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Detection of radioactive isotopes of polonium is important for understanding natural processes, management and assessment of radioactive waste, and nuclear forensics applications. Further, the most common methods for preparation of polonium samples for alpha spectrometry are electrodeposition and spontaneous deposition which are time consuming. Here, we compare three approaches utilizing rapid microprecipitation from bismuth phosphate, copper sulfide, or tellurium alongside traditional spontaneous deposition methods. From these experiments, results show that copper sulfide microprecipitation recoveries are similar to spontaneous deposition on silver and less time consuming with an approximate five-fold decrease in preparation time, including in the presence of complex matricesmore » like seawater.« less

Particulate mass estimation from 3-pixel images is desirable in many fields. Red–green–blue (RGB) analysis and Boolean logic were shown to estimate the mass of luminescent tracers in microscopic images. With a controlled background intensity, an estimation error of 1.8 to 3.5% was achieved; in uncontrolled backgrounds, an error of about 18% was achieved. RGB analysis is a valuable tool for spatial location of particulates. This work shows it is possible to estimate the particulate mass in an image and gives RGB an extension into mass quantification that has far-reaching impacts in fields involving the fate and transport of particulate matter.

A rapid method to separate Ta, Po, Au, Pt, and W from a sample containing mixed fission and activation products was developed using three commercially available extraction chromatography resins stacked in series. When the separation was tested using all the target activation products, even those with short half-lives were measurable. Finally, combining multiple extraction chromatography resin cartridges in tandem allows for multiple short-lived activation products to be separated from one sample addition without the complication of multiple steps.

Nitrous oxide (N₂O) was used as a reaction gas to investigate the gas phase ion-molecule interactions using the Agilent 8900 QQQ-ICP-MS. A multi-element standard containing 45 elements with masses ranging from 9 to 208 u was measured in the presence and absence of N₂O. The main product ion species observed were oxides and nitrides. Comparison of the N₂O reaction results with similar measurements conducted with O₂ revealed that N₂O was more effective at forming oxides in general: the elements Cd and Pb were shown to produce oxides with N₂O where the reaction did not occur with O₂. Nitrous oxide wasmore » also shown to produce a significant amount of nitride species in a few cases. The general reactivity was shown to be consistent with density functional theory (DFT)-predicted reaction enthalpies, such that all predicted exothermic reactions produced product ions at levels at least 1% of the unreacted ion. Our results show that reaction enthalpy is a reasonable predictor of reactivity with N2O on the timescales of the interactions in non-thermal ICP-MS/MS systems. Our work demonstrates the utility of two relatively new platforms (commercial elemental ICP-MS/MS and EMSL Arrows interface to the NWChem program suite), which allows for the study of a large number of elements within a short period. While DFT with the basis sets utilized here is not the most accurate computational method, it is also not computationally expensive and is shown to be suitable for predicting gas phase reactivity in the QQQ-ICP-MS for the majority of ions studied. Here, the ease and rapidity of data collection and DFT calculations has the potential to be very impactful for the identification of targeted reaction chemistries to be leveraged for analytical method development, such as for the inline separation of isobaric interferences from analytes of interest.« less

Tracing the flow of solid matter during an explosion requires a rugged tag that can be measured by a unique identifiable signature. Silica-covered semiconductor quantum dots (QDs) provide a unique and tunable photoluminescent signature that emits from within a sacrificial outer layer. Five types of silica-covered zinc sulfide QDs were synthesized and covalently bound to commercial luminescent powders. The combination of five dots and five powders enables a matrix of 25 unique tags. The tracers are shown to be tolerant of environments associated with chemical explosives and provides a unique tag to evaluate debris fields.