气相色谱-质谱法同时测定海水中甲基汞、乙基汞和三丁基锡

Simultaneous determination of methyl mercury,ethyl mercury and tributyltin in seawater by gas chromatography–mass spectrometry

建立气相色谱–质谱法同时测定海水中甲基汞、乙基汞和三丁基锡的分析方法。海水样品用乙酸调节pH后,用四苯基硼酸钠进行衍生,经HP–5MS毛细柱分离,选择离子监控(SIM)模式检测,以外标法定量。甲基汞、乙基汞和三丁基锡的质量浓度在0.1~2 mg/L范围内与色谱峰面积呈良好的线性关系,相关系数均大于0.998,检出限分别为0.015,0.015,0.010 mg/L,样品平均加标回收率为78.1%~90.2%,相对标准偏差为2.3%~4.5%(n=6)。该方法前处理简单,可用于海水中有机汞和有机锡的同时测定。

A method for the simultaneous determination of methyl mercury,ethyl mercury and tributyltin in seawater by gas chromatography–mass spectrometry(GC–MS)was established.The pH of seawater samples was adjusted by acetic acid.The samples were derived by sodium tetrapenylborate and then separated by HP–5MS(30 m×0.25 mm,0.25μm)column,finally determined by GC–MS with selected ion monitoring and quantified with external standard method.The mass concentrations of methyl mercury,ethyl mercury and tributyltin had a good linear relationship with the chromatographic peak area in the range of 0.1–2 mg/L,the correlation coefficients were all more than 0.998,and the detection limits were 0.015,0.015 and 0.010 mg/L,respectively.The average recoveries were 78.1%–90.2%,and the relative standard deviations were 2.3%–4.5%(n=6).The method is simple in pretreatment,which can be used for simultaneous determination of organomercury and organotin in seawater.