Stability studies of carbamate pesticides and analysis by gas chromatography with flame ionization and nitrogen-phosphorus detection.
As a result of thermal stability studies of carbamate pesticides, a method has been proposed for their direct determination by gas chromatography in the ranges 1-20 and 0.1-1 mg l(-1), using flame ionization and nitrogen-phosphorus detection, respectively. The method allows the determination of propham, propoxur, carbofuran, carbaryl, methiocarb, isopropoxyphenol and naphthol in powdered potato samples. The analytes were previously extracted with a light petroleum-dichloromethane (1:1, v/v) mixture and preconcentred by solid-phase extraction through a C8 cartridge. The recoveries obtained from spiked potato samples (n=4 replicates) at two concentration levels, 10 and 0.5 mg of pesticide per kg of sample, were in the ranges 72-115 and 50-73%, with relative standard deviations of 2-7 and 5-8%, respectively. The detection limits were 50-210 and 41-53 microg kg(-1) with flame ionization and nitrogen-phosphorus detection, respectively, and reaching the maximum residue levels, 0.05 mg kg(-1) for methiocarb and propoxur, set by the Real Decreto 280/1994 (based on the European directive).
Santos Delgado
M J
MJ
Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, Madrid, Spain.
Rubio Barroso
S
S
Fernández-Tostado
G T
GT
Polo-Díez
L M
LM
D002138:Calibration; D002219:Carbamates; D002849:Chromatography, Gas / Q000379:methods*; D007306:Insecticides / Q000032:analysis*; D009584:Nitrogen; D010758:Phosphorus; D012680:Sensitivity and Specificity
D002219:Carbamates; D007306:Insecticides; D010758:Phosphorus; D009584:Nitrogen