o remove excess d i s s o l v e d n i t r o g e n gas and then cooled t o the d e s i r e d temperature. "7 The s p e c i f i c c o n d u c t i v i t y was then b e t t e r than 5 x 10 ' mhos. Some of the samples of substances i n v e s t i g a t e d i n t h i s study were r e c r y s t a l l i z e d and some were not, as i s shown i n the footnotes of the t a b l e s of r e s u l t s . The samples were d i s s o l v e d i n the c o n d u c t i v i t y water t o form a stock s o l u t i o n . The r e s i s t a n c e of s o l u t i o n i n the c e l l was arranged t o be 2000 ohms; the c o n c e n t r a t i o n r e q u i r e d t o arrange t h i s being determined i n a separate c o n d u c t i v i t y bridge w i t h a sample of s o l u t i o n prepared from the stock s o l u t i o n . About hOO cc. of s o l u t i o n was placed i n the c e l l . The c o n c e n t r a t i o n of h y d r o c h l o r i c a c i d i n the r e f e r -ence c e l l was adjusted i n each case t o be about 100 ohms l e s s than the r e s i s t a n c e of the e l e c t r o l y t i c s o l u t i o n . The c o n d u c t i v i t y of the e l e c t r o l y t i c s o l u t i o n i n the c e l l (Ax=0) a t zero f i e l d ( i . e . at a f i e l d s t r e n g t h of 250 volts/cm.) was e s t a b l i s h e d by r e p l a c i n g the h y d r o c h l o r i c a c i d reference c e l l w i t h a Leeds and Northrop ac. - dc. decade r e s i s t a n c e box i n p a r a l l e l w i t h a v a r i a b l e condenser, and a d j u s t i n g the r e s i s t a n c e box t o o b t a i n a balance. The low v o l t a g e i n p u t pulse i s a p p l i e d t o the bridge t o o b t a i n - 29 -t h i s balance. The pulse source was a 26 v o l t General Radio pulse-generator, which was a l s o used t o e s t a b l i s h zero f i e l d balance a g a i n s t the h y d r o c h l o r i c a c i d r e f e r e n c e s o l u t i o n . 5. I I Temperature F l u c t u a t i o n and P o l a r i z a t i o n E f f e c t s The ( & R ) ^ - _ which has been shown i n the t a b l e s as a constant v a l u e , i n f a c t f l u c t u a t e d w i t h time i n two ways. F i r s t due t o f l u c t u a t i o n s i n temperature of the bath by as much as 1°C. during the course of an experiment, there corresponded a d r i f t i n ( S R ) x _ Q . This would of course be p r o p o r t i o n a l t o the d i f f e r e n c e of the temperature co-e f f i c i e n t s of r e s i s t a n c e f o r the e l e c t r o l y t e and f o r the h y d r o c h l o r i c a c i d reference s o l u t i o n . The value of ( $R)Y_ - 0 a l s o d i f f e r e d depending on whether t h i s was taken before or a f t e r passage of a h i g h v o l t a g e p u l s e . The procedure was adopted t o take f o r each h i g h f i e l d r e s i s t a n c e measurement i t s own zero f i e l d r e s i s t a n c e r e f e r e n c e p o i n t , which was determined as the . mean of the zero f i e l d r e s i s t a n c e readings measured immediately preceding and one minute succeeding the passage of the h i g h v o l t a g e p u l s e . The values of s e r i e s r e s i s t a n c e given i n the t a b l e s were adjusted on t h i s b a s i s . However i n view of the experiments, as w e l l as those of Fuoss (28)-, on the slow r e t u r n t o e q u i l i b r i u m a f t e r the passage of a h i g h v o l t a g e p u l s e , i t may have been b e t t e r t o take only the reading preceding the high f i e l d pulse as the tru e e q u i l i b r i u m v a l u e . - 30 -IV. EXPERIMENTAL RESULTS The experimental r e s u l t s are presented i n Tables I I I t o X I , and i l l u s t r a t e d i n g r a p h i c a l form by f i g s . 11 t o 19. They can be arranged i n t o three c a t a g o r i e s : ( I ) glutamine and 1(+) a r g i n i n e monohydrochloride showing n e g l i g i b l e Wien e f f e c t ( l e s s ' t h a n 0.% at 100 KV./cm.); ( i i ) p-amino benzoic a c i d , a c e t i c a c i d , s u l f a n i l i c a c i d , 1(+) glutamic a c i d and g l y c i n e showing i n c r e a s e s i n conductance of between 2% and 6$, and ( i i i ) protamine s u l f a t e and agar showing a conductance i n c r e a s e of about k-0%. The r e s u l t s are more f u l l y d iscussed l a t e r . - 31 -Table I I I Conductance i n h i g h e l e c t r i c f i e l d s of 1.25 x -4-10 M glutamine r e l a t i v e t o 6 x 10"^  M HC1 at 26.5°C. P u l s e r Primary Pulse S e r i e s Resistance HC1 Side Soln. Side F i e l d A A//, ac. v o l t s K.V. ohms K.V./cm. % 0 0 172 0 0 0 14-. 5 1.9 165 0 21 0.35 30.4- 4..0 161 0 5^ 0.55 60.0 7.9 159 , 0 88 0.64-100 13.2 159 0 111 0.64-Notes: 1. P r e p a r a t i o n : The glutamine (GBI Brand) was r e - c r y s t a l l i z € t wice from water, oven 'dried, then d i s s o l v e d i n c o n d u c t i v i t y water. 2. The zero f i e l d r e s i s t a n c e of the glutamine s o l u t i o n was 2010 ohms; and s p e c i f i c r e s i s t a n c e of 4-.0 x: IO4" ohms. - 32 -Table 17 Conductance i n h i g h e l e c t r i c f i e l d s of 2.0 x IO"1* M 1(+) arginine-monohydrochloride r e l a t i v e t o 6 x 10"^ M HC1 at 26.*f°C. P u l s e r S e r i e s Resistance Primary Pulse HC1 Side S o l n . Side F i e l d AA/Ao ac. v o l t s K . V . ohms K.7./cm % 0 0 225 0 0 0 25.2 3.3 225 0 37 0 53.3 6.8 215 0 76 0.51 89.5 11.9 213 0 132 0.61 Notes: 1. P r e p a r a t i o n . The 1(+) a r g i n i n e monohydrochloride (GBI Brand) was d i s s o l v e d d i r e c t l y i n t o the c o n d u c t i v i t y water. 