Utilizing HRAM Orbitrap mass spectrometry to quantitate 106 drugs of abuse in urine

Significance of the topic

Accurate and robust quantitation of drugs of abuse in urine is critical for forensic and clinical toxicology laboratories. High-resolution mass spectrometry with Orbitrap technology provides the sensitivity and specificity required to detect a broad panel of compounds, support overdose investigations, compliance monitoring, and performance testing.

Objectives and study overview

This study presents a rapid UHPLC–HRAM mass spectrometry workflow to confirm and quantify 106 common drugs of abuse in urine. The method aims for baseline separation of isomers, broad dynamic range from 0.1 to 5000 ng/mL, and high throughput using a 7 minute chromatographic run.

Methodology

• Sample preparation: Solid phase extraction using mixed-mode SCX SPE plates; conditioning, loading, washing, and dual elution steps
• Chromatography: Vanquish Horizon UHPLC system with Accucore C18 Plus column; 7 minute gradient from 97/3 to 1/99 mobile phase A/B
• Data acquisition: Targeted full-scan and data-dependent MS2 with a predefined mass list for 106 analytes; resolution 60 000 for MS1 and 15 000 for MS2; isolation window m/z 1.5; optimized collision energies

Instrumentation

• Thermo Scientific Vanquish Horizon UHPLC system
• Thermo Scientific Orbitrap Exploris 120 mass spectrometer
• Thermo Scientific SOLAµ SCX solid phase extraction plates
• TraceFinder software for data processing and quantitation

Main results and discussion

• Separation and detection of 106 drugs eluting between 0.45 and 5 minutes, including clear resolution of isomeric pairs
• Limits of quantitation as low as 0.1 ng/mL for select metabolites and upper linearity up to 5000 ng/mL for most analytes; correlation coefficients above 0.99
• Mass accuracy maintained around 1 ppm across chromatographic peaks at low concentration levels
• Reproducibility confirmed by low relative standard deviations in internal standard signals across calibration series

Benefits and practical applications

This workflow offers a fast, comprehensive, and flexible solution for routine toxicology analysis. Key advantages include:

• High throughput with a 7 minute run time per sample
• Wide dynamic range suitable for trace-level screening and clinical quantitation
• Reliable isomer separation to minimize false positives
• Easy customization of compound lists and library updates via user-friendly software

Future trends and applications

• Expansion of analytical panels to cover emerging synthetic drugs and novel metabolites
• Automation of sample preparation and data review for increased laboratory throughput
• Integration with advanced data analytics and artificial intelligence for pattern recognition and epidemiological insights
• Adaptation of the workflow to alternative biological matrices such as blood, oral fluid, or hair

Conclusion

The rapid UHPLC Orbitrap Exploris 120 workflow demonstrates robust performance for quantifying a broad spectrum of drugs of abuse in urine, delivering sensitivity, specificity, and speed required in modern forensic and clinical toxicology. Its customizable design and high-throughput capability make it well suited to evolving laboratory needs.

References

1. United Nations Office on Drugs and Crime. World Drug Report 2021.
2. Thermo Fisher Scientific Technical Note 74138: Evaluation of custom injection programs and larger internal diameter capillary for strong solvent sample effects mitigation in liquid chromatography.