Determination of Multiresidue Pesticides in Botanical Dietary Supplements Using Gas Chromatography Triple Quadrupole Mass Spectrometry (GC MS/MS)
A simplified sample preparation method in combination with gas chromatography triple quadrupole mass spectrometry (GC MS/MS) analysis was developed and validated for the simultaneous determination of 227 pesticides in green tea, ginseng, gingko leaves, saw palmetto, spearmint, and black pepper samples. The botanical samples were hydrated with water and extracted with acetonitrile, magnesium sulfate, and sodium chloride. The acetonitrile extract was cleaned up using solid phase extraction with carbon coated alumina/primary secondary amine with or without C18. Recovery studies using matrix blanks fortified with pesticides at concentrations of 10, 25, 100, and 500 mg/kg resulted in average recoveries of 70 99% and relative standard deviation of 5 13% for all tested botanicals except for black pepper, for which lower recoveries of fortified pesticides were observed. Matrix matched standard calibration curves revealed good linearity (r(2) 0.99) across a wide concentration range (1 1000 mg/L) Nine commercially available tea and 23 ginseng samples were analyzed using this method. Results revealed 36 pesticides were detected in the 9 tea samples at concentrations of 2 3500 mg/kg and 61 pesticides were detected in the 23 ginseng samples at concentrations of 1 12500 mg/kg.
Journal of agricultural and food chemistry