Comparison of micellar electrokinetic capillary chromatographic method with high-performance liquid chromatographic method for the determination of imidazolidine-2-thione (ethylenethiourea) in formulated products

A micellar electrokinetic capillary chromatographic (MECC) method was developed for routine analysis of the carcinogenic compound imidazolidine-2-thione (ETU) in commercial ethylenebis-(dithiocarbamate) fungicides (EBDC). The MECC method was compared with a previously developed high-performance liquid chromatographic (HPLC) method. Both methods demonstrated good precision, accuracy, linearity, and sensitivity. The relative standard deviations (RSD) for precision ranged from 0.04 to 5.09% for the MECC method and from 0.47-5.22% for the HPLC method. The recoveries for accuracy ranged from 98.3 to 100.6% for the MECC method and from 99.5 to 104.9% for the HPLC method. No matrix interference was observed in either method. The column efficiency of MECC (N = 12491) was 15 times higher than that of HPLC (N = 813). The instrument detection limit (IDL) and the method detection limit (MDL) of the MECC method were 0.25 and 0.30 mu g/mL, which were 25 and 15 times higher than the IDL (0.01 mu g/mL) and the MDL (0.02 mu g/mL) of the HPLC method, respectively. The most important advantages of the MECC method over the HPLC method are the shorter run time and the reduction in solvent waste. The total run times for analyzing a sample were 11 min for the MECC method and 15 min for the HPLC method, and the volume of waste solvent for the MECC method (49.0 mu L/sample) was 153 times less than that for the HPLC method (7.5 mL/sample). This research has proven that the routine ETU analysis in formulated EBDC products by the MECC method is comparable with traditional the HPLC method and the MECC method is better than the HPLC method if the run time and the cost of solvent are considered.