Validation studies were based on Ribani, Bottoli, Collins, Jardim, and Melo (2004) and guidelines for validation of Brazil's National Institute of Metrology (INMETRO, 2007) and Australia's National Association of Testing Authorities (NATA, 2012). Repeatability in this study refers to multiple measurements of the same sample on the same day (intraday). Initial studies were carried out to investigate a possible matrix effect, thus calibration solutions of the analyte were prepared in two different matrices: a simple solution of ethanol at 13% vol. (simulating a wine matrix) and wine (sample wo4). The effect was assessed by comparing the slopes of both curves (NATA, 2012) as well as by application of F-test (homogeneity of variances) and student's t test (comparison of two means) (INMETRO, 2007)