A high-performance liquid chromatographic-tandem mass spectrometric method for the determination of ethyl glucuronide and ethyl sulfate in urine validated according to forensic guidelines

Confirmation of ethanol administration in racing greyhounds by LC-MS-MS

Ethanol is a prohibited substance in professional animal racing as its administration causes physiological effects such as depression of the central nervous system. Regulation of potential doping agents, including those that inhibit performance, is critical to ensure integrity and animal welfare in greyhound racing, but the detection of ethanol is complicated by dietary and/or environmental exposure. In response, a reliable analytical method capable of detecting recent ethanol administration in greyhound urine samples was validated and implemented. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) was used to investigate the variation in urinary ethanol metabolites; ethyl-β-D glucuronide (EG;γ ¯ EG $$ {\overline{\gamma}}_{\mathrm{EG}} $$  = 1.0 μg/ml,s EG $$ {s}_{\mathrm{EG}} $$  = 3.3 μg/ml) and ethyl sulfate (ES;γ ¯ ES $$ {\overline{\gamma}}_{\mathrm{ES}} $$  = 0.9 μg/ml,s ES $$ {s}_{\mathrm{ES}} $$  = 1.9 μg/ml) levels from a reference population of 202 racing greyhounds. These were compared to urine samples collected following administration of ethanol to one male and one female greyhound. Results were used to establish a threshold within the national rules of greyhound racing:γ ¯ EG $$ {\overline{\gamma}}_{\mathrm{EG}} $$ andγ ¯ ES $$ {\overline{\gamma}}_{\mathrm{ES}} $$  > 20 μg/ml in urine are defensible criteria to confirm ethanol administration to greyhounds. Case studies of competition samples are provided to demonstrate the forensic translation of this work.

A Liquid Chromatography-Tandem Mass Spectrometry Assay for Quantification of Ethyl Glucuronide and Ethyl Sulfate in Urine

Ethyl glucuronide and ethyl sulfate emerged as the biomarkers of choice for detection of ethanol use as the required sample is urine, enabling easy and noninvasive collection. Further, these biomarkers have a longer detection window in urine than blood ethanol. A liquid chromatography-tandem mass spectrometry method was developed and clinically validated using electrospray ionization in negative mode and selected reaction monitoring. A simple dilution was used for sample preparation on 100 microliters of urine. Gradient elution had a run time of 7 min. The reportable range was established to be 180-100,000 ng/mL for ethyl glucuronide and 50-46,600 ng/mL for ethyl sulfate and between-run imprecision was <7% for both analytes.

Elimination of matrix effects in urine for determination of ethyl glucuronide by liquid chromatography-tandem mass spectrometry

RATIONALE

Alcohol use disorder affects 4% to 5% of the world's population. Analysis methods are available for various biological fluids to detect this disorder. Determination of ethyl glucuronide in urine by the liquid chromatography-tandem mass spectrometry (LC/MS/MS) method is frequently used in forensic toxicology. These analyses are known to cause matrix effects.

METHODS

The presented study describes the elimination of matrix effects for ethyl glucuronide. This study used two different LC/MS/MS systems containing orthogonal and z-spray ion sources. Ethyl glucuronide was analyzed in negative polarity in electrospray ionization. A different dilution method was chosen for each study. The methods were developed and validated according to the European Medicines Agency bioanalytical method validation parameters.

RESULTS

The lower limit of quantitation of the developed methods was 0.025 μg/mL for ethyl glucuronide. The calibration curve of ethyl glucuronide was between 0.025 and 100 μg/mL with a correlation coefficient of >0.99 for the two methods.

CONCLUSIONS

It was determined that the analyses using the z-spray ion source were more affected by the matrix effect. The two validated methods involve rapid analysis time and simple sample preparation. Also, the methods were applied to real patients' urine.

