Quantitative Analysis of THC and Metabolites in Urine With a Simple, Fast, and Clean Oasis PRiME HLB μElution Plate

Importance of the Topic

Determining THC and its primary metabolites in urine is vital for forensic toxicology, clinical diagnostics, workplace testing, and monitoring of cannabis consumption trends.

Study Objectives and Overview

This application note outlines a simplified workflow for the quantitative measurement of Δ-9-THC, 11-hydroxy-Δ-9-THC (THC-OH), and 11-nor-9-carboxy-Δ-9-THC (THC-COOH) in human urine. The aim is to deliver a rapid, reproducible sample preparation using Oasis PRiME HLB μElution plates coupled with UPLC-MS/MS analysis.

Methodology and Instrumentation

Enzymatic hydrolysis of urine samples with β-glucuronidase was followed by direct solid-phase extraction on Oasis PRiME HLB μElution plates, eliminating sorbent conditioning, equilibration, evaporation, and reconstitution steps. The μElution format allowed eluates to be diluted and injected directly.

• UPLC: ACQUITY UPLC I-Class system with BEH C18 column (1.7 μm, 2.1×50 mm) at 40 °C.
• Mobile phases: 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B); 4-minute gradient at 0.6 mL/min.
• MS/MS: Xevo TQ-S triple quadrupole in positive ESI mode; MRM detection with two transitions per analyte; optimized cone voltages and collision energies.

Key Results and Discussion

Extraction recoveries averaged 91.9% for THC-OH, 91.5% for THC-COOH, and 60.6% for THC, with RSDs below 7.5%. Matrix effects remained under 15%. Chromatographic peaks were sharp (peak width <3 s) and eluted within 3 min.

• Calibration linearity: R2 ≥0.997 over 0.1–100 ng/mL for THC-OH/COOH and 0.2–100 ng/mL for THC.
• LLOQs: 0.1 ng/mL for THC-OH and THC-COOH; 0.2 ng/mL for THC.
• QC performance: accuracy within ±10%, precision RSD <2% across low, medium, and high levels.

Benefits and Practical Applications

• Speed: no conditioning or solvent evaporation reduces sample prep time.
• Consistency: uniform recoveries and minimal matrix effects support reliable quantitation.
• Throughput: 96-well μElution format enables automated workflows.
• Robustness: cleaner extracts extend column life and reduce MS source contamination.

Future Trends and Possible Applications

Oasis PRiME HLB μElution technology could be extended to multi-class drug screening, on-line SPE integration, and high-resolution mass spectrometry. Further developments may focus on greener solvents, miniaturization, and fully automated sample-to-result platforms.

Conclusion

The combination of Oasis PRiME HLB μElution plates with UPLC-MS/MS provides a fast, simple, and robust method for accurately quantifying THC and its metabolites in urine, meeting regulatory validation criteria and enhancing laboratory efficiency.

Reference

1. Lee R., Traynor A., LeCount J., Wood M. Quantitative analysis of 11-nor-carboxy Δ9-THC in urine using UPLC-MS/MS. Waters Application Note 720004808EN (2012).
2. Bansal S., DeStefano A. Key elements of bioanalytical method validation for small molecules. The AAPS Journal 9(1): E109-E114 (2007).