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Journal of Analytical Methods in Chemistry
Volume 2015 (2015), Article ID 535387, 7 pages
Research Article

Analysis of Reaction between -Lipoic Acid and 2-Chloro-1-methylquinolinium Tetrafluoroborate Used as a Precolumn Derivatization Technique in Chromatographic Determination of -Lipoic Acid

1Faculty of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland
2Białystok Provincial Sanitary and Epidemiological Station, Department of Food Products, Food-Contact Articles and Nutrition Research, Legionowa 8, 15-099 Bialystok, Poland

Received 29 October 2014; Revised 5 January 2015; Accepted 20 January 2015

Academic Editor: Shao-Nong Chen

Copyright © 2015 Magdalena Godlewska et al. 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.


The present study offers results of analysis concerning the course of reaction between reduced α-lipoic acid (LA) and 2-chloro-1-methylquinolinium tetrafluoroborate (CMQT). In water environments, the reaction between CMQT and hydrophilic thiols proceeds very rapidly and the resultant products are stable. For the described analysis, optimum reaction conditions, such as concentration of the reducing agent, environment pH, and concentration of the reagent were carefully selected. The spectrophotometric assay was carried out measuring absorbance at  nm (i.e., the spectral band of the obtained reaction product). Furthermore, the calibration curve of lipoic acid was registered. It was concluded that the Lambert-Beer law was observed within the range 1–10 μmol L−1. Later, the reaction between LA and CMQT was used as precolumn derivatization in a chromatographic determination of the lipoic acid in the range 2.5–50 μmol L−1. Practical applicability of the designed methods was evaluated by determining lipoic acid in Revitanerv pharmaceutical preparation which contains 300 mg LA in a single capsule. The error of the determination did not exceed 0.5% in relation to the declared value.