N 1935 (OTTO) 1-Nitroso-2-naphthol, 97% Cas 131-91-9 - used for the removal and preconcentration of Pb(II), Cu(II), Cr(III) from waste, as well as drinking water. It is also used in the preconcentration of cobalt using C(18) microcolumn with flow injection that is coupled to a flame atomic absorption spectrometry (FI-FAAS) system. 1-Nitroso-2-naphthol is used in the preparation of 1-nitroso-2-naphthol-sodium nitrite reagent.