Postmortem Alcohol

• Author: James G. Wigmore
• Pages: 373-418

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 

Postmortem Alcohol

The analysis a nd interpretation of alcohol testing postmortem is more

complicated than in blood samples collected from living subject s. Fac-

tors such as postmortem dif‌fu sion and putrefaction (partial ly as a result

of high postmortem blood sugar concentrations) can af‌fect the results.

Blood can be collected from a variety of areas, such as the heart, i liac

(leg) vein, or a hematoma (blood clot), rather than from just venous blood,

which is routinely collected from living persons in dri nking-and-driving

cases. As well the alcohol concentration can be determined in v itreous

humor (VH), liver, bile, or muscle. Postmortem biomarkers of alcohol

ingestion can assist in determ ining whether the postmortem blood al-

cohol concentration (BAC) has been af‌fected by putrefaction.

In general, the postmortem BAC is not as stable as blood collected

from living subjects for the following reason s:

• Postmortem blood is not sterile.

• Numerous bacteria and yeasts that migrate from the gut post-

mortem are present in the blood.

• Postmortem blood can have very high glucose concentration.

7.01 METHODS OF ANALySIS

Headspace gas chromatography (GC) is the current preferred method of

alcohol analysis in postmortem blood samples, as it is for antemortem

samples. It is recommended, however, that t-butanol be employed as the

internal sta ndard rather than n-propanol, which is commonly used for an-

temortem samples, as n-propanol is a putrefactive product (, ).

  Wigmore on Alcohol

Reference Number: 

Reference Number: 

, ., .. ,  .. . “Determination of Etha-

nol in Fresh and Purif‌ied Postmortem Tissues.” Journal of Chromatog-

raphy, : –,  ( tables,  f‌igures,  references)

Abstract: Postmortem blood and tissues were analyzed for etha nol by GC

and Widmark (potassium dichromate) methods. The Widmark method

should not be used in postmortem blood. One Widmark ana lysis showed

a reading as high as .g/mL of oxidizable material, c alculated as

ethanol, whereas the GC ana lysis showed no ethanol. In postmortem

blood samples, the glucose concentration ranged from  to , mg/

dL. Of f‌ive ethanol-negative postmortem blood samples that were pre-

served in % NaF and stored at room temperature, three samples pro-

duced ethanol with time and one showed an increase to .g/mL.

Samples with % NaF that were refrigerated showed no increase after

 days. Urine samples stored at room temperature with no preserva-

tives showed only slight increases in ethanol, up to .g/mL, and

the f‌luctuations in urine alcohol concentration (UAC) with time were

small compared with the cha nges in BAC. It is recommended that blood

samples be preserved with % NaF and refrigerated.

Widmark’s method is reliable for the deter mination of ethanol only in

the absence of distillable volatiles such as methanol, acetaldehyde, iso -

propyl alcohol, -propanol, and -butanol.

Reference Number: 

’, .., ..  , . , . ,  . . “Gas

Chromatographic Procedures for Determination of Ethanol in Post-

mortem Blood Using t-Butanol and Methyl Ethyl Ketone as Internal

Standards.” Forensic Science International, : –,  ( tables, 

f‌igures,  references)

Abstract: Three GC procedures for the determination of alcohol in post-

mortem blood are described using methyl ethyl ketone (MEK) or t-butyl

alcohol as internal sta ndards and headspace GC, or using t-butyl alcohol

and headspace GC. For the t-butyl alcohol headspace GC method, a n

Rtx-BAC column was used measuring  m × . mm, internal diam-

eter (ID) × . μm. Pipetted into the headspace vials were . mL of the

sample and . mL of the internal st andard.

Postmortem Alcohol  

Reference Number: 

Our study demonstrates that using t-butanol or methyl e thyl ketone as

internal standards resulted in precise ethanol determinations in post-

mortem blood, whether applie d to procedures with packed or capillary

columns, with direct injection or headspace ga s chromatography. Addi-

tionally, the use of these internal standards with capillar y headspace

gas chromatography allows for the identif‌ication of other volatiles in

postmortem specimens, specif‌ically n-propanol, that may aid in distin-

guishing antemortem ingestion from postmortem synthesis of ethanol.

Reference Number: 

, ., . ,  .. . “Evaluation of Ethanol Analy-

sis on Brain and Liver by Head-Space Gas Chromatography.” Forensic

Science International, : –,  ( table,  references)

Abstract: A headspace GC method is described for the determi nation of

ethanol concentration in brain and liver tissues. A Multifract F- was

used, and the internal standard was t-butanol. The ef‌fect of the fat con-

tent of the sample on the alcohol analysis was determined using spike

samples of water (% fat content), skimmed milk (.%), homogenized

milk (.%), and heavy cream (%). As the fat content increased, the in-

ternal sta ndard peak height decreased compared with the peak height of

ethyl alcohol. At a spiked ethyl alcohol concentration of .g/mL,

the measured results were ., ., ., and .g/ mL, for

water, skim milk, homogenized milk, and heavy cream, respectively. t-

Butanol is more fat soluble than ethyl alcohol. The ratio of the ethanol

concentration of the brain and blood is between .: and .:. There

was a poor correlation between blood and liver ethanol concentration.

This is thought to be due to the natu ral oxidative losses of ethanol in the

liver and the variable fat content of the sample.

The direct headspace chromatographic method as ap plied to the deter-

mination of ethanol in the brain is a reliable indication of antemor tem

concentration of ethanol in the central nervous system. This is true de-

spite the postmortem changes that may occur in the bod y or in vitro.

The methodology does not yield a s reliable results for the analysis of

ethanol in the liver, which presents the additional problem of remark-

able postmortem oxidation of ethanol.