超高效液相色谱-四极杆飞行时间质谱测定茶叶中手性农药茚虫威对映体残留

为了满足茶叶中手性农药茚虫威对映异构体残留检测的需要,采用超高效液相色谱-四极杆飞行时间质谱(UHPLC-Q-TOF/MS)分析茶叶中手性农药茚虫威对映异构体的残留。采用乙腈提取,Florisil和GCB混合柱净化,Lux 3μCellulose-1手性柱拆分,0.40mL/min V(0.10%甲酸水溶液)∶V(甲醇)=15∶85的溶液作为流动相,UHPLC-Q-TOF/MS基质外标法定性定量分析。茚虫威两个对映体在0.002 5～0.600mg/L浓度范围内满足线性关系,相关系数r为0.997 3和0.993 1,仪器检测限为0.001mg/L;绿茶在0.01、0.10、1.00mg/kg 3个添加浓度水平下,平均添加回收率为80.75%～101.69%,相对标准偏差(RSD)小于15%,方法定量限为0.002 5mg/kg。该方法准确、可靠,能够满足茶叶中茚虫威手性对映体残留分析的需要。

Enantioseparation and Quantification of Chiral Pesticide Indoxacarb Residues in Tea by UHPLC-Q-TOF/MS

In order to meet the need of enantioseparation and quantification of chiral pesticide indoxacarb residue determination in tea, an effective reversed phase chiral analytical method was developed for the resolution and determination of indoxacarb enantiomers in tea by ultra- high pressure liquid chromatography-quadrupole-time of flight mass spectrometry （UHPLC-Q-TOF/MS）. Indoxacarb enantiomers were extracted by acetonitrile followed by Florisil and GCB mix-column cleanup from tea, then separated on a Lux 3 μ Cellulose 1 column with V（0.10% formic acid）∶V（methanol）=15∶85 as the mobile phases at 0.40 mL/min. Over the concentrations in the range of 0.002 5-0.600 mg/L for both of indoxacarb enabtiomers, the correlation coefficients (r) of the calibration curves are 0.997 3 and 0.993 1 for each other, and the estimated limits of detection(LODs) are 0.001 mg/L. The average recoveries of two indoxacarb enantiomers in green tea at three spiked concentration levels(0.01, 0.10 and 1.00 mg/kg) range from 80.75% to 101.69% with relative standard deviations (RSDs) lower than 15% (n=6). The limits of quantitation (LOQs) of two indoxacarb enabtiomers are 0.002 5 mg/kg in green tea. The result shows that this method is reliable, accurate and suitable for the residue determination of indoxacarb enantiomers in tea.