DuPont Crop Protection, Stine-Haskell Research Center, Newark, DE 19714, USA.
Anal Chim Acta. 2013 Mar 20;768:1-11. doi: 10.1016/j.aca.2013.01.011. Epub 2013 Jan 16.
A sample extraction and purification procedure that uses ammonium-salt-induced acetonitrile/water phase separation was developed and demonstrated to be compatible with the recently reported method for pesticide residue analysis based on fast extraction and dilution flow injection mass spectrometry (FED-FI-MS). The ammonium salts evaluated were chloride, acetate, formate, carbonate, and sulfate. A mixture of NaCl and MgSO4, salts used in the well-known QuEChERS method, was also tested for comparison. With thermal decomposition/evaporation temperature of <350°C, ammonium salts resulted in negligible ion source residual under typical electrospray conditions, leading to consistent method performance and less instrument cleaning. Although all ammonium salts tested induced acetonitrile/water phase separation, NH4Cl yielded the best performance, thus it was the preferred salting out agent. The NH4Cl salting out method was successfully coupled with FI/MS/MS and tested for fourteen pesticide active ingredients: chlorantraniliprole, cyantraniliprole, chlorimuron ethyl, oxamyl, methomyl, sulfometuron methyl, chlorsulfuron, triflusulfuron methyl, azimsulfuron, flupyrsulfuron methyl, aminocyclopyrachlor, aminocyclopyrachlor methyl, diuron and hexazinone. A validation study was conducted with nine complex matrices: sorghum, rice, grapefruit, canola, milk, eggs, beef, urine and blood plasma. The method is applicable to all analytes, except aminocyclopyrachlor. The method was deemed appropriate for quantitative analysis in 114 out of 126 analyte/matrix cases tested (applicability rate=0.90). The NH4Cl salting out extraction/cleanup allowed expansion of FI/MS/MS for analysis in food of plant and animal origin, and body fluids with increased ruggedness and sensitivity, while maintaining high-throughput (run time=30s/sample). Limits of quantitation (LOQs) of 0.01mgkg(-1) (ppm), the 'well-accepted standard' in pesticide residue analysis, were achieved in >80% of cases tested; while limits of detection (LODs) were typically in the range of 0.001-0.01mgkg(-1) (ppm). A comparison to a well-established HPLC/MS/MS method was also conducted, yielding comparable results, thus confirming the suitability of NH4Cl salting out FI/MS/MS for pesticide residue analysis.
一种采用铵盐诱导乙腈/水相分离的样品提取和净化程序被开发出来，并被证明与最近报道的基于快速提取和稀释流动注射质谱（FED-FI-MS）的农药残留分析方法兼容。评估的铵盐有氯化物、醋酸盐、甲酸盐、碳酸盐和硫酸盐。还测试了在著名的 QuEChERS 方法中使用的 NaCl 和 MgSO4 混合物进行比较。由于热分解/蒸发温度<350°C，在典型的电喷雾条件下，铵盐几乎不会产生离子源残留，从而导致一致的方法性能和更少的仪器清洗。虽然所有测试的铵盐都诱导了乙腈/水相分离，但氯化铵产生了最佳的性能，因此它是首选的盐析剂。氯化铵盐析法成功地与 FI/MS/MS 耦合，并对 14 种农药活性成分进行了测试：氯虫酰胺、氰霜唑、氯嘧磺隆乙酯、涕灭威、灭多威、甲磺隆甲酯、氯磺隆、三氟啶磺隆甲酯、唑嘧磺草胺、氟吡草腙甲酯、氯吡嘧磺隆、氯吡嘧磺隆甲酯、敌草隆和环嗪酮。用 9 种复杂基质（高粱、大米、柚子、油菜籽、牛奶、鸡蛋、牛肉、尿液和血浆）进行了验证研究。该方法适用于所有分析物，除了氯吡嘧磺隆。该方法被认为适用于 126 个分析物/基质案例中的 114 个进行定量分析（适用性率=0.90）。氯化铵盐析提取/净化允许 FI/MS/MS 分析植物和动物源性食品以及体液的扩展，同时提高了耐用性和灵敏度，同时保持高通量（运行时间=30s/样本）。0.01mgkg(-1)（ppm）的定量限（LOQs），这是农药残留分析中的“公认标准”，在超过 80%的测试案例中实现；而检测限（LODs）通常在 0.001-0.01mgkg(-1)（ppm）的范围内。还与一种成熟的 HPLC/MS/MS 方法进行了比较，结果相当，从而证实了氯化铵盐析 FI/MS/MS 用于农药残留分析的适用性。
