Abstract:By determining stable carbon and nitrogen isotope composition of large quantities of real dried shark fins products, the δ13C and δ15N value scopes were obtained. The samples can be identified by the comparison of carbon, nitrogen isotope compositions between real shark fins products and them. The carbon and nitrogen isotope ratios of 24 dried shark fins products were determined by element analyzer- isotope ratio mass spectrometry (EA-IRMS). Obvious difference in carbon and nitrogen isotope ratios was between real dried shark fins products and fake ones. The δ13C and δ15N values of real shark fins products ranged from -16.553‰ to -11.065‰ and 8.803‰ to 19.122‰, respectively, while those of fake shark fins products ranged from -18.122‰ to -16.507‰ and 6.253‰ to 7.313‰. Eleven samples were distinguished as fake shark fins products from all the 24 samples by the comprehensive judgment of the two indicators. This method is fast and convenient, and can be used to evaluate the quality of dried shark fin products. In addition, for those fake dried shark fins products made by leftover material of shark, which cannot be judged by PCR technique, this method can be applied to clearly differentiate real dried shark fins products with them, thus can remedy the defect of PCR method.
