Simple Determination of 4-Methylimidazole in Soft Drinks by Headspace SPME GC–MS

A simple method to detect 4-methylimidazole in soft drinks is described. This method is based on headspace solid-phase micro-extraction and gas chromatography–mass spectrometry (HS-SPME GC–MS). The HS-SPME parameters (selection of fiber, extraction temperature, heating time, and pH) were optimized and selected. Under the established condition, the detection and the quantification limit were 1.9 and 6.0 μg L −1 using 4 mL of the liquid sample, respectively. The relative standard deviation for five independent determinations at 100.0 and 500.0 μg L −1 was less than 8 %. The calibration curve was y = 0.6027 x –0.0033 with a linearity of r 2 = 0.997. Using the proposed method, the levels of 4-MEI were detected in a range from 94.0 to 324.8 μg L −1 . The comparison of liquid chromatography tandem mass spectrometry (LC–MS/MS) with the proposed method was performed and the agreement with LC–MS/MS for all samples was acceptable.