SIMULTANEOUS VOLTAMMETRIC DETERMINATION OF MOLYBDENUM AND COPPER IN BIOLOGICAL SAMPLES

A selective, sensitive and reliable voltammetric method for the simult aneous determination of Cu and Mo is developed. Both metals form compl exes with 8-hydroxyquinoline (oxine). Mo gives two reduction peaks wit h oxine in acidic chloride media at -0.52 V and -0.58 V, while copper exhibits only one at -0.14 V. Common heavy metals do not interfere at all. The limit of detection is 0.29 ng/ml for Mo and 0.14 ng/ml for Cu after preconcentration on the hanging mercury drop electrode for 30 s at -0.2 V. The R.S.D. at a concentration level of 10 ng/ml is 3.8% fo r Cu and 5.3% for Mo. The method is applied to different biological sa mples.