MULTIVARIATE STATISTICAL CHARACTERIZATION OF THE TOLERANCE OF ARGON INDUCTIVELY-COUPLED PLASMAS TO ORGANIC-SOLVENTS

The tolerance of Argon-inductively coupled plasmas to the introduction of organic solvents, defined by Matsunaga's parameter and by ''limiti ng aspiration rate'', has been correlated with their nature by statist ical methods. The main physical variables of solvents obtained from th e technical literature were used as independent variables to perform p rincipal component analysis (PCA) and factorial discriminant analysis (FDA). Thus the variables which had the greatest influence on heat exc hange nebulization and transport processes were determined. Organic so lvents were classified into different groups characterized by their to lerance in plasma operation. In the PCA study, the second principal co mponent was the most significative to differentiate between the tolera nce of solvents and it showed a high correlation with surface tension, viscosity and heat of vaporization. Scores of the organic solvents be longing to the same class can be adjusted to straight lines and their positions in the plane (expressed as ordinates in the origin) as well as the slope values are characteristics of organic solvent groups. The results of FDA confirms those obtained with PCA. Multivariable regres sion was applied to obtain predictive equations of the limiting aspira tion rate for organic solvents, in terms of their main physical variab les. (C) 1997 Elsevier Science B.V.