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.