分散固相萃取-超高效液相色谱-串联质谱法测定禽蛋中氟虫腈及其代谢产物

建立了分散固相萃取-超高效液相色谱-串联质谱检测禽蛋中氟虫腈及其代谢产物氟甲腈、氟虫腈硫醚和氟虫腈砜的方法。样品用含1%(体积分数)乙酸的乙腈提取后,加无水硫酸钠、十八烷基键合硅胶(C18-N)及氨基-丙基乙二胺(NH2-PSA)3种净化剂,旋涡振荡,对样品进行净化。以Shim-pack GIST C18色谱柱(50 mm×2.1 mm,2μm)进行分离,以甲醇和1 mmol/L乙酸铵水溶液为流动相进行梯度洗脱,在电喷雾离子源负离子模式和多反应检测(MRM)模式下进行定性定量分析。考察了净化剂中无水硫酸钠、C18-N和NH2-PSA的用量对加标回收率的影响,优化了实验条件。结果表明:4种化合物在0.4~100μg/L范围内线性关系良好,相关系数r2≥0.998 9;回收率为95.09%~103.26%;定量限为0.2μg/kg。该方法前处理简单,回收率高,重复性好,可作为禽蛋中氟虫腈及其代谢产物的有效检测方法。

Determination of fipronil and its metabolites in bird eggs by ultra-performance liquid chromatography-tandem mass spectrometry with dispersive solid phase extraction

An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine fipronil and its metabolites (fipronil desulfinyl, fipronil sulfone and fipronil sulfide) in bird eggs. The samples were extracted with acetonitrile containing 0.1%(v/v) acetic acid, and then purified by a mixture of anhydrous sodium sulfate, octadecyl carbon silica gel (C₁₈-N) sorbent and ethylenediamine-N-propyl carbon silica gel (NH₂-PSA) sorbent. The analysis was performed by a UPLC-MS/MS system with Shim-pack GIST C₁₈ column (50 mm×2.1 mm, 2 μm). The mobile phases consisted of methanol and 1 mmol/L ammonium acetate aqueous solution by gradient elution, and multiple reaction monitoring (MRM) mode with negative electrospray ionization was used. The effect of the dosages of anhydrous sodium sulfate, C₁₈-N and NH₂-PSA in cleaning-up agent was studied. The main influence factors and analytical conditions were modified. Four linear calibration curves were obtained with correlation coefficients r² ≥ 0.9989. The recoveries were determined at three concentrations and ranged from 95.09%-103.26%. The limit of quantification (LOQ) was 0.2 μg/kg. It is suitable for the determination of fipronil and its metabolites in bird eggs.