Determination Of Phenolic Endocrine Disrupting Chemicals By Gas Chromatography/Mass Spectrometry

Alkylphenols （APs）, bisphenol A （BPA） and alkylphenol polyethoxylates （APEOs）,known as phenolic endocrine disrupting chemicals, are widely and stable present invarious environmental medias. Phenolic endocrine disrupting chemicals can bedetermined by a variety of methods. Gas chromatography/mass spectrometry （GC/MS）is widely used in the field of environmental monitoring, and can be used to the detectionof nonylphenol （NP）, octylphenol （OP）, nonylphenol polyethoxylates （NPEOs） andbisphenol A （BPA）. But GC/MS has not been adopted to the determination ofderivatized octylphenol polyethoxylates （OPEOs）, currently. In order to achieve thesimultaneous detection of phenolic endocrine disrupting chemicals, such as nonylphenolmono-and diethoxylates （NP₁-2EO）,4-tert-octylphenol mono-and diethoxylates（4-t-OP₁-2EO）,4-tert-octylphenol （4-t-OP）, NP and BPA, GC/MS method has beenestablished. Derivatization reagent for seven kinds of phenolic endocrine disruptingchemicals is N,O-bis（trimethylsilyl）trifluoroacetamide （BSTFA） and trimethylch-lorosilane （TMCS）. The pre-treatment conditions, such as extraction solvent, pH,salinity, derivatization reagent and temperature were optimized. The selectionquantitative ions of nonylphenol monoethoxylate （NP₁EO）, nonylphenol diethoxylate（NP₂EO）4-tert-octylphenol monoethoxylate （4-t-OP₁EO） and4-tert-octylphenoldiethoxylate （4-t-OP₂EO） were determined.Using dichloromethane as the extraction solvent, the water samples was extractedby liquid-liquid extraction （LLE） with the spiked recoveries and relative standarddeviations （RSD） were73.5～112.0%and5.1～9.5%respectively. Then the targetcompounds were derivatized with BSTFA+TMCS （99:1） and finally the silylderivatized products were determined by GC/MS. Under the selected chromatographicconditions, seven kinds of phenolic endocrine disrupting chemicals can get baselineseparation. The detection limits of the method were0.40ng/L for NP, NP₁EO andNP₂EO;0.56ng/L for4-t-OP;0.46ng/L for4-t-OP₁EO;0.44ng/L for BPA;0.88ng/L for4-t-OP₂EO. The correlation coefficients were between0.9893and0.9999. The methodmentioned above is labour-saving and needless of extra expensive equipments, and canrealize routine analysis in regular laboratories.Seven kinds of phenolic endocrine disrupting chemicals in Chongqing surfacewater have been detected by this established method of liquid-liquid extraction， derivatization-GC/MS. Meanwhile, the spatial and temporal characteristics of thesephenolic endocrine disrupting chemicals in the Chongqing surface water were analyzed.The paper presents that: seven kinds of phenolic endocrine disrupting chemicals weregenerally present in all sampling sites, and among the target compounds, NP was thepredominant pollutant of Chongqing surface water. The concentrations of seven kindsof phenolic endocrine disrupting chemicals were ranged from8.1to47.9ng/L （for4-t-OP）,945.9to5878.0ng/L （for NP）,9.2to62.5ng/L （for4-t-OP₁EO）,50.8to745.3ng/L （for NP₁EO）,31.0to102.1ng/L （for4-t-OP₂EO）,14.9to175.9ng/L （forBPA）,70.2to387.6ng/L （for NP₂EO）, respectively. Compared to the WaterEnvironment Quality Standards, the concentration of NP in Chongqing surface waterwas lower than the Freshwater Standards recommended by the U.S. EnvironmentalProtection Agency （EPA）, which is not more than6.6μg/L. The concentration of NP inJuly was higher than it in December. The concentration of NP increased in first and thendecreased from upstream to downstream, and the concentrations of the other phenolicendocrine disrupting chemicals, decreased from upstream to downstream.