MSFIA-LOV system for 226 Ra isolation and pre-concentration from water samples previous radiometric detection

Automatic multicommuted flow systems applied in sample treatment for radionuclide determination in biological and environmental analysis

The presence of artificial and natural radioactivity in the environment is currently a topic of great relevance and ecological interest, even in human health issue, due to the increase of different anthropogenic activities. The use of multicommuted flow analysis techniques (e.g. Multi-Syringe Flow Injection Analysis - MSFIA, Lab-On-Valve - LOV and Lab-In-Syringe - LIS) has allowed the automation of radiochemical procedures to separate and preconcentrate radionuclides in environmental and biological samples. In comparison with the manual approach commonly used in routine analysis for radioactivity monitoring, the automation has enabled the development of highly reproducible methodologies with a great analysis frequency. Moreover, during the analytical procedure, the intervention of the analyst is drastically reduced, minimizing the radiological risk. The automation also offers significant advantages such as minimum consumption of time and reagents, reducing the cost and the generation of waste, contributing to the green chemistry. In this review, several multicommuted flow analysis techniques (MSFIA, LOV and LIS) reported in the last decade applied for the development of automatic sample treatment methodologies, used to separate, preconcentrate and quantify ⁹⁰Sr, ⁹⁹Tc, natural U and ²²⁶Ra in biological and environmental samples are described and critically compared.

Dynamic Flow Approaches for Automated Radiochemical Analysis in Environmental, Nuclear and Medical Applications

Automated sample processing techniques are desirable in radiochemical analysis for environmental radioactivity monitoring, nuclear emergency preparedness, nuclear waste characterization and management during operation and decommissioning of nuclear facilities, as well as medical isotope production, to achieve fast and cost-effective analysis. Dynamic flow based approaches including flow injection (FI), sequential injection (SI), multi-commuted flow injection (MCFI), multi-syringe flow injection (MSFI), multi-pumping flow system (MPFS), lab-on-valve (LOV) and lab-in-syringe (LIS) techniques have been developed and applied to meet the analytical criteria under different situations. Herein an overall review and discussion on these techniques and methodologies developed for radiochemical separation and measurement of various radionuclides is presented. Different designs of flow systems with combinations of radiochemical separation techniques, such as liquid-liquid extraction (LLE), liquid-liquid microextraction (LLME), solid phase extraction chromatography (SPEC), ion exchange chromatography (IEC), electrochemically modulated separations (EMS), capillary electrophoresis (CE), molecularly imprinted polymer (MIP) separation and online sensing and detection systems, are summarized and reviewed systematically.

An Automated SeaFAST ICP-DRC-MS Method for the Determination of 90Sr in Spent Nuclear Fuel Leachates

To reduce uncertainties in determining the source term and evolving condition of spent nuclear fuel is fundamental to the safety assessment. ß-emitting nuclides pose a challenging task for reliable, quantitative determination because both radiometric and mass spectrometric methodologies require prior chemical purification for the removal of interfering activity and isobars, respectively. A method for the determination of ⁹⁰Sr at trace levels in nuclear spent fuel leachate samples without sophisticated and time-consuming procedures has been established. The analytical approach uses a commercially available automated pre-concentration device (SeaFAST) coupled to an ICP-DRC-MS. The method shows good performances with regard to reproducibility, precision, and LOD reducing the total time of analysis for each sample to 12.5 min. The comparison between the developed method and the classical radiochemical method shows a good agreement when taking into account the associated uncertainties.

Determination of low-level Radium isotope activities in fresh waters by gamma spectrometry

A new portable sampling system was developed to extract Radium isotopes from large volumes (up to 300L) of fresh surface- and ground-waters of low Ra-activities (<5mBq/L). Ra is quantitatively adsorbed on a small amount (6.5g) of MnO₂-coated acrylic fibers, which are then dried and burned at 600°C in the laboratory. The resulting Mn-oxide powder (about 2cm³ when compacted) is then analyzed through gamma-ray spectrometry which allows measurement of the whole Ra quartet (²²⁶Ra, ²²⁸Ra, ²²⁴Ra and ²²³Ra) in a single counting of a few days. The usual relative standard combined uncertainties (1σ) are 2-3% for ²²⁶Ra, ²²⁸Ra and ²²⁴Ra; and less than 10% for ²²³Ra. This method was applied to the analysis of Ra in karstic waters of the Lez aquifer, and surface- and ground-waters of the upper and middle Vidourle watershed (South of France). The analyzed waters have relatively low ²²⁶Ra activities (1-4mBq/L) in both cases, regardless of the contrasted geology (Mesozoic limestone vs crystalline Variscan basement), but clearly distinct (²²⁸Ra/²²⁶Ra) ratios in agreement with the differences in Th/U ratios of the two drained areas. Short-lived Ra isotopes (²²⁴Ra and ²²³Ra) appear to be mainly influenced by near-surface desorption/recoil processes for most of the sampling sites.