A validated UPLC-MS/MS assay for the quantification of amino acids and biogenic amines in rat urine

A UPLC-MS/MS assay, employing a reversed-phase separation, has been applied to the analysis of a number of common amino acids and biogenic amines in rat urine. Analytes were derivatised, using 6‑aminoquinolyl‑N‑hydroxysuccinimidyl carbamate (AccQTag Ultra™). Derivatisation with this reagent, by increasing the hydrophobicity of the analytes, enables better retention by improving reversed-phase chromatographic properties and also improves ionisation efficiency to enhance MS-detection. The method allows for the determination of 38 amino compounds in 7.5 min, including baseline resolution of critical isomers. The assay has been validated for the absolute quantification of 29 amino compounds in rat urine, over a concentration range of 0.6–200 μM, for the purpose of exploratory metabolite phenotyping. Acceptable linearity (R2 > 0.995) and intra- and inter-day accuracy (<20.7%) and precision (