Development of a fast and selective separation method to determine histamine in tuna fish samples using capillary zone electrophoresis

This paper reports on the development of a fast and selective separation method by capillary zone electrophoresis (CZE) for the determination of histamine in tuna fish samples. The background electrolyte was composed of 60 mmol L−1 hydroxyisobutyric acid and 10 mmol L−1 sodium hydroxide at pH 3.3. The internal standard used was imidazole. Separations were performed in a fused uncoated silica capillary (32 cm total length, 8.5 cm effective length and 50 μm internal diameter) with direct UV detection at 210 nm. The samples and standards were injected hydrodynamically (50 mbar, 3 s) from the outlet capillary end (nearest to the detector) and the electrophoretic system was operated under normal polarity and constant voltage conditions of 30 kV (positive polarity on the injection side). The migration time of histamine in the proposed method was only 0.34 min. The method was then validated and different tuna fish samples were analyzed. Good linearity (R2>0.999), a limit of detection 0.14 mg L−1, intra-day precision better than 3.5% (peak area of sample), and recovery in the range of 94–108% were obtained. The results of the histamine concentration determined in the samples by the CZE method were compared with the LC–MS/MS method.