Determination Of Phenolic Endocrine Disrupting Chemicals In Surface Water Of Dianchi Lake By Gc/ms

Phenols endocrine disrupting chemicals is a kind of organic chemicals which have typical estrogen effect. Of particular interest in this study are the four representative phenolic chemicals:4-tert-octylphenol (4-t-OP),4-cumylphenol (4-CP),4-nonylphenol (4-NP) and bisphenol A (BPA).4-NP and 4-t-OP, as the major degradation products of alkylphenol polyethoxylate, are widely used in industrial production. BPA and 4-CP as important industry materials are also ubiquitous in daily necessities. These four kinds of phenols endocrine disrupting chemicals have great environmental harmfulness and potential threat to human and wildlife. In this paper, derivatization methods in pretreatment were discussed in detail. Then the optimal derivatization method was applied to simultaneously identify the concentrations of 4-NP,4-t-OP, BPA and 4-CP in surface water of Dianchi Lake by gas chromatography-mass spectrometry (GC-MS).Firstly, according to the detection characteristics of phenols by GC/MS, the methods for derivatization of target phenols with Phenyltrimethyl-ammonium (PTA-OH) and N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) with respects to derivatization solvents, amount of derivatizing reagent, reaction temperature and reaction time were discussed. The results showed that the optimum derivatization conditions for methylation with PTA-OH were ethyl acetate as reaction solvent and final solvent at 20℃for 5min (derivatizing reagent/target phenols>250, mol/mol), under which the instrumental detection limits for these target phenols were lower than 0.1pg/μL. The optimum derivatization conditions for silylation with BSTFA were acetone as reaction solvent and final solvent at 20℃for 65min (derivatizing reagent/target phenols>67000, mol/mol), under which the instrumental detection limits for these target phenols were lower than 0.2pg/μL. Two derivatization methods have decreased the instrumental detection limits of target chemicals by 50-fold, and could be used in pretreatment followed by GC/MS for determination of target phenols. However, considering the little influence of excess derivatization and the lower baseline of chromatogram when taking PTA-OH as reagent, PTA-OH was chosen as reagent for the derivatization of target phenols in surface water.Then, samples from 10 national control sections in Dianchi Lake were detected for target phenols by filtration and solid phase extraction, followed by the optimum derivatization method and GC/MS analysis. The results showed that four kinds of phenols were wildly found in surface water of Dianchi Lake. The concentrations of,4-t-OP,4-CP 4-NP and BPA were determined to be N.D.-56.5ng/L,23.3-48.5ng/L,13.6-141.6ng/L and N.D.-4713.6ng/L, respectively. Among these samples, the highest concentrations were obtained at Duanqiao site, which is the most close to downtown of Kunming City. The concentration of BPA detected in some sites of Dianchi Lake was higher than that background level of both domestic and international water systems.