Application of the 6-aminoquinolyl-N-hydroxysccinimidyl carbamate (AQC) reagent to the RP-HPLC determination of amino acids in infant foods

The validation of a pre-column derivatization procedure with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) to the determination of the amino acid content by RP-HPLC with fluorescence detection (λ excitation 250 nm, λ emission 395 nm) in milk-cereal based infant foods was carried out. The analytical parameters: linearity (0.0025–0.2 mM), precision of the method (0.2–3.5% variation coefficients), accuracy (derivatization: 86–106% average recovery and method: 88.3–118.2% average recovery) and the limits of detection (0.016–0.367 μM) and quantification (0.044–1.073 μM) were determined. Glutamic acid, proline and leucine were the most abundant amino acid whereas the lowest contents corresponded to tyrosine and cysteine.