ATOMIC-ABSORPTION SPECTROSCOPIC DETERMINATION OF MOLYBDENUM IN AQUEOUS TETRATHIOMOLYBDATE SOLUTIONS

The flame atomic absorption spectroscopic determination of molybdenum, in aqueous solutions of tetrathiomolybdate (MoS42-, TTM) and paramoly bdate species (Mo7O242-, PM) has been investigated. A serious signal d ecrease occurred, if molybdenum has been present as tetrathiomolybdate species, and the sensitivity loss has been 85%. To improve the sensit ivity, the solutions of TTM have been digested by wet-acid treatment, and made 0.14 mol . 1(-1) ammonia. Finally, Mo has been determined by AAS using a nitrous oxide-acetylene flame. The range of the calibratio n was 0-100 mg . 1(-1) and the relative standard deviation of the slop e was less than 1%.