(293c) Fiber Optic Enzymatic Biosensor Array for Measurement of Halogenated Hydrocarbon Mixtures Using a Chemometric Approach

Halogenated hydrocarbons are among the most common environmental contaminants in groundwater, due to their widespread use and their recalcitrance to natural attenuation. Halogenated alkanes (1,2-dichloroethane, 1,2-dibromoethane) could cause health problems and could be found in most environmental groundwater monitoring sites. Traditional laboratory-based analytical methods for these halogenated hydrocarbon mixtures is usually time-consuming and expensive. Biosensors could avoid these disadvantages by providing real-time in-situ measurement with highly specific and sensitive detection. We have developed a biosensor platform that includes a biological component that detects the analyte through an enzymatic reaction, a transducer to translate the biological signal into an optical signal, and a detector that recognizes the signal and correlates it to the concentration of analyte. Recently, we have developed a biosensor array consisting of multiple biosensors with different enzymes that have different activity toward the analytes in a mixture. Chemoemtric approaches are used to process these data.

In this study, a pH-based biosensor array system has been used to demonstrate the biosensor array and chemometric approach for analysis. The individual pH-based biosensors are made by using dehalogenase-expressing bacteria as the biocomponent and pH optodes as transducer. The reaction of the dehalogenases with the analytes generates protons and the pH optodes detect the resulting pH change. A set of dehalogenases is applied in different biosensors in order to build up a pH-based biosensor array, while sequential calibration on individual biosensor may be required prior to measurement. The biosensor array was capable of resolving mixtures of halogenated hydrocarbons with good accuracy. Results with different calibration methods and chemometric approaches will be discussed.