Capillary electrochromatography for pesticide analysis: effects of environmental matrices

An insecticide, pirimicarb, and a fungicide, azoxystrobin, were analyzed by capillary electrochromatography. Nine environmental matrices derived from soil, plant and animal extracts were used. After a series of 311 consecutive injections with no washing between injections, retention times increased by ca. 0.5 min. The use of exaggerated application rates for metabolism studies enabled the detection of xenobiotic pesticide degradates by UV absorbance. A 1.2 mm path length, high-sensitivity flow cell gave a gain in sensitivity; however, a further increase in sensitivity of at least two orders of magnitude is required for pesticide residue analysis. Analyte stacking using large volume injections of aqueous samples led to a large increase in retention times.