Zincon solution is prepared by dissolving 0.13g of the powder in aqueous N NaOH (2mL diluted to 100mL with H2O). This gives a deep red colour which is stable for one week. It is a good reagent for zinc ions but also forms stable complexes with transition metal ions. [UV-VIS: Bush & Yoe Anal Chem 26 1345 1954, Hunter & Roberts J Chem Soc 820 1941, Platte & Marcy Anal Chem 31 1226 1959] The free acid (see above) has been recrystallised from dilute H2SO4. [Fichter & Scheiss Chem Ber 33 751 1900, Beilstein 16 IV 421.]
