液相色谱-原子荧光光谱联用测定水中烷基汞
发布时间：2019-06-25 21:03
【摘要】：根据国家文件的有关要求,将《水质烷基汞的测定液相色谱/原子荧光法》列入2016年度环保部标准制修订计划,项目统一编号为2016-16。本文采用液相色谱-原子荧光法(LC-AFS)测定水中甲基汞和乙基汞,主要内容和结论如下:首先,对LC-AFS仪器参数进行优化后的条件为:C18色谱柱分离,流动相为5%甲醇+1.2g/L L-半胱氨酸+4.62g/L乙酸铵,流速为1.0mL/min,氧化剂、载流、还原剂分别为0.2%K2S2O8+0.5%KOH、5%HCl、0.2%KBH4+0.5%KOH,灯电流:30mA、负高压:300V,载气流量:300ml/min、屏蔽气流量:1000ml/min。以最佳条件测定标准曲线,甲基汞和乙基汞在(0.1~10)μg/L浓度范围内线性关系良好,相关系数优于0.9990。第二,以液液萃取和固相萃取对水样进行预处理,通过LC-AFS测定后计算加标回收率。对于低、中、高3种浓度,液液萃取对甲基汞、乙基汞的回收率在76%~114%之间,相对标准偏差为4.1%~7.4%;以自制巯基棉、C18萃取盘、C18萃取柱3种固相萃取法进行实验,对应低、中、高3种浓度,巯基棉富集对甲基汞的回收率分别为103%、96.0%、65.8%,乙基汞的回收率分别为96.3%、54.6%、23.0%,回收率不稳定;C18萃取盘对甲基汞、乙基汞的回收率在34.4%~57.4%之间;C18萃取柱对甲基汞、乙基汞的回收率分别在55.4%~73.1%之间。通过比较回收率、方法检出限、操作难易、成本等因素,液液萃取为最优方法。第三,以液液萃取-LC-AFS方法进行实际水样及加标回收率的测定,实际水样包括自来水、水库及污水处理厂出口水样。自来水及水库水中均未检测到甲基汞和乙基汞;仅在团岛污水处理厂、娄山河污水处理厂检测到甲基汞浓度分别为0.29 ng/L、0.11 ng/L,低于《污水综合排放标准》等标准中的限值。整体回收率在74.0%~116.7%之间,可满足分析要求。本课题通过改进现有方法的不足之处,建立了适用于水中甲基汞、乙基汞的分析方法,确保基质干扰最少,降低样品的检出限,提高精密度、准确性及重复性。以该方法测定实际水样,以期为今后水中甲基汞和乙基汞含量的分析、污染防治工作及相关标准的修订提供方法依据。
[Abstract]:According to the relevant requirements of the national document, the determination of alkyl mercury in water quality by liquid chromatography / atomic fluorescence spectrometry was included in the revised plan of the standard system of the Ministry of Environmental Protection in 2016. the unified number of the project is 2016 / 16. In this paper, methyl mercury and ethyl mercury in water were determined by liquid chromatography-atomic fluorescence spectrometry (LC-AFS). The main contents and conclusions are as follows: firstly, the parameters of LC-AFS instrument are optimized as follows: C _ (18) column separation, mobile phase 5% methanol 1.2g/L L-cystine 4.62g/L ammonium acetate, flow rate 1.0 mL / min, oxidant, current carrier and reductant 0.5% KOH, respectively. 5% HCL, 0.2% KBH4 0.5% KOH, lamp current: 30mA, negative high voltage: 300V, carrier gas flow rate: 300ml min, shielded gas flow rate: 1000ml min. The linear range of methylmercury and ethyl mercury was (0.1 渭 g 路L) 渭 g 路L ~ (- 1), and the correlation coefficient was better than 0.999 0 渭 g 路L ~ (- 1) in the range of (0.1 渭 g 路L) 渭 g 路L ~ (- 1). Secondly, the water samples were pretreated with liquid-liquid extraction and solid phase extraction, and the standard recovery was calculated after LC-AFS determination. For low, medium and high concentrations, the recovery of liquid-liquid extraction of methylmercury and ethyl mercury is between 76% and 11.4%, and the relative standard deviation is 4.1% 鈮，
本文编号：2506004
[Abstract]:According to the relevant requirements of the national document, the determination of alkyl mercury in water quality by liquid chromatography / atomic fluorescence spectrometry was included in the revised plan of the standard system of the Ministry of Environmental Protection in 2016. the unified number of the project is 2016 / 16. In this paper, methyl mercury and ethyl mercury in water were determined by liquid chromatography-atomic fluorescence spectrometry (LC-AFS). The main contents and conclusions are as follows: firstly, the parameters of LC-AFS instrument are optimized as follows: C _ (18) column separation, mobile phase 5% methanol 1.2g/L L-cystine 4.62g/L ammonium acetate, flow rate 1.0 mL / min, oxidant, current carrier and reductant 0.5% KOH, respectively. 5% HCL, 0.2% KBH4 0.5% KOH, lamp current: 30mA, negative high voltage: 300V, carrier gas flow rate: 300ml min, shielded gas flow rate: 1000ml min. The linear range of methylmercury and ethyl mercury was (0.1 渭 g 路L) 渭 g 路L ~ (- 1), and the correlation coefficient was better than 0.999 0 渭 g 路L ~ (- 1) in the range of (0.1 渭 g 路L) 渭 g 路L ~ (- 1). Secondly, the water samples were pretreated with liquid-liquid extraction and solid phase extraction, and the standard recovery was calculated after LC-AFS determination. For low, medium and high concentrations, the recovery of liquid-liquid extraction of methylmercury and ethyl mercury is between 76% and 11.4%, and the relative standard deviation is 4.1% 鈮，
本文编号：2506004
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