1-(2-Pyridylazo)-2-naphthol is an indicator in complexometry and a reagent for the extraction and spectrophotometric determination of many transition metals.
1. Z. Holzbecher et al. Handbook of Organic Reagents in Inorganic Analysis Chichester, 1976. 2. K.L. Cheng et al., eds. Handbook of Organic Analytical Reagents Boca Raton, 1982, p. 185.