Accompanying alcohol analysis
The accompanying alcohol analysis is a forensic medical procedure in which blood or serum is examined for so-called accompanying alcohols .
basis
The accompanying alcohols contained in alcoholic beverages are absorbed together with ethanol and, like this, also distributed with the bloodstream in the body water. The accompanying alcohols methanol , n-propanol and isobutanol , which are relevant from a forensic point of view , differ only slightly from that of ethanol in terms of their water solubility. Like ethanol, they are mainly broken down by alcohol dehydrogenase (ADH) as a catalyst. As a result, ethanol can influence the breakdown of the accompanying alcohol. Gas chromatography is the method of choice for separating the accompanying alcohols and ethanol .
Ingredients markers
In the last few years a new type of accompanying alcohol analysis has been developed that detects beverage-specific substances that arise during the production of the beverage. Ideally, these markers should only be present in this drink and not in other beverages, foods or the environment.
For example, previous beer consumption could be clearly demonstrated by the detection of iso-alpha-acid compounds in the blood, which arise from the hops used in the brewing process. These compounds could be detected in blood several hours after beer consumption in controlled drinking studies that included beers with low and high levels of hops. This methodology presents new possibilities for accompanying alcohol analysis, while other ingredient-specific markers (e.g. for wine or spirits) are already in the development phase.
meaning
The procedure is particularly relevant in the case of drunk driving to confirm or refute claims after drinking or to search for signs of alcoholism .
After-drinking allegations
Occasionally, accused persons explain their alcoholism in the context of traffic offenses by saying that they only consumed a large amount of an alcoholic drink after participating in road traffic. This after-drink should then explain the blood alcohol concentration determined with the blood sample . If no credible witnesses are available to confirm or refute this information, the accompanying alcohol analysis can, under certain circumstances, be used to check the information on after-drinking. It is necessary to know the drink allegedly drunk and the time of the night. If, during the examination, the pattern of the accompanying alcohols in the allegedly drunk beverage is not found in the blood, this is an indication against the allegation of late drinking. The accompanying alcohols n-propanol and isobutanol are of particular importance for the characterization of beverages.
Alcohol sickness markers
At an ethanol level of around 100 mg / kg, the ADH is blocked by ethanol to such an extent that the breakdown of methanol and 2-propanol is completely inhibited. Above this threshold value, both alcohols are regenerated induced by ethanol. As a result, the levels of both substances increase with a longer alcoholisation phase.
Apart from the methanol-rich fruit brandies, the methanol levels are mainly due to the ethanol-induced regeneration. Methanol levels above 10 mg / kg are an indication of problematic alcohol consumption without prolonged periods of alcoholism.
No 2-propanol can be found in correctly manufactured alcoholic beverages. It is produced in the body by reduction from acetone , which can also be determined in the blood by gas chromatography. During exercise or alcoholism, the concentrations of acetone and 2-propanol in the blood can rise. In addition to methanol, both substances are indicators of problematic alcohol use.
Like other laboratory parameters , these markers are not indicative of alcohol abuse.
swell
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Individual evidence
- ↑ Rodda LN, Gerostamoulos D, Drummer OH: The rapid identification and quantification of iso-α-acids and reduced iso-α-acids in blood using UHPLC-MS / MS: validation of a novel marker for beer consumption. , Anal Bioanal Chem. 2013 Dec; 405 (30): 9755-67, PMID 24177342