摘要:
将三油酸甘油酯-醋酸纤维素复合膜(TECAM)用作被动采样器，开展水体中一甲基锡(MMT)、二甲基锡(DMT)、一丁基锡(MBT)、二丁基锡(DBT)、三丁基锡(TBT)、二苯基锡(DPhT)和三苯基锡(TPhT)等7种有机锡氯化物的富集实验，膜样品经甲醇/醋酸溶液提取、乙基化衍生和正己烷萃取等前处理后，用气相色谱-质谱法(GC-MS)进行定性和定量检测，得到水体中痕量有机锡污染的相关指纹信息。结果表明，7种目标化合物均可在TECAM膜上富集，48 h后均可达到平衡状态；有机锡富集能力差异较大，其TECAM膜/水分配系数(logKTECAM)与其辛醇-水分配系数(logKow)呈现显著正相关性(r=0.97, n=7)。甲基锡富集能力较低，但可定性筛查；而苯基锡和丁基锡等5种目标化合物在TECAM膜上的被动采样速率在0.06～0.16 L·g-1·d-1范围变化，经反演所得其在水体中的时间加权平均浓度与传统的主动采样法所得浓度没有显著差异(P>0.05)。因此，基于TECAM被动采样技术可以实现水体中极性范围较广的痕量有机锡污染筛查取证。
关键词:
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甲基锡
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丁基锡
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苯基锡
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被动采样
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半渗透膜
Abstract:
The triolein-embedded cellulose acetate membrane (TECAM) as a passive sampler is used to enrich seven organotin compounds including monomethyltin (MMT), dimethyltin (DMT), monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPhT) and triphenyltin (TPhT) chlorides. Organotin compounds in the TECAM are extracted by methanol/acetic acid (9:1 V/V), and ethylated by sodium tetraethylborate followed by n-hexane extraction, and are then analyzed using a gas chromatography-mass spectrometer (GC-MS) to study its fingerprint information in water. The results show that all the seven target compounds can be enriched with TECAM with an equilibrium time of 48 hours. The enrichment capacities of TECAM towards organotin are quite different. Organotin’s membrane/water partition coefficient (logKTECAM) is positively correlated with their octanol/water partition coefficient (logKow) (r=0.97, n=7). Although the enrichment capacities of methyltin are low, they still can be qualitatively analyzed by this method, while the sampling rates of MBT, DBT, TBT, DPhT and TPhT vary in the range of 0.06-0.16 L·g-1·d-1. Moreover, there is no significant difference between the time-weighted averaged concentration derived by TECAM and the average concentration obtained by active sampling (P>0.05). The passive sampling technology based on TECAM can be used for forensic fingerprint of trace organotin pollutants with a wide range of polarities in water.
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