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Using Capillary Electrophoresis to Quantify Organic Acids from Plant Tissue: A Test Case Examining Coffea arabica Seeds
Published on: November 12, 2016
Fast high-throughput method for the determination of acidity constants by capillary electrophoresis: I. Monoprotic
Elisabet Fuguet1, Clara Ràfols, Elisabeth Bosch
1Departament de Química Analítica, Universitat de Barcelona, Barcelona, Spain.
Abstract:
A new and fast method to determine acidity constants of monoprotic weak acids and bases by capillary zone electrophoresis based on the use of an internal standard (compound of similar nature and acidity constant as the analyte) has been developed. This method requires only two electrophoretic runs for the determination of an acidity constant: a first one at a pH where both analyte and internal standard are totally ionized, and a second one at another pH where both are partially ionized. Furthermore, the method is not pH dependent, so an accurate measure of the pH of the buffer solutions is not needed. The acidity constants of several phenols and amines have been measured using internal standards of known pK(a), obtaining a mean deviation of 0.05 pH units compared to the literature values.
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