Electrochemical ion-sensors in clinical chemistry - challenges and perspectives                  

Andrzej Lewenstam 

Abo Akademi University, Center for Process Analytical Chemistry and Sensor Technology ProSens (PROSENS), Biskopsgatan 8, Turku 00410, Finland
AGH University of Science and Technology, Faculty of Materials Science and Ceramics (AGH UST), Mickiewicza 30, Kraków 30-059, Poland

Abstract

Electrochemical sensors and associated electroanalytical methods are used on a massive scale in clinical analysis. It is owing to their attractive functional parameters and the possibility of their use in high throughput random access analyzer as well as in bed-side and point-of care disposable testing. In particular, potentiometric and amperometric measurements of pH, gases, electrolytes and glucose frequently employed [1]. Emphasis on the reliability of instruments, traceability of measurments, cost reduction of tests and running costs of the laboratory, and last but not least, automation increase the need for improvements and innovations which take place through the introduction of new materials and manufacturing technology of the sensors. This, in turn, introduces new research challenges, among which - alongside the traditional tasks such as improving the properties of electroactive components and electrodes – is the miniaturization of sensors (nanosensors), their integration  (all-solid-state) and the need for direct measurement in short time, in a small sample volume and regime of low detection limits [2-4].

For signal interpretation and theoretical modeling, the present demands for new applications of ion-sensors actually mean that one should leave the current theoretical paradigm of potentiometry, which assumes equilibrium or stationary states. A new theoretical interpretation should be able to predict potentiometric signal in time and space. This can be done by resolving Nernst-Planck-Poisson (NPP) system of equations [5]. Furthermore, with the NPP it is possible to address the desired target function (e.g. linear calibration curve) via reverse modeling. The latter procedure can be used for the optimization of sensor properties e.g. to lower the detection limit of ion-selective electrodes or as a diagnostic tool [6].

In the lecture - on the example of measurement standards developed by the International Federation of Clinical Chemistry (IFCC) [1] – the role of world-wide valid recommendations is emphasized. In a real life, both new sensor designs and theoretical interpretations of the response are finally confronted with reasonably conservative regulations concerning the quality of measurements as accepted in medical diagnostic practice. This approach will allow to tune research enthusiasm of the speaker and to adjust the message for a realistic presentation of the prospects and challenges in the ion-sensor research field.

References

[1]  A. Lewenstam, Clinical analysis of blood gases and electrolytes by ion-sensitive sensors, in: S. Alegret, A. Merkoci (eds.), Electrochemical Sensor Analysis (Comprehensive Analytical Chemistry vol. 49), Chapter 1, Elsevier, Amsterdam 2007.

[2]  J. Bobacka, A. Ivaska, A. Lewenstam,  Chem. Rev., 108 (2008) 329.

[3]  J. Migdalski, B. Baś, T. Błaż, J. Golimowski and A. Lewenstam, J. Solid State Electrochem., 13 (2009) 149.

[4]  B. Paczosa-Bator, M. Stepień, M. Maj-Żurawska, A. Lewenstam,  Magnesium Res., 22 (2009) 10.

[5]  T. Sokalski, W. Kucza, M. Danielewski, A. Lewenstam, Anal. Chem., 81 (2009) 5016.

[6]  B. Grysakowski, J.J. Jasielec, B. Wierzba, T. Sokalski, A. Lewenstam, M. Danielewski, J. Electroanal. Chem., (2011) doi:10.1016/j.jelechem.2011.04.026.

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Presentation: Tutorial lectore at SMCBS'2011 International Workshop, by Andrzej Lewenstam
See On-line Journal of SMCBS'2011 International Workshop

Submitted: 2011-10-04 18:23
Revised:   2011-10-05 19:04
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