HPLC Determination of 2-Methylimidazole and 4-Methylimidazole in Imidazole

HPLC was applied to the determination of 2-methylimidazole and 4-methylimidazole in imidazole. XDB C18 chromatographic column was used as stationary phase, and a mixture of 0.05 mol·L-1 KH2PO4 buffer solution (pH 3.5) and methanol (95+5) was used as mobile phase. Flow-rate of the mobile phase was set at 1.0 mL·min-1, and diode array detection at 210 nm was adopted in the determination. Linear relationships between values of peak area and mass concentration of 2-methylimidazole and 4-methylimidazole were kept in the same range of 0.10-25.0 mg·L-1, with detection limits (3S/N) of 20 and 40 mg·kg-1 respectively. Tests for recovery were made at the concentration levels of 1.00,5.00, 20.0 mg·L-1 of the standard, giving values of recovery and RSD′s (n=7) in the ranges of 89.0%-103% and 0.58%-3.0% respectively.