Determination of heterocyclic amines by capillary electrophoresis with UV-DAD detection using on-line preconcentration

This paper proposed a method with capillary zone electrophoresis (CZE) for analysis of eight heterocyclic amines in a commercial meat matrix. The influence of composition, pH and concentration of buffer, and applied voltage were investigated. A 5 mmol/L formic acid–ammonium formate solution at pH 2.20 was chosen as the running electrolyte. Also several solid-phase extraction actions were performed for the clean-up of the samples. With 3 s hydrodynamic injection, detection limits ranging from 0.554 to 1.783 μg/g was obtained. To improve sensitivity, field-amplified sample injection (FASI) was used with the conditions of 3 s hydrodynamic injection of a water plug and 25 s electrokinetic injection of the sample. And methanol–water (1:1 in volume) was applied as the sample solvent. Under above conditions, detection limits ranged from 1.329 to 19.39 ng/g, which were at least 50 times lower than those with hydrodynamic injection.