2. The zero f i e l d r e s i s t a n c e of the 1(+) a r g i n i n e mono-hy d r o c h l o r i d e s o l u t i o n was I 9 8 O ohms; and the s p e c i f i c r e s i s t a n c e was 4-.0 x 10^ " ohms. - 33 -40 80 FIELD 120 K V / C M . F i g u r e 11. The conductance i n hi g h e l e c t r i c f i e l d s of 1 .25 z IO-4" M glutamine r e l a t i v e t o 6 x 10"5 M HC1 at 26o5°C 40 80 FIELD 120 K V / C M . 160 F i g u r e 12. The conductance i n hi g h e l e c t r i c f i e l d s of 2.0 x 10 M 1(+) A r g i n i n e Monohydrochloride r e l a t i v e t o 6 x 10"5 M HC1 a t 26. lf°C. - 3>+ -Table V Conductance i n h i g h e l e c t r i c f i e l d s of 5.0 x 10"^  M p-amino-benzoic a c i d r e l a t i v e t o ^ .^ x 10 - l f M HC1 at 21°C. P u l s e r Primary Pulse S e r i e s HC1 Side Resistance S o l n . Side F i e l d ac. v o l t s K.V. ohms K.V./cm % 0 0.6 129 0 6.6 1.0 13 1.7 125 0 19 2.0 25 3.3 121 0 37 3-0 37.5 5.0 119 0 55 3.7 h2 5.6 118 0 62 3.8 62.5 8.3 115 0 92 h.7 75 9.9 109 0 110 6.1 87 11.5 106 0 128 6.9 Notes: 1. P r e p a r a t i o n : The F i s h e r S c i e n t i f i c Co. Reagent Grade para-amino-benzoic a c i d was d i r e c t l y d i s s o l v e d i n c o n d u c t i v i t y water. 2. Zero f i e l d r e s i s t a n c e of the p-amino benzoic a c i d ( R x _ Q ) was 393 ohms: and s p e c i f i c r e s i s t a n c e 7.7 x 103 ohms. - 35 -Table 71 Conductance i n h i g h e l e c t r i c f i e l d of 3.75 x 10"^ M a c e t i c a c i d r e l a t i v e t o 0.7 x 10~ l + M HC1, at 24-.0°C. P u l s e r Primary Pulse S e r i e s HC1 Side Resistance Soln. Side F i e l d ac. v o l t s K.7. ohms K.7./cm % 0 0 118 0 0 11.2 1.5 112 0 17 0.36 22 .3 3 .0 98 0 33 . 1.2 4,5.0 6.0 67 0 67 3 .0 62 .1 8.2 hh 0 91 ^ 80 .2 10.6 27 0 118 5.^  90 .2 . 11 .9 21 0 132 5.7 Notes: 1. P r e p a r a t i o n : The a c e t i c a c i d was p u r i f i e d by t r i p l e vacuum d i s t i l l a t i o n , and d i l u t e d i n c o n d u c t i v i t y water of s p e c i f i c conductance of 5 x 10-7 mhos. 2. Zero f i e l d r e s i s t a n c e of a c e t i c a c i d ( R x « 0 ) w a s 1^ 90 ohms; and s p e c i f i c r e s i s t a n c e 3*39 x 104" ohms. 3. Zero f i e l d r e s i s t a n c e of HC1 was 1570 ohms. - 36 -120 KV/CM. F i g u r e 13. The conductance i n hig h e l e c t r i c f i e l d s of 5 x 10"3 M p ramino benzoic a c i d r e l a t i v e t o l+.5x IO-1* M HC1 at 21 °C. 120 KV / CM. F i g u r e l 1 * . The conductance i n hig h e l e c t r i c f i e l d s of 3.75 x IO"4* M a c e t i c a c i d r e l a t i v e t o 0.7 x 10-'+ HC1 at 2*f.0°C. - 37 -Table' V I I Conductance i n h i g h e l e c t r i c f i e l d s i of 0.61 M g l y c i n e r e l a t i v e t o 2 x 10" 5.M HC1 at temperatures of 25.8°C. and 26.0°C. P u l s e r Primary Pulse S e r i e s Resistance HC1 Side So l n . Side F i e l d ac. v o l t s K.V. ohms Temperature 25.8°C. K.V./cm % 0 0 107 160 0 0 17.8 2.3 95 160 2h.h 0.39 36.5 1+.8 72 160 50 i . i 4 -70.0 9.3 38 Temperature 160 26.0°C. 98 2.25 0 0 70 160 0 0 19.2 2.6 61 160 27.8 0.29 50.5 6.7 50 160 70 0.65 70.5 9.3 30 160 98 1.30 90.0 11.9 23 160 12*f 1.53 Notes: 1. P r e p a r a t i o n : The g l y c i n e was three times r e c r y s t a l l i z e d from water, oven d r i e d , then d i s s o l v e d i n c o n d u c t i v i t y water. 2. The zero f i e l d r e s i s t a n c e of the g l y c i n e was 3066 ohms; and s p e c i f i c r e s i s t a n c e 6.1 x IO 4 - ohms. 4 0 8 0 120 . 160 F IELD K V / C M . F i g u r e 15. The conductance i n high e l e c t r i c f i e l d s of 0.61 M g l y c i n e r e l a t i v e t o 2 x 10-5 M HC1 at temperatures of 25.8°C. and 26 o0°C. - 39 -Table V I I I Conductance i n h i g h e l e c t r i c f i e l d s of 6.55 x 10"^ M s u l f a n i l i c a c i d r e l a t i v e t o 7 x 10"^ M HC1 at temperatures of 23.5®C. and 26A°C. P u l s e r Primary Pulse S e r i e s Resistance ac. v o l t s K.V. 0 39.5 69.0 0 14-. 1 37.1 83.O 0 5.2 9.1 0 1.9 .^9 11.0 HC1 Side Soln. Side F i e l d ohms Temperature 23.5°C. 24-9 0 229 0 215 0 Temperature 26.4-°C. 208 0 199.5 0 195 0 189 0 K.V./cm 0 56 101 0 21 55 122 0 1.09 1.87 0 0.4-7 0.72 1.04-Notes: 1. Preparations Baker's Reagent Grade S u l f a n i l i c a c i d (NH 2C 6H l fS03H.H 2O: M.W. 191.20) was d i s s o l v e d i n c o n d u c t i v i t y water. 2. Zero f i e l d r e s i s t a n c e of s u l f a n i l i c a c i d was 1820 ohms; and s p e c i f i c r e s i s t a n c e 3«64- x Hr" ohms. 3. A d r i f t of the n u l l p o i n t at zero f i e l d was observed, whose magnitude was as much as 12 ohms, i n the t r i a l a t 26.4-°C. Thus the r e s i s t a n c e values t a b u l a t e d represent a mean of zero f i e l d r e s i s t a n c e readings taken s h o r t l y before and s h o r t l y a f t e r the a c t u a l f i e l d measurements. This d r i f t i s a t l e a s t i n p a r t due t o changes i n bath temperature. - ko -Table IX Data on the conductance i n hi g h e l e c t r i c f i e l d s of 1.22 x 10"3 M glutamic a c i d r e l a t i v e t o 6 x 10"? M HC1 a t 26.2°C P u l s e r S e r i e s Resistance A/VA Primary Pulse HC1 Side Sol n . Side F i e l d ac. v o l t s K.V. ohms K.V./cm % 0 0 210 0 0 0 lh. 0 1.9 208 0 21 0.1 37.0 h.9 186 0 5^  1.2 70.5 9.3 155 0 103 3-7 95 12.6 126 0 14-0 *f.2 101+ 13.8 120 0 153 h.5 Notes: 1. P r e p a r a t i o n . The 1(+) glutamic a c i d (GBI Brand) was r e - c r y s t a l l i z e d t w ice from water, oven d r i e d , then d i s s o l v e d i n c o n d u c t i v i t y water. 2. The zero f i e l d r e s i s t a n c e of 1(+), glutamic a c i d was 2009 ohms; and s p e c i f i c r e s i s t a n c e h.17 x IO4" ohms. - Ifl i 2 < < © 23.5* C • 2 6 . 