柱前衍生-液相色谱-串联质谱法测定环境水体中草甘膦及其代谢产物的影响因素研究

来源:用户上传      作者:董建芳 董会军 李义 赵峰 马天翼 刘雪瑜

　　摘 要：为了更好地了解水中草甘膦及其代谢产物氨甲基膦酸的浓度水平，采用柱前衍生-液相色谱-串联质谱法对其进行测定。采用Inert Sustain Bio C18 HP色谱柱，乙腈-5 mmol/L乙酸铵水溶液作为流动相，水浴-超声50 ℃衍生60 min，正离子模式，内标法定量，测定水样中的草甘膦和氨甲基磷酸;并探讨了质谱条件、色谱条件、衍生条件、保存时间、采样保存容器、金属离子因素对草甘膦回收率的影响。结果表明，草甘膦和氨甲基膦酸的方法定量限分别为0.030，0.028 μg/L，加标回收率为83.4%～108%，相对标准偏差（n=6）为2.6%～8.0%。通过大量实际样品测定，内标物回收率控制在74.5%～129%。采用的测定方法准确，抗干扰能力强，检测结果能够满足《地下水质量标准》（GB/T 14848―2017）Ⅰ类水限值要求，研究结果对保护水体生态安全具有重要的参考价值。
　　关键词：质谱分析;液相色谱-串联质谱法;环境水体;草甘膦;氨甲基膦酸;影响因素
　　中图分类号：X592;O657.63 文献标识码：A DOI： 10.7535/hbgykj.2022yx01010
　　Abstract：In order to better understand the concentration level of glyphosate and its metabolite aminomethyl phosphonic acid in water，the precolumn derivatization-liquid chromatography-tandem mass spectrometry was used to determine the contents.Glyphosate and aminomethyl phosphoric acid were determined in water samples in the conditions with Inert Sustain Bio C18 HP column，and acetonitrile-5 mmol/L ammonium acetate aqueous solution was used as the mobile phase，water bath ultrasonic derivatization at 50 ℃ for 60 min，positive ion mode and the contents of glyphosate and aminomethyl phosphonic acid were determined by using internal standard method.The effects of mass spectrometry conditions，chromatographic conditions，derivatization conditions，storage time，storage container and metal ions on the recovery were discussed.The results show that the method quantitative limits of glyphosate and aminomethyl phosphonic acid are 0.030 and 0.028 μg/L respectively.The recovery rates range from 83.4% to 108% with relative standard deviations （n=6） ranging from 2.6% to 8.0%.Through the determination of a large number of actual samples，the recovery rates of internal standard are controlled at 74.5% to 129%，the method is accurate and has strong anti-interference ability，which can meet the requirements of class Ⅰ water limit in the quality standard for groundwater （GB/T 14848-2017）.The results of the research have important guiding significance for the protection of water safety.
　　Keywords：mass spectrometry analysis;liquid chromatography-tandem mass spectrometry;environmental water;glyphosate;aminomethyl phosphonic acid;influencing factors
　　 草甘膦（glyphosate，GLY）是一N内吸传导型广谱灭生性除草剂，其主要的代谢产物是氨甲基膦酸（aminomethyl phosphonic acid，AMPA）。近年来，草甘膦以高效、低毒被广泛应用，但是随着草甘膦的产量和使用量日益增加，大量的草甘膦能够在土壤中被吸附、迁移，并通过扩散转移到水体中[1-3]。草甘膦具有较长的半衰期（7～315 d，通常为45～60 d），导致草甘膦在环境水体中不断累积并持续存在[1]，对人体健康具有一定的毒性，对生态环境具有潜在的危害，因此其安全问题成为关注的焦点[2-6]，国际癌症研究机构（IARC）研究报告也指出，草甘膦农药可能会引发淋巴腺癌和肺癌。在中国《生活饮用水卫生标准》（GB 5749―2006）和《地下水质量标准》（GB/T 14848―2017）中均设有草甘膦指标，同时给出了相应的限值要求，生活饮用水的限值为0.7 mg/L，地下水的Ⅰ类水限值为0.1 μg/L。
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