Spectrophotometric determination of iron and copper in milk, foodstuffs and body tissues with 1-(2-quinolylazo)-2,4,5-trihydroxybenzene

1-(2-Quinolylazo)-2,4,5-trihydroxybenzene has been proposed as a sensitive chromogenic reagent for the simultaneous determination of iron and copper in presence of thiosemicarbazide. The molar absorptivities are 1.86 x 10(4) l.mole(-1).cm(-1) at 510 nm for iron and 2.54 x 10(4) l.mole(-1).cm(-1) at 550 nm for copper. Trace levels of these two metals have been determined in some foodstuff's, body tissues and milk samples.