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

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.

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.

Development of a Column-Switching HPLC-MS/MS Method and Clinical Application for Determination of Ethyl Glucuronide in Hair in Conjunction with AUDIT for Detecting High-Risk Alcohol Consumption

It is critical to assess the severity of alcohol consumption in certain diseases such as alcohol liver disease and alcohol addiction. Ethyl glucuronide (EtG) is a highly stable metabolite of ethanol in hair; thus, it was proposed as a long-term monitoring marker for alcohol consumption. Therefore, an HPLC-MS/MS method for EtG in hair was developed and applied to a clinical setting to assess the relevance of the EtG concentration and/or the Alcohol Use Disorders Identification Test (AUDIT) score to high-risk alcohol consumption. EtG was extracted from 10 mg of hair using water and analyzed using on-line sample purification coupled to HPLC-MS/MS. The diagnostic performances of the EtG concentration and/or the AUDIT score for detecting high-risk alcohol consumption were statistically evaluated between alcohol addicts (n = 44) and average alcohol users (n = 19). The on-line sample purification resulted in labor-saving with smaller sample amount. Both the EtG concentrations (4.0⁻587.4 pg/mg vs. 12.9⁻74.9 pg/mg) and the AUDIT scores (4⁻40 vs. 5⁻28) obtained from the alcohol addicts were significantly higher than those from the average alcohol users. The performance evaluation demonstrated that the integration score of the EtG concentration and the AUDIT score increased diagnostic performance for high-risk alcohol consumption.