Online Column Preconcentration Coupled With Pressurized Capillary Electrochromatography For The Analysis Of Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons?PAHs?are important environmental and food contaminants because of their carcinogenic,teratogenic and mutagenic properties.Polycyclic aromatic hydrocarbons have an adverse effect on human health as they can be directly inhaled by attaching on the surface of particles or intaked through the food chain.Preconcentration of trace polycyclic aromatic hydrocarbons prior to analysis is an important task since their concentrations are very low in the environment.In this thesis,we developed an analytical method for PAHs by online column enrichment coupled with pressurized capillary electrochromatography?pCEC?and compared the analytical performances of two enriching particles,i.e.,C₁₈ and PAH-specific particles in on-line column enrichment.An extensive review was made in the first chapter with respect from brief introduction to PAHs,and enrichment and analytical methods for polycyclic aromatic hydrocarbons,to concise theory and applications?especially in PAHs analysis?of capillary electrochromatography.In the second chapter,we compared the separation performances of PAHs-specific and C₁₈particles packed capillary column in pCEC for PAHs,and separation conditions of pressurized capillary electrochromatography were optimized.The results demonstrated the superior separation performance of PAHs-specific particles over C₁₈ particles.The optimized electrochromatographic conditions were as follows:Mobile phase:acetonitrile?ACN?:Tris?10 mM,pH 8.5?=80:20;Flow rate:0.2 mL/min;Separation voltage:-16 kV.Limits of detections?LODs?of 16 PAHs were obtained in the range 0.22-2.43 mg/L with relative standard deviations?RSDs?of retention time,peak height and area varying in the ranges 0.16-1.95%,1.43-4.10%and 1.36-4.43%,respectively.In the third chapter,we established online C₁₈ column preconcentration coupled with pCEC for detection of PAHs.Enrichment factors of 20-243 and LODs of 2.33-22.83?g/L for PAHs were obtained under the optimized enriching conditions?Eluent:20?L ACN,Sample volume:5 m L?,improving the pCEC sensitivity dramatically.The RSDs of retention time,peak height and area were various in the ranges 0.82-6.86%,5.38-12.81%and 5.37-19.15%,respectively.In the fourth chapter,PAHs-specific particles were used as the adsorbent in online online column precentration of PAHs with pCEC detection.Enrichment factors up to 445-fold were obtained for 16 PAHs under optimization of the preconcentration conditions?Eluent:20?L methanol,Sample volume:5 mL?,resulting decreased LODs down to 1.3-15.56?g/L.The RSDs of retention time,peak height and area varied in the ranges 0.41-3.37%,3.77-16.65%and 3.30-17.73%,respectively.The final chapter summarizes the whole thesis and prospect the applications of the proposed method in real samples.