Determination of 4(5)-methylimidazole in foods and beverages by modified QuEChERS extraction and liquid chromatography-tandem mass spectrometry analysis.

The determination of carcinogenic 4(5)-methylimidazole (4-MeI) in complex matrices at trace levels is a challenge because of its higher polarity and weaker column retention capability. Here, we proposed a novel method for the quantification of 4-MeI in various foods and beverages using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The evaluated QuEChERS extraction with LC-MS/MS method showed excellent linearity (1-200 μg/L, with correlation coefficient (R2) > 0.999), trueness (91-113%), and precision (relative standard deviation (RSD) ≤ 12.3%), but low matrix effect (92-108%) for cola, tea, beer, coffee beverage, bread, biscuit and instant coffee. The expanded measurement uncertainty was less than 34.4% at 95% confidence level. The proposed method can be successfully applied to determine 4-MeI in 28 commercial foods and beverages purchased from local market. Therefore, we believe this method is likely to provide a potential for 4-MeI determination in practical application.