INTERPRETATION OF THE INTERFERENCE MECHANISMS OCCURRING IN THE DETERMINATION OF ANTIMONY(III) BY HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY, BASED ON NORMAL REDUCTION POTENTIALS

A comparative study was made of the magnitude of the interference that some chemical species produce in different inorganic acid media during the determination of Sb by hydride generation atomic absorption spectrometry (HGAAS). Differences were found in the effect of Al-III, Cr-VI, Mo-VI, Sn-IV, Ni-II, Co-II, Cu-II and Bi-III; on the basis of these results it is possible to recommend the appropriate acidic medium for the determination of Sb by HGAAS depending on sample composition, An evaluation of interference mechanisms is also included, On the basis of results previously reported and those obtained in this work, a complete scheme, covering all the different interference mechanisms, is proposed. In particular, the use of conditional reduction potentials, and of their variation with pH, provides a basis for deducing, in a general way, whether or not a particular chemical species is capable of producing interference.