Urine homogentisic acid and tyrosine: Simultaneous analysis by liquid chromatography tandem mass spectrometry

Hughes, A T, Milan, A M, Christensen, P, Ross, Gordon, Davison, A S, Gallagher, J A, Dutton, J J and Ranganath, L R (2014) Urine homogentisic acid and tyrosine: Simultaneous analysis by liquid chromatography tandem mass spectrometry. Journal of Chromatography B-Analytical Technologies in the Biomedical and Life Sciences, 963. pp. 106-112. ISSN 1570-0232

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Alkaptonuria (AKU) is a rare debilitating autosomal recessive disorder of tyrosine metabolism. Deficiency of homogentisate 1,2-dioxygenase results in increased homogentisic acid (HGA) which although excreted in gram quantities in the urine, is deposited as an ochronotic pigment in connective tissues, especially cartilage. Ochronosis leads to a severe, early-onset form of osteoarthritis, increased renal and prostatic stone formation and hardening of heart vessels. Treatment with the orphan drug, Nitisinone, an inhibitor of the enzyme 4-hydroxyphenylpyruvate dioxygenase has been shown to reduce urinary excretion of HGA, resulting in accumulation of the upstream pre-cursor, tyrosine. Using reverse phase LC-MS/MS, a method has been developed to simultaneously quantify urinary HGA and tyrosine. Using matrix-matched calibration standards, two product ion transitions were identified for each compound and their appropriate isotopically labelled internal standards. Validation was performed across the AKU and post-treatment concentrations expected. Intrabatch accuracy for acidified urine was 96-109% for tyrosine and 94-107% for HGA; interbatch accuracy (n=20 across ten assays) was 95-110% for tyrosine and 91-109% for HGA. Precision, both intra- and interbatch was

Item Type: Article
Additional Information: Copyright © 2014 Elsevier B.V. All rights reserved.
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Pure Connector
Date Deposited: 12 Nov 2014 16:44
Last Modified: 08 Mar 2024 00:49
URI: https://ueaeprints.uea.ac.uk/id/eprint/50893
DOI: 10.1016/j.jchromb.2014.06.002

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