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In the analysis of biological samples with sub ng/g uranium concentrations, pre-concentration has been shown to improve the detection limit for the determination of uranium. Recovery corrected kinetic phosphorescence analysis (KPA) combines pre-concentration and separation of uranium by anion-exchange from human tissues dissolved in 6M HCl, with the radiochemical yield determined by alpha-spectrometry, using232U as a tracer. Total uranium is determined by KPA after correction for chemical recovery. Twenty-one randomly selected dissolved tissue samples from the United States Transuranium and Uranium Registries (USTUR) Case 0242 were chosen for comparative analyses. The set of samples included dissolved bone and soft tissues. Uranium concentrations for seven of the samples had not been previously reported. Direct KPA could not be used to determine uranium concentrations of five unreported tissues. Three of these tissues had uranium concentrations at or below the KPALQvalue of 0.028 ng/ml and two tissues had known matrix interferences. All seven of the unreported tissues were successfully analyzed by recovery corrected KPA; concentrations ranged from 9 to 1380 ng per tissue, including those that could not be analyzed by direct KPA due to matrix problems. Recovery corrected KPA gives results similar to direct KPA where matrix interferences and low detection limits are not encountered. A comparison of the direct method of KPA versus recovery corrected KPA shows marked improvement for the determination of uranium in samples that heretofore either uranium was not detected or the sample had to be drastically diluted to minimize matrix effects in order to measure uranium. [ABSTRACT FROM AUTHOR]

The determination of transuranic (TRU) content in nuclear wastes, reactor materials, process solutions, and various other matrices is required in support of material assessment, environmental restoration, and waste processing activities. We have found that direct measurement of TRU is possible using surface passivated ion implanted planar silicon diode detectors. The performance and durability of modern silicon diodes enables direct detection of alpha-particles, with retention of some spectral information, through small air gaps or under direct contact with liquid or solid samples. We will present results on the performance of silicon diode detectors for the determination of TRU in liquids. [ABSTRACT FROM AUTHOR]

A method utilizing extractive scintillating resin for 99Tcmonitoring in aqueous solutions is presented. These extractive scintillatorscombine analyte selective uptake and scintillating properties to produce dualfunctionality analytical resins. These resins were produced by (1) co-locatedextraction chromatographic resin and plastic scintillating beads, (2) immobilizingfluors in macroporous polystyrene supports to which chains of monomethylatedpolyethylene glycol have been grafted and (3) co-immobilizing organic scintillatingfluors and a quaternary ammonium extractant (Aliquat-336) within macroporousacrylic and polystyrene supports. The first and third resins selectively extractpertechnetate ions from dilute acid whereas the second resin selectively extractspertechnetate ions from high ionic strength solutions. These resins were utilizedin ~0.20 ml pore volume columns while 99Tc was continually monitoredwith commercially available scintillation detection systems. Manual and automatedmicrofluidics were used to deliver sample and reagent solution for loadingand elution of the 99Tc. The detection efficiencies were determinedto be 45 and 70% for acrylic and polystyrene based resins, respectively, andindependent of extractant. Minimum detectable 99Tc concentrationusing the Aliquat-336/acrylic-based resin was 6.2 Bq . l –1 for a 50-mlsample and 30-minute count time. The new methodology was applied towards analysisof contaminated groundwater samples and nuclear waste simulants. [ABSTRACT FROM AUTHOR]