‘Electronic tongue’ for detection of metals
Development of an Analytical Methodology for Quantification of Stable Elements in Radioactive Solutions Using Electronic Tongue Multisensor Systems
Tech Area / Field
- CHE-ANL/Analytical Chemistry/Chemistry
- ENV-MIN/Monitoring and Instrumentation/Environment
- ENV-RWT/Radioactive Waste Treatment/Environment
8 Project completed
Senior Project Manager
Genisaretskaya S V
Khlopin Radium Institute, Russia, St Petersburg
- St Petersburg State University / Scientific Research Institute of Chemistry, Russia, St Petersburg\nNPO Mayak, Russia, Chelyabinsk reg., Oziorsk
- UMIST, UK, Manchester\nBattelle Energy Alliance LLC (BEA) / Idaho National Laboratory, USA, ID, Idaho Falls\nAalborg University, Denmark, Aalborg
Project summarySeveral countries, including Russia, have generated significant amounts of hazardous liquid waste due to military and civil nuclear activities. Since the issue of waste disposal was not properly addressed in the past, liquid effluents from various sources were simply collected and mixed for storage. Nowadays there are already millions of litres of highly radioactive liquids with very perse, complicated and, sometimes, scarcely known or understood chemical compositions, varying from storage tank to storage tank. Methods of liquid waste treatment are gaining momentum at present. Adequate knowledge about the composition of waste is a prerequisite for any responsible method of waste treatment. Though many analytical methods and instruments are widely available, the problem of qualitative and quantitative analysis of liquid radioactive waste and any radioactive liquids is not a trivial matter. Even if non-radioactive substances are the targeted analytes, the instrument used for analysis will be inevitably contaminated. At least several different techniques will be needed to characterize a variety of inorganic and organic components in the media. A few, if any, of these techniques can operate in remote way thus exposing humans to radiation. The analysis becomes cumbersome, very expensive, slow and unaffordable on a large scale.
Chemical sensors based on electrochemical sensing principles, e.g. potentiometry and voltammetry, are very promising instruments for solving the aforementioned tasks. Most of sensors are well suited for direct measurements and can be easily operated remotely and automatically with the help of flow-injection methodologies. Electrochemical sensors can easily be miniaturized, enabling cheaper batch production of sensors, smaller size of hardware and micro volume of samples minimizing risks of contamination during analysis and problems with final utilization of the sensors themselves. Though some chemical sensors such as pH electrodes were well known for a century, a decisive breakthrough in sensors' application to multicomponent analysis of complex analytes was made during the last decade. Multisensor systems combining arrays of non-specific sensors with multivariate calibration and pattern recognition data processing engines (an "electronic tongue") rapidly and successfully developed in the recent years can provide for competitive solution to urgent analytical problems. Chemical sensors, exhibiting enhanced cross-sensitivity (partial sensitivity and selectivity) are comprised into multisensor arrays producing pattern-like multidimensional response containing meaningful information about multiple components in liquid. Multivariate data analysis of array response produces quantitative parameters e.g. concentrations of multiple nutrients in liquid and/or qualitative attributes, e.g. an analyte can be recognized (identified) as a whole and assigned to a certain class or type of similar liquids. Sensor systems, just like discrete sensors, are suited for direct measurements and can be operated and governed remotely using simple and cost-effective hardware. Sensor array detectors can also be miniaturized. Cross-sensitive materials for multisensor arrays, which are chemically stable and durable enough to be applied to the analysis of radioactive liquids under hostile conditions, will be developed.
The principle aim of the project is to promote design of a novel "electronic tongue" multisensor system and development of practicable methodology of its analytical application to multicomponent quantitative analysis of crucial non-radioactive components in radioactive liquids, such as technological solutions and waste waters. Targeted analytes will include those originating from equipment corrosion such as iron, nickel, chromium, manganese; non-radioactive decay products such as zirconium, molybdenum and different rare-earth elements, and background elements including sodium, potassium, calcium and aluminium. Standard analytical methods such as ICP MS, AAS, AES, optical and luminescence spectroscopy, etc., will be widely applied to obtain reliable information about qualitative and quantitative composition of targeted analytes and proper modelling of synthetic complex solutions to be used in the project. A variety of novel chemical sensors and sensor arrays most suitable for project goals will be researched on the basis of useful analogies between organic solvent extraction and materials for chemical sensing. A functional laboratory prototype of flow-injection system with multisensor detection will be designed and tested in a set of project specific analytes. Adequate methods of multidimensional data processing will be elaborated and tested. Methodology of sensor system multivariate calibration employing reference data of independent analytical methods and/or simulated solution approach will be worked out with particular attention to long-term stability of calibration models and inter-instrumental compatibility. The issues of adequate sampling and sample preparation will be thoroughly addressed to eliminate unfavourable influence of highly acidic or alkaline analytes on the sensor performance and analytical results. The "electronic tongue" sensor system proposed will also be applicable to environmental monitoring, liquid waste analysis and smart process control in the nuclear industry.
Though the “electronic tongue” will be researched and developed as a novel analytical methodology it should be considered as a complementary approach to the existing analytical techniques and instruments rather than a ‘self-sufficient’ alternative method. The "electronic tongue", if developed successfully, is well suited for rapid and inexpensive multicomponent quantitative evaluation of a number of crucial components of typical liquid waste in remote automatic way without immediate human involvement. If further analysis with respect to wider range of components, higher precision or unknown analytes is necessary the whole variety of analytical methodologies should still be applied. Thus, the "electronic tongue" is going to be an efficient and cost-effective instrument for rapid assessment of composition and an on-line alarm system for detecting situations where further analytical study by different methods is required.
The project is designed as multidisciplinary concerted effort carried out by the team of highly qualified researchers in complementary areas such as radiochemistry, various fields of analytical science, solvent extraction, chemical sensors and sensor systems, multivariate data analysis and sampling. Project participants have already initiated fruitful research interaction.