UBC Theses and Dissertations
High-throughput analysis using novel sample preparation method and direct analysis in real time mass spectrometry Jing, Wenqiang
Qualitative and quantitative determination of trace compounds in complex samples is critically important in all fields of scientific research. The direct coupling of suitable sample preparation methods and direct analysis in real time mass spectrometry (DART-MS) has been shown to be a promising solution to trace analysis of compounds in complex matrices. In Chapter 1, a technical introduction of DART-MS and a review of some of the most common sample preparation techniques in trace analysis are presented. The coupling of sample preparation and DART-MS are also briefly reviewed in this chapter. Chapter 2 presents the direct coupling of dispersive magnetic solid-phase extraction (DMSPE) to DART-MS using a metal iron probe and its application in the trace analysis of six triazine herbicides in aqueous environmental samples. The ratio of magnetic core to graphene oxide in the sorbents and other key parameters in both DMSPE and DART-MS were investigated and optimized. This developed method combined the advantages of these two analytical techniques, and good analytical performance was achieved. In Chapter 3, a sorbent and solvent co-enhanced DART-MS method (SSE-DART-MS) was demonstrated for the determination of trace phthalic acid esters (PAEs) in water. Six common organic solvents were added on to two graphitic carbon nitride-based materials (g-C₃N₄) with different morphologies to study the enhancement effect. In Chapter 4, nine silica-supported ionic liquids (ILs) with different hydrophobicity were synthesized. They were then used separately as coatings for the solid-phase microextraction of five PAEs followed by DART-MS analysis to study how the hydrophobicity of sorbents influence the signals of analytes in DART-MS, and further investigation is needed to verify the general trend. In Chapter 5, the principle of deep eutectic solvent-based microwave-assisted extraction (DES-MAE) was systematically studied. The study also showed that in most cases, adding water will reduce the heating efficiency of DES under microwave irradiation, and DES containing carboxylic acid may react with cellulose, hemicellulose, and lignin to promote cell wall destruction. Chapter 6 summarizes the work presented and provides a brief outlook for future directions.
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