Determination of Heterocyclic Amines in Meat Matrices Using Enhanced Matrix Removal-Lipid Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

A simple, fast, and efficient method, "enhanced matrix removal of lipids" (EMR-lipid), was proposed, optimized, and validated for identifying five polar heterocyclic amines (HCAs) in meat samples that ranged from high-protein (beef and chicken) to high-fat (pork bacon) matrices. The protocol involves an initial solid-liquid phase extraction followed by a rapid dispersive solid-phase extraction using EMR-lipid sorbents and salting-out partitioning. Acetonitrile containing formic acid at two levels (1% and 2%) efficiently extracted HCAs from different meat matrices. Liquid chromatography-tandem mass spectrometry (MS/MS) with selective reaction monitoring mode was developed for qualitative and quantitative analysis. The highest MS/MS responses and better peak separation of analytes were achieved by adjusting mobile phases to pH 3.0 with instrumental detection limits between 0.01 and 0.05 ng/mL. Good linearity of standard curves was obtained in both pure solvents and postspiked meat extracts between 0.5 and 50.0 ng/mL. The validation results showed good precision, accuracy, and sensitivity for detecting HCAs in spiked meat samples. Satisfactory recoveries of four HCAs were achieved: 65% to 111% in beef, 71% to 106% in bacon, and 42% to 77% in chicken. Matrix effects were also assessed and showed less than -20% of ion suppression in bacon extract, while a medium to high signal suppression was observed in beef (-37% to -55%) and chicken (-28% to -52%). This optimized EMR-lipid method provides acceptable results and advantages for determining trace level HCAs in complex meat matrices.