基于稳定同位素比值鉴别鱼翅干制品的品质

Identification of the Quality of Dried Shark Fins Products Based on Stable Isotope Ratio

建立了基于元素分析-同位素比值质谱联用技术(EA-IRMS)分析鉴别鱼翅干制品品质的方法。在测定真鱼翅干制品的稳定碳、氮同位素组成的基础上,获得了真鱼翅干制品的δ13C值、δ15N值区间,通过对比待测样品与真鱼翅样品之间的差异,进而对待测样品进行真假鉴别。利用本方法共测定了24份鱼翅样品的碳氮同位素比值,结果发现:真鱼翅和假鱼翅的碳氮同位素比值有着显著差别,真鱼翅样品的δ13C和δ15N值分别分布在-16.553‰^-11.065‰和8.803‰~19.122‰之间;而假鱼翅样品的δ13C和δ15N值范围分别为-18.122‰^-16.507‰和6.253‰~7.313‰。通过碳氮同位素比值这两个指标的综合判定,得到24个鱼翅样品中有11个假鱼翅样品。该方法可简便、快速地鉴别鱼翅干制品的品质,同时可弥补PCR检测技术无法判断用鲨鱼下角料压模而成的鱼翅干制品的局限性。

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.