Determination Of Ethyl Glucuronide In Hair Research Articles

Variability on ethyl glucuronide concentrations in hair depending on sample pretreatment, using a new developed GC–MS/MS method

Quantitative determination of ethyl glucuronide in keratin matrix, particularly in hair samples, provides a significant contribution to the evaluation of the extent of ethanol intake. The first-choice method to carry out this analysis is LC–MS/MS, but other techniques may be used. The aim of this work is: a) to develop and validate a GC–MS/MS method for ethyl glucuronide determination in hair; b) to compare GC–MS/MS and LC–MS/MS in analysis of real samples; c) to compare EtG concentration obtained after hair cutting and pulverization.About 30 mg hair samples were washed, pulverized and soaked in 1 ml deionized water. After incubation, the solution was purified through a SPE anion exchange cartridge; the eluate was dried under nitrogen stream, derivatized with PFPA and reconstituted in n-hexane. Then, the sample was injected in the GC–MS/MS system, operating in negative chemical ionization mode and in selected reaction monitoring. The two most intense transitions were used to monitor ethyl glucuronide and deuterated internal standard. All the validation parameters fulfilled the international acceptance criteria. LOD and LOQ were set at 2.0 and 3.0 pg/mg respectively.This method was applied to 194 hair samples collected from teetotallers and alcohol consumers and represents a suitable alternative to LC–MS/MS for the determination of EtG in hair samples, in particular when scarce quantity of hair is available. This study confirmed that pulverization of hair increases the concentration of EtG, but some variability of EtG levels remains probably due to the presence of non-homogeneous material even though pulverization.

Gas chromatographic determination of ethyl glucuronide in hair: Comparison between tandem mass spectrometry and single quadrupole mass spectrometry

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., 7pg/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 400pg/mg hair, with a limit of detection (LOD) of 0.05pg/mg hair and a lower limit of quantification (LLOQ) of 0.2pg/mg hair, compared to an LOD of 0.5pg/mg hair and LLOQ of 1.5pg/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<30mg/pg hair (mean CV=1.7%) than for EtG concentrations>30mg/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., 7pg/mg hair).

P1: GC-MS or GC-MS/MS for the determination of ethyl glucuronide in hair?

Introduction Ethyl glucuronide (EtG) in hair is currently used as a long-term alcohol marker, and methods with low LOQs are required to differentiate teetotalers from moderate drinkers according to the cut-offs (i.e., 7 pg/mg hair). The determination of EtG may be performed by either LC-MS/MS or GC-(MS/)MS. The use of negative ion chemical ionization (NICI) improves the analytical sensitivity of GCMS, whereas similar LOQs were observed for GC-MS and GC-MS/MS (C.L. Crunelle et al. , Drug Alcohol Depend. 2014;134:1-11). However, the direct comparison of GC-MS and GC-MS/MS in NICI has never been investigated. This study compares GC-MS and GCMS/ MS in NICI mode for EtG determination in hair in order to assess the additional qualitative and quantitative advantages of GCMS/ MS. Methods Hair segments from 64 volunteers (teetotalers, moderate drinkers and excessive drinkers) were analyzed by GC-MS and GCMS/ MS operated in NICI mode on the same instrument. Samples were processed according to I. Kerekes et al. (Ther. Drug Monit. 2013;35:527-529) using a derivatization with heptafluorobutyric anhydride. Results The LOD and LOQ obtained using GC-MS/MS were 0.005 pg/mg and 0.017 pg/mg respectively, compared to a LOD of 0.022 pg/mg and LOQ of 0.075 pg/mg with GC-MS. R 2 of calibration curves of both methods were above 0.998. Furthermore, lower background noise was observed using GC-MS/MS. The obtained EtG concentrations from the hair samples were similar (mean CV = 1.01 %). The differences between both methods were larger for lower EtG concentrations (mean CV = 1.67 %) than for higher EtG concentrations (mean CV = 0.64 %). This suggests a higher selectivity of GC-MS/MS at lower concentrations. Conclusions By using GC-MS/MS, a higher analytical selectivity and an improved signal to noise ratio, can be achieved. However, using GC-MS/MS instead of GC-MS would not change interpretation of the samples’ EtG concentration regarding the differentiation between teetotalers, moderate drinkers and excessive drinkers.