4 ° C 4 0 8 0 FIELD 120 K V / C M , 160 F i g u r e 16; The conductance i n high e l e c t r i c f i e l d s of 6.55 x 10-5 M s u l f a n i l i c a c i d r e l a t i v e t o 7 x 10-5 M HC1 at temperatures of 23.5°C. and 26A°C. 120 K V / C M . F i g u r e 17. The conductance i n h i g h e l e c t r i c f i e l d s of 1.22 x 10~1 M 1(+) glutamic a c i d r e l a t i v e t o 6 x 10-5 M HC1 at 26.2°C. - 1+2 -Table X Conductande i n h i g h e l e c t r i c f i e l d s of 7.9 x 1 0 " ? grams/cc. protamine s u l f a t e r e l a t i v e t o 5 x 1 0 " ? M H C 1 a t 26°C. and 6 x 1 0 " ? M H C 1 at 27.3*0. P u l s e r Primary Pulse S e r i e s Resistance HCL Side Soln. Side F i e l d ac. v o l t s K.7. ohms K.V./em. % Temperature 26°C. 0 0 107 0 0 0 lh.5 1.9 0 58 21 7.9 37 h.9 0 307 4-7 19.7 Temperature 27.3°C. 0 0 382* 0 0 0 28.2 3.7 20 0 hi 17.2 70.2 9.3 0 290 89 32.0 Notes: 1. P r e p a r a t i o n . Reagent grade protamine s u l f a t e was d i s s o l v e d i n c o n d u c t i v i t y water. 2. The zero f i e l d r e s i s t a n c e of the protamine s u l f a t e was 2100 ohms; and s p e c i f i c r e s i s t a n c e h.2 x 1QT ohms. * Note that an a d d i t i o n a l e x t e r n a l r e s i s t a n c e of 102 ohms was added i n t h i s i n s t a n c e t o a l l o w balancing at zero f i e l d , s i n c e the bridge had only permitted i n s e r t i o n of up t o 311 ohms. - h3 -Table XI Conductance i n high e l e c t r i c f i e l d s of 3 x lO'^g 1 cc Agar r e l a t i v e t o HC1 a t 25°C. P u l s e r Primary Pulse S e r i e s Resistance HC1 Side Soln. Side F i e l d *a/a. ac. v o l t s K.V. ohms K.V./cm. % Run 1 0 0 0 hO 0 0 7.0 0.9 0 138 9.3 M-.7 13.8 1.9 0 28h 18 6.9 Run 2 0 0 258 0 0 0 3M- h.h 0 282 h2 25.9 Run 3 0 0 516* 0 0 0 i+7. h 6.3 0 177 64- 33.2 6h.5 8.6 0 259 37.2 Notes: 1. P r e p a r a t i o n . The agar sample was d i r e c t l y d i s s o l v e d i n c o n d u c t i v i t y water. 2. The zero f i e l d r e s i s t a n c e of agar was 208h ohms; and s p e c i f i c r e s i s t a n c e h.2 x IO4" ohms. 3. Concentration of HC1 was 5 x IO"? M i n run 1, 6 x 10"5 M i n run 2, and 7 x 10"5 M i n run 3. * Note th a t an a d d i t i o n a l e x t e r n a l r e s i s t a n c e of 320 ohms was added i n t h i s i n s t a n c e t o a l l o w balancing at zero f i e l d , s i n c e the bridge had only permitted i n s e r t i o n of up t o 311 ohms. 20 40 FIELD 60 KV / C M . 80 F i g u r e 18. The conductance i n high e l e c t r i c f i e l d s of 7.9 x 10-5 grams/cc.. Protamine S u l f a t e r e l a t i v e t o 5 x 10"? M HC1 at 25°C. and 6 x 10-5 M HC1 at 27.3°C. 60 K V / C M . F i g u r e 19. The conductance i n h i g h e l e c t r i c f i e l d s of 3 x IO* 4 , grams/cc. Agar r e l a t i v e t o HC1 a t 25°C - h5 -V. DISCUSSION OF RESULTS 6. Theories of the Wien E f f e c t (a) I n t e r i o n i c a t t r a c t i o n theory f o r strong e l e c t r o l y t e s . A strong e l e c t r o l y t e i s d e f i n e d t o be one i n which the ions are completely d i s s o c i a t e d . The e l e c t r o s t a t i c a t t r a c t i o n s and r e p u l s i o n s between the i o n s of the s o l u t e do not permit a p e r f e c t l y random d i s t r i b u t i o n ; r a t h e r on the time average there w i l l be more ions of u n l i k e s i g n than of l i k e s i g n i n the neighborhood of a given i o n . In the absence of an e x t e r n a l f i e l d t h i s i o n atmosphere has a c e n t r a l l y symmetrical d i s t r i b u t i o n . One of the c h a r a c t e r i s t i c s of t h i s atmosphere i s t h a t i t has a f i n i t e time of r e l a x a t i o n , i . e . , i t does not disappear i n s t a n t a n e o u s l y when the c e n t r a l i o n i s removed. When a s t a t i o n a r y s m a l l e l e c t r i c f i e l d i s a p p l i e d , causing the c e n t r a l i o n t o move, the d i s t r i b u t i o n of the i o n atmosphere becomes asymetric, i . e . , the atmosphere i n f r o n t of the i o n has not s u f f i c i e n t time t o b u i l d up, and the atmosphere t o the r e a r has not s u f f i c i e n t time t o decay t o e q u i l i b r i u m v a l u e . The net charge of counter-ions t o the r e a r of the c e n t r a l i o n thus becomes greater than i n f r o n t , tending t o decrease the m o b i l i t y of the i o n s , and thus gives r i s e t o the r e l a x a t i o n f o r c e which r e t a r d s the motion of the c e n t r a l i o n . Aside from the f r i c t i o n a l f o r c e of the s o l v e n t opposing the movement of the i o n i n the e l e c t r i c f i e l d , there i s a f u r t h e r r e t a r d -a t i o n f o r c e c a l l e d the e l e c t r o p h o r e t i c e f f e c t or hydro-- 4-6 -dynamical e f f e c t which i s a consequence of the s o l v a t i o n of i o n s . The e f f e c t a r i s e s s i n c e each moving i o n c a r r i e s s olvent w i t h i t ; then the c e n t r a l i o n moving i n a d i r e c t i o n opposite t o i t s i o n atmosphere appears t o be moving i n a solvent which i s not s t a t i o n a r y , but r a t h e r , one moving w i t h the i o n atmosphere. At i n f i n i t e d i l u t i o n the i o n atmosphere, and consequently both the r e l a x a t i o n and e l e c t r o p h o r e t i c e f f e c t s , disappear. Both the r e l a x a t i o n and e l e c t r o p h o r e t i c e f f e c t s form the b a s i s of the Debeye-Huckel - Onsager theory of e l e c t r o l y t i c conductance at ord i n a r y low f i e l d