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Mohanpur, India

Kanrar B.,Export Testing Laboratory | Mandal S.,Export Testing Laboratory | Bhattacharyya A.,Export Testing Laboratory
Journal of Chromatography A | Year: 2010

A rapid, specific and sensitive multiresidue method to determine 42 pesticides in made tea, tea infusion and spent leaves has been developed and validated for the routine analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was reproducible (Horwitz ratio (HorRat) <0.5 at 50 ng/g) and validated by the analysis of sample spiked at 50 and 100 ng/g in made tea, tea infusion and spent leaves. The samples were extracted with ethyl acetate + cyclohexane (9:1; v/v), and the extracts were cleaned up by dispersive solid phase extraction with primary secondary amine sorbent + graphitized carbon black + Florisil. The recoveries of all the pesticides were between 70% and 120% with a relative standard deviation of less than 15% and correlation coefficient for each pesticide was R2 ≥0.99. The matrix effect on signal of respective compounds was measured by comparing matrix-matched calibration standards with those in solvent-only. The limits of quantitation (LOQ) met the requirements of the maximum residue limits (MRLs) for pesticides in tea as recommended by the European Union. © 2010 Elsevier B.V. All rights reserved. Source


Kanrar B.,Export Testing Laboratory | Mandal S.,Export Testing Laboratory | Bhattacharyya A.,Export Testing Laboratory
Journal of AOAC International | Year: 2010

A rapid, specific, and sensitive multiresidue method to determine 67 pesticides in made tea, tea infusion, and spent leaves was developed and validated for routine analysis by GC/MS with an approximately 29 min GC run time. The method was reproducible (HorRat <0.5 at 50 ng/g) when validated at 50 and 100 ng/g. The samples were extracted with ethyl acetate-cyclohexane (9 + 1, v/v), and the extracts were cleaned up by dispersive SPE with primary-secondary amine sorbent + graphitized carbon black + Florisil. The recoveries of all the pesticides were within 70-120% with an RSD of <20% at 50 ng/g and R2 > 0.99. The matrix effect on the signals of the compounds was corrected by using matrix-matched calibration standards. The LOQ met the requirements of the maximum residue limits for pesticides in tea as recommended by the European Union. Source

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