The use of quinoxaline-2-carboxylic acid and its derivatives as analytical reagents

Quinoxaline-2-carboxylic acid and 3-chloro and 3-hydroxy derivatives have been studied as analytical reagents. The solubility products of the metal salts, the optimum pH range for complete precipitation and the thermal behaviours of the metal complexes have been established. Quinoxaline-2-carboxylic acid allows the gravimetric determination of Cu(II), Cd(II), Zn(II), Co(II), Ni(II) and Pd(II); with the 3-chloro and 3-hydroxy derivatives, only palladium(II) could be precipitated quantitatively.