Method based on a colloid indicator, used to identify metals from drinking water

The paper presents a new analytical method for identifying of chromium, copper and lead from drinking water. Its novelty consists in introducing a selected methyl orange –dye for identification and dozing of three metals. The method is applicable both for drinking and mineral water in which the degree of interaction with other compounds or impurities is relatively low. The three metals are usually qualitatively and quantitatively analysed by standard classical methods: colorimetry or atomic absorption spectrophotometry. But these methods require some reagents, also are energy consuming and have high cost. The new method is cheaper, faster and the colloidal dye can be applied in situ. The method for determination of: chromium, copper and lead from drinkable waters consists in introducing a fixed amount of dye and measuring absorption of the formed metal-dye associates. Most organic dyes are basic or acids compounds and present colloidal association. Their tendency to associate in colloidal micelles was first studied by conductivity. Due to the flat shape their molecules form layered lamellar micelles, resembling like a “package of cards”. Methyl orange is recognized as a colloidal type dye. The intensity of characteristic bands is proportional to the amount of colloid indicator (methyl orange- dye) and number of metal-dye associates present in the system. Thus the concentration of metals in water can be determined. Due its capacity to determine qualitatively and quantitatively the three selected metals in drinking water, the paper presents ecological importance.