Analytical Applications of 2-Propionyl-I-Naphthol Oxime: Part I. Reactions with Metal Ions and Gravimetric Determination of Copper

[2-propiony1-1-naphthol oxime has been found to be a wide-spectrum precipitant for a number of metal ions. It also gives colour react ions with some ions. Cu2+ gives a buff coloured bis-chelate Cu(C13H2O2N)2 precipitated at pH 1.5-2.5 insoluble in acetic and dil. mineral acids. From 10­-40 mgms. of Cu2+ has been determined gravimetrically, the average error being less than 0.1 per cent. Determination of copper in the presence of moderate amounts of (10-20 mg.) of Zn2+, Cd2+, Ni2+ and Co2+ has been found to be satisfactory. The entrainment of Fe3+ by the Cu2+ chelate has been found to be eliminated using 1:1 ethanol: ether wash liquid]