改进的QuEChERS方法结合液相色谱-四极杆-飞行时间质谱快速筛查与确证调味茶中52种农药残留

Rapid screening and identification of 52 pesticide residues in flavored tea by improved QuEChERS combined with liquid chromatography-quadrupole-time-of-flight mass spectrometry

建立了调味茶中52种农药残留的QuEChERS方法结合液相色谱-四极杆-飞行时间质谱(LC-Q-TOF-MS)快速筛查方法。采用乙腈提取样品,经 N -丙基乙二胺(PSA)、石墨化炭黑(GCB)、C 18 净化,LC-Q-TOF-MS测定。结果表明:52种农药在调味茶中4个添加水平(10、20、50和100 μ g/kg )下的回收率均在70%~120%之间,相对标准偏差(RSD, n =3)均小于20%, 52种农药线性良好,线性相关系数( r )均大于0.99。52种添加农药的筛查限为0.001~0.01 mg/kg ,定量限为0.002~0.02 mg/kg ,均低于添加农药的欧盟最大残留限量(MRL)标准。该方法样品前处理简单、分析时间短、灵敏、可靠,适用于茶叶中多种农药残留的检测。

An improved method to screen 52 pesticide residues in flavored tea using QuEChERS coupled with liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) has been investigated. The flavored tea was extracted with acetonitrile and purified using by primary secondary amine (PSA), graphitized carbon black (GCB) and C 18 sorbent. The resultant residues were then analyzed using LC-Q-TOF-MS. The recoveries of all the pesticides in flavored tea at the four spiked levels of 10, 20, 50 and 100 μ g/kg were 70%-120% and the relative standard deviations (RSDs, n =3) were less than 20%. The calibration curves of the 52 pesticide residues had good linear relationships, and the correlation coefficients were more than 0. 99. The screening detection limits (SDLs) and the limits of quantitation (LOQs) for the 52 pesticides were in the range of 0.001-0.01 mg/kg and 0.002-0.02 mg/kg , respectively, which were lower than maximum residue limits standard permitted by the European Union (EU). This method is simple, rapid, reliable, and can meet the requirements for the simultaneous determination of 52 pesticide residues in flavored tea.