On-line electrodialytic matrix isolation for chromatographic determination of organic acids in wine

Abstract

Chromatographic determination of organic acids is widely performed, but the matrix often calls for lengthy and elaborate sample preparation prior to actual analysis. Matrix components, e.g., proteins, non-ionics, lipids etc. are typically removed by a combination of centrifugation/filtration and solid phase extraction (SPE) that may include the use of ion-exchange media. Here we report the quantitative electrodialytic transfer of organic acids from complex samples to ultrapure water in seconds using cellulose membranes modified with N,N-dimethylaminoethyl methacrylate, which essentially eliminates the negative ζ-potential of a regenerated cellulose membrane surface. The transfer characteristics of the ion transfer device (ITD) were evaluated with linear carboxylic acids. While the ion transfer efficiencies may be affected by the acid dissociation constants, in most cases it is possible to achieve quantitative transfer under optimized device residence time (solution flow rate) and the applied voltage. In addition, the transfer efficiency was unaffected by the wide natural variation of pH represented in real samples. The approach was applied to organic acids in various samples, including red wine, considered to represent an especially difficult matrix. While quantitative transfer of the organic acids (as judged by agreement with standard pretreatment procedures involving SPE) was achieved, transfer of other matrix components was <5%. The processed samples could then be chromatographically analyzed in a straightforward manner. We used ion exclusion chromatography with direct UV detection; in treated samples; there was a dramatic reduction of the large early peaks observed compared to only 0.45μm membrane filtered samples.

Organic Acids and Polyphenols Determination in Polish Wines by Ultrasound-Assisted Solvent Extraction of Porous Membrane-Packed Liquid Samples

“…If the results are compared with wines of different countries [2,39,40,41,42,43], one can observe high variances both for organic acids and for polyphenols. If the different grapes are grown in the countries characterized by different weather conditions, soil characteristics, and also viticultural practices, and the modifications in winemaking procedures are considered, these may be expected results.…”

Effect of Issatchenkia terricola WJL-G4 on Deacidification Characteristics and Antioxidant Activities of Red Raspberry Wine Processing

“…The non-Saccharomyce yeast Pichia fermentans JT-1-3 was reported to have the ability to degrade citric acid from 12.3 to 11.0 g/L in kiwifruit wine, and to degrade citric acid by 43.35% in blueberry wine [20,36]. The reduction of organic acids may reduce the formation of "fermentation bouquet", leading to a better wine taste, quality and purchase desire [37]. Values were given as the means ± standard deviation (n = 3), and the different letters within each row were significantly different (p < 0.05).…”

Matrix isolation with an ion transfer device for interference-free simultaneous spectrophotometric determinations of hexavalent and trivalent chromium in a flow-based system

“…While cationic and anionic species are quantitatively transferred to oppositely placed individual acceptor streams by the applied electric field, non-ionic compounds, low mobility species like proteins, and particulate matter are not transferred and are wasted together with the depleted sample. Electrodialytic matrix isolation was demonstrated to be of utility in the determination of anionic species like carboxylic acids [22] and cationic species like heavy metal ions [23] in real samples. Furthermore, the electrodialytic matrix isolation was successfully applied for Cr speciation analysis [24] with sub-g L -1 limits of detection by inductively coupled plasma-mass spectrometry (ICP-MS).…”