An environment-friendly spot test method with digital imaging for the micro-titration of citric fruits.

An environment-friendly spot test method with digital imaging for the micro-titration of citric fruits. Talanta. 2020 Jan 01;206:120219 Authors: de Oliveira LMA, Dos Santos VB, da Silva EKN, Lopes AS, Dantas-Filho HA Abstract A new method to determine the total titratable acidity of orange, lemon and passion fruit, based on a spot test obtained from digital images and using anthocyanins as the biodegradable indicator, is presented for the first time. The colorimetric reactions were carried out by acid-base titration on a microscale, employing anthocyanin with a microplate for spot test purposes, with detection by digital imaging. To obtain highly precise data, a chamber based on a diffuser was developed to control the illumination supplied by the light emitting diodes, and coupled to a smartphone to acquire adequate digital images. High precision was obtained with a relative standard deviation of 0.758% for n = 95. The RGB values were extracted from the digital images and used as analytical signals, the values being correlated with the micro-volume of the titrant and used to construct the titration curves and obtain the first and second derivatives, respectively. For comparative purposes, the official AOAC (Association of Official Analytical Chemists) and MAPA (Ministry of Agriculture, Livestock and Food Supply of Brazil) methods were used and the results compared by applying the paired t-test at the 95% confidence level (n =â€...
Source: Talanta - Category: Chemistry Authors: Tags: Talanta Source Type: research