Government of Ontario

CFS - TIS - Alcohol Analysis Information - RESCINDED

Centre of Forensic Sciences

Technical Information Sheets

Toxicology


Alcohol Analysis Information - (Rescinded March 16, 2012) – PDF, 55 kb


Introduction

The Toxicology Section performs analyses on body fluids (e.g., blood, urine, vitreous humour) and non-biological samples (e.g., liquids) to determine the presence/absence of alcohol.

There are several alcohols detected by this laboratory including ethanol (ethyl alcohol), which is found in alcoholic beverages, methanol (methyl alcohol, wood alcohol), and isopropanol (isopropyl alcohol, rubbing alcohol). Additionally, acetone can also be identified and quantitated by this method.

Instrumentation Method

Gas Chromatography (GC)
Chromatography is an analytical technique used to separate compounds based on their chemical and structural properties. Gas chromatography uses a pressurized gas in the separation of compounds. Head space gas chromatography is a technique used to analyze compounds present in the vapour above a liquid sample.

Examination

All items are visually examined to check the seal numbers (if present), the contents and the integrity of the packaging.

Instrumental Analysis

GC Headspace Alcohol Analysis
This analysis is used to detect and quantitate ethanol, methanol, isopropanol, and acetone by GC headspace. Additionally, the method is capable of detecting signs of putrefaction (i.e., n-propanol). Quality control test results for ethanol indicate that the analyses are accurate within + 5 mg/100 mL for concentrations less than or equal to 100 mg/100 mL, and + 5 per cent for those greater than 100 mg/100 mL.

Interpretation

Blood ethanol interpretations provided in reports are generally limited to cases where the detected concentration may be associated with fatalities, or may have had toxic interactions with other drugs.

Ethanol may arise from putrefaction. If signs of putrefaction have been detected, this will be stated in the report.

Alcohol will be reported only if present at an amount discernable from other constituents in the sample. The interpretation may be dependent upon the quality of the sample and its suitability for analysis.

Definitions of specific terms used to report findings are included in the Glossary.

Glossary

Abbreviations
Results of alcohol analyses are reported as concentrations expressed as mg/100mL. For an explanation of these abbreviations, please see the chart below.

Abbreviation/ Unabbreviated

g/gram

mg/milligram

L/litre

mL/millilitre

Central Nervous System Depression
A lowering of the functional activity of the brain and spinal cord. Depression of the respiratory and cardio-regulatory centres are most relevant toxicologically.

Detected
The drug has been identified in the sample. Identification is based on criteria specific to the analytical technique.

Not Detected
The drug is either not present, or is present, but at an amount that cannot be discerned from other constituents in the sample.

Putrefaction
The decomposition of organic material, involving microorganisms.

Traces
The drug was detected at a concentration below that which can be quantitated. The use of this term does not imply clinical efficacy.