Real-time monitoring of the pH of white wine and beer with colorimetric sensor arrays (CSAs)

The real-time monitoring of the pH values of alcoholic beverages was performed with a compact wireless device based on a colorimetric detection method with the Hue (H) as the analytical signal working in a pH range of 2.50-6.50. This device represents the first colorimetric pH meter reported in the literature monitoring in realtime the pH value of colored solutions. This pH meter consists of I) a nitrocellulose membrane impregnated with a pH-sensitive gel; II) a CCD camera for color acquisition; III) an electronic board with the calibration profiles of H vs. pH, and IV) a display to read the measured pH. It was applied to the pH determination of a white wine, a prosecco white wine, and a double malt beer leading to the values of pHwine= 3.30, pHprosecco= 3.33, pHbeer = 4.29. The analytical performance is comparable to the glass electrode with an accuracy error <= 0.05 pH units.