Dissipation kinetics and assessment of processing factor for chlorpyrifos and lambda-cyhalothrin in cardamom.

Thomas George, S Naseema Beevi, George Xavier, N Pratheesh Kumar, Jayesh George

Index: Environ. Monit. Assess. 185(6) , 5277-84, (2013)

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Abstract

The dissipation kinetics and method for estimation of residues of chlorpyrifos and lambda-cyhalothrin in cardamom were studied and developed. The limit of detection and limit of quantitation arrived for the compounds were 0.01 and 0.025 μg g(-1), respectively. Gas chromatographic response of chlorpyrifos and lambda-cyhalothrin residues was linear in the range of 0.01-0.50 μg g(-1) and the mean recovery obtained was 97.3 % for chlorpyrifos and 98.9 % for lambda-cyhalothrin with satisfactory relative standard deviation values. The mean initial residues of chlorpyrifos applied at a concentration of 0.05 % in cardamom was 2.5 μg g(-1) and the residue was 8.1 μg g(-1) after processing, with a processing factor of 3.24, while lambda-cyhalothrin when applied at 0.0025 % resulted in initial residues of 1.63 μg g(-1) that magnified to 4.86 μg g(-1) on curing, with a processing factor of 2.98. The half-life of chlorpyrifos was in the range of 5.1-5.24 days while that of lambda-cyhalothrin was in the range of 4.40-4.55 days. The processing factor arrived at in the above experiment lead to the conclusion that the residues of chlorpyrifos got magnified to 3.24-3.68 times and that of lambda-cyhalothrin got magnified to 2.98-3.46 times of initial residues, consequent to loss of weight due to dehydration during curing.