Screening for a Panel of 12 Toxicologically-Relevant Drugs in Urine using Tof-MRM

Significance of the Topic

The reliable detection of toxicologically relevant drugs in urine is essential for forensic investigations, clinical toxicology and workplace testing. Rapid screening combined with confirmatory analysis streamlines workflows, reduces time to results and supports high confidence in substance identification.

Aims and Overview of the Study

This work evaluates the performance of a time-of-flight multiple reaction monitoring approach (Tof-MRM) on the Xevo G2-XS QTof with the UNIFI platform to screen and confirm 12 drugs of forensic relevance in urine. The study aims to demonstrate sensitivity, selectivity and linearity across low nanogram-per-milliliter concentrations using a single LC-MS workflow.

Methodology

Sample Preparation

• Authentic pooled urine spiked with 12 drugs at concentrations from 0.05 to 50 ng/mL and a blank control
• Five-fold dilution with LC mobile phase prior to injection

Chromatographic and Mass Spectrometric Conditions

• ACQUITY UPLC I-Class FTN for separation using established Forensic Toxicology Screening gradient
• Xevo G2-XS QTof operated in Tof-MRM mode monitoring two transitions (quantifier and qualifier) per analyte
• Collision energy ramp of 10–40 eV (constant 40 eV for norbuprenorphine qualifier)

Instrumentation Used

• ACQUITY UPLC I-Class (FTN) system
• Xevo G2-XS QTof high-resolution mass spectrometer
• UNIFI Scientific Information System for data acquisition and processing

Main Results and Discussion

• All 12 drugs detected with high selectivity at low ng/mL levels using simple dilution
• Representative qualifier chromatograms confirmed clear separation and absence of interferences in blank urine
• Calibration curves (example: 6-monoacetylmorphine) displayed excellent linearity across the tested range
• Tof-MRM sensitivity matched or exceeded traditional targeted triple quadrupole methods

Benefits and Practical Applications of the Method

• Single-platform workflow enables both broad non-targeted screening (Tof-MS E) and targeted confirmation (Tof-MRM)
• Reduced sample preparation complexity and analysis time
• High throughput capability for forensic, clinical and workplace drug testing laboratories

Future Trends and Potential Applications

• Expansion to include emerging psychoactive substances and larger analyte panels
• Integration with automated sample handling for higher throughput
• Application in clinical toxicology for rapid patient monitoring
• Coupling high-resolution screening with quantitative Tof-MRM for comprehensive workflows

Conclusion

The study successfully demonstrates that Tof-MRM on a high-resolution QTof instrument provides a fast, sensitive and selective method for confirming multiple drugs in urine with minimal sample processing. This unified approach simplifies workflows, improves confidence in results and can be readily expanded to broader toxicology applications.

References

1. Development of a clinically relevant liquid chromatography tandem mass spectrometry assay for 13 drugs of abuse in urine, Ann. Clin. Biochem. 2010, 47, 415–422.
2. Drug screening in medical examiner casework by high-resolution mass spectrometry (UPLC-MSE-TOF), J. Anal. Toxicol. 2013, 37(8), 580–593.
3. Forensic Toxicology Screening Application Solution. Waters Brochure 720004830EN.
4. Quantitation of high resolution MS data using UNIFI: acquiring and processing full scan or Tof-MRM datasets, 720005605EN, 2016.