杨丽莉 王美飞 胡恩宇 戴维

摘要：建立衍生化-溶剂提取-气质联用（GC-MS）测定水中痕量烷基汞的分析方法。用巯基固相萃取柱富集水中的烷基汞，4 mol/L 盐酸洗脱，在HAc-NaAc缓冲体系（pH 4～5）下与50μL 四丙基硼化钠（1% THF）衍生反应，0.5 mL 正己烷提取烷基汞的衍生物，采用气相色谱-质谱联用选择离子方式（SIM）进行检测，以4-溴氟苯为内标定量，在2～200 ng/L 范围内线性良好，1 L 水样中甲基汞和乙基汞的检出限可达1 ng/L 以下。实际样品添加回收率在69.7%～80.9%之间，准确度好;平行5次进行精密度试验，相对标准差在8.5%～10.3%之间。结果表明：方法稳定性好、操作方法实用，可用于水中痕量烷基汞的测定。

关键词：烷基汞;衍生化;溶剂提取;气相色谱-质谱联用;水样

中图分类号： O657.63;X832文献标志码： A文章编号：1674–5124（2021）12–0073–06

Determination of alkyl mercury in water by derivatization- solvent extraction-gas chromatography -mass spectrometry

YANG Lili，WANG Meifei，HU Enyu，DAI Wei

（Nanjing Environment Monitoring Center， Nanjing 210013， China）

Abstract： A sensitive and repeatable method was developed and applied to determine alkyl mercury in water byderivatization- solventextraction-gaschromatography-massspectrometry （GC-MS）. The watersamples were extracted by SH solid-phase extraction column. The SPE column was eluted by 4 mol/L HCl and the acidic solution was adjusted to neutral. Then HAC-NaAC buffer （pH 4-5） and 50μL sodium tetrapropylborate （NaBPr4） solution （1% THF）were added to the solution. The derivatives can be completely extracted by 0.5 mL n-hexane. The analytes were determined by GC-MS in SIM mode and quantified by internal standard method. The results showed that the alkyl mercury derivatives had a good linear relationship in the rang 2 ng/L to 200 ng/L. The limits of detection were less than 1 ng/L in about 1 L water samples. The recoveries of the analytes in real water samples spiked with standards were all in the range of 69.7% to 80.9%. Th erelative standard deviations （RSD） were between 8.5% to 10.3%（n=5）. The results show that the method is sensitive and accurate for the determination of the alkyl mercury in water samples.

Keywords ： alkyl mercury; derivatization; solvent extraction; gas chromatography-mass spectrometry; water sample

0引言

環境八大公害事件之一的“水俣病”发生以来，世界各国达成了汞污染防治的共识，2017年《水俣公约》正式生效，我国也将和所有签约国一道严格控制汞排放和防治汞污染。汞（Hg）及其化合物在自然界中分布广泛，由于易与大部分金属形成合金，在传统和现代工业、化学药物和电子电器中都得到广泛应用，由此产生的废气、废水和废渣都会将汞污染转移至环境中，存在于环境中的汞有多种形态，可以在大气、水、土壤、生物体中迁移、循环和累积，是环境中广泛存在的污染物。汞的毒性与形态密切相关，与其他重金属不同在于可转化为毒性更强的有机汞（主要是甲基汞和乙基汞），兼有重金属和有机物双重毒性特点，可通过食物链放大最终毒害人体健康。……