Gas chromatographic methodology for the determination of some halogenated pesticides

A Gas Chromatography (GC) methodology has been validated for the determination of some halogenated pesticides. Complete separation of the pesticide prepared in ethyl acetate was achieved on Rtx - 1 column with dimension, 30m × 0.25mm × 0.25μm. The GC equipped with electron capture detector was run using column temperature programmed from 80°C (2 min) to 200°C (15 min) at the rate of 4°C/min giving a total analysis time of 47 min. The detector and injector were respectively at temperatures of 300 and 225°C. The method was validated with respect to precision in terms of reproducibility of retention times and peak heights, linearity and minimum detectable quantity of the pesticides. Under the operated GC conditions, diuron eluted first while heptachlor epoxide was the last to elute. The chromatographic detector was more sensitive to α-endosulfan and β-endosulfan with Minimum Detectable Quantity (MDQ) of 0.002 ng. The detector was however, less sensitive to captan with MDQ of 0.08 ng. Margins of errors associated with the precision of the method in terms of reproducibility of retention times yielded standard deviation in the range of 0.026-0.063. © Maxwell Scientific Organization, 2010.