Alcohol use disorder in the perioperative period: a summary and recommendations for anesthesiologists and pain physicians

Excessive alcohol consumption and alcohol use disorder (AUD) increase the risk of perioperative morbidity and mortality. Aspiration, malnutrition, coagulopathies, seizures, and hemodynamic alterations are only a few of the major concerns related to acute alcohol intoxication and AUD. There are also numerous physiological effects, changes in medication metabolism and pharmacology, and adverse events related to chronic alcohol consumption. These are all important considerations for the anesthesiologist in the perioperative management of a patient with AUD. Pain perception and thresholds are altered in patients with acute and chronic alcohol use. Medications used to manage AUD symptoms, particularly naltrexone, can have significant perioperative implications. Patients on naltrexone who continue or stop this medication in the perioperative period are at an increased risk for undertreated pain or substance use relapse. This review highlights key considerations for the anesthesiologist and pain physician in the perioperative management of patients with active AUD (or those in recovery). It discusses the effects of acute and chronic alcohol use on pain perception and thresholds, provides guidance on the perioperative management of naltrexone and low-dose naltrexone, and reviews a multimodal approach to pain management.

Biomarkers of moderate alcohol intake and alcoholic beverages: a systematic literature review

The predominant source of alcohol in the diet is alcoholic beverages, including beer, wine, spirits and liquors, sweet wine, and ciders. Self-reported alcohol intakes are likely to be influenced by measurement error, thus affecting the accuracy and precision of currently established epidemiological associations between alcohol itself, alcoholic beverage consumption, and health or disease. Therefore, a more objective assessment of alcohol intake would be very valuable, which may be established through biomarkers of food intake (BFIs). Several direct and indirect alcohol intake biomarkers have been proposed in forensic and clinical contexts to assess recent or longer-term intakes. Protocols for performing systematic reviews in this field, as well as for assessing the validity of candidate BFIs, have been developed within the Food Biomarker Alliance (FoodBAll) project. The aim of this systematic review is to list and validate biomarkers of ethanol intake per se excluding markers of abuse, but including biomarkers related to common categories of alcoholic beverages. Validation of the proposed candidate biomarker(s) for alcohol itself and for each alcoholic beverage was done according to the published guideline for biomarker reviews. In conclusion, common biomarkers of alcohol intake, e.g., as ethyl glucuronide, ethyl sulfate, fatty acid ethyl esters, and phosphatidyl ethanol, show considerable inter-individual response, especially at low to moderate intakes, and need further development and improved validation, while BFIs for beer and wine are highly promising and may help in more accurate intake assessments for these specific beverages.

Rapid and simple LC–MS/MS determination of urinary ethyl glucuronide, naltrexone, 6β-naltrexol, chlordiazepoxide, and norchlordiazepoxide for monitoring alcohol abuse

In this study, a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed to detect ethyl glucuronide (EtG), which is a biomarker for monitoring alcohol consumption, and naltrexone (NTX), 6β-naltrexol (6βNTX), chlordiazepoxide (CDP), and norchlordiazepoxide (norCDP), which are analyzed to confirm the presence of medications for alcohol dependence treatment. The protein precipitation method was conducted to rapidly prepare samples. LC–MS/MS analysis was performed in the multiple-reaction monitoring mode. The analytes were separated using a Scherzo SM-C18 (2.0 × 100 mm, 3 µm) column. The calibration ranges were 5–1000 ng/mL for EtG, 6βNTX, CDP, and norCDP, and 1–100 ng/mL for NTX, with the correlation coefficients (r) being ≥ 0.994, and the weighting factor being 1/x2. The lower limit of quantification was 1–5 ng/mL. The method was also validated for precision, accuracy, selectivity, dilution integrity, recovery, matrix effect, and stability. The developed method was successfully applied for the determination of EtG, NTX, 6βNTX, CDP, and norCDP in urine samples obtained from 49 probationers who received alcohol dependence treatment orders. The method developed herein can be used to monitor the drug-based treatment of alcohol abuse and alcohol consumption during the treatment of individuals under probation.

