Systematic Toxicological Analysis (STA) Using the ACQUITY QDa Mass Detector

Significance of the Topic

Systematic toxicological analysis in biological matrices is essential for reliable detection of xenobiotics in clinical and forensic settings. Effective sample preparation coupled with robust screening methods ensures high sensitivity and throughput in laboratories tasked with monitoring toxicologically relevant substances.

Objectives and Overview of the Study

This study aimed to evaluate a fast and simple solid-phase extraction protocol using Oasis PRiME HLB µElution for preparing human urine and plasma samples spiked with 100 xenobiotics. The extracted samples were screened using UPLC separation and the ACQUITY QDa Mass Detector under the Waters STA method.

Materials and Methodology

The workflow involved:

• Preparation of mixed spiking solutions of analytes at 25 µg/mL, spiked into urine and plasma to 200 and 500 ng/mL levels
• Sample cleanup using Oasis PRiME HLB µElution 96-well plates: loading, washing with 5% methanol, and elution with acetonitrile/methanol containing formic acid
• Drying under nitrogen at 50 °C and reconstitution in ammonium formate buffer with acetonitrile
• UPLC separation with a 15-minute gradient and data acquisition in full scan mode at multiple cone voltages

Used Instrumentation

• Waters ACQUITY UPLC H-Class PLUS System
• Waters ACQUITY QDa Mass Detector
• Oasis PRiME HLB µElution plates
• Porvair nitrogen sample concentrator
• ChromaLynx Application Manager and MassLynx Software

Results and Discussion

The method demonstrated high detection rates at 200 ng/mL:

• Human urine: 93% of analytes detected (tentative or positive matches)
• Human plasma: 98% of analytes detected

Average library match factors above 700 indicated confident identifications, with retention times within 0.35 min of reference values. The process proved reproducible and sensitive across matrices.

Benefits and Practical Applications

• Rapid and simplified SPE workflow without preconditioning
• High throughput via automation in 96-well format
• Cost-effective qualitative screening for forensic and clinical laboratories
• Robust extraction with cleaner chromatograms

Future Trends and Opportunities

Advances may include expanded spectral libraries, integration with automated liquid handling, miniaturized extraction formats, and enhanced data analytics for non-targeted screening. The low-cost QDa detector could find broader use in routine toxicology and environmental monitoring.

Conclusion

The combination of Oasis PRiME HLB µElution SPE, UPLC separation, and ACQUITY QDa detection provides a straightforward, sensitive, and cost-efficient STA workflow for screening toxicologically relevant compounds in urine and plasma.

References

1. Goshawk J, Lee R, Wood M. Evaluation of the Potential of the ACQUITY QDa Mass Detector for Use in Forensic Chemistry and Drug Control Laboratories. Waters Technology Brief, 2017.
2. Lee R, Roberts M, Paccou A, Wood M. Development of a New UPLC/MS Method for Systematic Toxicological Analysis. Waters Application Note, 2009.
3. Rosano TG, Swift TA, Wood M. Postmortem Drug Screening by Non-Targeted and Targeted UltraPerformance Liquid Chromatography Technology. Journal of Analytical Toxicology, 2011;35:411-423.