Application Of Magnetic Solid Phase Extraction And Dispersive Liquid Liquid Microextraction In Residual Analysis

Sample pretreatment,namely the separation and detection of trace component in complex sample systems,is not only the most difficult task for all of the pharmaceutical analysis workers,but also an important and indispensable link in the process of drug analysis.As the development of environmental monitoring,drug research and development and food safety,traditional classic sample pretreatment methods,such as liquid-liquid extraction and solid phase extraction,can no longer satisfy people's needs due to the repeated operation,and organic solvents consuming.As the target analyte concentration is becoming lower and the sample matrix is more and more complex,it has brought more difficulties to analysts.Therefore,it is necessary to develop new sample pretreatment methodologies in terms of low cost,simpliness,rapidness and efficiency.In recent years,the dispersive liquid-liquid microextraction?DLLME?and magnetic solid phase extraction?MSPE?as new sample pretreatment methods have attracted lots of analysts'attention,due to their convenient operation low cost and high sensitivity.The present thesis focused on the theme of"developing new sample pretreatment method".It mainly includes the following parts:1.DLLME combined with online derivatization gas chromatography-mass spectrometry?GC-MS?was developed for the determination of benzophenones?BPs?UV filers in water samples,including BP,2,4-dihydroxybenzophenone?DHBP?,4-hydroxybenzophenone?ALI?,2-hydroxy-4-methoxybenzophenone?AM?,2-hydroxy-4-octanoxybenzophenone?C?and2,2'-dihydroxy-4,4'-dimethoxy benzophenone?D?.Influential factors for on-line derivatization were investigated,including temperature of the injection port,the splitless time,the volume of derivatization reagent for on-line derivatization;and for DLLME,including the extraction agent,the dispersing agent,the proportion of the extraction agent and the dispersing agent,the volume of sample solution,the sample pH,the salt concentration for DLLME.The method was also applied to the analysis of UV filters in water samples from Han river,the Yangtze river and East lake to study the matrix effect on DLLME efficiency in real samples.The result showed that,the proposed method provided many advantages such as cost effective,easy to operate,high extraction efficiency and environment benign.In a word,it is promising in the real applications.2.A novel magnetic nanoparticle?MNP?with hydrophobic divinylbenzene?DVB?and hydrophilic sulfonate functionalities were successfully prepared via“thiol-ene”click chemistry.By using the different properties of the MNPs,coupling with a variety of detection means,different sample pretreatment methods were developed.The presence of sulfonate groups featured the material excellent aqueous dispersibility,which ensured the convenience and improved reproducibility in operation.The application of Fe₃O₄-DVB-SO₃^-MNPs was demonstrated by the extraction of polycycylic aromatic hydrocarbons?PAHs?,including naphthalene,acenaphthene,fluorine,phenanthrene,anthracene,fluoranthene and pyrene,from environmental water samples followed by GC-MS analysis.The main factors influencing the extraction,including the type of the desorption solvent,the agitation mode,the amount of MNPs,extraction and desorption time and salt addition sample solution,were investigated in detail.Under the optimized conditions,the proposed method showed satisfactory reproducibility with intra-day and inter-day relative standard deviations less than 16.5%and 14.4%,and low limits of detection in the range of 0.6-2.1 pg/mL.This developed method was also successfully used for the determination of the PAHs in genuine lake and river environmental water samples by standard addition methods.All the studied PAHs were detected in these waters.This method,which is speedy and convenient,has great potential in the preconcentration of trace analytes in complex matrix.3.Fe₃O₄-DVB-SO₃^-MNPs were used for MSPE of five angiotensin II receptor antagonists?ARA-IIs?,including telmisartan,olmesartan medoxomil,irbesartan,losartan potassium and candesartan cilexetil,from human urine and plasma samples based on reversed-phase and cation-exchange mixed-mode mechanism.Under the optimized MSPE conditions,coupled to HPLC-FLD,this proposed method was found to be accurate and precise with relative standard deviations of less than 11.7%,and good recovery of 80.1%-119.5%for both samples.The linear ranges were 0.2-2000ng/mL and 0.2-2500 ng/mL along with correlation coefficients being above 0.9923and 0.9928 for urine and plasma samples,respectively.Limits of detection were0.01-5.74 ng/mL and 0.01-1.31 ng/mL respectively.The proposed MSPE was a reliable and convenient sample pretreatment method,and had the potential for isolating and enriching the ARA-IIs in biological samples.