Aerobic Biodegradation Studies of Nonylphenol Ethoxylates in River Water Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry
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- 作者：Niels Jonkers ; Thomas P. Knepper ; and Pim de Voogt
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：January 15, 2001
- 年：2001
- 卷：35
- 期：2
- 页码：335 - 340
- 全文大小：114K
- 年卷期：v.35,no.2(January 15, 2001)
- ISSN：1520-5851
文摘
The aerobic biodegradation of nonylphenol ethoxylates(A9PEO) was kinetically investigated in a laboratory-scalebioreactor filled with river water, spiked at a concentrationof 10 mg L-1 nonionic surfactants. Analyses of the samplesapplying liquid chromatography-electrospray massspectrometry (LC-ES-MS) after solid-phase enrichmentrevealed a relatively fast primary degradation of A9PEO with>99% degradation observed after 4 days. Contrary tothe generally proposed degradation pathway of EO chainshortening, it could be shown that the initiating step of thedegradation is 
-carboxylation of the individual ethoxylatechains: metabolites with long carboxylated EO chainsare identified (A9PEC). Further degradation proceeds graduallyinto short-chain carboxylated EO with the most abundantspecies being A9PE2C. The oxidation of the nonyl chainproceeds concomitantly with this degradation, leading tometabolites having both a carboxylated ethoxylate and analkyl chain of varying lengths (CAPEC). The identity ofthe CAPEC metabolites was confirmed by the fragmentationpattern obtained with LC-ES-MS/MS. Both A9PEC andCAPEC metabolites are still present in the bioreactor after31 days. In the aerobic degradation pathway, A9PEO2 isformed only to a minor extent and is even further degradedin several days. The endocrine disruptor nonylphenolwas not found as a metabolite in this study.
-carboxylation of the individual ethoxylatechains: metabolites with long carboxylated EO chainsare identified (A9PEC). Further degradation proceeds graduallyinto short-chain carboxylated EO with the most abundantspecies being A9PE2C. The oxidation of the nonyl chainproceeds concomitantly with this degradation, leading tometabolites having both a carboxylated ethoxylate and analkyl chain of varying lengths (CAPEC). The identity ofthe CAPEC metabolites was confirmed by the fragmentationpattern obtained with LC-ES-MS/MS. Both A9PEC andCAPEC metabolites are still present in the bioreactor after31 days. In the aerobic degradation pathway, A9PEO2 isformed only to a minor extent and is even further degradedin several days. The endocrine disruptor nonylphenolwas not found as a metabolite in this study.