Rapid gas chromatographic screening of residues of nine organochlorine pesticides in chicken fat

ABSTRACT

The official pesticide extraction techniques for complex matrices such as fat and tissues are tedious to perform, multi-step and can result in extracts containing interferences that can complicate the analysis. A new multiresidue technique for the extraction and quantitative gas chromatographic screening of 9 insecticides [lindane, heptachlor, aldrin, heptachlor epoxide, p, p['] DDE, dieldrin, endrin, p, p['] DDD and p, p['] DDT] as residues in chicken fat is presented. The 9 insecticides, plus dibutyl chlorendate internal standard, were fortified into half gram chicken fat and blended with 2 g C 18 [octadecylsilyl derivatized silica reversed phase material]. The C18/fat matrix blend was fashioned into a column by adding the blend to a 10 ml syringe barrel containing 2 g activated florisil. The insecticides were then eluted from the column with 8ml acetonitrile and a portion [2 micro L] of the acetonitrile elute was then directly analyzed by gas chromatography with electron capture detection. Unfortified blank controls were treated similarly. The resultant extracts contained the pesticide analytes [31.25 - 500 ng/g] that were free from interfering compounds when analyzed. Correlation coefficients for the 9 extracted pesticide standard curves [linear regression analysis, n = 5] ranged from 0.9957 + 0.0012 to 0.9999 + 0.0001. Average relative percentage recoveries [83 + 5.8 percent to 98 + 5.2 percent, n = 25 for each insecticide] inter assay [6.1 +3.2 percent to 15.9 + 6.7 percent, n = 25 for each insecticide] and intraassay [1.8 percent to 4.8 percent, n = 5 for each insecticide] variabilities were indicative of an acceptable methodology for the analysis and screening of these residues in chicken fat