Selective post-column derivatization coupled to cation exchange chromatography for the determination of histamine and its precursor histidine in fish and Oriental sauce samples

Histamine is a biogenic amine that is formed from histidine by action of the enzyme histidine decarboxylase and can be toxic at high intakes. Thus, the quantification of these analytes in foods constitutes a significant axis of food safety. In this study we present the development, validation and application of a new method for the determination of histamine and its precursor histidine in fish products and oriental sauces. The analytes were separated rapidly through a cation exchange column using an acidic mobile phase (7 mmol L-1 nitric acid) and reacted downstream with o-phthalaldehyde in post-column mode in the absence of nucleophilic reagents. The derivatives were detected spectrofluorimetrically at lambda(ex)/lambda(em). - 360/440 nm. Following investigation of the chromatographic and post-column conditions, the method was validated as for its intended applications. The limits of detection were 0.16 and 0.17 mu mol L-1 for histidine and histamine respectively (ca. 0.1 mg kg(-1)) and the precision was better than 5%. Various food samples were successfully analyzed without matrix interferences following minimal pretreatment. The percent recoveries ranged between 91.3 and 117.9%.

Automated summary

A new method for the determination of histamine and its precursor histidine in fish products and oriental sauces was developed, validated, and successfully applied for various food samples without matrix interferences. The method showed good precision and recovery rates, with limits of detection of 0.16 and 0.17 mu mol L-1 for histidine and histamine respectively.