Application of multivariate statistical methods for the control of metals in ethanol production in the sugar industry

Samples coming from the production of alcohol from molasses were analyzed in order to determine the contents of metals (Zn, Cd, Pb, Cu, Ca, Mg, Na and K). The techniques used to carry out these analyses were: anodic stripping voltammetry in the differential-pulse mode DPASV (Zn, Cd, Pb and Cu), atomic emission spectrophotometry EAS (Na and K) and atomic absorption spectrophotometry AAS (Ca and Mg). Once the analysis had been carried out, the results obtained were subjected to a statistical study (Cluster analysis and principal components analysis) aimed at extracting the maximum of information. As a result of this study, it was verified that the contents of metals are independent of the time (whenever the production conditions remain constant), so that it is unnecessary to analyze any intermediate process samples. In this same way, with the knowledge of the contents of certain metals (Cd, Pb and Cu), one has enough information to be able to have a quite precise idea of the content of all the other studied metals.