A modified method of separating Tl(I) and Tl(III) in aqueous samples using solid phase extraction

Tangfu Xiao,Philippe C. Baveye,Qingxiang Xiao,Atta Rasool

doi:10.1186/s13065-018-0502-6

Abstract

In spite of the development of new measurement techniques in recent years, the rapid and accurate speciation of thallium in environmental aqueous samples remains a challenge. In this context, a novel method of solid phase extraction (SPE), involving the anion exchange resin AG1-X8, is proposed to separate Tl(I) and Tl(III). In the presence of diethylene triamine pentacetate acid (DTPA), Tl(III) and Tl(I) can be separated by selective adsorption of Tl(III)-DTPA onto the resin, Tl(III) is then eluted by a solution of HCl with SO2. The validity of this method was confirmed by assays of standard solutions of Tl(I) and Tl(III). The proposed method is shown to have an outstanding performance even in solutions with a high ratio of Tl(I)/Tl(III), and can be applied to aqueous samples with a high concentration of other electrolytes, which could interfere with the measurement. Portable equipment and reagents make it possible to use the proposed method routinely in the field.

Highlights

Thallium (Tl), a toxic trace metal and one of the USEPA’s priority metal pollutants [1]
To check the interferences of complexing ions, wastewater samples were pressure-filtered through a 0.45 μm membrane filter and 100 mL of the 10 mM diethylene triamine pentacetate acid (DTPA) solution were added to 100 mL of filtered water, was divided into two aliquots, one aliquot was spiked by standard solutions of Tl(I) and Tl(III), another without
This enables the separation of Tl(I) and Tl(III) by the anion exchange resin AG1-X8 with the Tl(III)-DTPA complex retaining on the solid phase extraction (SPE)

Summary

Introduction

Thallium (Tl), a toxic trace metal and one of the USEPA’s priority metal pollutants [1]. The objective of the research presented in this manuscript is to combine the use of the AG1-X8 resin for the separation of Tl(I) and Tl(III) with DTPA used as the complexing agent In principle, this approach should enable the pre-concentration of trace levels of Tl(III) and make it possible to quantitatively determine Tl(I) and Tl(III) in wastewater in the presence of high concentrations of potentially interfering ions. This approach should enable the pre-concentration of trace levels of Tl(III) and make it possible to quantitatively determine Tl(I) and Tl(III) in wastewater in the presence of high concentrations of potentially interfering ions Another advantage of this approach is that it should be simple to implement under field conditions, as separation of Tl(I) and Tl(III) is performed in the field via the addition of DTPA and separation by the SPE resin prior to measurement by ICP-MS. To elute the Tl(III)-DTPA complex from the column 15 mL of a 0.1 M HCl-SO2 solution were loaded on the SPE (5 × 3 mL aliquots) the eluent collected for Tl(III) analysis

Aim

Results and discussion

Conclusions