Article

Validation of a headspace solid-phase microextraction-GC-MS/MS for the determination of ethyl glucuronide in hair according to forensic guidelines

Labor Krone, Bad Salzuflen, Germany.
Forensic science international (Impact Factor: 2.14). 03/2010; 196(1-3):3-9. DOI: 10.1016/j.forsciint.2009.07.023
Source: PubMed

ABSTRACT

The analysis of ethyl glucuronide (EtG) in hair is a powerful tool for chronic alcohol abuse control because of the typical wide detection window of the hair matrix and due to the possibility of segmentation, allowing evaluation of alcohol consumption in different periods. Additionally, EtG in hair is often the only diagnostic parameter of choice for alcohol abuse when other clinical parameters such as ALT, AST, gammaGT and CDT (asialotransferrin and disialotransferrin) are in the normal range and EtG in urine negative. In this paper, we describe the development, optimization and validation of a new method based on hair extraction with water, clean-up by solid phase extraction (SPE), derivatization with heptafluorobutyric anhydride and headspace solid-phase microextraction (HS-SPME) in combination with GC-MS/MS according to forensic guidelines. The assay linearity of EtG was confirmed over the range from 2.8 to 1000 pg/mg hair, with a coefficient of determination (r(2)) above 0.999. The LLOQ was 2.8 pg/mg and the LLOD was 0.6 pg/mg. An error profile calculated according to the "Guide to the Expression of Uncertainty in Measurement" (GUM) at 99% confidence intervals for the range 5-750 pg/mg hair did not exceed 10%. This range corresponds to more than 98% of the positive samples analysed.

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    • "Tandem mass spectrometry (MS/MS) minimizes background interferences and allows multiple reaction-monitoring (MRM) and should thus result in higher sensitivity and selectivity. Indeed, GC–MS/MS methods operated in EI mode showed an improved sensitivity [10] [11], but this increase could not be observed between GC–NICI– MS and GC–NICI–MS/MS methods [12] [13]. "
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    ABSTRACT: Ethyl glucuronide (EtG), a minor metabolite of ethanol, accumulates in hair and is currently used as a long-term marker for the detection of chronic and excessive alcohol consumption. Sensitive methods are required to differentiate teetotalers from moderate drinkers according to the established cut-off (i.e., 7 pg/mg hair). The aim of this study was to develop a sensitive method using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) operated in the negative ion chemical ionization (NICI) mode. The validated method was applied to hair samples from teetotalers, moderate and excessive alcohol consumers, and results were compared to a previously validated GC-NICI-MS method. The developed GC-NICI-MS/MS method showed linearity over a range from 2 to 400 pg/mg hair, with a limit of detection (LOD) of 0.05 pg/mg hair and a lower limit of quantification (LLOQ) of 0.2 pg/mg hair, compared to an LOD of 0.5 pg/mg hair and LLOQ of 1.5 pg/mg hair obtained with GC-NICI-MS. Furthermore, lower background noise was observed using GC-NICI-MS/MS. Comparison of results of hair samples (n = 58) obtained by GC-NICI-MS and GC-NICI-MS/MS showed no significant difference between both methods (paired-sample t-test, p > 0.05; mean CV = 1.0%). The differences between both methods were larger for EtG concentrations < 30 mg/pg hair (mean CV = 1.7%) than for EtG concentrations > 30 mg/pg hair (mean CV = 0.7%). This suggests a higher selectivity of GC-NICI-MS/MS at lower concentrations. In conclusion, by using GC-NICI-MS/MS, a higher analytical selectivity and an improved signal to noise ratio, can be achieved. Although GC-NICI-MS would not change the interpretation of the EtG concentrations, the present GC-NICI-MS/MS method should preferentially be used for the determination of EtG in hair, especially when differentiating between teetotalers and moderate drinkers according to the current cut-off (i.e., 7 pg/mg hair).
    No preview · Article · Dec 2014 · Forensic Science International
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    • "Their subjects consumed a fixed daily amount of alcohol, and this helped to define the lower end of the continuum. Agius and colleagues [18] recently reported a headspace solid phase microextraction method in combination with a GC/MS/MS (gas chromatography/ tandem mass spectrometry) procedure to measure hair EtG. "
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    ABSTRACT: Widespread concern about illicit drugs as an aspect of workplace performance potentially diminishes attention on employee alcohol use. Alcohol is the dominant drug contributing to poor job performance; it also accounts for a third of the worldwide public health burden. Evidence from public roadways--a workplace for many--provides an example of work-related risk exposure and performance lapses. In most developed countries, alcohol is involved in 20-35% of fatal crashes; drugs other than alcohol are less prominently involved in fatalities. Alcohol biomarkers can improve detection by extending the timeframe for estimating problematic exposure levels and thereby provide better information for managers. But what levels and which markers are right for the workplace? In this paper, an established high-sensitivity proxy for alcohol-driving risk proclivity is used: an average eight months of failed blood alcohol concentration (BAC) breath tests from alcohol ignition interlock devices. Higher BAC test fail rates are known to presage higher rates of future impaired-driving convictions (driving under the influence; DUI). Drivers in alcohol interlock programmes log 5-7 daily BAC tests; in 12 months, this yields thousands of samples. Also, higher programme entry levels of alcohol biomarkers predict a higher likelihood of failed interlock BAC tests during subsequent months. This paper summarizes the potential of selected biomarkers for workplace screening. Markers include phosphatidylethanol (PEth), percent carbohydrate deficient transferrin (%CDT), gammaglutamyltransferase (GGT), gamma %CDT (γ%CDT), and ethylglucuronide (EtG) in hair. Clinical cut-off levels and median/mean levels of these markers in abstinent people, the general population, DUI drivers, and rehabilitation clinics are summarized for context.
    Preview · Article · Feb 2012 · Drug Testing and Analysis
    • "The validation results were presented in detail in previously published HS-SPME–GC–MS/MS method [21] and GC–MS/NCI method [12]. "
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    ABSTRACT: This paper addresses the suitability of ethyl glucuronide in hair (EtGH) strands other than 3cm for alcohol consumption. This issue will be addressed (a) by statistically comparing the distribution of EtGH results for 3cm hair strands to other hair strands analysed from 4126 cases and (b) by examining the stability of EtGH in an 8cm hair strand and two 12cm hair samples of two volunteers and a post-mortem case using 1cm segmental analysis. For 3464 driving license re-granting Medical and Psychological Assessment (MPA) cases, the detection of alcohol consumption using hair lengths longer than 3cm was never significantly less than for 3cm hair lengths, even up to 12cm hair lengths analysed non-segmented. For 662 non-MPA cases, where, in contrast to MPA cases, generally no abstinence was required, an increase in the EtGH positivity rate was observed with increasing hair length analysed up to 9cm, indicating that EtG-washout effects seem to play a minor role if any. For both MPA and non-MPA hair samples less than 3cm, a drastic, significant increase in the number of positive EtGH samples were observed, compared to 3cm hair lengths, strongly supportive of EtGH incorporation from sweat after a recent alcohol consumption. Segmental studies indicated that EtG is stable in the hair matrix up to 12cm long, hence supporting the above results. Even though both the statistical and the stability studies are preliminary results which need to be confirmed by other studies, they both provide evidence for the determination of alcohol consumption using EtGH in hair lengths longer than 3cm. Amendments to the Consensus of the Society of Hair Testing, the German driving license re-granting guidelines and EWDTS hair guidelines with respect to testing for abstinence and/or alcoholism are proposed for the benefit of the donors.
    No preview · Article · Oct 2011 · Forensic science international
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