Ethyl Glucuronide Determination in Hair for Evaluation of Long-Term Alcohol Abstention in Liver Transplant Candidates

Ethyl Glucuronide Determination in Hair for Evaluation of Long-Term Alcohol Abstention in Liver Transplant Candidates

Determination of ethyl-glucuronide in hair for heavy drinking detection using liquid chromatography-tandem mass spectrometry following solid-phase extraction

The detection of ethyl-beta-D-6-glucuronide (EtG), a stable phase II metabolite of ethanol, is of interest in both clinical and forensic contexts with the aim of monitoring alcohol abuse. We present a liquid chromatography-electrospray ionisation-tandem mass spectrometry method for the detection and quantification of EtG in hair. Thirty milligrams of washed and cut hair were cleaned up using solid-phase extraction graphite cartridges. Separation was then performed using an Uptisphere-3SI column, and the detection was operated in the negative mode. After validation, the method was applied to hair samples taken from four fatalities (F) with documented excessive drinking habits, 12 heavy drinkers (HD) and seven social drinkers (SD). The method exhibits limits of detection and quantification of 4 and 10 pg/mg, respectively. Intra- and inter-assay standard deviation and relative bias were less than 20% over the calibrating range (10 to 3,000 pg/mg). EtG hair concentrations in SD were <10 pg/mg and >50 pg/mg for F and HD (range, 54 to 497 pg/mg). The present assay appears convenient to carry out owing to the very small quantity of hair samples required to determine an effective heavy alcohol consumption (EtG hair concentration >50 pg/mg).

Ethylglucuronide Determination in Urine and Hair from Alcohol Withdrawal Patients

Two methods for the determination of ethylglucuronide (EtG) in urine and in hair have been developed by liquid chromatography- tandem mass spectrometry. These two methods were fully validated, including linearity (0.25-100 microg/mL in urine; 0.05-5 ng/mg in hair; r(2) > 0.99, n = 5), limits of detection (0.1 microg/mL in urine, 0.025 ng/mg in hair) and quantitation (lowest level of the calibration curve), extraction efficiency (> 55%), within-day and between-day imprecision and bias (CV and mean relative error < 15%), matrix effect, and relative ion intensity. These methods have been applied to 541 urine samples and 17 hair specimens collected from 156 alcohol withdrawal patients. The determination of ethanol versus EtG in urine was compared, and also the convenience of EtG determination in hair. EtG in urine and in hair proved to be a powerful tool for monitoring abstinence in these patients.

Microwave-assisted extraction: a simpler and faster method for the determination of ethyl glucuronide in hair by gas chromatography–mass spectrometry

Alcohol is the most frequently abused "addictive substance" that causes serious social problems throughout the world; thus, alcoholism is of particular interest in clinical and forensic medicine. Alcohol biomarkers are physiological indicators of alcohol exposure or ingestion and may reflect the presence of an alcohol use disorder. The glucuronide conjugation is a minor pathway of ethanol metabolism. Ethyl glucuronide (EtG) is a marker of recent alcohol consumption that detects alcohol use reliably over a definite time period. The present paper describes a new method for the determination of EtG in hair. It is based both in the microwave-assisted extraction (MAE), to extract the analyte from hair samples, and gas chromatography-mass spectrometry (GC-MS), to identify and quantify the EtG in selected ion monitoring (SIM) mode. The method was applied to 15 hair samples from occasional alcohol users, obtaining positive results in all cases. It was fully validated, including a linear range (0.3-10 ng/mg) and the main precision parameters. In summary, the use of microwave-assisted extraction turned out to be a substantially simpler, faster, and a more sensitive procedure than any other conventional sample preparations.

Ethyl glucuronide concentration in hair is not influenced by pigmentation

This work shows that the concentration of ethyl glucuronide (EtG) in hair, a marker for the evaluation of the alcohol consumption, is not influenced by the presence or absence of melanin. The results confirm that, unlike many other substances, the EtG determination in hair has not to take into account the hair colour for the correct interpretation of hair testing results.