s . For convenience i n d i s c u s s i o n the i o n atmosphere i s o f t e n regarded as a t h i n s p h e r i c a l s h e l l of charge of r a d i u s r Q ; t h i s r a d i u s corresponding t o the maximum i n the charge d i s t r i b u t i o n of the i o n atmosphere, and i n the symbols of Earned and Owen (16) i s given by the expressions 2 r * DKT 1 1 I f a h i g h e l e c t r i c f i e l d , of the order of a few hundred K.V./cm., i s a p p l i e d t o the s o l u t i o n , the ions are given very h i g h v e l o c i t i e s , so great t h a t an i o n would t r a v e l s e v e r a l times the th i c k n e s s ( 2 r 0 ) of the i o n atmo-sphere i n the time i t would take the atmosphere t o form ( i . e . during the r e l a x a t i o n t i m e ) . Therefore the ions mov-i n g i n h i g h f i e l d s have l o s t t h e i r i o n atmosphere, and behave almost the same as ions i n a s o l u t i o n at i n f i n i t e d i l u t i o n , which, because of the great i n t e r i o n i c d i s t a n c e s , have no i o n atmosphere. The r e t a r d i n g r e l a x a t i o n f o r c e - h7 -disappears, i n c r e a s i n g the m o b i l i t y of the i o n , and r e s u l t -i n g i n the Wien e f f e c t , i . e . an in c r e a s e i n conductance of the s o l u t i o n ; however the small r e t a r d a t i o n due t o the e l e e t r o p h o r e t i c e f f e c t should remain, assuming t h a t the s o l v a t i o n of the ions i s un a f f e c t e d by the speed of the i o n s , s i n c e the sol v a t e d counterions are s t i l l present at app r e c i a b l e s o l u t e c o n c e n t r a t i o n s . (b) Ion A s s o c i a t i o n Theory f o r weak e l e c t r o l y t e s . Weak e l e c t r o l y t e s i n the presence of h i g h f i e l d s e x h i b i t d e v i a t i o n s from Ohm's Law which are c e t . par. many times greater than those of strong e l e c t r o l y t e s of e q u i v a l e n t i o n i c s t r e n g t h . The conductance i s found t o be p r o p o r t i o n a l t o the f i e l d s t r e n g t h X f o r a con s i d e r a b l e range, and i t s l i m i t corresponds approximately t o the conductance f o r complete d i s s o c i a t i o n of the weak e l e c t r o l y t e . Onsager (19) proposed a theory t o evaluate the e q u i l i b r i u m constant i n weak e l e c t r o l y t e s by c o n s i d e r a t i o n of the r a t e s of d i s -s o c i a t i o n and recombination of the i o n s . Bjerrum evaluated the p r o b a b i l i t y of formation of i o n p a i r s ( t o be defined) below from f r e e ions i n s o l u t i o n by c o n s i d e r i n g Coulomb f o r c e s and thermal f o r c e s a c t i n g on the i o n s . By a p p l y i n g the Maxwell-Boltzmann d i s t r i b u t i o n law, he d e r i v e d an expression f o r the p r o b a b i l i t y of two ions being separated by a d i s t a n c e r . The p r o b a b i l i t y - s e p a r a t i o n curve f o r two ions of opposite s i g n has a minimum i n p r o b a b i l i t y at a separation of r = q, where the p r o b a b i l i t y r i s e s r a p i d l y f o r r l e s s than q and r i s e s s l o w l y f o r r greater than q. - 1+8 -Onsager assumed th a t ions separated by a d i s t a n c e l e s s than q could be considered as a s s o c i a t e d , t h a t i s , as an i o n p a i r w h i l e f o r r greater than q the i o n s are assumed t o be f r e e , t h a t i s completely d i s s o c i a t e d . For weak e l e c t r o l y t e s , t h a t i s s m a l l i o n i c c o n c e n t r a t i o n s , q i s much l e s s than r Q (the r a d i u s of the i o n atmosphere). Onsager shows th a t the e l e c t r i c f i e l d produces a s h i f t i n the minimum of the p r o b a b i l i t y d i s t r i b u t i o n f u n c t i o n , i . e . i n q, and thus a change i n the i o n i z a t i o n constant, i . e . on the average more ions w i l l have a s e p a r a t i o n greater than q i n the presence of the f i e l d . T h i s change K(X) v a r i e s l i n e a r l y KCo) w i t h the f i e l d X, and depends on i . the valence of the i o n s , i i . the m o b i l i t y of the i o n s , i i i . on the i n i t i a l degree of d i s s o c i a t i o n <^0, i v . on the d i e l e c t r i c constant D. The r e l a t i v e change of conductance i n weak e l e c t r o -l y t e s i s expressed according t o Onsager (19) i n the symbols of. Harned and Owen (16), by the f o l l o w i n g formula: ^ x = .o r i " • Weak ampholytes' such as the amino acid s behave as weak e l e c t r o l y t e s . According t o the z w i t t e r i o n theory an ampholyte can e x i s t as ( i ) a doubly charged molecule, t h a t i s one charge of each s i g n , ( i i ) as a p o s i t i v e i o n w i t h an OH" counterion, ( i i i ) or as a negative i o n w i t h an or H^o* counterion. There i s an e q u i l i b r i u m process between s t a t e ( i ) and s t a t e s ( i i ) and ( i i i ) , w i t h the i o n i z a t i o n - '+9 -constant K b r e p r e s e n t i n g e q u i l i b r i u m between ( i ) and ( i i ) and K a between ( i ) and ( i i i ) . I n s t a t e ( i ) the t o t a l charge equals zero, so t h a t i n t h i s form the ampholyte does not c o n t r i b u t e as a current c a r r i e r , but only does so when i n s t a t e s ( i i ) or ( i i i ) . Each of these i o n i z a t i o n constants can be changed i n the presence of a f i e l d as i n Onsager's theory, g i v i n g r i s e t o a change i n c o n d u c t i v i t y . When K a and K D are g r e a t l y d i f f e r e n t , one need only consider