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Simultaneous voltammetric determination of free tryptophan, uric acid, xanthine and hypoxanthine in plasma and urine

SYSNO ASEP	0521718
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Simultaneous voltammetric determination of free tryptophan, uric acid, xanthine and hypoxanthine in plasma and urine
Author(s)	Hasoň, Stanislav (BFU-R)_{RID, ORCID} Ostatná, Veronika (BFU-R)_{RID, ORCID} Fojta, Miroslav (BFU-R)_{RID, ORCID}
Number of authors	3
Article number	135132
Source Title	Electrochimica acta. - : Elsevier - ISSN 0013-4686 Roč. 329, JAN 2020 (2020)
Number of pages	10 s.
Publication form	Online - E
Language	eng - English
Country	GB - United Kingdom
Keywords	boron-doped diamond ; pencil graphite ; amino-acids ; carbon electrodes ; electrochemical oxidation
Subject RIV	CG - Electrochemistry
OECD category	Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
R&D Projects	GA18-18154S GA ČR - Czech Science Foundation (CSF)
Method of publishing	Open access
Institutional support	BFU-R - RVO:68081707
UT WOS	000498391900034
EID SCOPUS	85074152340
DOI	10.1016/j.electacta.2019.135132
Annotation	We have designed an improved electrochemical analysis of clinical samples in bodily fluids. The method allows reliable identification of several coexisting substances (tryptophan, uric acid, xanthine and hypoxanthine) present on different physiological levels. We prepared in situ electrogenerated graphite oxides (GrO) directly on the surface of a graphite pencil electrode. GrO presence enhances electrooxidation signals of small aromatic molecules and can shift their oxidation potentials. The oxidation potentials of tryptophan and tyrosine in their free and protein-bound forms, and free xanthine are very close to each other on common carbon-based materials. We found that free tryptophan's oxidation signal is significantly more enhanced (about 11-times) than the free tyrosine signal (only negligibly in the given conditions). Distinguishing xanthine's oxidation signal from that of the free tryptophan is allowed by their approximately 60 mV separation, sufficient for parallel determination by signal deconvolution. Additionally, we show that proteins containing tyrosine and/or tryptophan behave as electro-inactive and do not interfere with free amino acid determination on the GrO-modified graphite electrodes, while they strongly influence all species' detection on other carbon-based materials. Determining all individual compounds was possible at corresponding physiological values after sole dilution of human plasma (urine) and direct measurement with no pre-separation steps. (C) 2019 Elsevier Ltd. All rights reserved.
Workplace	Institute of Biophysics
Contact	Jana Poláková, polakova@ibp.cz, Tel.: 541 517 244
Year of Publishing	2021
Electronic address	http://apps.webofknowledge.com/InboundService.do?customersID=Alerting&mode=FullRecord&IsProductCode=Yes&product=WOS&Init=Yes&Func=Frame&DestFail=http%3A%2F%2Fwww.webofknowledge.com&action=retrieve&SrcApp=Alerting&SrcAuth=Alerting&SID=F1U16JK9pRLeJ9ufBLv&UT=WOS%3A000498391900034

Number of the records: 1