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- Author or Editor: K. Volkers x
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Abstract
Two simple diphosphonates, CH6P2 O6(MDP) and C2 H8 P2 O7 (HEDP),have been irradiated with neutrons to produce the corresponding 32P-labeled compounds. After irradiation for 0.5–5 hours in a thermalneutron flux of 4.2 . 1016 n . m —2 s—1 the irradiated compounds were dissolved and fractionated using a SephadexG10 column. The separated fractions were identified using planar paper chromatographyand autoradiography. The labeling yield was ca 35% for each of the compounds,and the specific activity attainable ranged up to 4.8 GBq . mol —1 . For practical applications, the labeled diphosphonates have to bepurified further.
Abstract
A radiotracer based method for the determination of the rate of expel of a swelling agent from a swelling agent saturated polymer foil induced by a second organic liquid (i.e., blowing agent for foaming of polymers) has been set up and tested. The method was applied to acetone swollen polyetherimide (PEI) foil and 1,1,1-trichloroethane and ethanol (blowing agents) systems. By combining the results of radiotracer measurements with those obtained by measuring foil weights, the amount of the respective blowing agents that replaced acetone in the PEI foil was determined.
Abstract
The use of ion chromatography with continuous UV detection for radiochemical separation of Cr with simultaneous yield determination is presented. The RNAA method consists of sample destruction in HNO3+HClO4, extraction of Cr(VI) with tribenzylamine in CHCl3, backextraction in NaOH and chromatography of chromate. From radiotracer experiments, the ratio of signals for51Cr and Cr spike was found to be constant for a chromium mass range of 15 to 100 
g. Application of the RNAA method to Cr determination in biological reference materials showed a reasonable agreement with the reference values. A relative standard deviation of 3% on the 100 g/kg level for homogeneous material was achieved.
Abstract
This study deals with the quantitative determination of eight REE's viz, La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu as an Integral part of a post-irradiation chemical separation scheme for the determination of 14 trace elements in biological materials. REE values are given for NBS Orchard Leaves SRM 1571, NBS Bovine Liver SRM 1577 and Bowen's Kale, as well as for some other biological (reference) materials of plant, animal and human origin. Chondritic-normalized REE patterns of these materials are discussed. It is shown that differentiations in REE-pattern between soil and plant may occur, and also that within the human body different modes of fractionation of REE's take place.
Abstract
The idea to use high performance liquid chromatography with continuous UV detection for multi-element radiochemical separation and simultaneous multi-element 
on-line
yield determination is introduced. The validity of the concept was evaluated by demonstrating the constancy of the ratio of the signals for a main isotope (60Co) and a carrier (59Co) as a function of the elemental mass processed in the separation. The suitability of the method for practical purposes is demonstrated by its application to the RNAA determination of cobalt in biological materials. It is concluded that the method, although not yet completely developed, bears the potential of improving both accuracy and precision of multi-element RNAA.
Abstract
Gas and oil companies frequently encounter build up of Naturally Occurring Radioactive Material (NORM) in their production and processing facilities. In the Netherlands NORM is subject to strict national regulations and, consequently, installations have to be screened on a regular basis. The availability of accurate and reliable NORM sampling and analysis techniques is therefore essential. A number of years ago, the 
Nederlandse Aardolie Maatschappij B.V.
(NAM) actively initiated an investigation on analysis techniques for NORM samples from gas and oil companies. Within this framework, Shell Research Amsterdam organized a four-stage interlaboratory test programme in which representative samples of increasing complexity were analyzed by a number of Dutch institutes. Whereas a large spread in results was observed in the first stage, results in the last stage deviated less than ±10% from the values certified by an independent referee institute, even for comple, sludge samples. It was found that in particular the use of different values for the 
-yields and branching ratios amongst the institutes was responsible for the initial spread.
