Studies on degradation of imazalil enantiomers in soil using capillary electrophoresis

A scheme was demonstrated to elucidate the degradation behaviors of the two enantiomers of the fungicide imazalil in soil using cyclodextrin-modified capillary zone electrophoresis. The separation buffer was 50 mmol/L NaH2PO4, 5 mmol/L (NH4)H2PO4, and 5 mmol/L beta-cyclodextrin (pH 3.0). The limits of detection of this CE method were 0.24 and 0.26 microg/mL for (-)- and (+)-imazalil, respectively. Five different soil conditions were investigated in laboratory microcosms: under sunlight; in darkness; under UV irradiation; in sterilized soil; and in soil with wheat planted in it. Radiation, microorganisms, and uptake by wheat benefited the degradation of imazalil in this study. The half-lives (t1/2) of imazalil in soil under the above conditions were 20, 30.5, 11, 27.5, and 21.5 days, respectively. The degradation rate of imazalil in soil under the five different sets of conditions decreased in the order: UV irradiation > sunlight > soil with wheat planted in it > sterilized soil > soil kept in darkness. Imazalil in soil (pH 8.2, slightly alkaline) collected in the suburbs showed non-enantioselective degradation.