The Toxicology Unit of the Michigan State Police serves the entire State of Michigan from one location at the Lansing Laboratory. Biological specimens (typically blood and urine) are submitted to the unit from law enforcement agencies in every county. Submitting agencies request the Toxicology unit's expertise to determine if alcohol or drugs played a role in OUIL/OWI, criminal sexual conduct, and death cases. The Toxicology Unit analyzes approximately 16,000 cases for the presence of alcohol and 5,500 cases for the presence of drugs per year.
Alcohol analyses are conducted using gas chromatography and drug examinations are conducted using gas chromatography/mass spectrometry. These techniques enable the identification and quantification of alcohol and drugs in biological specimens for law enforcement agencies across the State.
Blood Alcohol Analysis
The Toxicology Unit analyzes approximately 16,000 cases per year for blood alcohol. This equates to testing sixty-five cases a day, five days a week. The methodology used to confirm the presence of alcohol is called gas chromatography. Forensic Scientists prepare blood samples for alcohol analysis by mixing an internal standard solution and blood in a glass vial. A sample of the heated headspace from the prepared vial is then injected into a gas chromatograph. This test allows the Forensic Scientist to determine whether alcohol is present and if so, in what concentration.
Toxicology Drug Analysis
Approximately 5,500 cases per year will go on for drug analysis. Samples are prepared using a methodology called solid phase extraction. The samples are passed through a solid chromatographic material where components of interest, the drugs, will bind. The bound drugs can then be eluted with a solvent and collected for analysis.
The methodology used to perform drug confirmation testing is called gas chromatography/mass spectrometry. The samples that are collected during solid phase extraction are injected into a gas chromatograph to further separate the components of interest. Once separated, the compounds enter the mass spectrometer. Inside the mass spectrometer they are fragmented with electrons and the fragments are recorded as mass to charge ratios. If a series of mass to charge ratios, called a mass spectrum, indicates that a drug is present, a database is searched and the unknown drug is matched to a known entry.