Imidazole dipeptides (IDPs) are found in the skeletal muscles and brains of various animals, and they exhibit unique functions like antioxidant and antiaging properties. Despite their importance, the metabolic mechanisms and physiological roles of IDPs remain unclear. Herein, we propose a method for the simultaneous analysis of IDPs, their constituent amino acids, and taurine, which are difficult to separate using conventional labeling reagents or columns, using liquid chromatography-single quadrupole mass spectrometry with PBr column and our highly sensitive labeling reagent, 1-fluoro-2,4-dinitrophenyl-5-l-valine-N,N-dimethylethylenediamineamide (l-FDVDA). This method successfully separated histidine and carnosine enantiomers as well as l-2-oxocarnosine with high antioxidant activity under the same conditions. Our labeling reagent was more stable than the other reagents and did not degrade and desorb from the analytes for at least 1 week at 4 °C. Furthermore, our method allows for the accurate analysis of IDPs, amino acids, and taurine in meats from various animal species, tissues, and breeds.
Keywords: amino acids; animals; imidazole dipeptides; liquid chromatography−mass spectrometry; meats; reversed phase-liquid chromatography.