Quantitative UPLC-MS/MS analysis of underivatised amino acids in body fluids is a reliable tool for the diagnosis and follow-up of patients with inborn errors of metabolism.
BACKGROUND
An electro-spray ionisation ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) application for the quantitative analysis of amino acids was developed. The suitability for the detection and follow-up of patients suffering from inborn errors of metabolism (IEM) was assessed by extensive cross-validation with ion-exchange liquid chromatography (IEX-LC) with post-column ninhydrin derivatisation, participation in external quality control (ERNDIM) and analysis of samples of patients with confirmed IEM.


METHODS
Prior to analysis plasma and urine samples were merely diluted 150-fold in mobile phase. Amino acids were detected in the multiple reaction monitoring mode (MRM) in the ESI-positive mode. The analytical results were compared with IEX-LC. External quality control scheme performance is presented.


RESULTS
Comprehensive analysis of amino acids in plasma and urine was achieved with a run-to-run time of 30min. Validation results were satisfactory and there was a very good correlation between UPLC-MS/MS and IEX-LC. Analytical results obtained in the external quality control scheme were essentially the same as those of the other participants. Patients suffering from IEM were readily identified.


CONCLUSIONS
UPLC-MS/MS analysis of amino acids in body fluids is rapid, reliable and suitable for the diagnosis and follow-up patients with IEM.
Waterval
W A Huub
WA
Laboratory of Biochemical Genetics, Department of Clinical Genetics, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
Scheijen
Jean L J M
JL
Ortmans-Ploemen
Marjon M J C
MM
Habets-van der Poel
Catharina D
CD
Bierau
Jörgen
J
D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000097:blood* / Q000652:urine*; D053000:Analytic Sample Preparation Methods; D001774:Blood Chemical Analysis / Q000379:methods*; D001826:Body Fluids / Q000737:chemistry*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D016014:Linear Models; D008297:Male; D008661:Metabolism, Inborn Errors / Q000097:blood / Q000175:diagnosis* / Q000652:urine; D008875:Middle Aged; D011786:Quality Control; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry; D016482:Urinalysis / Q000379:methods*
D000596:Amino Acids