Separation and determination of 4-methylimidazole, 2-methylimidazole and 5-hydroxymethylfurfural in beverages by amino trap column coupled with pulsed amperometric detection

A method for simultaneous determination of 4-methylimidazole (4-MeI), 2-methylimidazole (2-MeI) and 5-hydroxymethylfurfural (HMF) in beverages was developed using solid-phase extraction (SPE) and amino trap column coupled with pulsed amperometric detection (AMTC-PAD). A single amino trap column (P/N: 046122) was first applied to separate the targeted analytes in samples after SPE pretreatment. This method demonstrated low limit of quantification (0.030 mg/L for methylimidazoles and 0.300 mg/L for HMF) and excellent linearity with correlation of determination (R2 = 0.999 for 2-MeI, 0.997 for 4-MeI and 0.998 for HMF). Nearly no 2-MeI was found in all soft drinks. However, 4-MeI could be detected in cola drinks and soft drinks containing caramel colour (ranging from 0.13 to 0.34 mg/L), whereas HMF were only found in cola drinks (ranging from 1.07 to 4.47 mg/L). Thus, AMTC-PAD technique would be a valid and inexpensive alternative to analysis of 4-MeI, 2-MeI and HMF.