Single-Step Hydrolysis and Derivatization of Homocysteine Thiolactone Using Zone Fluidics: Simultaneous Analysis of Mixtures with Homocysteine Following Separation by Fluorosurfactant-Modified Gold Nanoparticles |
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Authors: | Apostolia Tsiasioti Constantinos K. Zacharis Paraskevas D. Tzanavaras |
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Affiliation: | 1.Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;2.Laboratory of Pharmaceutical Analysis, Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; |
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Abstract: | Herein, we report a new automated flow method based on zone fluidics for the simultaneous determination of homocysteine and homocysteine thiolactone using fluorimetric detection (λext = 370 nm/λem = 480 nm). Homocysteine thiolactone is hydrolyzed on-line in alkaline medium (1 mol L−1 NaOH) to yield homocysteine, followed by reaction with o-phthalaldehyde in a single step. Derivatization is rapid without the need of elevated temperatures and stopped-flow steps, while specificity is achieved through a unique reaction mechanism in the absence of nucleophilic compounds. Mixtures of the analytes can be analyzed quantitatively after specific separation with fluorosurfactant-capped gold nanoparticles that are selectively aggregated by homocysteine, leaving the thiolactone analogue in solution. As low as 100 nmol L−1 of the analyte(s) can be quantified in aqueous solutions, while concentrations > 2 μmol L−1 can be analyzed in artificial and real urine matrix following 20-fold dilution. The percent recoveries ranged between 87 and 119%. |
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Keywords: | homocysteine thiolactone homocysteine zone fluidics o-phthalaldehyde fluorosurfactant-modified gold nanoparticles |
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