[Simultaneous determination of dichlorvos and trichlorfon in agricultural products by GC-FPD].
We studied a gas chromatographic method for the determination of dichlorvos (DDVP) and trichlorfon (DEP) in agricultural products. DDVP and DEP were extracted from agricultural products with acetone and re-extracted with ethyl acetate instead of dichloromethane. DDVP and DEP were eluted in one fraction on a silica gel column using n-hexane-acetone (1:1). DEP is a thermally labile compound, so it was derived to a more thermally stable compound by acylation with N-methylbis(trifluoroacetamide) and pyridine in acetone at 60 degrees C for 2 hours. DDVP and the DEP-TFA derivative were determined simultaneously by GC-FPD. The recoveries of DDVP and DEP from agricultural products spiked at levels of 0.1 microgram/g were 72.6-117.7% and 86.2-106.6%, respectively. The detection limits were 0.03 microgram/g in powdered tea and < or = 0.01 microgram/g in other samples. An interlaboratory study by 6 laboratories was conducted to validate this proposed method for 6 crops. Repeatability ranged from 3.1 to 7.8% for DDVP and from 3.4 to 8.3% for DEP, and reproducibility, from 6.9 to 15.5% for DDVP, and from 7.9 to 21.8% for DEP. Precision values were well within statistically predicted levels.
Yamada
Nobuyuki
N
Sendai City Institute of Public Health: 2-5-10, Oroshi-machi-higashi, Wakabayashi-ku, Sendai-shi 984-0002, Japan.
Takahata
Jutaro
J
Sasaki
Kumiko
K
Toyoda
Masatake
M
Nakamura
Ryuji
R
Yoshida
Kikuyoshi
K
D002849:Chromatography, Gas; D018556:Crops, Agricultural / Q000737:chemistry*; D004006:Dichlorvos / Q000032:analysis*; D015203:Reproducibility of Results; D014236:Trichlorfon / Q000032:analysis*
D004006:Dichlorvos; D014236:Trichlorfon