A novel fast-dried urine spot-based method for the analysis of EtS and EtG in urine by liquid chromatography tandem mass spectrometry

Ethyl sulfate (EtS) and ethyl glucuronide (EtG) in urine are biomarkers to monitor ethanol consumption. Due to their high polarity, severe matrix effects have been observed during analysis of EtS and EtG in urine by liquid chromatography tandem mass spectrometry (LC-MS/MS), which can lead to a loss of sensitivity and accuracy. In the present study, a novel and simple sample preparation approach based on fast-dried urine spot was established to reduce the matrix effect of EtS and EtG in urine. 20 μL of urine was dropped on the Whatman 903# paper and was subsequently dried by microwave in one minute. After ultrasonic assisted extraction with 500 μL of methanol, the analysis was conducted using an LC-MS/MS system. Limits of detection were 5 ng/mL and linear ranges were 10 ng/mL-10 μg/mL for both EtS and EtG. Matrix effects were in the range of 99.3-107.8% for EtS and 86.7-91.0% for EtG at three QC levels. Matrix effects for EtS and EtG were compared between the current method and other sample preparation methods including protein precipitation, and solid-phase extraction. The results showed that this fast-dried urine spot-based extraction method could eliminate matrix effects significantly in analysis of urine EtS and EtG by LC-MS/MS.

Quantitative Determination of Ethyl Glucuronide and Ethyl Sulfate in Postmortem and Antemortem Whole Blood Using Phospholipid Removal 96-Well Plate and UHPLC-MS-MS

Postmortem ethanol formation is a well-known problem in forensic toxicology. Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are ethanol metabolites that can be used to distinguish antemortem alcohol intake from postmortem formation of ethanol and in addition can be a helpful tool in assessment of the hip-flask defense. To an aliquot of 100 µL whole blood, internal standard (IS) and water was added before protein precipitation treatment (PPT) with ice-cold acetonitrile (ACN). The supernatants were filtered through a 96-well phospholipid removal plate, evaporated to dryness and reconstituted in 150 µL water/ACN/formic acid (FA). Identification of compounds was performed using multiple reaction monitoring (MRM) in negative mode. Gradient elution was performed on a C18 column with methanol (MeOH) and 0.1% FA. The run time was 4.5 min, and 0.5 µL was injected on an ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS-MS) instrument. Linearity was achieved (coefficient of determination (R²) ≥ 0.999) for EtG in the range of 0.089 to 22 mg/L (0.40–100 µM) and EtS 0.025 to 6.3 mg/L (0.20–50 µM). The limit of quantification (LOQ) was 0.067 mg/L (0.30 µM) for EtG and 0.019 mg/L (0.15 µM) for EtS. Between assay accuracy was –15% to 8% and precision reported as relative standard deviation (RSD) was ≤ 4.5%. Precision, estimated as the RSD of the concentration difference between results from two independent analyses of authentic whole blood samples, was ≤ 6.7%. Recovery was ≥ 61% for EtG and ≥ 77% for EtS and matrix effects (ME) were 99% to 103%. Method comparison was carried out with a previously used UHPLC–MS-MS method, and satisfactory agreement was achieved, and external proficiency testing control samples had z-score < ± 1. The method has been used in routine work for more than 4 years analyzing about 6,000 antemortem and postmortem whole blood samples and has proven to be robust and reliable.

Ethyl Glucuronide and Ethyl Sulphate in Urine: Caution in their use as markers of recent alcohol use

AIM

To clarify the role of the ethanol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS), in monitoring alcohol consumption.

METHOD

We recruited 7 female and 17 male volunteers who were instructed to consume a quantity of beer (containing 48 gm ethanol) with food in one session. We examined urinary excretion of EtG and EtS over time and looked for correlations between the concentrations of the metabolites EtG and EtS.

RESULTS

EtG concentrations in urine varied between 0.026 and 430.372 μg/ml with average values between 11.85 μg/ml (SD 19.75), 30 min after alcohol intake, and 100.39 μg/ml (SD 101.34), 4.5 h after alcohol intake. EtS urinary concentration ranged from 0.006 to 101.432 μg/ml with average values between 4.77 μg/ml (SD 5.42), 30 min after alcohol intake, and 30.14 μg/ml (SD 27.20), 4.5 h after alcohol intake. Spearman's test showed that urinary EtG and EtS correlated significantly at several time points.

CONCLUSION

The great interindividual variability in their excretion suggests caution in the use of urinary measurement of these metabolites in forensic investigations.

