Solid phase chelating extraction and separation of inorganic antimony species in pharmaceutical and water samples for graphite furnace atomic absorption spectrometry

A separation procedure for antimony(III) and antimony(V) was developed with the use of chelating celluloses. Sb(III) was separately preconcentrated on imino diacetic acid-ethyl cellulose in the acidic pH range, in which the uptake of Sb(V) was negligible in the mu g L-1 concentration range. On the other hand, both Sb species Sb(V) and Sb(III) were pre-concentrated on a chloride form of 2,2'-diaminodiethylaminecellulose. These solid phase extraction procedures were combined with graphite furnace atomic absorption spectrometry (SPE-GFAAS) for Sb detection. Pharmaceutical compounds of organic and inorganic types (ten compounds), as well as mineral water samples (twelve types) were analyzed. Detection limits of 0. 18 mu g L-1 Sb(III) and 0.25 mu g L-1 Sb(V) were found in aqueous sample solutions and water samples, respectively, considering a 25-fold pre-concentration. The total Sb, mostly in the form of Sb(V), could be determined in phosphate-containing pharmaceuticals, while in phosphoric acid, Sb(III) was the dominant form. In all other types of samples the Sb content was below the detection threshold, and therefore, the potential suitability of the SPE-GFAAS method for the determination of Sb(III) species was proven by recovery tests of spiked samples. This method ensures the required detection power with regard to the allowable Sb limits established by international organizations. (c) 2007 Elsevier B.V. All rights reserved.