Please use this identifier to cite or link to this item: http://cmuir.cmu.ac.th/jspui/handle/6653943832/37668
Title: Determination of gallic acid with rhodanine by reverse flow injection analysis using simplex optimization
Authors: Phakthong W.
Liawruangrath B.
Liawruangrath S.
Issue Date: 2014
Publisher: Elsevier
Abstract: A reversed flow injection (rFI) system was designed and constructed for gallic acid determination. Gallic acid was determined based on the formation of chromogen between gallic acid and rhodanine, resulting in a colored product with a λmax at 520 nm. The optimum conditions for determining gallic acid were also investigated. Optimizations of the experimental conditions were carried out based on the so-call univariate method. The conditions obtained were 0.6% (w/v) rhodanine, 70% (v/v) ethanol, 0.9 mol L-1 NaOH, 2.0 mL min-1 flow rate, 75 μL injection loop and 600 cm mixing tubing length, respectively. Comparative optimizations of the experimental conditions were also carried out by multivariate or simplex optimization method. The conditions obtained were 1.2% (w/v) rhodanine, 70% (v/v) ethanol, 1.2 mol L-1 NaOH, flow rate 2.5 mL min-1, 75 μL injection loop and 600 cm mixing tubing length, respectively. It was found that the optimum conditions obtained by the former optimization method were mostly similar to those obtained by the latter method. The linear relationship between peak height and the concentration of gallic acid was obtained over the range of 0.1-35.0 mg L-1 with the detection limit 0.081 mg L-1. The relative standard deviations were found to be in the ranges 0.46-1.96% for 1, 10, 30 mg L-1 of gallic acid (n=11). The method has the advantages of simplicity extremely high selectivity and high precision. The proposed method was successfully applied to the determination of gallic acid in longan samples without interferent effects from other common phenolic compounds that might be present in the longan samples collected in northern Thailand. © 2014 Elsevier B.V. All rights reserved.
URI: http://www.scopus.com/inward/record.url?eid=2-s2.0-84907375408&partnerID=40&md5=21d3a5c0c7db641df0f7f109fc4b9d4c
http://cmuir.cmu.ac.th/handle/6653943832/37668
ISSN: 00399140
Appears in Collections:STRI: Journal Articles

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