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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