Development of a Bioelectronic Tongue -Applications for Wastewater Analysis

Sammanfattning: A bioelectronic tongue has been developed for applications in wastewater analysis. The development of a biosensor array with complex signal analysis started from the idea of using group-selective phenol biosensors (tyrosinase and horseradish peroxidase) with chemometric analysis for signal processing. In a first step the ability to simultaneously determine each analyte in synthetic binary phenol mixtures was evaluated using multivariate data analysis on the responses from a single tyrosinase-modified solid graphite electrode. The next step was to construct a suitable device where different biosensors could be used in an array for multi-parameter detection of samples. Screen-printed electrodes of carbon and noble metals were first evaluated with the purpose of identifying electrodes that could be used as a basis for immobilisation of phenol- and pesticide-sensitive enzymes (horseradish peroxidase, soybean peroxidase, cellobiose dehydrogenase, acetylcholinesterase and butyrylcholinesterase). These enzymes were then immobilised on an array of eight radially distributed electrodes. To host the array and to provide equal hydrodynamics at each electrode in the array, a special electrochemical cell was constructed to enable flow-injection and steady-state measurements. Together with multivariate data analysis has this array system been successfully used for qualitative discrimination of wastewater samples as well as for quantitative determination of their toxicity and other pollution parameters such as chemical oxygen demand and biological oxygen demand. Pre-processing of data before multivariate analysis was shown to be necessary for reducing the noise that otherwise can hide the desired structural information. Several strategies to overcome noise problems due to drift in biosensors have been developed.