Combination of solid-phase extraction with microextraction techniques followed by HPLC for simultaneous determination of 2-methylimidazole and 4-methylimidazole in beverages.

Affiliation

College of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou 510640, China. Electronic address: [Email]

Abstract

A sensitive analytical method for the monitoring 2-methylimidazole and 4-methylimidazole (2-MI and 4-MI) is desirable due to their carcinogenic property. Here, we propose a highly sensitive method basing on the combination of solid-phase extraction and dispersive liquid-liquid microextraction techniques followed by high-performance liquid chromatography to simultaneously determine 2-MI and 4-MI in beverages. Dansyl chloride was used as a derivatizing reagent. Microextraction parameters were optimized by Plackett-Burman design and response surface methodology. Results show that derivatization led to significant improvements in chromatographic behavior for 2-MI and 4-MI due to increased hydrophobicity. The method shows good linearity (R2 ≥ 0.9985), satisfactory precision (%RSD ≤ 8.3%) and low limit of quantification (20 ng/mL), and was successfully applied to determine 2-MI and 4-MI in carbonated drinks, beers and energy drinks, achieving satisfactory recoveries (85-101%). This method provides a potential for routine analysis of 2-MI and 4-MI at the nanogram per milliliter level in beverages.

Keywords

Dansyl chloride,Dispersive liquid-liquid microextraction,Imidazoles high-performance liquid chromatography,

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