Development and validation of a quantitative method for discriminating Korean and Japanese red seabream (Pagrus...

In this study, a robust and validated UHPLC-QqQ-MS/MS method was developed to quantify anserine and carnosine levels and their ratios to distinguish the geographical origin of red seabream (Pagrus major) from Japan and Korea. Comprehensive optimization of column types, mobile phase pH, organic solvent ratios, and internal standards identified the optimal conditions: an HILIC column at pH 5 with 75 % acetonitrile and PEH as the internal standard. The method exhibited excellent sensitivity, linearity, accuracy, and precision, establishing anserine as the most reliable biomarker for origin discrimination. Statistical analysis revealed significantly higher anserine concentrations in Japanese red seabream across all seasons (p < 0.0001), with a threshold of 227 mg/100 g. In contrast, carnosine levels and the anserine/carnosine ratio showed limited discriminatory power. This analytical technique offers a robust solution to address seafood mislabeling and has the potential for broader application in verifying the origin of marine species.