A New Method for the Determination of Ethanol in the Blood and

We have established a new method for the determination of ethanol and other gaseous substances in even minute amounts of biological material by utilizing a Curie-point pyrolyzer (Model JHP 3, Japan Analytical Industry) connected to GC or GC-MS. No pretreatment of the biological material is needed and the procedure is based on the principle that volatile or gaseous substances can be evaporated from biological materials by pulse heating and introduced for analysis directly to a GC or GC-MS. The blood from rats that had been administered ethanol-d6 orally, as well as blood and urine collected from healthy volunteers that had ingested alcoholic drinks and blood and tissue specimens taken from autopsied cadavers were examined for ethanol concentrations by both this new method and by the usual head space-GC method. To test this new method, one microliter of the blood or urine was injected into a tubularly folded ferromagnetic alloy (Pyrofoilョ) and heated pulsatively five times at 160°C (pulse heating). The vapor that evaporated from the sample then was directly introduced to the GC or GC-MS, and the time required to complete the analysis took approximately 5 min. In parallel, for comparison purposes, portions of the same samples (0.2-0.5g) were examined by means of the head space method as well. The measured values of ethanol-d6 and ethanol in the rat blood and in the human whole blood, blood plasma, and urine that were obtained by this pulse heating procedure correlated almost perfectly with those obtained by head space method. These results show the accuracy and reproducibility of this new method. Further, “pulse heating” makes it possible to determine the presence of ethanol very quickly from a very small amount of the specimen. We have termed this new investigative method for determining volatile and gaseous substances the “pulse heating method”. Informatively, nitrous oxide (N2O, laughing gas) was identified by this pulse heating GC-MS procedure from the blood and organ specimens of a victim that had succumbed to gas asphyxia.