ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

High-sensitivity thiocyanate spectrophotometric method for determination of perrhenate, an analogue of radioactive pertechnetate, under acidic condition

Hui Hu, Long-Li Sun, Yan-Ling Gao, Tian Wang, Yue-Fei Zhang, Hui-Xiong Wu, and Xiao-Hui Chen

Fuzhou University, Fuzhou, China

E-mail: huhui@fzu.edu.cn

Abstract: Spectrophotometric method is a simple and effective in situ analytical method for contaminants monitoring, but further improvement of its sensitivity and detection limit for radionuclides determination remains highly desirable. Herein, we report a simple and highly sensitive thiocyanate spectrophotometric method for the determination of radioactive Tc(VII) by studying its chemical analogue Re(VII) in different aqueous media. The colorless thiocyanate reacted with Re(VII) in hydrochloric acid solution in the presence of SnCl₂ producing a stable colored Re(IV)-SCN complex, which was extracted into ethyl acetate and then measured at 427 nm. Under optimized conditions, a strong linear relationship can be obtained in the range of 0.25–10 mg L⁻¹ for Re(VII) with R² value > 0.9942, and the sensitivity of the method was found to be 0.004 μg cm⁻² with detection limit of 0.027 mg L⁻¹. This assay provides highly sensitive detection of Re(VII) in environmental media that is high in NO₃⁻, Cu²⁺, and Fe³⁺. We applied it to the determination of Re(VII) in the wide range of background solutions, including deionized water, groundwater, and seawater, and analysis results showed that none of the molar absorptivities for both groundwater and seawater backgrounds was statistically different from the deionized water background when the paired Student’s t test, at 95% confidence level, was applied. The operational simplicity, accuracy, and precision of the proposed method suggest that it can be a good alternative for the in situ analysis of pertechnetate in environmental media.

Keywords: Pertechnetate ; Spectrophotometry ; Thiocyanate ; High sensitivity ; In situ analysis 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0660-y

Chemical Papers 73 (5) 1093–1101 (2019)