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Quantitation of drugs of abuse in body fluids is challenging due to the varying concentrations and substantially different chemical and physical properties of the drugs, interfering matrices, occasionally small volumes of sample to test, and the presence of many similar compounds. Further, constant evolution of drugs makes it harder to identify and quantitate them. Currently, most of the quantitative analysis is done using a selected reaction monitoring (SRM) approach on a triple-stage quadrupole mass spectrometer. This approach is inherently targeted and misses new compounds. Also, the SRM duty cycle limits monitoring, and quantitating large numbers of analytes is very difficult if not impossible. For the first time, high-resolution, accurate mass spectrometry based on Orbitrap™ technology offers a practical solution for the challenge at hand. The high resolution of up to 140,000 FWHM enables separation of drugs and metabolites from interferences. Fast positive/negative switching catches acidic, basic and neutral drugs. Better than 3 ppm mass accuracy assures confidence in identification, and fragment ions from the HCD cell further confirm the identity beyond a reasonable doubt. All of this is made simple by using Thermo Scientific TraceFinder and ExactFinder software, which help attain high productivity and confidence in routine targeted and general unknown screening applications.
Here we describe the application of Orbitrap technology-based workflow solutions for quantitation of drugs and metabolites in urine, plasma, whole blood, and oral fluid matrices.
For additional resources, search the Orbitrap Science Library
Overview
Workflow Overview for EtG/EtS
Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are sensitive and specific urinary biomarkers of recent alcohol intake that are of great interest in today’s forensic toxicology laboratories.
The workflow described here uses a simple dilute-and-shoot method for sample preparation and a Thermo Scientific Exactive Plus MS operated in Full Scan MS mode at 100,000 FWHM resolution. For EtG the LOQ is 100 ng/mL, while the LOD is 25 ng/mL. For EtS, the LOQ is 25 ng/mL, while the LOD is 10 ng/mL.
resources
Analysis of ETG, ETS using the Thermo Scientific Exactive Mass Spectrometer
Johnson K.
Slide Presentation
Quantitation of Urinary Ethyl Glucuronide and Ethyl Sulfate Using Ultrahigh Resolution LC-MS
Johnson K, Kozak M.
Application Note 488b
Sample Preparation
Sample Preparation Workflow for EtG/EtS
The sample preparation for quantitation of EtG and EtS in urine involved a simple dilute-and-shoot approach.
resources
Analysis of ETG, ETS using the Thermo Scientific Exactive Mass Spectrometer
Johnson K.
Slide Presentation
Quantitation of Urinary Ethyl Glucuronide and Ethyl Sulfate Using Ultrahigh Resolution LC-MS
Johnson K, Kozak M.
Application Note 488b
Mass Spectrometry
Mass Spectrometry Workflow forEtG/EtS
A Thermo Scientific Exactive mass spectrometer with a HESI source was coupled to a Thermo Scientific Accela 1250 uHPLC system. The MS was operated in Full Scan MS mode at a resolution of 100,000 FWHM with alternating positive/negative switching. The column eluent was diverted to waste for a specified period of time after the sample injection before being sent to the MS. The Exactive™ MS was calibrated at the beginning of the day and used for the entire analysis. No lock mass or internal calibration was used.
resources
Analysis of ETG, ETS using the Thermo Scientific Exactive Mass Spectrometer
Johnson K.
Slide Presentation
Quantitation of Urinary Ethyl Glucuronide and Ethyl Sulfate Using Ultrahigh Resolution LC-MS
Johnson K, Kozak M.
Application Note 488b
Data Analysis
Data Analysis Workflow for EtG/EtS
Thermo Scientific TraceFinder software was used for quantitation. The software extracts chromatograms using accurate m/z, identifies detected peaks using retention time, and quantitates using the area under the peaks.
resources
Analysis of ETG, ETS using the Thermo Scientific Exactive Mass Spectrometer
Johnson K.
Slide Presentation
Quantitation of Urinary Ethyl Glucuronide and Ethyl Sulfate Using Ultrahigh Resolution LC-MS
Johnson K, Kozak M.
Application Note 488b
Thermo Fisher Scientific
United States
