This study reports a sweeping and micelle to solvent stacking (MSS) method for fast stacking of nitroimidazoles
in capillary zone electrophoresis (CZE). The optimal experimental conditions are run buffer of
25 mM sodium phosphate (pH 1.5) and 0.50% (v/v) methanol, micellar solution of 30 mM sodium dodecyl
sulfate, applied voltage of 28 kV, and sample and micellar solution injection of 100 s. By applying this
new on-line preconcentration technique, the nitroimidazoles content can be determined within 9 min
with the limit of detection (S/N = 3) ranging 2.3–3.0 ng/mL, which is lower than that of conventional CZE
analysis. The proposed MSS technique affords 20-, 12- and 38-fold improvements in sensitivity for the
detection of dimetridazole, metronidazole and secnidazole, respectively. The relative standard deviations
(RSDs) of intra-day and inter-day are 2.1–3.6% and 2.7–4.6% (n = 6), respectively. The recoveries in
pretreated rabbit plasma at spiked levels of 5.0–10.0 g/mL are 92.0–101.1% with RSDs lower than 3.4%.
The proposed sweeping and MSS-CZE is a highly sensitive method for the detection of nitroimidazoles in
biological and clinical samples and has been successfully applied to analyze nitroimidazoles in pretreated
rabbit plasma.