A sensor array containing 9 cross-reactive sensing fluorescent elements with different affinity and selectivity to 10 metal cations (Ca2+, Mg2+, Cd2+, Hg2+, Co2+, Zn2+, Cu2+, Ni2+, Al3+, Ga3+) is described. The discriminatory capacity of the array was tested at different ranges of pH and at different cation concentrations using linear discriminant analysis (LDA). Qualitative identification of cations can be determined with over 96% of accuracy in a concentration range covering 3 orders of a magnitude (5-5000 mu M). Quantitative analysis can be achieved with over 90% accuracy in the concentration range between 10 and 5000 mu M. The array performance was also tested in identification of nine different mineral water brands utilizing their various electrolyte compositions and their Ca2+, Mg2+, and Zn2+ levels. LDA cross-validation routine shows 100% correct classification for all trials. Preliminary results suggest that similar arrays could be used in testing of the consistency of the purification and manufacturing process of purified and mineral waters.