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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.

A comparison between chiral cyclodextrin-modified microemulsion electrokinetic chromatography (CD-MEEKC) and cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) for the enantiomeric separation of esbiothrin was carried out. For both methods, the separation conditions were optimized by varying CD types and concentration, running buffer pH and compositions, organic modifiers, and temperature. The optimal CD-MEEKC conditions were 0.8% n-heptane, 2.3% SDS, 6.6% n-butanol, 90.3% 10 mM sodium tetraborate containing 3% (w/v, the ratio of CD mass to microemulsion volume) methyl-beta-cyclodextrin, pH 10, 25 degrees C. The optimized CD-MEKC conditions were 3.3% SDS, 96.7% 10 mM sodium tetraborate containing 5% (w/v) beta-CD, pH 10, 25 degrees C. The difference in physicochemical properties of the buffer and CDs resulted in different optimal CD type. The competitive distribution between the microemulsion (or micelle) and chiral CD contributed to the chiral separation. Both methods provided excellent separation (R(s) approximately 3) with similar migration time (ca. 15 min). CD-MEEKC provided higher separation efficiencies (>300000) than CD-MEKC (>200000). The LODs for CD-MEEKC and CD-MEKC were 4.7 microg/mL and 3.2 microg/mL, respectively. The RSDs of migration time and peak area for CD-MEEKC were slightly higher than for CD-MEKC. Both the demonstrated CD-MEEKC and CD-MEKC methods provided high efficiencies, low LODs, and reproducible enantioseparations of esbiothrin.