Development of a method for the determination of 9 currently used cotton pesticides by gas chromatography with electron capture detection.
A reliable, sensitive, and reproducible method was developed for quantitative determination of nine new generation pesticides currently used in cotton agriculture. Injector temperature significantly affected analyte response as indicated by electron capture detector (ECD) chromatograms. A majority of the analytes had an enhanced response at injector temperatures between 240 and 260 degrees C, especially analytes such as acephate that overall had a poor response on the ECD. The method detection limits (MDLs) were 0.13, 0.05, 0.29, 0.35, 0.08, 0.10, 0.32, 0.05, and 0.59 ng/mL for acephate, trifuralin, malathion, thiamethozam, pendimethalin, DEF6, acetamiprid, brifenthrin, and lambda-cyhalothrin. This study provides a precision (0.17-13.1%), accuracy (recoveries=88-107%) and good reproducible method for the analytes of interest. At relatively high concentrations, only lambda-cyhalothrin was unstable at room temperature (20-25 degrees C) and 4 degrees C over 10 days. At relatively low concentrations, acephate and acetamiprid were also unstable regardless of temperature. After 10 days storage at room temperature, 30-40% degradation of lambda-cyhalothrin was observed. It is recommended that acephate, acetamiprid, and lambda-cyhalothrin be stored at -20 degrees C or analyzed immediately after extraction.
Zhang
Baohong
B
Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409-1163, United States. zhangb@ecu.edu
Pan
Xiaoping
X
Venne
Louise
L
Dunnum
Suzy
S
McMurry
Scott T
ST
Cobb
George P
GP
Anderson
Todd A
TA
D002138:Calibration; D002849:Chromatography, Gas; D004583:Electrons; D003368:Gossypium; D010575:Pesticides / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry; D013696:Temperature
D010575:Pesticides; D012997:Solvents