Sensors based on polymer modified electrodes

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been carried out. PVC mini-ion-selective electrodes of dimensions suitable for insertion into a catheter (French-8) were constructed and used t o determine plasmatic sodium. The performance of the electrodes suggests that selectivity against other commonly analysed plasma cations is superior to that obtained with currently available sodium electrodes employing either glass or PVC membranes. The membrane developed containing methyl ptert-butylcalix[4]aryl acetate as ionophore has a particularly good selectivity (around 1000-fold) against lithium ions. Sodium levels in blood plasma have been successfully measured by both steady-state and flow-injection methods. The results correlate closely with independent values obtained from a hospital-based SMAC analyser, and with measurements carried out using atomic absorption spectrocopy.

general principles covering the formation and properties are understood the actual materials synthesised are not so clearly characterised. This study is concerned with relating the characteristics of laboratory grown PPyfilms t o the change i n conductivity they exhibit o n exposure t o NO, gas. PPy films are prepared in the doped form for gas sensors and are generally amorphous; also those prepared electrochemically are fairly porous so that characterisation at the molecular level is difficult. Our studies have shown that microstructure and response are highly dependent o n growth conditions, in particular the counter ion present in the polymer backbone. This paper concentrates particularly on preparations from aqueous solutions such as potassium chloride, where the PPy film is thought t o consist of an oxidised polypyrrole backbone with CI- counter ions.

B13. DEVELOPMENT OF AN OPTICAL FIBRE ALUMINIUM SENSOR IN A FLOWING SYSTEM E. Blanco Gonzalez, R. Pereiro Garcia, M. E. Diaz Garcia and A. Sanz-Medel, Department of Physical and Analytical Chemistry, University of Oviedo, Spain, R. Narayanaswamy, Department of Instrumentation and Analytical Science, UMIST, Manchester, UK In the last few years the advantages of chemical sensors based on optical fibres have been widely recognised and consequently the development of these devices has been pursued with intense interest. This type of sensor is based on the change in the optical characteristics of a reagent phase incorporated o n t o the tip of an optical fibre, through which the change is detected. The reagent phase usually consists of a chemically specific reagent immobilised on a polymeric solid support. Recently, the use of optical fibre sensors in a flowing system has also been reported.’ This may therefore be applicable in FIA and HPLC techniques. This paper presents preliminary studies o n the development of an optical fibre sensor for aluminium ions. Oxine derivative Kelex 100 has been immobilised on several solid supports (non-ionic resins) and their reaction with aluminium investigated. The suitability of each of the reagent phases in an optical sensor in a flowing system has been evaluated and several possible applications will be suggested.

B16. DEVELOPMENT OF A TEST RIG FOR EVALUATING METAL OXIDE GAS SENSORS I N SOLVENT ANALYSIS A. Bruce and S. J. Haswell, Tharnes Polytechnic, Wellington Street, Woolwich, London SE18 6PF, UK A sensor array of semiconductor metal oxide gas sensors was subjected t o various concentrations of solvents in a dynamic gas circuit with nitrogen as the carrier gas. The accuracy of the gas concentrations was monitored using a gas chromatograph previously calibrated using the exponential dilution method. The fully automated array was controlled using twelve bit analog to digital/digital to analog converters via an IEE 488 GPlB to an IBM compatible computer. The data were saved on a spreadsheet (Lotus 123 compatible) and analysed using chemometric techniques. Examples of quantitative and qualitative solvent recognition will be described for the various systems.

Reference 1. Narayanaswamy, R., and Sevilla, F.,

111,

Analyst, 1986, 111, 1085.

