Determination of organic acids by capillary electrophoresis with simultaneous addition of Ca and Mg as complexing agents

Abstract

SummaryA capillary electrophoretic method, with divalent cations as complexing agents in the electrolyte, has been developed for separation and determination of the low molecular weight organic acids most commonly found in wine, viz. formic, fumaric, succinic, oxalic, mahc, tartaric, acetic, lactic, and citric acids. The separation conditions optimized were electrolyte concentration, organic flow modifier concentration, type and concentration of complexing agents in the electrolyte, and injection time. The best resolution of some of the acids studied was achieved by use of an electrolyte containing tetraborate buffer (10 mM) at pH 9.3, an organic flow modifier (tetradecyltrimethylammonium hydroxide), and Ca 2+ (10 ppm) and Mg 2+ (10 ppm) as complexing agents. Other conditions used in the method were hydrostatic injection (10 cm height for 30 s), detection at 185 nm, and temperature 20 ~ For all the acids studied detector response was linear for the concentration ranges considered. The repeatability of each point on the calibration plot for standards (n = 4)was generally better than 1%. The method was applied to samples of must, wine, brandy, and vinegar from the Jerez region.

Use of Alternative Wood for the Ageing of Brandy de Jerez

“…No direct relationship is observed either for this acid between its concentration and the toasting level of the wood. These levels of lactic acid are much higher than those found by Moreno et al [57] in brandy samples of the three commercial categories (Solera, Solera Reserva, and Solera Gran Reserva), although they are similar to those found by other authors in Brandy de Jerez samples [25,37], being the lowest ones more typical of Solera brandies and the highest ones, of Solera Gran Reserva brandies [37].…”

“…Its detection and quantification in the samples of aged distillates of our study are due to the previous seasoning process of the barrels which have been used for our study. There are several studies proving the presence of non-volatile organic acids (tartaric, malic, succinic...) in Brandy de Jerez [25,31,37,56,57], due to the use of barrels which had been previously seasoned with Sherry wine, as is the case of the barrels used for this study.…”

A review of the analytical methods to determine organic acids in grape juices and wines

“…3). In some methods, organic modifiers, as methanol (Huang, Luckey, Gordon, & Zare, 1989;Vorarat, Aromdee, & Podokmai, 2002) or complexion agent, as Ca 2+ and/or Mg 2+ salts (García-Moreno, Jurado-Campoy, & García-Barroso, 2001;Mato, Huidobro, Simal-Lozano, & Sancho, submitted;Moreno, Jurado, & Barroso, 2003) were added to electrolyte to alter the relative order of solute migration or selectivity.…”

Rapid method for the determination of organic acids in wine by capillary electrophoresis with indirect UV detection

“…CE methods for organic acids encompass direct detection (Castiñeira, Peña, Herrero, & García-Martín, 2000, 2002García Moreno, Jurado Campoy, & García Barroso, 2001;Mato, Suárez-Luque, & Huidobro, 2007;Moreno, Jurado, & Barroso, 2003;Saavedra & Barbas, 2003) and indirect detection (Arellano, Andrianary, Dedieu, Couderc, & Puig, 1997;Bianchi, Careri, & Corradini, 2005;De Villiers et al, 2003;Esteves, Lima, Lima, & Duarte, 2004;Kandl & Kupina, 1999;Kelly & Nelson, 1993;Kenney, 1991;Klampfl, Katzmayr, & Buchberger, 1998;Levi, Wehr, Talmadge, & Zhu, 1993;Sing Fung & Man Lau, 2003;Stathakis & Cassidy, 1995). Although methods based on low UV-absorbance direct detection are more sensitive, not all commercially available equipments possess detection capability at 200 nm or below.…”