Multiplex Solid Phase Dansylation For The Analysis Of Environmental Estrogens By LC-MS

Environmental estrogens have endocrine disrupting effects and similar physiological effects.These pollutants are enriched in organisms and transmitted in the aquatic environment and food chain,which can cause a series of serious problems,such as imbalance in population proportions,reduced male fertility,destruction of ecosystems,interruption of population reproduction,and even extinction of some species.Therefore,the monitoring of these compounds is particularly crucial,and it requests advanced analytical methods,which should be sensitive,accurate,and efficient.With these methods,the relevant scientific support was provides for the prevention and control of environmental estrogens.Liquid chromatography-mass spectrometry(LC-MS)is one of the most important methods for the analysis of estrogens.However,the accuracy of the results are challenged by the conventional external caliberation methods due to the matrix effects.The isotope labeling method can accurately analyze most compounds with labelable groups,and are often used to eliminate matrix effects,with which ion suppression from co-eluting compounds,sample loss and the differences of instrument operating conditions could be corrected,without the limitation of lack of commercialization of isotope internal standards,which are difficult to obtain.In order to improve the analytical throughput,a multiplex labeling strategy based on a group of isotope dansyl chlorides was developed and used for the labeling of estrogens,in which multiple samples could be the analyzed in a single run.Because of the trace levels of estrogens in environmental samples,it is difficult to analyze by LC-MS directly.In this experiment,magnetic C18 materials which could be used to efficiently enrich these compounds was magnetized by solvothermal synthesis,and applied in magnetic solid phase extraction(MSPE)to enrich and purify the estrogens from the samples.Finally,a method consisting solid phase multiplex isotope labeling and LC-MS was developed and applied for the analysis of estrogens in environmental samples.The method was systematically evaluated by recovery,accuracy,precision,LODs,LOQs and linear quantitative range.The method had high recovery(86.8%-93.2%),stable reproducibility(intro-day RSDs<3.5%,inter-day RSDs<5.5%),excellent accuracy(96.8%-108.3%),low LODs and LOQs(0.1-0.5 ng/L and 0.5-2 ng/L,respectively),the quantitative concentration range maintains good linearity within 0.01-100μg/L(R~2>0.999),which confirmed the applicability in the analysis of estrogens in complex samples.With this method,seven estrogens in Daliao river estuary and chicken manure were analyzed,and the results revealed that the estrogens were widely existed in the environment.It was found that the concentration of estrogens was 211.1-246.4 ng/L in Daliao river estuary,and the main estrogens were estrone(E1,45.2-52.6 ng/L),diethylstilbestrol(DES,50.4-65.2 ng/L)and hexaneestrol(HES,19.2-23.7 ng/L).The concentration of estrogens was 19.01-34.75μg/kg in chicken manure,and E1(13.25-14.36μg/kg)was the main component of estrogens,accounting for more than 60%,followed by DES(1.57-2.03μg/kg)and HES(1.82-2.11μg/kg),which might be derived from additives in feed.We believe this method possesses a wide range of applications,not only for the analysis of environmental samples,but also many other complex samples.