the l a r g e r one of these constants. Strong ampholytes must be considered the same as strong e l e c t r o l y t e s , i . e . . completely d i s s o c i a t e d , each i o n having I t s own cou n t e r i o n atmosphere. (c) P o l y e l e c t r o l y t e s P o l y e l e c t r o l y t e s may be d i v i d e d i n t o strong and weak p o l y e l e c t r o l y t e s . A strong p o l y e l e c t r o l y t e i s one whose f r e e monomers would be completely d i s s o c i a t e d i n t o i o n s . A weak p o l y e l e c t r o l y t e i s one whose f r e e monomers would only p a r t l y d i s s o c i a t e i n t o i o n s . I n f a c t p r o t e i n s are some complex combination of these. Theories f o r the behavior of p o l y e l e c t r o l y t e s i n an e l e c t r i c f i e l d have been developed by Fuoss (2,9,12). The s t a t i s t i c a l c o i l c h a r a c t e r i s t i c of a n e u t r a l polymer i s distended by the i n t r a m o l e c u l a r Coulomb r e p u l s i o n among the b u i l t - i n i ons of the pol y -e l e c t r o l y t e , but t h i s i s p a r t i a l l y screened by the counter-ions which are h e l d i n the volume of the c o i l by the t o t a l i o n i c f i e l d . One would expect a weak type of p o l y e l e c t r o l y t t e t o behave more c l o s e l y l i k e a n e u t r a l polymer, that i s , tend towards c o i l i n g , w h i l e the stronger type would tend t o be - 50 -distended as desc r i b e d . For strong p o l y e l e c t r o l y t e s a dynamic e q u i l i b r i u m e x i s t s between f r e e and a s s o c i a t e d counterions, the former being those outside of the average r a d i u s of the polymer c o i l . The a s s o c i a t e d counterions do not c o n t r i b u t e t o counterion c u r r e n t , thus the con-ductance of a p o l y e l e c t r o l y t e i s t h e r e f o r e l e s s than t h a t of the corresponding monomeric s a l t at the, same concentrat-i o n ( i . e . many of the counterions are t i e d up i n or near the c o i l ) . The p o l y i o n has no sharp boundary due t o i n t r a m o l e c u l a r Brownian motion; however, we can imagine a zone i n which the 1>ptential energy of the p o l y i o n i s of the order of kT, and d e f i n e t h i s zone as the per i p h e r y of the p o l y - i o n . A sm a l l decrease i n p o t e n t i a l energy due t o the presence of an e x t e r n a l f i e l d , should t h e r e f o r e s u f f i c e t o remove some of the p e r i p h e r a l a s s o c i a t e d counterions and t h e r e f o r e i n c r e a s e the po p u l a t i o n of f r e e counterions and thus the conductance. One would thus expect a l a r g e Wien e f f e c t ; i n f a c t the conductance should be much greater than the conductance at i n f i n i t e d i l u t i o n , (d) C o l l o i d a l E l e c t r o l y t e s In c o l l o i d a l e l e c t r o l y t e s , such as those from s a l t s of long chain f a t t y a c i d s which c o n t a i n an i o n i z a b l e group attached t o a l a r g e organic r e s i d u e , the i o n i c m i c e l l e theory assumes th a t the anions of the f a t t y a c i d s a l t s form l a r g e aggregates c a l l e d i o n i c m i c e l l e s , which have a h i g h charge due t o the many component i o n s . The m i c e l l e w i l l have a higher m o b i l i t y than the normal i o n - 51 -s i n c e the charge i s p r o p o r t i o n a l t o the volume, i . e . r J , w h i l e the v i s c o u s r e s i s t a n c e i s p r o p o r t i o n a l t o the r a d i u s , 1. e. r Q . Formation of m i c e l l e s can take place only i f - t h e cohesive f o r c e s between the i n t r a m i c e l l a r u n i t s are greater than the Coulomb r e p u l s i v e f o r c e s between u n i t s (the former being greater f o r l a r g e r i n t r a m i c e l l a r u n i t s . For unaggregated charged u n i t s (strong e l e c t r o l y t e s ) the c o n d u c t i v i t y would i n c r e a s e i n an e l e c t r i c f i e l d t o the l i m i t i n g conductance f o r i n f i n i t e d i l u t i o n . For i o n i c m i c e l l e s , removal of the i o n atmosphere around the m i c e l l e by a h i g h e l e c t r i c f i e l d would l e a d t o a very l a r g e Wien e f f e c t as expected from the theory f o r strong e l e c t r o l y t e s c a r r y i n g a l a r g e number of charges. This Wien e f f e c t would be much l a r g e r than the l i m i t i n g conductance f o r the corresponding unaggregated m i c e l l a r u n i t s , because upon removal of the i o n atmosphere by the e l e c t r i c f i e l d , the m i c e l l e has r e l a t i v e l y a greater m o b i l i t y than the corresponding unaggregated u n i t . 2, I n t e r p r e t a t i o n of Experimental R e s u l t s The experimental data as p l o t t e d i n the graphs of f i g s . 11 t o 19, can be d i v i d e d i n t o three c a t a g o r i e s according t o the magnitude of the Wien e f f e c t . i . Glutamine, and arginine-monohydrochloride which may be c l a s s i f i e d as r e l a t i v e l y strong e l e c t r o l y t e s , show small increases i n conductance at 100 K.V./cm. The chemical formula f o r glutamine i s i - 52 -H 2N H H / I » HOOC - C - C - C - CONHo I I I H H H From the experimental data of f i g . 