Magnetic Moleculary Imprinted Polymer-magnetic Solid Phase Extraction Coupled With Ultra Performance Liquid Chromatography-tandem Mass Spectrometry For The Deter Mination Of Hippuic Acid And Methyhippuric Acid In Urine Samples

Objective:In this work,hippuric acid?HA?as template molecule was selected to prepare a novel magnetic molecularly imprinted polymer?MMIP,Fe₃O₄@SiO₂@MIP?.The prepared Fe₃O₄@SiO₂@MIP as magnetic solid phase extraction?MSPE?adsorbent was coupled with ultra performance liquid chromatography-tandem mass spectrometry?UPLC-MS/MS?to develop a novel MSPE?MMIP?-UPLC-MS/MS?Fe₃O₄@SiO₂@MIP-MSPE-UPLC-MS/MS?methodforthe determination of HA and methylhippuric acid?MHA,2-MHA,3-MHA,4-MHA?in urine samples.Method:Hippuric acid as template molecule was selected to prepare Fe₃O₄@MIPs,the synthesis conditions and raw material ratio were optimized,and Fe₃O₄@SiO₂@MIP was also characterized?FT-IR,SEM,etc.?.The separation conditions were optimized to achieve the chromatographic separation of HA and 3 isomers of MHA?2-MHA,3-MHA and 4-MHA?.The operating conditions of MS was also optimized.Several factors affecting extraction efficiency were optimized,including extraction time,adsorption solvent,adsorbent amount,pH,desorption solvent and desorption time.Under optimal conditions,the analytical performance of the method?detection limit linear range RSD?was evaluated and the selectivity of Fe₃O₄@SiO₂@MIP was also investigated.This method was compared with the standard method and other existing detection methods.This method was applied to analysis of HA and MHA in the real urine samples from the toluene-exposed workersResult:The Fe₃O₄@SiO₂@MIP was successfully prepared.The chromatographic conditions was successfully optimized,and HA and 3isomers of MHA reached baseline separation.The mass spectrometry was also speculated.The factors influencing the adsorption capacity of novel adsorbent was investigated.Meanwhile,a novel method was established.Under the optimum extraction conditions?amount of Fe₃O₄@SiO₂@MIP,25 mg;pH value,6;extraction time,2 min;desorption solvent,1 mmol/L NaOH aqueous solution;desorption time,10 min;ionic strength,0%NaCl concentration?,the analytical performance of Fe₃O₄@SiO₂@MIP-MSPE-UPLC-MS/MS for the determination of HA and MHA were:the limits of detection?LODs?,based on signal-to-noise?S/N?of 3,were found to be in the range of0.089?g/L?HA?to 0.17?g/L?4-MHA?;linearity was obtained in the range of 0.5–10000?g/L,The RSDs was found to be in the range of9.4-12.4?N=6,c=10?g/L?.Conclusion:The prepared Fe₃O₄@SiO₂@MIP was applied to MSPE and coupled with UPLC-MS/MS to develop a novel method for detecting of HA and MHA in urine sample rapidly and accurately.Compared with the current health industry standard method,the developed method obtained many advantages on sample analysis time,selectivety and sensitivity.