Main Organic Acids in Rice Wine and Beer Determined by Capillary Electrophoresis with Indirect UV Detection Using 2, 4-Dihydroxybenzoic Acid as Chromophore

Chip-based separation of organic and inorganic anions and multivariate analysis of wines according to grape varieties

This report describes the use of electrophoresis microchips integrated with contactless conductivity detection for the determination of organic acids and inorganic anions in wine samples and the subsequent classification based on the grape varieties. The best separation was achieved using a buffer composed of 30 mmol L^-1 2-(N-morpholino)ethanesulfonic acid, 15 mmol L^-1l-histidine and 0.05 mmol L^-1 cetyltrimethylammonium bromide (pH 5.8), allowing the determination of chloride, nitrate, sulfate, oxalate, tartrate, maleate, succinate, citrate, acetate, lactate, pyroglutamate and phosphate within ca. 100 s. The relative standard deviations obtained for the migration times were lower than 2%, while the obtained values for peak areas ranged from 2.5 to 8.4%. The limits of detection achieved for all compounds ranged between 3.0 and 12.6 μmol L^-1. A total of 18 wines from Brazil and Chile were successfully investigated, including red, white and rosé, and the anionic species were quantified with recovery values between 92 and 117%. A statistical difference has not been observed between the data obtained by using electrophoresis microchips integrated with contactless conductivity detection (ME-C⁴D) and capillary electrophoresis with ultra-violet detection (CE-UV) and thus the results from newly developed method is validated. Finally, similarities among the anionic profile of wines were investigated by using a multivariate approach, and it was possible to discriminate samples mainly by grapes varieties. Furthermore, the proposed methodology has provided instrumental simplicity and good analytical performance, demonstrating to be useful for routine quality control of wines.

Application of Capillary Electrophoresis to the Analysis of Bioactive Compounds in Herbal Raw Materials

The article is a summary of scientific reports from the last 16 years (2005-2021) on the use of capillary electrophoresis to analyze polyphenolic compounds, coumarins, amino acids, and alkaloids in teas or different parts of plants used to prepare aqueous infusions, commonly known as "tea" or decoctions. This literature review is based on PRISMA guidelines and articles selected in base of criteria carried out using PICOS (Population, Intervention, Comparison, Outcome, Study type). The analysis showed that over 60% of articles included in this manuscript comes from China. The literature review shows that for the selective electrophoretic separation of polyphenolic and flavonoid compounds, the most frequently used capillary electromigration technique is capillary electrophoresis with ultraviolet detection. Nevertheless, the use of capillary electrophoresis-mass spectrometry allows for the sensitive determination of analytes with a lower limit of detection and gives hope for routine use in the analysis of functional foods. Moreover, using the modifications in electrochemical techniques allows methods sensitivity reduction along with the reduction of analysis time.

Fast determination of lactic, succinic, malic, tartaric, shikimic, and citric acids in red Vranec wines by CZE-ESI-QTOF-MS

A fast and simple method with CZE coupled to ESI/QTOF-MS was optimized and validated for quantitative determination of organic acids (lactic acid, succinic acid, malic acid, tartaric acid, shikimic acid, and citric acid) in red wines. The BGE was ammonium acetate and the separation of the analytes was performed in a polybrene-coated capillary in the presence of EOF. The sample preparation included dilution and filtration of the wine. The method showed satisfactory performance characteristics: good linearity for each organic acid, with correlation coefficients ranging from r²  = 0.9902 (shikimic acid) to r²  = 0.9990 (tartaric acid). The limit of quantification was between 0.0034 mM (for shikimic acid) and 0.107 mM (for citric acid), and the recovery data fell between 95.8% (malic acid) and 102.7% (lactic acid); the total run time was less than 4 min. The RSD values for the interday repeatability and intraday reproducibility were between 3.44 and 9.50%, and between 1.75 and 8.29%, respectively. Seventeen Macedonian red Vranec wines were studied demonstrating a wide variation in the organic acids' concentration, which should be most probably due to the variation of the climate conditions in the vine areas.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

This review work presents and discusses the main applications of capillary electromigration methods in food analysis and Foodomics. Papers that were published during the period February 2015-February 2017 are included following the previous review by Acunha et al. (Electrophoresis 2016, 37, 111-141). The paper shows the large variety of food related molecules that have been analyzed by CE including amino acids, biogenic amines, carbohydrates, chiral compounds, contaminants, DNAs, food additives, heterocyclic amines, lipids, peptides, pesticides, phenols, pigments, polyphenols, proteins, residues, toxins, vitamins, small organic and inorganic compounds, as well as other minor compounds. This work describes the last results on food quality and safety, nutritional value, storage, bioactivity, as well as uses of CE for monitoring food interactions and food processing including recent microchips developments and new applications of CE in Foodomics.