Sorption-photometric determination of 1-naphthol with polyurethane foams

Two approaches to sorption-photometric determination of 1-naphthol in waters with application of polyurethane foams are offered. The first approach was based on sorption of coloured 1-naphthol azoderivative, which was formed by the reaction with 4-nitrophenyldiazonium tetrafluoroborate (NFD). In the second variant, 1-naphthol is first sorbed by a polyurethane foam, and it is then transformed into a coloured azoderivative by sorbent treatment of a NFD solution. A coloured 1-naphthol azoderivative was determined immediately in the polyurethane foam using diffuse reflectance spectroscopy. Calibration graphs are linear in the interval of concentrations of 0.01 - 1 mu g/ml. The analytical results indicated that a selective and sensitive analytical procedure could be easily applied to determination of 1-naphthol concentration in waters.