Biomarkers of Alcohol Consumption in Body Fluids - Possibilities and Limitations of Application in Toxicological Analysis

BACKGROUND

Ethyl alcohol is the most popular legal drug, but its excessive consumption causes social problems. Despite many public campaigns against alcohol use, car accidents, instances of aggressive behaviour, sexual assaults and deterioration in labor productivity caused by inebriated people is still commonplace. Fast and easy diagnosis of alcohol consumption is required in order to introduce proper and effective therapy, and is crucial in forensic toxicology analysis. The easiest method to prove alcohol intake is determination of ethanol in body fluids or in breath. However, since ethanol is rapidly metabolized in the human organism, only recent consumption can be detected using this method. Because of that, the determination of alcohol biomarkers was introduced for monitoring alcohol consumption over a wider range of time.

OBJECTIVE

The objective of this study was to review published studies focusing on the sample preparation methods and chromatographic or biochemical techniques for the determination of alcohol biomarkers in whole blood, plasma, serum and urine.

METHODS

An electronic literature search was performed to discuss possibilities and limitations of application of alcohol biomarkers in toxicological analysis.

RESULTS

Authors described the markers of alcohol consumption such as: ethanol, its nonoxidative metabolites (ethyl glucuronide, ethyl sulfate, phosphatidylethanol, ethyl phosphate, fatty acid ethyl esters) and oxidative metabolites (acetaldehyde and acetaldehyde adducts). We also discussed issues concerning the detection window of these biomarkers, and possibilities and limitations of their use in routine analytical toxicology for monitoring alcohol consumption or sobriety during alcohol therapy.

Evaluation of a novel method for the analysis of alcohol biomarkers: Ethyl glucuronide, ethyl sulfate and phosphatidylethanol

Currently available markers and methods to evaluate alcohol consumption are indirect and suboptimal, or rely on self-report, which have inherent problems. Direct metabolites of alcohol, phosphatidylethanol (PEth), ethyl sulfate (EtS), and ethyl glucuronide (EtG), are known to improve diagnostic accuracy. In this study, methods were established for the identification of PEth in erythrocytes and EtG and EtS in serum using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The three biomarkers were tested and validated in volunteer teetotalers (n = 4) and drinkers (n = 10), and applied in patients (n = 8) hospitalized with alcohol-related problems. Linearity of each assay was demonstrated from 22.5 to 900 nM for EtG, 40-3175 nM for EtS, and 21-750 nM for PEth. The methods were highly selective, precise (<5% coefficient of variation), and had optimal accuracy (within 10% of the nominal value) for all three analytes. Recovery for all three compounds exceeded 90%. A preliminary investigation into the window of detection of these biomarkers after a single occasion of moderate alcohol consumption revealed that EtG and EtS could be detected and quantified over the short term (days) and PEth over the long term (weeks). All three biomarkers showed high sensitivity and specificity in distinguishing between abstinence and any alcohol use at the cut-off values of 22.5 nM for EtG, 40 nM for EtS, and 21 nM for PEth. We have established simultaneous assays for EtG, EtS, and PEth for routine clinical use in confirming abstinence and exposure, and detecting under-reporting of alcohol use, relevant in clinical and non-clinical settings.

Considerations regarding the validation of chromatographic mass spectrometric methods for the quantification of endogenous substances in forensics

The requirement for correct evaluation of forensic toxicological results in daily routine work and scientific studies is reliable analytical data based on validated methods. Validation of a method gives the analyst tools to estimate the efficacy and reliability of the analytical method. Without validation, data might be contested in court and lead to unjustified legal consequences for a defendant. Therefore, new analytical methods to be used in forensic toxicology require careful method development and validation of the final method. Until now, there are no publications on the validation of chromatographic mass spectrometric methods for the detection of endogenous substances although endogenous analytes can be important in Forensic Toxicology (alcohol consumption marker, congener alcohols, gamma hydroxy butyric acid, human insulin and C-peptide, creatinine, postmortal clinical parameters). For these analytes, conventional validation instructions cannot be followed completely. In this paper, important practical considerations in analytical method validation for endogenous substances will be discussed which may be used as guidance for scientists wishing to develop and validate analytical methods for analytes produced naturally in the human body. Especially the validation parameters calibration model, analytical limits, accuracy (bias and precision) and matrix effects and recovery have to be approached differently. Highest attention should be paid to selectivity experiments.