11, the i n c r e a s e i n r e l a t i v e conductance at 100 K.V./cm. of the 1.25 x IO""4" M glutamine i s seen t o be 0.56$, and i t approaches a l i m i t i n g v alue f o r higher f i e l d s . Thus, t h i s ampholyte behaves as a strong e l e c t r o l y t e , however no i o n i z a t i o n constant data are a v a i l a b l e t o check these r e s u l t s . The chemical formula f o r 1(+) a r g i n i n e monohydrochloride i s : NH H H H H H I i i i • i HCltH 2N - C - N - C - C - C - C - COOH t i l l H H H NH 2 From the experimental data of f i g . 12, the i n c r e a s e i n r e l a t i v e conductance at 100 K.V./cm. of the 2.0 x 10 - l f M a r g i n i n e monohydrochloride i s seen t o be 0.h8%; and approaches a l i m i t i n g value f o r higher f i e l d s . Therefore t h i s ampholyte appears t o behave as a strong e l e c t r o l y t e , however, t h i s r e s u l t may be l a r g e l y due t o the h y d r o c h l o r i c a c i d which i s a s s o c i a t e d w i t h the a r g i n i n e , but which i s f r e e d i n s o l u t i o n . The h i g h c o n d u c t i v i t y of the HC1 ions (which may be regarded as a bound i m p u r i t y ) pre-dominates t o such an extent t h a t the Wien e f f e c t due t o the a r g i n i n e alone i s masked. i i . A c e t i c a c i d , p-amino benzoic a c i d , g l y c i n e , s u l f a n i l i c a c i d , and glutamic a c i d are r e p r e s e n t a t i v e of weak e l e c t r o l y t e s and weak ampholytes showing r e l a t i v e - 53 -conductance incre a s e s of l.h% t o 5*5% a t 100 K.V./cm. f i e l d . The chemical formula f o r a c e t i c a c i d i s : H i H - C - COOH I H From the experimental data of f i g . 1*+, the i n c r e a s e i n r e l a t i v e conductance at 100 K.V./cm. of the 3.75 x IO"*4" M a c e t i c a c i d i s seen t o he h.6%. This r e s u l t compares f a v o r a b l y w i t h 5*1% r e l a t i v e conductance i n c r e a s e s i n 7 A x IO""4" M h y d r o c h l o r i c a c i d as measured by B a i l e y (3). The i o n i z a t i o n constant of a c e t i c a c i d i s 1.7 x 10"5« The chemical formula f o r the ampholyte p-amino  benzoic a c i d i s : HOOC - ^ " " ^ - NH 2 From the experimental data of f i g . 13, the r e l a t i v e conductance i n c r e a s e at 100 K.V./cm. of the 5 x 10"3 M p-amino benzoic a c i d i s seen t o be 5*5%* even l a r g e r than f o r a c e t i c a c i d . No i o n i z a t i o n constant data are a v a i l a b l e , so t h a t these r e s u l t s cannot be compared q u a n t i t a t i v e l y . The chemical formula f o r g l y c i n e i s : H i H - C - COOH I NH 2 From the experimental data of f i g . 15* the in c r e a s e i n r e l a t i v e conductance at 100 K.V./cm. of the 0.61 M g l y c i n e i s seen t o be 1.9%* G l y c i n e i s an amino a c i d , and behaves as a weak ampholyte, w i t h both a c i d i c and b a s i c r e a c t i o n s . The a c i d r e a c t i o n f o r g l y c i n e i s w r i t t e n as - 54- -. + J. (NH3 CH 2 COOH)+^r m^E2 COO" + H w i t h the i o n i z a t i o n constant = 4-.4-7 x 10~3, while the b a s i c r e a c t i o n i s w i t h the i o n i z a t i o n constant Kg = 6.04- x 10"5 a t 25°C The r e a c t i o n whose ions are present i n s o l u t i o n i n greater c o n c e n t r a t i o n , and t h e r e f o r e the Wien e f f e c t which w i l l predominate, i s represented by the a c i d i o n i z a t i o n . t h i s case, the l a r g e r alone need t o be considered. The conductance i n c r e a s e of 1.9$ f o r g l y c i n e cannot be compared t o tha t f o r a c e t i c a c i d , since the concentrations a r e . f a r d i f f e r e n t . Berg and Patterson (5) f o r e q u i v a l e n t concentrations and f i e l d strengths show t h a t the r e l a t i v e i n c r e a s e at 100.K.V./cm. v a r i e s from 1,1% t o 4-.3$ as an im p u r i t y c o n c e n t r a t i o n ammonium c h l o r i d e i s v a r i e d from 10"^ M t o zero. Our r e s u l t s f a l l w i t h i n t h i s range, but the p u r i t y of our sample of g l y c i n e i s u n c e r t a i n . The chemical formula f o r the ampholyte s u l f a n i l i c a c i d I s : 0 From the experimental data of f i g . 16, the r e l a t i v e conductance i n c r e a s e of the 6.55 x 10"-* M s u l f a n i l i c a c i d at 100 K.V./cm. i s seen t o be 1.4-$. The l a r g e r a c i d -4-i o n i z a t i o n constant i s 6.2 x 10 which i s l a r g e r than t h a t And i f the i o n i z a t i o n constants are f a r d i f f e r e n t as i n OH 0 - ?? -f o r a c e t i c a c i d (1.7 x 10"?) so th a t one would expect a smaller Wien e f f e c t , and t h i s i s found t o be c o r r e c t . The chemical formula f o r the ampholyte 1(+) glutamic a c i d i s : H H NH i i i 2 HOOC - G - C - C - COOH I I I H H H From the experimental data of f i g . 17, the r e l a t i v e conductance in c r e a s e at 100 K.V./cm. of the 1.22 x 10"3 M 1(+) glutamic a c i d i s seen t o be 2.6$. The Wien e f f e c t i s smaller than t h a t f o r a c e t i c a c i d , however, data on the i o n i z a t i o n constants i s not a v a i l a b l e . i i i . Protamine s u l f a t e and agar are p o l y e l e c t r o l y t e and show very l a r g e conductance i n c r e a s e s at h i g h e l e c t r i c f i e l d s , as one would expect from.the Wien e f f e c t theory f o r p o l y e l e c t r o l y t e s as o u t l i n e d i n the previous s e c t i o n . Protamine s u l f a t e i s a polypeptide whose main c o n s t i t u e n t i s the amino a c i d a r g i n i n e , however i t i s not w e l l - d e f i n e d c h e m i c a l l y . From the experimental data of f i g . 