Automated separation of 99Tc using plastic scintillation resin PSresin and openview automated modular separation system (OPENVIEW-AMSS)

A new method based on selective fluorescent polymers (PSresin) for the analysis of 90Sr in presence of 210Pb in environmental samples

⁹⁰Sr is of major concern in emergency and environmental control plans. It is one of the main fission products in nuclear facilities and is a high-energy beta emitter that presents chemical properties similar to those of calcium. ⁹⁰Sr is commonly detected using methods based on liquid scintillation counting (LSC) following a chemical separation to remove potential interferences. However, these methods generate mixed wastes (hazardous and radioactive). In recent years, an alternative strategy using PSresins has been developed. For ⁹⁰Sr analysis with PSresins, ²¹⁰Pb is the main interferent that should be considered, as it is also strongly retained in the PSresin. In this study, a procedure was developed involving a precipitation with iodates to separate lead from strontium before the PSresin separation. Moreover, the method developed was compared with well-established and routinely used methods based on LSC, revealing that the new method produced equivalent results in less time and with less waste generation.

PSresin for the analysis of alpha-emitting radionuclides: Comparison of diphosphonic acid-based extractants

The analysis of radionuclides is complex, with high economic and time costs. For this reason, there is a need to develop new methods and strategies to reduce these costs. One important group in the analysis of radionuclides is the actinides, which are the main constituents assessed in the total gross alpha together with radium and radon test used to measure radioactivity in drinking water. Moreover, in nuclear dismantling processes, the possible spread of the released radionuclides has to be controlled, which is measured by many techniques, depending on the radionuclides, through scintillation. This work presents a new method to analyse actinides using plastic scintillation resins (PSresins) packed in a solid-phase extraction cartridge. The proposed method combines chemical separation and sample measurement into a single step, reducing the effort, time and reagents required for analysis as well as decreasing the amount of waste generated. The PSresins compared in this study contained three selective extractants based on methylenediphosphonic acid with different radicals, which has a high affinity for tri-, tetra-, and hexavalent actinides in dilute acids. These extractants were immobilised on plastic scintillation microspheres at a ratio of 1/1:6, producing a retention and detection efficiency of 100% for ²⁴¹Am, ²³⁰Th, Uranium and ²³⁸Pu. The retention and detection efficiency were 20% and 100%, respectively, for ²¹⁰Po and low for ²²⁶Ra.

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.