A dilute-and-shoot flow-injection tandem mass spectrometry method for quantification of phenobarbital in urine

RATIONALE

Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the gold standard of urine drug testing. However, current LC-based methods are time consuming, limiting the throughput of MS-based testing and increasing the cost. This is particularly problematic for quantification of drugs such as phenobarbital, which is often analyzed in a separate run because they must be negatively ionized.

METHODS

This study examined the feasibility of using a dilute-and-shoot flow-injection method without LC separation to quantify drugs with phenobarbital as a model system. Briefly, a urine sample containing phenobarbital was first diluted by 10 times, followed by flow injection of the diluted sample to mass spectrometer. Quantification and detection of phenobarbital were achieved by an electrospray negative ionization MS/MS system operated in the multiple reaction monitoring (MRM) mode with the stable-isotope-labeled drug as internal standard.

RESULTS

The dilute-and-shoot flow-injection method developed was linear with a dynamic range of 50-2000 ng/mL of phenobarbital and correlation coefficient > 0.9996. The coefficients of variation and relative errors for intra- and inter-assays at four quality control (QC) levels (50, 125, 445 and 1600 ng/mL) were 3.0% and 5.0%, respectively. The total run time to quantify one sample was 2 min, and the sensitivity and specificity of the method did not deteriorate even after 1200 consecutive injections.

CONCLUSIONS

Our method can accurately and robustly quantify phenobarbital in urine without LC separation. Because of its 2 min run time, the method can process 720 samples per day. This feasibility study shows that the dilute-and-shoot flow-injection method can be a general way for fast analysis of drugs in urine. Copyright © 2016 John Wiley & Sons, Ltd.

Quantification of EtG in hair, EtG and EtS in urine and PEth species in capillary dried blood spots to assess the alcohol consumption in driver's licence regranting cases

BACKGROUND

In Belgium, the analysis of indirect biomarkers such as carbohydrate deficient transferrin (CDT%), gamma-glutamyltransferase (GGT), aspartate aminotransferase/alanine aminotransferase (AST/ALT) and mean corpuscular volume (MCV), is currently used to monitor the alcohol consumption in cases of fitness to drive assessment. We evaluated the use of direct ethanol markers for this purpose, exclusively determined in matrices obtained via non- or minimally invasive sampling.

METHODS

Three validated quantitative methods (ethylglucuronide (EtG) in hair and urine, ethylsulfate (EtS) in urine, and phosphatidylethanol species (PEth 16:0/18:1, PEth 18:1/18:1 and PEth 16:0/16:0) in capillary dried blood spots (C-DBS)) were used. Fifty volunteers, for whom fitness to drive had to be assessed and for whom a blood analysis for indirect biomarkers was requested, were included in the study. The sampling and analysis of hair, urine and C-DBS were added to the process currently used.

RESULTS

Hair EtG (24/50) and C-DBS PEths (29/50) are more sensitive than the currently used indirect biomarkers (13/50 for CDT%) to detect excessive and chronic alcohol consumption and allow to disprove an abstinence period. Urinary EtG and EtS are useful parameters to determine recent alcohol consumption.

CONCLUSION

The combined use of the three strategies allows better inference about the evolution of the alcohol consumption prior to the sampling. Moreover, the exclusive use of non- or minimally invasive sampling (hair, urine and C-DBS) allows this to be performed directly during the fitness to drive assessment by regular staff members. This approach offers the potential to improve the Belgian driver's licence regranting process.

