Potassium, sodium, and calcium are crucial electrolytes of human blood. Among the functions of the electrolytes are maintenance of osmotic pressure and water distribution in the various body fluid compartments, maintenance of the proper pH, regulation of the proper function of the heart and other muscles, involvement in oxidation-reduction or electron transfer reactions, and participation in catalysis as cofactors for enzymes. Therefore, abnormal levels of electrolytes may be either the cause or the consequence of a variety of disorders, and thus the determination of electrolytes in different body fluids in general and in whole human blood particularly is one of the most important functions of the clinical laboratory . Serum or plasma is the usual specimen employed for assay of potassium, sodium, and calcium but not whole human blood. This research intended to create a sensor-array capable of analysing potassium, sodium, and calcium ion-activity in whole human blood based on miniaturised ion-sensors and zero-current direct potentiometry. This research dealt with sensing-side of the sensor-array hoping for integration of these sensors with microelectronics or discrete parts based electronics in due time. Clinics use single electrodes for K+, Na+, and Ca2+ sensing in body fluids. However, single sensing is costly and in emergency cases time consuming as well. Therefore a portable, battery-operated cost- and time-effective sensor array is needed for multi-sensing of r, Na +, and Ca2 + either in emergency cases in field or for patient near bed-side measurement/monitoring. The approach of this thesis to the problem is as follows: This thesis has five phases, all equally important. The first phase, a theoretical phase, mainly deals with the determination of the technique which fits best with chemical sensors and integration with microelectronics, and the decision among many alternative chemicals, whether natural or man-made, available for multi-sensing realisation, by taking into account all the best efforts devoted to development of chemical-sensors. The second phase is the miniaturisation process of the electrochemical sensor-array, either ion-sensors or reference electrode, as much as possible. The third phase is multi-sensing application of the sensorarray for sensing K+, Na+, and ci+ with binary and mixed electrolytes and with artificial and whole human blood respectively, the fourth phase is the sensor-array response with only millilitre or microlitre volumes of whole human blood and the fifth phase is the integration of a sensor array with discrete, parts based, electronic circuitry. So, as a new application a disposable reference electrode has been realised which reasonably fits with the sensor array for the analysis of potassium, sodium, and calcium in whole human blood. Since all the single sensing of these cations have been realised by using a conventional reference electrode, either silver/silver chloride or calomel electrode, which is a bulky and expensive alternative, this research prepared, tested, and implemented a new disposable reference electrode for the sensor-array based on a poly (vinyl alcohol) matrix incorporating a proper amount of Kel. Having a successfully working miniaturised reference electrode, valinomycin, ETH 157, and ETH 1001 ionophores have been used as the selective materials for potassium, sodium, and calcium in whole human blood, respectively. Multisensing applications have only used solutions as testing medium whereas the work described in this thesis goes one step further and uses artificial and whole human blood with fairly reasonable responses.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:285141 |
| Date | January 1998 |
| Creators | Yalcinkaya, Fikret |
| Publisher | University of Sussex |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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