Solid phase micro-extraction of metal ions

A fused silica fibre coated with poly(dimethylsiloxane) was modified to produce a micro probe with ion exchanging capability. The liquid ion exchanger, di-(2-ethylhexyl)phosphoric acid (HDEHP), was used for the modification. The probe was used for the extraction of bismuth(III) from aqueous nitric acid solution. The extracted Bi(III) was desorbed into an acidic potassium iodide solution. The yellow colored BiI₄ ^– complex formed was determined by spectrophotometry.