salting2.df: Salting out effects in forensic blood alcohol determination

In dafs: Data Analysis for Forensic Scientists

Salting out effects in forensic blood alcohol determination

Description

Blood alcohol measurements determined by headspace gas chromatography have been challenged on the grounds that the presence of the preservative sodium fluoride in blood samples artificially increases headspace alcohol concentrations due to a salting out effect. Blood samples containing varying amounts of ethanol and sodium fluoride (NaF) were tested using semi-automated headspace gas chromatography with n-propyl alcohol as the internal standard to assess the validity of this challenge. Miller et al found, in fact, that under these test conditions the measured alcohol levels are systematically depressed as the amount of sodium fluoride in the blood sample increases.

Blood was drawn from each of four subjects at two time points, first near the time of estimated peak blood alcohol concentration and then approximately 1.5 hours later. Samples were initially analyzed with NaF at manufacturer's levels (ca. 10 mg/mL).

Usage

data(salting2.df)

Format

A data frame containing four variables

[,1]	subject	numeric factor	subject identifier 1-4
[,2]	time	numeric factor	time sample taken 0 or 1.5h
[,3]	NaF	numeric factor	the level of sodium fluoride added in mg/mL
[,4]	EtOH	numeric	alcohol concentration in g/100mL

Details

Note that the blocking and treatment factors in this data frame are numeric. Therefore, to use them as such will require the use of factor or ordered.

Author(s)

B. A. Miller et al.

References

B.A. Miller, S.M. Day, T.E. Vasquez, F.M. Evans, Absence of salting out effects in forensic blood alcohol determination at various concentrations of sodium fluoride using semi-automated headspace gas chromatography, Science & Justice, Volume 44, Issue 2, April 2004, Pages 73-76.

dafs documentation built on April 11, 2022, 5:06 p.m.