Method for alcohol determination in biological liquids by sensing with a solid state detector

Abstract

A new method is described for quantitative alcohol determination in equilibrated headspace gas of biological liquids by means of a solid state metal oxide semiconductor (MOS) detector. After equilibration of the NaCl saturated specimen at 40 °C or other convenient temperature in a closed vessel, a Taguchi MOS sensor is momentarily exposed to the headspace vapor. The resulting dc voltage change from the baseline conditions accurately reflects the alcohol concentration of the liquid specimen, and can be read in direct alcohol concentration units. Calibration is linear to 3.00 g/liter (300 mg/dl). Values for analytical recovery ranged from 98 to 102%. Correlation of results for blood alcohol concentration by this method (y(i)) and an automated gas chromatographic reference method (x(i)) was y, g/liter = 0.991x+0.014, with r=0.997 for 103 blood specimens having concentrations ranging from 0 to 2.89 g/liter (0-289 mg/dl), with a mean difference (x(i)-y(i)) = -6 mg/liter (0.6 mg/dl). The method is sensitive to 0.01 g/liter (1 mg/dl) and can be readily automated. An internal standard is not required.