Pyrethroids residues analysis in Indonesian commercial tea by GC-ECD

Abstract

Monitoring of pesticides residue including pyrethroids is required since they are major contaminants in tea and have been regulated in European Union and countries such as China, Australia, Japan and America. This study aimed to analyze several pyrethroids in Indonesian commercial tea. The analysis was done by applying low volume solid-liquid extraction followed by quantification by gas chromatography-electron capture detector as a relatively cheaper alternative instrument in pesticides monitoring compared to mass spectrophotometer. The detection limits of the method were 0.006 mg/kg for deltamethrin, 0.05 mg/kg for fenvalerate, 0.10 mg/kg for cypermethrin and 0.05 mg/kg for λ-cyhalothrin. The linearity of the method was good with coefficient correlation of higher than 0.997 at 0.3 to 2.0 mg/kg. The repeatability of the method was also good with lower % relative standard deviations compared to two-thirds of Horwitz coefficient of variation and European Commission guideline. The recoveries were all in the range suggested by European Commission. Weak matrix effect was observed for deltamethrin and cypermethrin while matrix suppression effect was observed for λ-cyhalothrin and fenvalerate. Analysis of tea samples planted and produced in Indonesia showed that the pyrethroid residue in the samples were all below the maximum residue limits while the risk assessment suggested that Indonesian commercial tea is safe for consumption.