Orbitrap Illustration

Designer Drugs

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

Workflow Overview for Designer Drugs

 
Identification and quantitation of ever-evolving designer drugs like cathinones, bath salts and other amphetamine derivatives in urine and other body fluids is being done at increasingly higher rates in forensic toxicology labs. These drugs are very similar in nature and difficult to identify. They also metabolize to form many different products depending on the drug and the body fluid sampled. The molecules may include isomers that need to be identified by chromatographic separation. As there are large numbers of these drugs that are constantly evolving, and their usage varies depending on geography, it is extremely difficult for analytical labs to identify and quantitate them. The analytical method workflow must handle very similar and highly polar molecules, matrix interferences, wide dynamic ranges and significant sample-to-sample differences caused by the varying nature of the urine matrix. Ideally, the method should be able to quantify the known drug metabolites and also qualitatively capture the new ones. Ultra-high resolution LC-MS systems, such as the Thermo Scientific Exactive Plus or Q Exactive system with resolution up to 140,000 FWHM and better than 3 ppm mass accuracy, are ideally suited to handle the challenge. The high resolution also enables separation of element specific isotopes (fine isotopes) in the mass spectrum. The presence or absence of the element-related fine isotopes helps to identify the elements and confirm the structures.
 
The workflow described here uses a simple dilute-and-shoot method, solid-phase extraction (SPE) or liquid-liquid extraction (LLE) for sample preparation and a Thermo Scientific Exactive Plus MS operated in Full Scan MS mode at 70,000 to 100,000 FWHM resolution. The ultra-high resolution and accurate mass with the calibration curves of the known metabolites are able to quantitate and simultaneously identify new drugs and metabolites by identifying new peaks. In many cases, the identity of the new drugs or metabolites can be confirmed using a slightly different data acquisition routine in which alternating full-scan MS and HCD MS are performed. The fragmentation data obtained with high resolution and accurate mass in this fashion enables unambiguous confirmation of the metabolites in the same run.
 




 

Resources

 

Identification of New Amphetamine-Related Designer Drugs Using Exactive High Resolution Accurate Mass Spectrometry

Frison G.
Slide Presentation
 

Analysis of Synthetic Cannabinoids (Spice) in Urine Utilizing HRAM

Van Natta K.
Slide Presentation