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Molecules 2018, 23(11), 3012;

Determination of Tryptophan and Its Major Metabolites in Fluid from the Anterior Chamber of the Eye in Diabetic Patients with Cataract by Liquid Chromotography Mass Spectrometry (LC-MS/MS)

Department of Analytical Chemistry, Medical University of Lublin, Chodźki 4A, 20-093 Lublin, Poland
Department of Retinal and Vitreal Surgery, Medical University of Lublin, Chmielna 1, 20-079 Lublin, Poland
Department of Pharmacology and Toxicology, National Veterinary Research Institute, 24-100 Pulawy, Poland
Author to whom correspondence should be addressed.
Academic Editor: Makoto Tsunoda
Received: 22 October 2018 / Revised: 12 November 2018 / Accepted: 15 November 2018 / Published: 17 November 2018
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Tryptophan (TRP) is to an essential amino acid and its catabolites are significant to human health. By using ultra-high-performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS), levels of three major components of kynurenic pathway namely tryptophan (TRP), kynurenic acid (KYNA) and kynurenine (KYN) in fluid from the anterior chamber of the eye were determined. The analysis was carried out on a Synergi 4 μ Fusion-RP column using gradient elution mode. For quantitative determination, l-tryptophan-amino-15N, 99 ATOM % 15N was used as an internal standard. The method was linear in the concentration range 4–2000 ng mL−1 for TRP, KYNA and KYN. The mean recoveries measured at four concentration levels for TRP, KYN and KYNA included the following ranges 94.3–96.1; 91.0–95.0; and 96.0–97.6%, respectively. The intra-day precision parameters were smaller than 4.4, 6.4 and 5% respectively. The developed method was applied to study the level of TRP, KYNA and KYN in eye fluid for the retrospective case series which included 28 patients suffering from cataracts and diabetes (n = 8). The experimental data was subjected to statistical analysis. The Mann-Whitney U-test revealed clear differences in the level of TRP catabolites and the ratios of TRP/KYN representing the activities of specific enzyme of kynurenine pathway in examined groups of patients. A level of probability p < 0.05 was used throughout a paper to denote statistically significant differences between the groups. View Full-Text
Keywords: chromatography; tryptophan metabolites; kynurenine pathway; cataracts; diabetes chromatography; tryptophan metabolites; kynurenine pathway; cataracts; diabetes

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Flieger, J.; Święch-Zubilewicz, A.; Śniegocki, T.; Dolar-Szczasny, J.; Pizoń, M. Determination of Tryptophan and Its Major Metabolites in Fluid from the Anterior Chamber of the Eye in Diabetic Patients with Cataract by Liquid Chromotography Mass Spectrometry (LC-MS/MS). Molecules 2018, 23, 3012.

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