Interferences of antimony(V) in the differentiation of antimony(III) from antimony(V) by extraction with ammonium tetramethylenedithiocarbamate using graphite furnace atomic absorption spectrometry

Procedures for the preparation of antimony sample solutions for the differentiation of antimony(III) from antimony(V) by extraction with ammonium tetramethylenedithiocarbamate (ammonium pyrrolidinedithiocarbamate, APDC) were examined. It was found that, when APDC is added to the antimony(V) solution of pH less than ca. 3, the antimony(V)-APDC complex is partially co-extracted with antimony(III) over the pH range 3.5–10. Further, the mixing of antimony(III) solution with acidic antimony(V) solution, prepared by oxidising antimony(III) potassium tartrate solution, leads to the incomplete extraction of antimony(III). A standard procedure for removing the interferences was established.