18, the r e l a t i v e conductance i n c r e a s e at 100 K.V./cm. of the 7*9 x 10"? g./cc. protamine s u l f a t e i s seen to be h0%. This i s c e r t a i n l y much l a r g e r than what one measures f o r the i n d i v i d u a l component amino a c i d s , which i s i n agreement w i t h expectations from the Wien e f f e c t theory f o r p o l y e l e c t r o l y t e s . Agar i s a pol y s a c c h a r i d e , i . e . a p o l y d e c t r o l y t e of of perhaps 100 u n i t s or more, of which the p r i n c i p a l b u i l d i n g u n i t i s D-galactopyranose, and although the - 56 -exact molecular weight i s unknown, the u n i t s of i t s chemical s t r u c t u r e can be w r i t t e n as: Prom the experimental data of f i g . 19, the r e l a t i v e conductance i n c r e a s e at 100 K.V./cm. of the 3 x IO"4" g./cc. agar i s seen t o be 37%• Agar a l s o show the very l a r g e Wien e f f e c t t h a t one would expect from a p o l y -e l e c t r o l y t e , y Q u a l i t a t i v e l y these r e s u l t s agree w i t h expectations from the t h e o r i e s p r e v i o u s l y o u t l i n e d . I t i s at present impossible t o attempt t o evaluate the r e s u l t s q u a n t i t a t i v e l y because these substances are i n general not s u f f i c i e n t l y w e l l d e f i n e d c h e m i c a l l y . 3. Other E f f e c t s (a) D i e l e c t r i c E f f e c t s I t has been suggested t h a t p a r t of the i n c r e a s e i n conductance i n high f i e l d s i s due t o a d i e l e c t r i c e f f e c t , inasmuch as amino a c i d s , polypeptides and peptones are known t o have h i g h d i e l e c t r i c constants. I n the presence of the hig h f i e l d there may be an in c r e a s e i n the d i p o l e l e n g t h r e s u l t i n g i n an i n c r e a s e i n p o l a r i z a t i o n . This e f f e c t should give r i s e t o c a p a c i t i v e unbalance. The method of bal a n c i n g permits s e p a r a t i o n of r e s i s t i v e and c a p a c i t i v e e f f e c t s as p r e v i o u s l y o u t l i n e d , - 57 -but no ap p r e c i a b l e c a p a c i t i v e change w i t h f i e l d was observed. I n t h i s work, the d i p o l e e f f e c t was not st u d i e d i n d e t a i l , and the l a r g e magnitude of the c a p a c i t i v e " s p i k e s " made observations of c a p a c i t i v e changes d i f f i c u l t . (b) The E f f e c t of I m p u r i t i e s I m p u r i t i e s of an e l e c t r o l y t i c nature w i l l , of course, have an e f f e c t on the zero f i e l d conductance of the s o l u t i o n s . Since many of the i m p u r i t i e s are of t e n d i f f i c u l t t o remove, p a r t i c u l a r l y from amino a c i d s and other b i o l o g i c a l m a t e r i a l , the Wien e f f e c t s can be masked by the presence of these a d d i t i o n a l f o r e i g n ions ( c u r r e n t c a r r i e r s ) . I n the present i n v e s t i g a t i o n , the r e s u l t s are probably a f f e c t e d by i m p u r i t i e s which could not be removed durin g the p r e p a r a t i o n of the samples. P a t t e r s o n (7) 11) i n v e s t i g a t e d s y s t e m a t i c a l l y the e f f e c t of i m p u r i t i e s (KBr) on the Wien e f f e c t of g l y c i n e and of p o l y - 1 * - v i n y l -N-n-butylpyridinium bromide r e l a t i v e t o h y d r o c h l o r i c a c i d and observed a r e d u c t i o n i n the Wien e f f e c t . (c.) Pulse Duration Another c o n s i d e r a t i o n of some Importance i s tha t of the r e l a x a t i o n time of the i o n atmosphere and the d u r a t i o n of the a p p l i e d e l e c t r i c p u l s e . In l a r g e molecules the r e l a x a t i o n time may be of s e v e r a l microsecond d u r a t i o n and thus e q u i l i b r i u m may not be reached during the du r a t i o n of the puls e . F u r t h e r i n v e s t i g a t i o n of t h i s phenomenon i s r e q u i r e d . - 58 -(d) E f f e c t of Temperature on R e l a t i v e Conductance I t i s of i n t e r e s t to note t h a t B a i l e y and P a t t e r s o n (3) have shown i n experiments on a c e t i c a c i d and l i t h i u m f e r r o c y a n i d e over the temperature range from 5°C. t o 55°C., th a t A A / /L^ w i l l v a ry by l e s s than 10$ f o r any choice of f i e l d i n t e n s i t y ; i n agreement w i t h the p r e d i c t i o n s of the above mentioned t h e o r i e s . The temperature v a r i a t i o n of A 0 i t s e l f i s of course great, so a s p e c i a l A 0 f o r each h i g h v o l t a g e pulse measurement was determined. (e) H y d r o c h l o r i c A c i d as a Reference E l e c t r o l y t e H y d r o c h l o r i c a c i d was chosen as a reference e l e c t r o l y t s i n c e i t s c a t i o n H + or H^O*, as the case may be, might be expected t o give a p o l a r i z a t i o n e f f e c t a t the e l e c t r o d e s equal t o the p o l a r i z a t i o n e f f e c t produced i n the other e l e c t r o l y t e s having the same c a t i o n . H y d r o c h l o r i c a c i d i t s e l f shows a small Wien e f f e c t , and was b e l i e v e d t o be p e r f e c t as a reference s o l u t i o n . I t seems th a t there i s some o b j e c t i o n t o the use of h y d r o c h l o r i c a c i d as a r e f e r e n c e e l e c t r o l y t e namely, t h a t at the small concentrations t h a t were employed, an a p p r e c i a b l e amount of the h y d r o c h l o r i c a c i d ions were depleted from the s o l u t i o n v i a p o l a r i z a t i o n at the e l e c t r o d e even during the d u r a t i o n of a s i n g l e h i g h v o l t a g e p u l s e . Inasmuch as i t was considered d e s i r a b l e t o make the c o n d u c t i v i t y c e l l r e s i s t a n c e