Solid-phase extraction of 4(5)-methylimidazole (4Mel) and 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole(THI) from foods and beverages with subsequent liquid chromatographic-electrospray mass spectrometric quantification

A method for the simultaneous determination of 4(5)-methylimidazole (4MeI) and 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) was developed using SPE and HPLC/MS. Solid-phase extraction using SCX Disc cartridges was used for isolation of the analytes from liquid samples. The lower LOQ was 0.1 ng/mL for 4Mel and 0.2 ng/ml, for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients > 0.999. The CV for the intra- and inter-day precision was < 5% (n = 6); the accuracy was in the range 98-103%. The recovery was 97 and >= 98% for THI and 4MeI respectively. The method was used to determine THI and 4MeI in beverages, coffee, caramel colours and other samples.