Determination of mercury by radiochemical displacement method

A radiochemical displacement method for the determination of micro amounts of Hg(II) has been developed. 65Zn was displaced from the Zn-1-(2-pyridylazo-2-naphthol) complex at pH 5 in borate buffers by Hg (II). 10-80 micrograms of mercury could be determined. Interference of various metal ions and methods for suppression have also been carried out.     

Determination of silicon in high purity metals by radiochemical NAA and CPAA

The indicator radionuclide³¹Si produced in neutron and deuteron activation analysis for silicon via the reactions³⁰Si(n,) and³⁰Si(d,p), respectively, is specifically separated from the irradiated sample by distillation as³¹SiF₄. In the case of aluminium, the distillation is carried out from a HF(HNO₃)H₂O₂ medium and in the case of molybdenum, niobium, tantalum, titanium and vanadium from a HF/HNO₃/HBr/H₂SO₄ medium. Using liquid scintillation counting, the achievable detection limits for neutron activation analysis are, depending on the type of the matrix, between 4–50 ng/g, and for the deuteron activation analysis of tantalum the detection limit is 5 ng/g.     

Determination of copper by a radiochemical displacement method

Determination of copper/II/ by radiochemical displacement of labelled cobalt from cobalt-o-hydroxybenzaldehyde isonicotinoyl hydrazone /Co-BIH/ complex has been studied. Borate buffer of pH 5 was found to be a suitable medium for quantitative displacement. 10–70 g of copper could be determined. The effect of various foreign metal ions on the determination has also been studied.     

Determination of mercury by radiochemical displacement

2–15 g of mercury has been determined by exchange with zinc in⁶⁵Zn labelled zinc sulphide. The influence of various ions which are likely to interfere in the determination of mercury has also been studied.     

Determination of chromium by radiochemical displacement

A rapid and sensitive method has been developed for the determination of microgram amounts of chromium based on the radiochemical displacement of⁶⁵Zn from labeled Zn-[1-(2-pyridylazo-2-naphthol]₂ complex by chromium. The effect of pH on the displacement of⁶⁵Zn was studied. 5–65 g of chromium could be determined with great accuracy. The effect of various ions on the displacement of⁶⁵Zn by chromium was investigated and the method developed was utilized for the determination of chromium content present in geological water samples. The results were compared with values obtained by Atomic Absorption Spectrophotometry.     

Determination of copper by radiochemical displacement

5–25 g of copper has been determined by exchange with zinc-65 labelled zinc sulphide. The effect of diverse ions on the determination has also been reported.     

Determination of cadmium by radiochemical displacement

Determination of cadmium by radiochemical displacement of zinc from a labelled ZnPAN complex has been studied. pH 5.5 in borate buffer was suitable for quantitative displacement. The effects of diverse ions on the displacement reaction are also reported.     

Determination of manganese by radiochemical displacement

The possibility of determination of 10–80 g of manganese by radiochemical displacement of zinc from a labelled zinc-PAN complex has been demonstrated. pH 6 borate buffer was suitable for quantitative displacement. The effect of diverse ions on the displacement reaction is also reported.     

The radiochemical purity determination of18F preparations

A simple and fast chromatographic method for determining the chemical form of¹⁸F is given.     

Chemical and radiochemical evaluation of the purity of99mTc extracted by MEK

Solvent extraction separation of^99mTc from⁹⁹Mo using methyl ethyl ketone(MEK) has been found to be an effective method of obtaining^99mTc of medicinal purity from low specific activity⁹⁹Mo. The authors have investigated the effect of alkali and molybdenum concentration on the extraction of⁹⁹Mo and^99mTc into methyl ethyl ketone. The possibility of methyl ethyl ketone forming enol and condensation products and its effect on the final extraction efficiency and purity of^99mTc has been studied. Sodium molybdate has been found to have a good salting out effect on^99mTc pertechnetate and hence^99mTc extraction can be better accomplished from low specific activity⁹⁹Mo solutions. The ketone seems to form traces of condensation products in the extraction procedure. These have been found to be coextracted with^99mTc into MEK but did not affect the extractability of^99mTc. It was observed that neutral alumina column removes these condensation products from MEK containing^99mTc. Alternately these could be filtered off by acidification of the final aqueous^99mTc solution. The studies indicate that under optimum experimental conditions methyl ethyl ketone separates^99mTc from⁹⁹Mo with high efficiency and yields^99mTc of high purity suitable for use in nuclear medicine in the form of various labelled compounds.     

