Detection of fish frauds (basa catfish and sole fish) via iKnife rapid evaporative ionization mass spectrometry: An in situ and real-time analytical method

Abstract

The fish fillets of basa catfish (Pangasius bocourti) and sole fish (Cynoglossus semilaevis Gunther) have similar appearance but different market values, leading to the possibility of adulteration for economic gains. In this study, a surgical knife, namely iKnife, was coupled to rapid evaporative ionization mass spectrometry (REIMS) to develop a high-throughput technique for in situ and real-time authenticating these two fish species. The iKnife generated informative aerosol, which was further aspired into mass spectrometry to acquire specific fingerprinting profiles. The spectra were multivariate statistical analyzed, and the most contributing ions responsible for the significant difference between the lipidomics profiles of basa catfish and sole fish were screened out. For instance, ions of m/z 281.2470, 279.2319, 699.4970, etc. were abundance in basa catfish, while m/z 301.2164, 327.2341, 764.5284, etc. were significant in sole fish. Subsequently, the validation of the method was carried out in terms of intra-day precision (RSD 5.06%–8.65%) and inter-day precision (RSD ≤9.17%). Finally, this established iKnife-REIMS method was successfully applied to blind samples from markets with an accuracy greater than 98%. The results indicated that the proposed iKnife REIMS method could be used to unambiguously authenticate these two easily adulterated basa catfish and sole fish, and provide the basis and potential for the high-throughput identification of marine resources on the market.