Comparison of dimethylformamide dialkylacetal derivatization reagents for the analysis of heterocyclic amines in meat extracts by gas chromatography–mass spectrometry Original Research Article

A simple and selective methodology for the analysis of heterocyclic amines (HAs) in a meat extract by gas chromatography–mass spectrometry (GC–MS) is proposed. A comparative study of several HAs derivatization procedures based on the formation of Schiff bases using N,N-dimethylformamide dialkylacetals reagents was performed. Optimization of the reaction conditions was carried out, such as reagent volume (2 μl to derivatize 1 ng of HAs) temperature (100 °C) and time (10 min). After that, the GC–MS working parameters for the analysis of HAs derivatives were also studied in order to achieve the best chromatographic separation with the maximum sensitivity. Among the derivatization reagents, N,N-dimethylformamide di-tert-butylacetal (DMF-DtBA) was selected because it provided the best yield in the derivatization process, and consequently the best sensitivity in the GC–MS method. Quality parameters such as limits of detection and repeatability were established using a meat extract sample. A complete validation of the methodology was achieved using a laboratory reference material previously analyzed in a European interlaboratory exercise.