Rezex roa organic acids ionic exchange column

The sugars and organic acids were determined by high-performance liquid chromatography (HPLC). The samples were diluted 10 times in ultrapure water and filtered through difluoride polyvinylidene membranes (0.45 μm pores, 13 mm diameter) (Millex HV, Millipore). Standard curves were built for the metabolites (glucose, fructose, maltose, maltotriose, citric acid, malic acid, acetic acid, succinic acid, and formic acid) (Sigma-Aldrich), which were diluted in ultrapure water (Direct Q3UV, Millipore, Massachusetts, USA). During the analysis, 5 μL of the sample was used. An UltiMate 3000 (Dionex, Germany) system that was equipped with a UV-Vis detector (at a 210 nm wavelength) for the detection of organic acids and with a refraction index detector for the detection of sugars (Shodex RI-101, Showa Denko, Japan) was used for this analysis. A Rezex ROA Organic Acids ionic exchange column (300 × 7.8 mm) (Phenomenex, Torrance, CA, USA) was used to separate the compounds at a steady temperature of 60°C, and 0.005 M sulfuric acid was used as a mobile phase at a flow rate of 0.6 mL/min. The chromatograms were integrated using Chromeleon Server monitoring software (Dionex). Identification was performed by comparing the retention times, and the quantification was established according to the standard curve for each analyte.

To quantify fermentation compounds by HPLC, samples were diluted 10 times in ultrapure water and filtered through 0.45-μm-pore and 13-mm-diameter polyvinylidene difluoride membranes (Millex HV, Millipore). Standard deviations were determined for metabolites (glucose, fructose, maltose, maltotriose, ethanol, methanol, glycerol, citric, aseptic, lactic, succinic and formic acids) (Sigma-Aldrich) diluted in ultrapure water (Direct Q3UV, Millipore, Massachusetts, USA). An Ultimate 3000 (Dionex, Germany) equipped with a UV-Vis detector (using a wavelength of 210 nm) for detecting organic acids and the refraction index of sugars and alcohols (Sodhex RI-101, Showa Denko, Japan) was used.
To separate compounds, a Rezex ROA Organic Acids ionic exchange column (300 × 7.8 mm; Phenomenex, Torrance, CA, USA) was used at 60°C, with 0.005 M sulfuric acid as the mobile phase with a flow rate of 0.6 mL.min^-1. The chromatograms were integrated using the software Chromeleon Server Monitor (Dionex); identification was performed by comparison of the retention times and quantification according to the standard deviation for each analyte.