Alternative sampling strategies for the assessment of alcohol intake of living persons

Monitoring of alcohol consumption by living persons takes place in various contexts, amongst which workplace drug testing, driving under the influence of alcohol, driving licence regranting programs, alcohol withdrawal treatment, diagnosis of acute intoxication or fetal alcohol ingestion. The matrices that are mostly used today include blood, breath and urine. The aim of this review is to present alternative sampling strategies that allow monitoring of the alcohol consumption in living subjects. Ethanol itself, indirect (carbohydrate deficient transferrin, CDT%) as well as direct biomarkers (ethyl glucuronide, EtG; ethyl sulphate, EtS; fatty acid ethyl esters, FAEEs and phosphatidylethanol species, PEths) of ethanol consumption will be considered. This review covers dried blood spots (CDT%, EtG/EtS, PEths), dried urine spots (EtG/EtS), sweat and skin surface lipids (ethanol, EtG, FAEEs), oral fluid (ethanol, EtG), exhaled breath (PEths), hair (EtG, FAEEs), nail (EtG), meconium (EtG/EtS, FAEEs), umbilical cord and placenta (EtG/EtS and PEth 16:0/18:1). Main results, issues and considerations specific to each matrix are reported. Details about sample preparation and analytical methods are not within the scope of this review.

Bioanalytical procedures and developments in the determination of alcohol biomarkers in biological specimens

Excessive alcohol consumption is a global problem, and consequently its evaluation is of great clinical and forensic interest. Alcohol biomarkers have been the focus of several research works in the past decades, with new compounds being studied in more recent years. The main objective of this review is to discuss topics for an analyst to consider when evaluating alcohol consumption through the analysis of alcohol biomarkers in biological specimens. For this, existing alcohol biomarkers will be reviewed, including carbohydrate-deficient transferrin, 5-hydroxytryptophol, ethanol, hemoglobin-associated acetaldehyde, fatty acid ethyl esters, ethyl glucuronide, ethyl sulfate and phosphatidylethanol. Additionally, their potential will be discussed, as well as analytical considerations, main challenges, limitations, data interpretation and existing methodologies for their determination in biological specimens.

Quantitation of Ethyl Glucuronide and Ethyl Sulfate in Urine Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Ethyl glucuronide and ethyl sulfate are minor conjugated metabolites of ethanol that can be detected in urine for several days after last ingestion of ethanol. The monitoring of ethanol use has both clinical and forensic applications and a longer detection window afforded by monitoring these metabolites is obvious. LC-MS/MS is used to analyze diluted urine with deuterated analogs of each analyte as internal standards to ensure accurate quantitation and control for any potential matrix effects. High aqueous HPLC is used to chromatograph the metabolites. Negative ion electrospray is used to introduce the metabolites into the mass spectrometer. Selected reaction monitoring of two product ions for each analyte allows for the calculation of ion ratios which ensures correct identification of each metabolite, while a matrix-matched calibration curve is used for quantitation.

High levels of agreement between clinic-based ethyl glucuronide (EtG) immunoassays and laboratory-based mass spectrometry

BACKGROUND

Immunoassay urine drug screening cups that detect use for two or more days are commonly used in addiction treatment settings. Until recently, there has been no comparable immunoassay test for alcohol use in these settings.

OBJECTIVES

The aim of this study was to assess the agreement of a commercially available ethyl glucuronide immunoassay (EtG-I) test conducted at an outpatient addiction clinic and lab-based EtG mass spectrometry (EtG-MS) conducted at a drug testing laboratory at three cut-off levels. High agreement between these two measures would support the usefulness of EtG-I as a clinical tool for monitoring alcohol use.

METHODS

Forty adults with co-occurring alcohol dependence and serious mental illnesses submitted 1068 urine samples over a 16-week alcohol treatment study. All samples were tested using EtG-I on a benchtop analyzer and 149 were randomly selected for EtG-MS analysis at a local laboratory. Agreement was defined as the number of samples where EtG-I and EtG-MS were both above or below a specific cut-off level. Agreement was calculated at low cut-off levels (100 and 250 ng/ml), as well as at a higher cut-off level (500 ng/ml) recommended by most by commercial drug testing laboratories.

RESULTS

Agreement between EtG-I and EtG-MS was high across all cut-off levels (90.6% at 100 ng/ml, and 96.6% at 250 and 500 ng/ml).

CONCLUSIONS

EtG immunoassays conducted at low cut-off levels in point-of-care testing settings have high agreement with lab-based EtG-MS. EtG-I can be considered a useful clinical monitoring tool for alcohol use in community-based addiction treatment settings.

