Spectrophotometric determination of mercury with iodide and rhodamine B (Penentuan spektrofotometri untuk merkuri dengan menggunakan Rhodamine B dan Iodida)

Abstract

Spectrophotometric methods for the trace amount determination of Hg(II) via extraction and polyvinylalcohol (PVAl) water stabilization was explored. The methods are based on the formation of ion-association complex of Hg(II) with Rhodamine B, [(HgI4)2-][(Rhodamine B)+]2 in highly acidic solution. Extraction using benzene showed the Beer’s law was obeyed for mercury(II) in the range of 5 to 27 μg Hg(II) / 20 mL of sample and molar absorptivity, ε = 17.68 × 104 L mole-1cm-1. For polyvinylalcohol (PVAl) stabilization method, Beer’s law showed the validity range of 10 to 120 μg Hg(II) / 10 mL of sample and molar absorptivity, ε = 16.84 × 103 L mole-1cm-1. The benzene-extraction method has been applied in assessing the performance of copper sulfide ion-exchanger in removing Hg(II). The result was comparable to the result obtained using cold vapor atomic absorption spectrometry (CVAAS).