greater than 2000 ohms i n order not t o overload the h i g h v o l t a g e p u l s e r , the c o n c e n t r a t i o n of the h y d r o c h l o r i c a c i d must be albout 6 x 10"5 M . During the passage of a s i n g l e 10,000 v o l t , - 59 -5 microsecond pulse, a simple e l e c t r o - c h e m i c a l c a l c u l a t i o n shows th a t about 7*5% of the h y d r o c h l o r i c a c i d ions between the e l e c t r o d e s are used up. In general, t h i s e f f e c t i s not so predominant i n the e l e c t r o l y t e under i n v e s t i g a t i o n , inasmuch as the c o n c e n t r a t i o n of the l a t t e r was g r e a t e r because of the lower c o n d u c t i v i t i e s i n v o l v e d . This would appear t o account f o r the shape of the pulse output from the bridge c i r c u i t a t high e l e c t r i c f i e l d s as observed i n f i g . 8 and photograph 3. At t h i s s m a ll c o n c e n t r a t i o n of h y d r o c h l o r i c a c i d , the nature of the complex dynamic r e a c t i o n s at the el e c t r o d e s becomes important, so t h a t t h i s may account f o r some of the observed f l u c t u a t i o n s of zero f i e l d balance during the i n t e r - h i g h - vo l t a g e pulse i n t e r v a l . This e n t i r e e f f e c t could be minimized by designing a c o n d u c t i v i t y c e l l w i t h a l a r g e r c e l l constant; thus p e r m i t t i n g higher e l e c t r o l y t e c o n centrations to be used. V I . SUMMARY AND CONCLUSIONS An apparatus was constructed t o measure the conduct-ance change of e l e c t r o l y t e s i n the presence of h i g h e l e c t r i c f i e l d s t o a h i g h degree of accuracy. This apparatus permits d i r e c t observation of pulse shape, and f o r separate compensation of r e s i s t i v e and c a p a c i t i v e unbalance. The amplitude of the r e c t a n g u l a r pulses can be e a s i l y v a r i e d from one t o s i x t e e n k i l o v o l t s ( c o r r e s -ponding t o f i e l d strengths up t o two hundred K.V./em. w i t h our c o n d u c t i v i t y c e l l s ) , the pulse wijth i t s 4 v a r i a b l e - 60 -from 0.1 t o 50 microsecond d u r a t i o n , and the r e p e t i t i o n r a t e can be v a r i e d from manual t o 20 pulses per second. With the high-vol t a g e - p u l s e bridge apparatus which has been des c r i b e d , the h i g h - f i e l d e l e c t r i c conductance of s e v e r a l s o l u t i o n s of b i o l o g i c a l l y i n t e r e s t i n g sub-stances was i n v e s t i g a t e d and c l a s s i f i e d . The substances i n v e s t i g a t e d , together w i t h the observed increment i n e l e c t r i c conductance at a f i e l d s t r e n g t h of 10? v o l t s per cm., and t h e i r c l a s s i f i c a t i o n s are l i s t e d : i . Ampholytes which behave as strong e l e c t r o l y t e s : 1. glutamine (1.25 x lO-'+M), 0.56$ 2. 1(+) a r g i n i n e monhydrochloride (2.0 x 10-4-M), 0.1+8$ i i . Weak e l e c t r o l y t e s and ampholytes which behave as weak e l e c t r o l y t e s : 3. a c e t i c a c i d (3.75 x l O " ^ ) , *+.6$ l+. p-amino benzoic a c i d (5 x 10"^M), 5*5% 5. s u l f a n i l i c a c i d (6.55 x 10~?M), l.h% 6. 1(+) glutamic a c i d (1.22 x 10"3M), 2.6$ 7. g l y c i n e (0.61 M), 1.9$ i i i . P o l y e l e c t r o l y t e s 8. protamine s u l f a t e (7.9 x 10"? g/cc.) k-0% 9. agar (3 x IO"4" g / c c ) , 37$ Some of the observed r e s u l t s have been compared w i t h those obtained by other methods, whi l e the remaining sub-stances have not been p r e v i o u s l y r e p o r t e d . . The r e s u l t s were discussed i n the l i g h t of a v a i l a b l e t h e o r e t i c a l i n f o r m a t i o n on the h i g h - f i e l d conductance e f f e c t i n va r i o u s types of e l e c t r o l y t e s . - 61 -BIBLIOGRAPHY 1. Adcock, W.A., and Cole, R.H. J.A.CS. 7JL, 2835, 194-9-2. Bailey, F.E., Patterson, A., and Fuoss, R.M. J.A.CS. 7jf, 184-5-6, 1952. 3. Bailey, F.E., and Patterson, A. J.A.CS. 7it, 4-756-9, 1952. 4-. Bailey, F.E., and Patterson, A. J. Polymer Sc. 9., 285, 1952. 5. Berg, D. and Patterson, A. J.A.CS. Z2, 14-82-4-, 1953. 6. Berg, D. and Patterson, A. J.A.CS. 25, 4-835-6, 1953. 7. Bluh, 0, and Terentiuk, F.- • J . Chem. Phys. 18, 1664-8, 1950. 8. Eckstrom, H.C and Schmelzer, C. Chem. Revs. 24-, 367, 1939. 9. Edelson, D. and Fuoss, R.M. J.A.CS. 2 i , 306, 1950. 10. Fucks, W. Annals der Physik (5), 12, 306, 1932. 11. Fuoss, R.M. and E l l i o t , M.A. J.A.CS. 6Z, 1339, 194-5. 12. Fuoss, R.M. J . Polymer Sc. 12, 185, 195*K 13. Glascoe and Lebacqz Pulse Generators. Vol. 5? Radiation Laboratory Series, McGraw H i l l , N.Y., 194-8. 14-. G l e d h i l l , J.A., and Patterson, A. Rev. Sc. Instr 20, 960, 194-9. 15. G l e d h i l l , J.A., and Patterson, A. J . Phys Chem. ^6, 999, 1952. 16. Harned, H.S. and Owen, B.B. The Physical Chemistry of E l e c t r o l y t i c Solutions. Rheinhold Publishing Corp., N.Y., 2nd e d i t i o n , 1950. pp. 95-HH-, 214--7. - 62 -17. Huter, W. Annals der physik (5), 24-, 253, 1935. 18. Malsch, J . and H a r t l e y , G.S. Z. Physik. Chem. A170. 321, 1934-. 19. Onsager, L. J . Chem Phys 2 , 599, 1934-. 20. V a l l e y , G.E., and Wallman, H. Vacuum Tube A m p l i f i e r s , R a d i a t i o n Lab. S e r i e s 18, McGraw H i l l , 194-8. 21. Wien, M. and Malsch, J . Annalen der Physik (4-), 83, 205, 1927. 22. Wien, M. Annalen der Physik 8^ , 327, 1927. 23. Wilson, W.S. D i s s e r t a t i o n , Yale U n i v e r s i t y , 1936. 

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