ANáLISE MULTIVARIADA DE IMAGENS NA QUíMICA: UM EXPERIMENTO PARA DETERMINA??O DO pH DE áGUAS POTáVEIS

摘要

A Multivariate Image Analysis (MIA) laboratory activity was proposed estimating pH of drinking water samples from its digital images after adding bromothymol blue as a pH indicator, and using the PLS multivariate calibration method. All computational work was done using GNU Octave free software. The MIA-PLS based approach exemplified with drinking water pH estimates is tailored to meet the needs of both students and researchers. MIA-PLS method was statically equivalent to the reference method using a conventional glass pH electrode. This lab activity combines analytical methodology, computing, and chemometrics.