Simultaneous Determination of 1-Methylimidazole, 2-Methylimidazole and 4-Methylimidazole in Sauced Meat Products by Ultra High Performance Liquid Chromatograhpy-Tandem Mass Spectrometry

An ultrahigh performance liquid chromatography-tandem mass spectorometric (HPLC-MS/MS) method was developed for the simultaneous determination of 1-methylimidazole (1-MEI), 2-methylimidazole (2-MEI) and 4-methylimidazole (4-MEI) in sauced meat products. The sample was extracted with water and the extracting solution was cleaned by Waters Oasis MCX SPEcolumn. The eluantwas dried under a stream of nitrogen and dissolved with initial mobile phase, the analytes were then separated by the Agilent Zorbax HILIC (2.1 mm×100 mm, 3.5 μm) using binary mobile phase gradient with acetonitrile and 5 mmol/L ammonium acetate. The compounds were ionized by positive electrospay, then detected under the multiple reaction monitoring (MRM) mode and quantified by the isotope internal standard method. The linearity of 1-MEI, 2-MEI and 4-MEI in the range from 30~400 ng/mL exhibited correlation coefficients greater than 0.9997. The limits of detection (LOD) and quantification (LOQ) were 10, 30 μg/kg. The average recoveries at three level spiked concentrations (30, 60, 300 μg/kg) ranged from 92.0% to 116.3%, with the relative standard deviations (n=6) between 0.70% and 3.96%. The method was applied to detect 36 sauced meat products, the 1-MEI was not detected in sauced meat products;the detection rate of 2-MEI was 5.5%, the content was 21.4~23.6 μg/kg, 4-MEI was detected in all of samples, the content was 3.1~306.6 μg/kg. The method was simple, rapid, sensitive and reliable, could be applied to determine1-MEI, 2-MEI and 4-MEI in sauced meat products.