Electromigrative separation techniques in forensic science: combining selectivity, sensitivity, and robustness

In this review we introduce the advantages and limitations of electromigrative separation techniques in forensic toxicology. We thus present a summary of illustrative studies and our own experience in the field together with established methods from the German Federal Criminal Police Office rather than a complete survey. We focus on the analytical aspects of analytes' physicochemical characteristics (e.g. polarity, stereoisomers) and analytical challenges including matrix tolerance, separation from compounds present in large excess, sample volumes, and orthogonality. For these aspects we want to reveal the specific advantages over more traditional methods. Both detailed studies and profiling and screening studies are taken into account. Care was taken to nearly exclusively document well-validated methods outstanding for the analytical challenge discussed. Special attention was paid to aspects exclusive to electromigrative separation techniques, including the use of the mobility axis, the potential for on-site instrumentation, and the capillary format for immunoassays. The review concludes with an introductory guide to method development for different separation modes, presenting typical buffer systems as starting points for different analyte classes. The objective of this review is to provide an orientation for users in separation science considering using capillary electrophoresis in their laboratory in the future.

Validation of a novel method to identify in utero ethanol exposure: simultaneous meconium extraction of fatty acid ethyl esters, ethyl glucuronide, and ethyl sulfate followed by LC-MS/MS quantification

Presence of fatty acid ethyl esters (FAEE), ethyl glucuronide (EtG), and ethyl sulfate (EtS) in meconium, the first neonatal feces, identifies maternal alcohol consumption during pregnancy. Current meconium alcohol marker assays require separate analyses for FAEE and EtG/EtS. We describe development and validation of the first quantitative liquid chromatography tandem mass spectrometry assay for 9 FAEEs, EtG, and EtS in 100 mg meconium. For the first time, these alcohol markers are analyzed in the same meconium aliquot, enabling comparison of the efficiency of gestational ethanol exposure detection. 100 mg meconium was homogenized in methanol and centrifuged. The supernatant was divided, and applied to two different solid phase extraction columns for optimized analyte recovery. Limits of quantification for ethyl laurate, myristate, linolenate, palmitoleate, arachidonate, linoleate, palmitate, oleate, and stearate ranged from 25-50 ng/g, with calibration curves to 2,500-5,000 ng/g. EtG and EtS linear dynamic ranges were 5-1,000 and 2.5-500 ng/g, respectively. Mean bias and between-day imprecision were <15 %. Extraction efficiencies were 51.2-96.5 %. Matrix effects ranged from -84.7 to 16.0 %, but were compensated for by matched deuterated internal standards when available. All analytes were stable (within ±20 % change from baseline) in 3 authentic positive specimens, analyzed in triplicate, after 3 freeze/thaw cycles (-20 °C). Authentic EtG and EtS also were stable after 12 h at room temperature and 72 h at 4 °C; some FAEE showed instability under these conditions, although there was large inter-subject variability. This novel method accurately detects multiple alcohol meconium markers and enables comparison of markers for maternal alcohol consumption.

Ethyl glucuronide and ethyl sulfate

Alcohol misuse is associated with significant morbidity and mortality. Although clinical history, examination, and the use of self-report questionnaires may identify subjects with harmful patterns of alcohol use, denial or under-reporting of alcohol intake is common. Existing biomarkers for detecting alcohol misuse include measurement of blood or urine ethanol for acute alcohol consumption, and carbohydrate-deficient transferrin and gamma-glutamyl transferase for chronic alcohol misuse. There is a need for a biomarker that can detect excessive alcohol consumption in the timeframe between 1 day and several weeks. Ethyl glucuronide (EtG) is a direct metabolite of ethanol detectable in urine for up to 90 h and longer in hair. Because EtG has high specificity for excess alcohol intake, it has great potential for use in detecting "binge" drinking. Using urine or hair, this noninvasive marker has a role in a variety of clinical and forensic settings.

Ethyl glucuronide (EtG): better than breathalyser or self-reports to detect covert short-term relapses into drinking

AIMS

The assessment of relapses is widely used as an outcome measure of alcohol dependence treatment. However, the methods of assessing relapses range from questionnaires to biological markers of alcohol for different time spans. The aim of this study was to compare the relapse rates of weekend home stays during long-term alcohol dependence treatment, assessed by ethyl glucuronide (EtG), breath alcohol tests and self-reports.

