International Journal of Pure and Applied Chemistry (IJPAC)

 

11. Effect of washing on pesticide residue in vegetables analysed by GC-ECD
 


Subhash Chandra *1, Anil N. Mahindrakar*2† D. M. Jadhav*3† , L.P. Shinde*4
 


*1Custom House Laboratory, Vasco-Da-Gama - 403 803, Goa, India,
*2† New Custom House Laboratory, Ballard Estate, Mumbai - 400 001, Maharashtra, India,
*3&4 N.E.S. Science College, Nanded - 431 605, Maharashtra, India.

Abstract: In this study the effect of washing on residue of chlorpyriphos and monocrotophos in capsicum and cauliflower was determined. The washing processes were carried out with normal and hot water with different span of time. The vegetables samples were washed with normal water, hot water and analysed by gas chromatography electron capture detection. The highest chlorpyriphos residue was found at raw stage in cauliflower (0.160 mg/kg) followed by capsicum (0.116mg/kg), and residue of monocrotophos was recorded in cauliflower (0.260mg/kg) and in capsicum (0.178mg/kg). The chlorpyriphos residue reduced in capsicum and cauliflower from 26 to 42% after normal water washing, and 36-74% reduced with hot water washing. Whereas monocrotophos residue was reduced in capsicum and cauliflower 23 to 39% after normal water washing and 35-72% reduced after hot water washing. The vegetable samples collected from the local market contained detectable residues representing approximate 80% rate of contamination. There were some of the vegetables samples contained chlorpyriphos and monocrotophos residues above maximum residue limits (MRLs). However, washing of vegetable reduced some extent of the pesticide residues. The samples were extracted with 1% acetic acid in acetonitrile mixture and cleaned up with primary secondary amine (PSA) and magnesium sulphate. Experiments on two fortification concentrations are carried out, and the limits of detection are 0.004, and 0.003 mg/kg for chlorpyriphos, monocrotophos respectively. The average recoveries of pesticide residues in cauliflower and okra samples are 90.0 to 105.0 %.

 

Keywords: Monocrotophos, Chlorpyriphos, GC-ECD. Capsicum, Cauliflower. 

 

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