Análise de especiação de antimônio em antimoniato de meglumina

Abstract

In this work the chromatographic conditions for the separation of species of antimony in the drug meglumine antimoniate were optimized. Furthermore, the effect of the treatment with hydrochloric acid in the sample was evaluated in order to convert Sb(III) species and Sb(V) complexed with meglumine in their free inorganic forms. The separation of Sb species was performed by liquid chromatography (LC) in an anion exchange column (PRP-X100) and detection by mass spectrometry with inductively coupled plasma (ICP-MS).The concentrations of Sb obtained by LC-ICP-MS were compared with those obtained by LC-ICP-MS using post-column derivatization by hydride generation (HG). The results of the total concentration of Sb were also evaluated, given by the sum of the concentrations of species determined by LC-ICP-MS, with the results obtained by spectrometry and inductively coupled plasma optical emission (ICP OES). After the evaluations of different mobile phases for separation of Sb species, the selected conditions were: HNO3 15 mmol L -1 at pH 6.0 for 5 min and 20 mmol l -1 EDTA at pH 4.5 for 10 min, both with a flow of 1.0 mL min -1. The presence of at least four kinds of Sb, the two free inorganic (Sb(III) and Sb(V)) and other complexed with meglumine was observed. The results obtained for Sb species in the sample without acid treatment were lower than those obtained for samples with acid treatment. This is probably due to the fact that complexed Sb species have been converted into their free inorganic species of Sb. The result obtained by LC-HG-ICP-MS after sample treatment for Sb(III) species showed no statistical difference (t test, p> 0.05, confidence interval 95%), compared with the result obtained by LC-ICP-MS. Likewise, the result for the total Sb, obtained by ICP OES also no statistically significant difference (t test, p> 0.05, confidence interval 95%) with the addition of Sb species obtained by LC-ICP- MS. Recovery tests were also made, higher concordance found to be 90% and 98% for Sb(V) and Sb(III), respectively.