METHODS

Two hundred and ninety-seven alcohol-dependent patients receiving a long-term inpatient treatment programme participated. After a weekend at home (Friday to Sunday) they were evaluated for relapse by personal interviews and with breath alcohol tests. A concomitantly collected urine sample was later assessed for EtG with liquid chromatography-tandem mass spectrometry (LC-MS/MS analysis).

RESULTS

Of the total, 37.7% of the patients were positive for EtG at least once. Breath alcohol tests had been positive in only 4.4% and in personal interviews only 5.7% of the patients had admitted relapse. 15.6% of EtG tests were positive, but breath alcohol tests were negative (Cohen's kappa = 0.056). Ninety-three per cent of the relapses were only detected by EtG.

CONCLUSION

In addition to breath alcohol tests and interviews, urinary EtG can clearly improve the verification of relapse in inpatient treatment programmes allowing for weekend stays at home. Without EtG testing, a high amount of relapses will stay undetected.

A fully validated method for the quantification of ethyl glucuronide and ethyl sulphate in urine by UPLC-ESI-MS/MS applied in a prospective alcohol self-monitoring study

A method for the quantification of ethyl glucuronide (EtG) and ethyl sulphate (EtS) in human urine is developed and fully validated according to international guidelines. Protein precipitation is used as sample preparation. During the development of the method on an UPLC-ESI-MS/MS system using a CSH C18 column, special attention was paid to reduce matrix effects to improve assay sensitivity and to improve detection of the second transition for EtS for specificity purposes. The method was linear from 0.1 to 10μg/mL for both analytes. Ion suppression less than 24% (RSD<15%) was observed for EtG and no significant matrix effect was measured for EtS. The recovery was around 80% (RSD<14%) for both compounds. This method provides good precision (RSDr and RSDt<10%) and bias (<15%) for internal and external quality control samples. The reproducibility of the method was demonstrated by the successful participation to proficiency tests (z-score<0.86). This method was finally used to analyze urine samples obtained from twenty-seven volunteers whose alcohol consumption during the 5 days before sampling was monitored. Concentrations between 0.5 and 101.9μg/mL (mean 10.9, median 1.4) for EtG and between 0.1 and 37.9μg/mL (mean 3.6, median 0.3) for EtS were detected in urine samples of volunteers who declared having consumed alcohol the day before the sampling. EtG and EtS concentrations in urine were highly correlated (r=0.996, p<0.001). A moderate correlation between the number of drinks the day before sampling and the concentration of EtG (r=0.448, p<0.02) or EtS (r=0.406, p<0.04) was observed. Using a cut-off value at 0.1μg/mL for EtG and EtS, this method is able to detect social alcohol consumption approximately 24h after the intake, without showing any false positive result.

EtG/EtS in Urine from sexual assault victims determined by UPLC-MS-MS

In cases of sexual assault, victims often present too late for the detection of ethanol in biological samples. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method was developed and validated for the determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in urine. Sample preparation prior to UPLC-MS-MS analysis was a simple sample dilution. The calibration ranges were 0.2-20 mg/L, and between-assay relative standard deviations were in the range of 0.7-7.0% at concentrations of 0.3, 3.0 and 7.0 mg/L. Urine samples were analyzed from 59 female patients presenting to the Sexual Assault Centre at St. Olav University Hospital in Trondheim, Norway between November 2010 and October 2011. EtG and EtS results were fully concordant, and positive in 45 of the 48 cases with self-reported alcohol intake. In contrast, ethanol was detectable in only 20 of these cases, corresponding to sensitivities of 94 and 42%, respectively. Of the patients reporting no alcohol intake, none had positive EtG/EtS findings. These data show that analysis of EtG and EtS greatly increases the detection window of alcohol ingestion in cases of sexual assault, and may shed additional light on the involvement of ethanol in such cases. The victims' self-reported intake of alcohol seems to be reliable in this study, according to the EtG/EtS findings.