12. Speciation Analysis of Inorganic Sb, Se and Te in Environmental Samples Using Modified TiO₂@MWCNTs Nanocomposite Packed Microcolumn prior to Hydride Generation-Inductively Coupled Plasma Optical Emission Spectrometry (HG-ICP-OES)

A simple, sensitive and selective method based on the combination of micro solid phase extraction and HG-ICP-OES for speciation analysis of Sb, Se and Te in environmental samples, has been developed. Titanium dioxide/multiwalled carbon nanotubes (TiO₂@MWCNTs) nanocomposite functionalized with Aliquat 336 was used as the sorbent material. Optimization of factors affecting the speciation of the target analytes was achieved using fractional factorial and Box-Behnken designs. Under optimum conditions, the limit of detection (n = 25) ranged from 1.0 to 1.6 ng L⁻¹. The repeatability and reproducibility (expressed in terms of relative standard deviation) ranged from 1.2–2.3% and 3.1–4.2%, respectively. The accuracy of the developed method was tested by the analysis of a certified reference material and spiked samples and the recovery percentages ranged from 96 to 109%. The proposed method was applied for the quantification of Sb, Se and Te species in real samples. The concentrations of total trace metals determined using the developed method were compared with those obtained using ICP-MS and the results obtained were in close agreement as statistically confirmed using Student paired t-test.