The algorithm and the program were developed for using statistical evaluation and time series analysis for automatic detn. of purity class of working liqs. and for generating temporary anal. databases cumulating impurity data on working liqs. Addnl. functions included (1) monitoring of liq. purity class with graphical presentation of variation of the purity class with time; (2) formulation of advice (to replace or not to replace the liq., when to make the next purity analysis).