Development of a radiochemical neutron activation analysis procedure for determination of rhenium in biological and environmental samples at ultratrace level

Advanced liquid and solid extraction procedures for ultratrace determination of rhenium by radiochemical neutron activation analysis

“…Recently, Re contents in Fucus vesiculosus collected southwest of Norway were found in the range of 60.8 to 84.9 ng g -1 [5]. In the same species collected in the North Atlantic within an international intercomparison exercise on the determination of 99 Tc, Re contents in the range of 23 to 90 ng g -1 were determined in our laboratory, and a possibility of competition between Re and Tc for accumulation in brown algae was suggested [6]. Analytical methods for low-level Re determination in various matrices comprise GFAAS, SIMS, RIMS, various modes of ICP-MS, and NAA [2].…”

“…After cooling for 3 weeks to allow for decay of the shorter-lived 182m Re (half-life of 2.67 d), the foil was dissolved in molten NaNO 2 , tungstic acid was precipitated with HCl. No further purification of the Re radioisotopes was needed [6]. In the mixture of the 183,184,184m Re radioisotopes, the activity of 184 Re dominated due to the chosen time of proton bombardment and half-lives of the respective radioisotopes.…”

“…The procedure described earlier [6] was used with slight modifications. The solution in 0.1 M HCl after microwave digestion / evaporation was extracted with 2 × 5 mL of 0.01 M zinc diethyldithiocarbamate (Zn(DDC) 2 ) in chloroform for 2 × 1 min.…”

“…A procedure employing new solid extractant materials (SEX) was used [6]. The SEX material was prepared by incorporation of liquid trioctyl-methylammonium chloride (Aliquat 336, the same active component as of Eichrom´s TEVA Resin) in an inert matrix made of modified PAN using a process proposed originally for the preparation of composite exchangers [7].…”

“…RNAA has not been used for Re determination in biological and environmental samples so far, although it provides a very low detection limit and lower uncertainty of results thanks to a possibility to control the chemical yield of the decomposition and separation steps. To be able to produce reliable data on Re concentrations in the environment, RNAA procedures based on use of liquid-liquid extraction (LLE) and extraction chromatography (EXC) have been elaborated in our laboratory recently [6]. In the present work, the existing procedures have been improved and another procedure has been made up.…”