UPLC-QTOF (ESI +) MS Analysis Applied for Targeted Profiling of Human Urine Amino Acids

摘要

Amino acids, the building blocks of proteins are providing fundamental information about metabolic status and early disease diagnosis. For an accurate interpretation of metabolic status, amino acid reference values for healthy humans are required. Most studies have pointed out that, the most accurate, reliable and sensitive tool to evaluate amino acids in biofluids ( blood or urine) is liquid chromatography coupled with mass spetrometry (LC/MS). The aim of this study was to determine and optimize the urine amino acids profile by LC-QTOF (ESI+) MS, comparatively, using two generic samples from a healthy male and female. Urine aminoacids were purified using solid phase extraction, a pre-column derivatization and liquid/liquid extraction according to Ez-Faast kit (Phenomenex). The derivatized samples were analyzed by LC-QTOF-(ESI+)-MS and data were processed by Data Analysis-Extracted Ion Chromatogram software. A number of 16 amino acids were found in both samples, the male urine showed higher values for 10 amino acids (hydroxyproline, alanine, sarcosine, lysine, histidine, tryptophan, leucine, phenylalanine, cysteine and tyrosine), while glutamine? and valine were higher in female urine. Most of the amino acids identified were essential amino acids found in both cases like: glutamine, proline, lysine, histidine, valine, tryptophan, leucine and phenylalanine. The main differences between the male vs female aminoacid fingerprints of urine were mainly quantitative and not qualitative. The amino acid concentrations ranged from 1.48 nmol/mg creatinine (proline) to 203.13 nmol/mg (histidine). The concentration of amino acids in man were 2 times? higher than for female, while? the percentages of essential amino acids were similar in both gender.