分散固相萃取-超高压液相色谱-串联质谱法测定茶叶中赤霉酸和α-萘乙酸

建立了分散固相萃取-超高压液相色谱-串联质谱分析茶叶中两种植物激素赤霉酸(GA3)与α-萘乙酸(NAA)含量的方法。样品经甲醇均质提取,采用弗罗里硅土、石墨化炭黑(GCB)、丙基乙二胺(PSA)和C18混合吸附剂分散萃取净化。采用HSS C18色谱柱(100mm×2.0mm,1.8μm),电喷雾电离(-),多反应监测模式扫描(MRM),UPLC-ESI(-)-MS/MS检测,外标法定量分析。GA3和NAA分别在0.05～5.0mg/kg与0.10～5.0mg/kg范围内线性关系良好,相关系数r≥0.9990,定量限分别为0.05与0.10mg/kg。GA3和NAA在0.1,0.5和1.0mg/kg水平上的添加回收率分别在85.0%～86.8%和82.9%～84.4%之间,精密度(RSD)≤4.5%。本方法操作简单、准确,适用于测定茶叶中GA3和NAA残留量。

Determination of Gibberellic Acid and α-Naphthlene Acetic Acid in Tea by Ultra-pressure Liquid Chromatography Tandem Mass Spectrometry with Dispersive Solid Phase Extraction

A rapid analytical method based on ultra-pressure liquid chromatography tandem mass has been developed for the determination of plant hormones gibberellic acid(GA 3) andα-naphthlene acetic acid(NAA) in tea.The analytes were extracted from the homogenizated sample using methonolic,cleaned-up with mixture of four sorbents Florisil,graphitized carbon black(GCB),primary secondary amine(PSA) and C 18.GA 3 and NAA were separated on HSS C 18 column(100 mm×2.0 mm,1.8μm)and determined on UPLC-MS / MS by negative-electrospray ionization(ESI-) using multiple reaction monitoring(MRM).Quantification was done by the external standard curves.The linear range of GA 3 and NAA was 0.05-5.0mg / kg and 0.10-5.0mg / kg respectively,the correlation coefficient(r) of both plant hormone standard curve was more than or equal to 0.9990,the limit of quantification of GA 3 was 0.05mg / kg and that of NAA was 0.10mg / kg.The recoveries of three levels spiked with 0.1,0.5and 1.0mg / kg were 85.0%-86.8%for GA3and 82.9%-84.4%for NAA,the relative standard deviations of both plant hormones were less than or equal to 4.5%.The method is simple,accurate and sensitive for the simultaneous determination of GA 3 and NAA residual in tea.