Multielement radiochemical neutron activation analysis of high purity aluminium

Summary A radiochemical neutron activation analysis technique for the determination of 51 elements in high purity aluminium via medium- and long-lived indicator radionuclides has been developed. It is based on a separation procedure involving the removal of ²⁴Na, produced via the reaction ²⁷Al(n,), on a hydrated antimony pentoxide column and further separation of the radionuclide mixture into 11 groups on two Dowex 1X8 columns and one Dowex 50X8 column from HCl/HF and HCl media as well as the extraction of copper with APDTC in chloroform. The indicator radionuclides for the significant impurities thorium and uranium, ²³³Pa and ²³⁹Np, were separated with satisfactory selectivity in one fraction. For 43 elements, the limits of detection are <10 ng/g, for thorium and uranium, they are 50 pg/g. The method was applied to the analysis of different high purity aluminium samples. For a number of elements, the results of this technique are compared with those of other techniques.

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Radiochemische Multielement-Neutronenaktivierungsanalyse von hochreinem Aluminium

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Dedicated to Prof. Dr. W. Fresenius on the occasion of his 75th birthday     

Improving the radiochemical purity determination of 123I-labeled metaiodobenzylguanidine

The HPLC method originally applied at the Nuclear Engineering Institute (IEN) for the radiochemical purity determination of ¹²³iodine labeled m-iodobenzylguanidine (¹²³I-mIBG) takes 18.5 min. The final product release also depends on this result, and to facilitate this stage, we aimed to decrease this analysis time. We also intended to use fewer toxic compounds, if feasible. The optimization approach used herein was a combination of factorial and mixture designs to study simultaneously the selected variables. Analysis time, resolution and chromatograms aspect were the measured responses. The qualitative analysis of these responses provided the best chromatographic separation conditions that were 52 mM KH₂PO₄ in a solution of ethanol and water (1:1), applying a flow rate of 0.50 mL min^?1 and C18 column (4.6 × 250 mm, 5 μm). These optimum conditions not only decreased the analysis time in 61 %, but also allowed the reduction of mobile phase toxicity. To assure reliable data, method validation was performed for these conditions. The method has proved its specificity, the detection limit found was 3.70 × 10^?4 MBq mL^?1 and the quantification limit has corresponded to 1.11 × 10^?3 MBq mL^?1. Repeatability and intermediate precision has not exceeded 3 and 5 %, respectively, and the accuracy has matched the interval of 95–105 %. This new method has been routinely applied in the radiochemical purity determination of ¹²³I-mIBG at IEN.     

Determination of cadmium in water samples by substoichiometric radiochemical method employing potassium ethyl xanthate

A radiochemical method has been developed for the determination of microgram amounts of cadmium based on the substoichiometric extraction of its 1:2 complex with potassium ethyl xanthate into 1:4 v/v mixture of pyridine and ethyl acetate from 2.5 M sodium formate. 10-90 micrograms of cadmium was determined with an average error of +/- 1.96%. The method developed was successfully applied to the determination of Cd contents in water samples.     

Analysis by radiochemical displacement: Determination of EDTA

A new radiochemical displacement method has been developed for the determination of EDTA /ethylene diamine-tetraacetic acid/. The displacement of labelled zinc from Zn:PAN complex by EDTA at pH 5.5 in borate buffers can be conveniently utilized for the determination of 50–150 g of EDTA. Effects of diverse ions on the determination have also been tested.     

Determination of cesium in seawater by radiochemical methods

Radiochemical methods for the determination of cesium in seawater are described. Preliminary substoichiometric concentration with nickel hexacyanoferrate(II) and tetraphenylborate and application of selective radiochemical techniques are used. The cesium content in Atlantic Ocean samples is 0.74 ± 0.03 μg l^-1. The method is applicable on board ship. The approach should be generally useful.     

Determination of nickel and cobalt by radiochemical displacement

A radiochemical displacement method has been developed for the determination of nickel and cobalt based on the release of Zn-65 from labelled Zn(PAN)₂ [1-(2-pyridylazo) 2-naphthol] complex in chloroform. The displacement behavior of Zn-65 by nickel and cobalt was studied in the pH range 5–7.5. The effect of various ions on the displacement was also examined. 2–20 g of nickel and cobalt was determined by the aid of calibration plots.     

Determination of radionuclide purity by gamma-spectrometry

The radionuclide purity of medical (^99mTc) and technical (⁶⁰Co,¹⁰⁹Cd) products was determined by γ-spectrometry. The impurities found allowed in all cases to draw conclusions on the method of production. The importance of radionuclide purity control is demonstrated.     

Determination of micro amounts of copper by radiochemical displacement

A radiochemical displacement method for the determination of microgram quantities of copper has been developed. The method consists of the displacement of labelled zinc from its complex with PAN. 5–60 g of copper can be determined at pH 5. Effect of various ions on the method has also been studied.     

Determination of trace amounts of palladium by radiochemical displacement

A method has been developed for the determination of trace amounts of palladium using radioactive mercury dithizonate as the reagent. Experimental conditions for the quantitative displacement of mercury from the reagent, calibration graph and the interfering effects of various ions have been studied. The method is sensitive down to 2 g of palladium present in 10 ml of the aqueous solution.