“…The polarographic method has been used to determine 1,4-naphthoquinone and maleic anhydride in phthalic anhydride (228) and hydroquinone in various monomers (119), to follow the effect of light on 2-methyl-l,4-naphthoquinone (9) and the 2-methyl-1,4-naphthoquinone-sodium bisulfite adduct (8), to study complex formation between quinalizarin and various metals (46), and to show that the vapor phase oxidation of phenanthrene gives possibly a monohydroxyphenanthraquinone (149). The determination of ar thraquinone by the polarographic technique is less accurate than the potentiorr etric method using titration with vanadium sulfate (275).…”