Acrylamide-modified graphene for online micro-solid-phase extraction coupled to high-performance liquid chromatography for sensitive analysis of heterocyclic amines in food samples.

Heterocyclic amines (HAs) are considered as potential mutagens and carcinogens, and are found in trace quantities (ng/g level) in food samples. Therefore, it is important to develop a selective and effective method to determine trace HAs in complex matrices. In this study, acrylamide-modified graphene (AMG) was successfully synthesised and showed good stability and permeability in aqueous and organic phases. AMG was used as an efficient adsorbent in the online micro-solid-phase extraction (μ-SPE) of trace HAs. The enrichment factors of the AMG μ-SPE column were determined as 78-166 for six HAs. An online method based on AMG μ-SPE coupled to high-performance liquid chromatography was developed. The limits of detection ranged from 0.70 to 2.5 ng/L. Trace HAs in spicy salted duck, baked fish, and fried chicken samples were determined and the concentrations of 2-amino-3-methylimidazo[4,5-f]quinoine, 2-amino-3,4-dimethylimidazo[4,5-f]quinoine, and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in these samples were 4.7-37.3, 8.1-15.4, and 43.3-109 ng/g, respectively. The recoveries for the six HAs ranged from 65.9% to 118%, and the relative standard deviation (RSDs) were less than 10.8%. The proposed online method was sensitive, reliable, and convenient for the analysis of trace HAs in food samples.