814. SENSORS BASED ON POLYMER MODIFIED ELECTRODES Malcolm R. Smyth, Dona1 Leech, Mary Meaney, Johannes G. Vos, School of Chemical Sciences, NlHE Dublin, Glasnevin, Dublin 9, Ireland, Pilar Dominguez, Jose-Maria Fernandez Alvarez and Paulino Tunon Blanco, Department of Analytical Chemistry, University of Oviedo, Oviedo, Spain The application of polymer modified electrodes as sensors for a range of inorganic and organic species is of increasing interest in analytical chemistry. In recent years, our studies have concentrated on the development of polymer modified electrodes based on [Ru(bpy),(PVP),CIICI as detection systems in f l o w injection analysis,’,* and o n the incorporation of antibody species, such as anti-human serum albumin, into polypyrrole.3 This paper will review the recent results that we have obtained using novel ruthenium containing polymers, and on further studies o n the incorporation of proteins into polymeric matrices.

References Barisci, J. N., Wallace, G. G., Wilke, E., Meaney, M., Smyth, M. R., and Vos, J. G., Electroanalysis, in the press. 2. Meaney, M., Smyth, M. R., Vos, J. G., and Wallace, G. G., Electroanalysis, submitted for publication. 3. John, R., Wallace, G. G., and Smyth, M. R., Biasensors, submitted for publication. 1.

B15. THE PREPARATION OF POLYPYRROLE LAYERS FOR NO, GAS SENSORS Jonathan M. Slater and Esther Watt, Centre for Analytical Science, Birkbeck College, Gordon House, 29 Gordon Squsre, London WC1H OPP, UK Polypyrrole (PPy) is a particularly stable conducting polymer which may be prepared in a doped form with room temperature conductivity in the range 1-100 S cm-1. The polymer has been extensively investigated for applications i n batteries, electronic devices and, more recently, gas sensors. However, while the

B17. A SENSOR FOR TRACE LEVELS OF PHENOLS IN WATER E. S. Bridgeland, V. H. P. Colclough, R. A. Jewsbury and N. D. Martin, Department of Chemical and Physical Sciences, The Polytechnic, Queensgate, Huddersfield HDl 3DH, UK A method is proposed for the remote sensing of phenolic pollutants at the n g g - ’ level in water. The sensor is based o n a flow injection system i n which phenols are hydroxylated enzymatically b y using phenol 2-mono-oxygenase and the resultant polyhydroxy phenols detected by their enhanced chemiluminescent oxidation. B18. IMMOBILISATION OF COMPONENTS OF ANTIGEN - ANTIBODY REACTION ON THE SURFACE OF SEMICONDUCTOR STRUCTURE AND CHARACTERISTICS OF THE PRODUCT Vladimir Zaitsev, Larisa Kolomietz and Victor Scopenco, Kiev State University, Institute of Molecular Biology and Genetics, Academy of Sciences of the Ukrainian SSR, USSR In order to construct an immune sensor, the surface of a semiconductor was modified by specific components of immune - chemical reaction. The control of immobilisation was achieved by an immune-enzyme test with chemiluminescence detection. For a blank experiment the structure with immobilised nonspecific antigen was used. It was shown that at chemical binding the antigen determinants are preserved. The stability of the active part of the sensor t o chemical attack was studied by incubation of the sensor i n salt buffers and detergents. Salt buffer treatment of the material with surfactants or 50% dioxyethane does not result in antigen elimination and immune activity decrease of the attached material. In a solution of urea of pH 2, in the presence of surfactant, activity decreases t o some extent with the adsorbed material losing its activity. The stability of the sensors during storage was investigated. The attached antigens were found t o keep their ability t o specific interaction for at least 3 months. The ability of immobilised antigen t o react with specific antibody is reversible. The greatest stability of this biological structure was achieved when 20% dioxyethane solution was used. In this detergent the antigen antibody bond is fully destroyed but the immune response of bound antigen in later reactions does not decrease.

C9. FOURIER TRANSFORM RAMAN SPECTROSCOPY IN INDUSTRIAL RESEARCH Stephen P. Church, Peter J. Stephenson, Courtaulds Research, P.O. Box 7 I I, Lockhurst Lane, Coventry CV6 5RS, UK, Pat J. Hendra, Department of Chemistry, The University, Southampton SO9 5NH, UK Considering the importance of Raman spectroscopy as an analytical technique it is perhaps surprising that Raman spec-