Solid Phase Extraction Coupled With Liquid Chromatography For Determination Of Typical Organic Pollutants In Environmental Water Samples

For the trace analysis of pollutants in environmental water,sample pretreatment technologies are usually used to extract and enrich the targeted analytes,coupled with chromatographic technologies for separation and determination.Solid phase extraction?SPE?technology has been widely used in environmental fields because of its advantages of low organic solvent consumption,high enrichment efficiency and recovery,ease easiness to automate.The purpose of this thesis is to establish a series of rapid,simple and high sensitive analytical methods by combining SPE with liquid chromatography?LC?for the analysis of organophosphorus and carbamate insecticides,chlorophenolic compounds?CPs?,fluoroquinolones antibiotics?FQs?in environmental water.Main research contents and results are as follows:1.Determination of organophosphorus and carbamate insecticide residues by solid phase extraction coupled with capillary liquid chromatographyIn order to shorten the analysis time and improve the analysis performance,SPE combined with capillary liquid chromatograph?CLC?was developed for extracting and detecting organophosphorus and carbamate insecticide residues in water.The factors affecting CLC separation detection performance and SPE efficiency were systematically investigated.The four insecticides were separated completely within 6min by CLC,when acetonitrile-water?50:50,v:v?was used as mobile phase and 200nm as detection wavelength.The optimal extraction efficiency was obtained by using self-filled C₁₈ SPE column,adding 15 g NaCl in 100 mL neutral samples with the flow rate of 5 mL min^-1,and using 3 mL ethyl acetate as the elution solvent.Under the above-optimized CLC and SPE condtions,the limits of detection and limits of quantification were 0.07–0.24?g kg^-1 and 0.23–0.80?g kg^-1,respectively.The recoveries of the SPE-CLC method for spiked tap and lake water samples ranged from71.45%to 109.25%with the relative standard deviations less than 9.28%.2.Magnetic solid phase extraction of five kinds of chlorophenolic compounds coupled with high performance liquid chromatography determinationIn order to establish a fast,simple and efficient SPE technique,magnetic multi-walled carbon nanotubes composites?mag-MWCNTs?were synthesized by solvothermal method followed by polydopamine modification and used as adsorbents for magnetic SPE?MSPE?.MSPE was coupled with high performance liquid chromatography?HPLC?for the rapid and highly effective extraction and determination of five chlorophenolic compounds?CPs?in water samples.The as-prepared mag-MWCNTs were fully characterized by scanning/transmission electronic scope?SEM/TEM?,XRD,TGA,FT-IR and VSM,showing homogeneous morphology,good stability and magnetic property.The factors affecting the efficiency of magnetic solid phase extraction were investigated.30 mg adsorbent was used to adsorb five kinds of chlorophenols in 40 mL neutral solution for 8 h,then the adsorbents was desorpted by 150?L methanol/acetate?99:1,v:v?for 5 min.Under the optimum conditions,the method has been applied to the determination of five chlorophenols,the detection limit was 0.36–1.29?g L^-1 and the quantitative limit was3.57–12.89?g L^-1.Spiked recoveries were attained between 70.1%–106.5%with RSDs of 0.2%–5.0%for four environmental water samples.3.Molecularly imprinted polymers for dispersive solid-phase extraction of fluoroquinolones coupled with high performance liquid chromatographyIn order to improve the selectivity of the extraction technique based on selective properties of molecularly imprinted polymer materials,the molecularly imprinted polymer materials with norfloxacin and enrofloxacin as templates were prepared by precipitation polymerization using multi-template imprinting strategy.The synthetic material were used as dispersive solid phase extraction adsorbents for selective extraction,enrichment and high sensitivity analysis of two fluoroquinolones in environmental water samples combined with high performance liquid chromatography.The morphology,specific surface area,functional group and thermal stability of the prepared double-template molecularly imprinted polymer materials were characterized,showing spherical morphology,uniform particle size and good thermal stability.The adsorption capacity and selectivity for norfloxacin and enrofloxacin were evaluated.The factors affecting the efficiency of dispersion solid phase extraction were investigated systematically.Finally,10 mg adsorbent was used to adsorb fluoroquinolones in neutral solution for 3 h,then the material was desorpted by150?L methanol/acetate?90:10,v:v?for 5 min.Under optimal conditions,good linearity was obtained in the range of 1–200?g L^-1,the detection limit was less than0.36?g L^-1.The method was applied to the analysis of two fluoroquinolones antibiotics in environmental water samples,spiked recoveries of three water samples were attained 80.9%–101.0%.