Aquatic degradation of triclosan and formation of toxic chlorophenols in presence of low concentrations of free chlorine
Aquatic degradation of triclosan and formation of toxic chlorophenols in presence of low concentrations of free chlorine
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DOI：
10.1007/s00216-005-0116-4
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发表时间：
2005-12-01
影响因子：
4.3
通讯作者：
Gómez, M
中科院分区：
文献类型：
--
作者：
Canosa, P;Morales, S;Gómez, M
研究了2-（2，4-二氯苯氧基）-5-氯苯酚（三氯生）在氯化水样中的降解情况。母体化合物及其转化产物的灵敏测定通过样品浓缩后的气相色谱-质谱检测实现，使用固相萃取吸附剂和目标化合物的甲硅烷基化。实验完成使用超纯水加标氯和三氯生浓度分别在低毫克/升和纳克/毫升范围。酚环的氯化和醚键的断裂被确定为三氯生的主要降解途径。这两种工艺都产生了两种四氯羟基二苯醚和一种五氯羟基二苯醚以及2，4-二氯苯酚。在任何实验中均未检测到2，3，4-三氯苯酚的形成;然而，注意到了大量的2，4，6-三氯苯酚。当三氯生被添加到游离氯浓度低于1毫克/升的自来水样品中时，也发现了所有这五种化合物。少量的三种二羟基苯酚（其结构中含有1至3个氯原子）也被确定为不稳定的三氯生氯化副产物。对几个原废水样品的分析表明，三氯生及其最稳定的副产物（2，4-二氯苯酚和2，4，6-三氯苯酚）的浓度很高，这进一步说明，当含有三氯生的产品与氯化自来水混合时，可能会发生上述转化。
The degradation of 2-(2,4-dichlorophenoxy)-5-chlorophenol (triclosan) in chlorinated water samples was investigated. Sensitive determination of the parent compound and its transformation products was achieved by gas chromatography with mass spectrometry detection after sample concentration, using a solid-phase extraction sorbent and silylation of the target compounds. Experiments were accomplished using ultrapure water spiked with chlorine and triclosan concentrations in the low mg/l and ng/ml ranges respectively. Chlorination of the phenolic ring and cleavage of the ether bond were identified as the main triclosan degradation pathways. Both processes led to the production of two tetra- and a penta-chlorinated hydroxylated diphenyl ether, as well as 2,4-dichlorophenol. The formation of 2,3,4-trichlorophenol was not detected in any experiment; however, significant amounts of 2,4,6-trichlorophenol were noticed. All of these five compounds were also identified when triclosan was added to tap-water samples with free chlorine concentrations below 1 mg/l. Minor amounts of three di-hydroxylated phenols, containing from one to three atoms of chlorine in their structures, were also identified as unstable triclosan chlorination by-products. The analysis of several raw wastewater samples showed the co-existence of important concentrations of triclosan and its most stable by-products (2,4-dichlorophenol and 2,4,6-trichlorophenol), reinforcing the potential occurrence of the described transformations when products containing triclosan are mixed with chlorinated tap water.