正相色谱串联质谱法直接进样测定水体中的草甘膦和2,4-滴残留
Detection of Glyphosate and 2,4-D in Water by Normal-phase Chromatography Electrospray Ionization Tandem Mass Spectrometry
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摘要:目的 建立直接进样测定饮用水和水源水中的草甘膦和2,4-滴的液相色谱质谱分析方法。方法 采用正相色谱柱:CAPCELL PAK ST柱(2.1 mm×150 mm), 流动相为乙腈/10 mmol/L的乙酸铵水溶液(pH=10.10)。水样直接过0.22 μm滤膜, 用高效液相色谱串联质谱分析检测。结果 草甘膦(100.0 ng/mL, 400.0 ng/mL)和2,4-滴(10.0 ng/mL, 40.0 ng/mL)在水中进行两个质量浓度的加标实验, 每个质量浓度平行测定6次。通过测定和工作曲线的计算, 得到草甘膦测定的结果为:95.3±3.8 ng/mL和402.7±20.8 ng/mL, 即平均回收率分别为95.3%和100.7%;2,4-滴测定的结果为:9.7±0.2 ng/mL和38.6±1.0 ng/mL, 即平均回收率分别为97.0%和96.5%。草甘膦在水中质量浓度范围在20.0~800.0 ng/mL, 线性相关系数为0.9992;2,4-滴在水中质量浓度范围在2.0~80.0 ng/mL, 线性相关系数为0.9996。在自来水中添加草甘膦和2,4-滴, 以10倍信噪比(S/N)计算, 在进样量10 μL时; 得到的本方法草甘膦和2,4-滴最低检测质量浓度分别为4.0 ng/mL和0.4 ng/mL。结论 该方法简单, 速度快, 准确度和灵敏度高, 满足测定日常地表水水体中百草甘膦和2,4-滴检测项目的需要。Abstract:Objectives To setup a method for detecting glyphosate and 2,4-D in drinking water by liquid chromatography-tandem mass spectrometry (LC-MS-MS).Methods Using Chromatographic column: CAPCELL PAK ST(2.1 mm × 150 mm) and mobile phase: acetonitrile/10 mmol/L ammonium acetate solution (pH=10.10) for the separation of samples; after passing a 0.22 μm filter membrane, samples were detected by LC-MS-MS.Results At spiked levels for glyphosate (100.0 ng/mL, 400.0 ng/mL) in water, the detected concentrations were 95.3±3.8 ng/mL and 402.7± 20.8 ng/mL, the average recoveries were 95.3% and 100.7%, and the linear regression coefficient for glyphosate at the concentration of 20.0~800.0 ng/mL was 0.9992. At spiked levels for 2,4-D (10.0 ng/mL, 40.0 ng/mL) in water, the detected concentrations were 9.7± 0.2 ng/mL and 38.6±1.0 ng/mL, the average recoveries were 97.0% and 96.5%, and the linear regression coefficient for 2,4-D at the concentration of 2.0~80.0 ng/mL was 0.9996. The limit of detection (S/N=10) for glyphosate was 4.0 ng/mL and for 2,4-D was 0.4 ng/mL.Conclusions The method was simple and fast, had a good accuracy and high sensitivity, which could meet the needs for the determination of paraquat glyphosate and 2,4-D in drinking water.
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