J.M. Gallardo ( ) · C.G. Sotelo · R.I. Perez-Martin Instituto de Investigaciones Marinas de Vigo (CSIC), Eduardo Cabello 6, E-36208 Vigo, Spain Z Lebensm Unters Forsch A (1997) 204: 336 —340  Springer-Verlag 1997 ORIGINAL PAPER Jose ´ M. Gallardo · Carmen G. Sotelo Ricardo I. Perez-Martin Determination of histamine by capillary zone electrophoresis using a low-pH phosphate buffer: application in the analysis of fish and marine products Received: 19 March 1996/Revised version: 22 July 1996 Abstract Histamine levels in samples of fish and mar- ine products were determined by capillary zone elec- trophoresis using phosphate buffer at pH 2.44 and UV detection at 214 nm. A plot of the area of the peaks versus histamine concentration was linear over the range of 1—100 ppm with a correlation coefficient of 0.9996. Calibration using the height of the peak also gave good correlation, with a correlation coefficient of 0.9969, at concentrations between 1 ppm and 20 ppm. The recovery of added histamine in different samples of fish and fish products was, on average, 99.65%. The method described in this work was used for the quanti- tation of histamine in fish and fish products. Key words Histamine · Capillary zone electrophoresis · Seafood products Introduction Tuna fish and other fish species of the Scombridae and Clupeidae families have been commonly found to con- tain high levels of the compound histamine, as a result of inadequate handling and preservation [1— 4]; the intake of this compound has been shown to be asso- ciated with the allergic intoxication known as scom- broid poisoning [2, 5]. Histamine is produced by the microbial degradation of the amino acid histidine due to the action of histidine decarboxylase and, the formation of high levels of his- tamine is well correlated with the number of micro- organisms present in the afore-mentioned fish, [1, 2, 6—8]. Several species of bacteria have been described to contain this enzyme, such as Enterobacteriaceae species, Pseudomonas, Clostridium perfringens and »ibrio spp [1, 3, 7, 9]. The microorganism which has the highest histidine decarboxylase activity is Morga- nella morganii, which is the main organism responsible for the production of high histamine concentrations in marine products [10, 11]. The presence of histamine in fish or fish products is of great significance from the quality point of view, as a spoilage indicator and as a public health hazard. The European Union has established regulations for hista- mine levels, such that they should be below 100 ppm in raw fish, and below 200 ppm in salted fish for species belonging to the Scombridae and Clupeidae families [12]. Different analytical methods have been developed in order to measure histamine levels in fish, such as fluorometric [13—15], gas chromatographic [16, 17] and HPLC [18— 21] methods. Most of the HPLC methods use pre- or post-column derivatization, with fluorescent derivatization agents, such as orthophthalaldehyde (OPA), used most com- monly. The use of these agents enhances both the sensitivity and the selectivity of the method. However, derivatization techniques have some disadvantages: usually they are time consuming, they require control- led reaction conditions, the derivative formed might have stability problems and, in the case of post-column derivatization, an effect of peak broadening and sample dilution might take place [21]. Capillary electrophoresis is a relatively new tech- nique which has a theoretical resolution that is higher than that of other instrumental analysis techniques such as HPLC; this high efficiency is due to its charac- teristic flat flow profile. Presently, the work on capillary electrophoresis is moving from qualitative to quantita- tive determinations. Different food components have been measured using capillary electrophoresis, for example proteins, amino acids and nucleotides, and only recently histamine was determined in extracts of fish prepared with 50% aqueous methanol [22].