A new atomic absorption-based method development for indirect determination of histamine in fish samples, dairy products, and alcoholic beverages by flame AAS
A new and sensitive analytical method for the indirect determination of histamine in fish samples, dairy products, and alcoholic beverages by flame atomic absorption spectrometry (FAAS) was developed. The method was based on the complex formation of histamine with Fe(III) and 2′,4′,5′,7′-tetrabromofluorescein (eosin) at pH 4.5, and then extraction into the micellar phase of polyethylene glycol dodecyl ether (Brij 35). In this study, an ultrasonic assisted cloud point extraction (UA-CPE) procedure was used for the separation/pre-concentration of histamine from the related sample matrices. The optimal conditions were established and a good pre-concentration was achieved using 25 μmol L−1 Fe(III), 5 μmol L−1 eosin, 10 mmol L−1 Brij 35, 0.7% (w/v) Na2SO4, pH 4.5 citrate buffer, equilibrium temperature of 45 °C, incubation time of 20 min and ultrasonication at 40 kHz and 300 W. At optimal conditions, a detection limit of 0.25 μg L−1 with a sensitivity improvement of 143-fold in the linear working range of 0.8–170 μg L−1 was obtained. The proposed method was evaluated for the analysis of some food samples and received a good recovery with the standard addition assay. In addition, the validity of the method was tested by intra-day and inter-day precision studies and recovery experiments, obtaining satisfactory results. To the best of our knowledge, this method was also the first study for indirect determination of histamine in the selected samples using UA-CPE coupled to FAAS.