Analysis of breath alcohol with a multisensor array: instrumental setup, characterization and evaluation

The purpose of this work was to evaluate if it was possible to measure the alcohol concentration in breath by a multisensor array, i.e. an electronic nose. The most important aspects were to clarify technical advantages and d isadvantages and if the technique is at all suitable for forensic breath al cohol analysis. Even though the system set-up was far from optimal it is cl ear that it was possible to quantify breath alcohol with a best-case root m ean square error=16.8 mol ppm ethanol (=0.037 mg/l). However, the method ne eds significant development especially of the sensor devices. The sensor ar ray was composed of ten metal oxide silicon field effect transistors (MOSFE T) with various catalytic gates and one infrared-based CO, sensor. The syst em was evaluated by monitoring the breath ethanol concentration of five tes t persons after intake of alcohol. Gas chromatography was used in parallel to measure the actual breath alcohol concentration. Different data evaluati on techniques applied were;projection to latent structure (PLS) and artific ial neural networks (ANN). (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.