Determination of the Nucleoside Reverse Transcriptase Inhibitors Lamivudine, Stavudine, and Didanosine in Human Urine by Micellar Electrokinetic Chromatography Using the Ionic Liquid-Based Cationic Surfactant 1-Tetradecyl-3-Methylimidazolium Bromide

Micellar electrokinetic chromatography (MEKC) with ultraviolet detection was employed for the simultaneous determination of the nucleoside reverse transcriptase inhibitors lamivudine, stavudine and didanosine with the ionic liquid-based cationic surfactant 1-tetradecyl-3-methylimidazolium bromide ([C14MIm]Br) as the pseudostationary phase. The composition, pH, and concentration of running buffer, surfactant concentration, separation voltage, and injection time were optimized. In comparison with conventional cationic surfactants, improved separation was observed using [C14MIm]Br. The applicability of the method was demonstrated by the analysis of human urine. The method exhibited wide linear ranges with limits of quantitation of 0.5, 0.3, and 1.0 μg/mL for lamivudine, stavudine, and didanosine, respectively. The intra-day and inter-day accuracies were from 91.5% to 114.0%. The precision, expressed as relative standard deviation (RSD), was less than 12.6% for the peak area. The recoveries of the analytes in the samples were between 91.8% and 97.3%. This approach is convenient, rapid, and economical for these analytes in biological samples.