GERSTEL THC Solution - Specification

Significance of the topic

The accurate quantification of Δ9-tetrahydrocannabinol (THC) and its primary metabolites in biological fluids is essential for forensic toxicology, clinical pharmacokinetics, and therapeutic monitoring. Automated workflows enhance reproducibility, minimize operator error, and support high-throughput analysis demands.

Study objectives and overview

The GERSTEL THC Solution is an integrated system designed to automate the sample preparation and GC/MS analysis of THC, 11-hydroxy-THC, and 11-nor-9-carboxy-THC in blood serum. The method targets reliable quantification in 0.5 mL serum samples, combining solid phase extraction, solvent evaporation, derivatization, and injection into a split/splitless GC inlet.

Methodology and instrumentation

The analytical workflow begins with manual dilution of serum and addition of isotopic internal standards. Key automated steps include:

• Solid Phase Extraction (SPE) to isolate analytes from serum matrix
• Evaporation of the SPE eluate using a multi-position evaporation station
• Reconstitution of residues in N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) for silylation
• Automated injection into a heated split/splitless injector for on-inlet derivatization
• GC/MS detection of trimethylsilyl derivatives on an Agilent 7890 GC coupled to a 5977 MSD

Used Instrumentation

• GERSTEL MultiPurpose Sampler (MPS Dual Head) with integrated gas supply
• GERSTEL Multi Position Evaporation Station (mVAP) with condenser pump
• GERSTEL Solvent Filling Stations (SFS 2) for reagent delivery
• SPE module configured for 1 mL cartridges (heating and shaking disabled)
• Agilent 7890 GC system with 5977 Mass Selective Detector and Split/Splitless inlet

Key results and discussion

The system accommodates up to 95 samples per sequence, equating to 29 samples per working day. Calibration curves demonstrate linearity from 0.7 to 50 ng/mL for THC, 0.9 to 50 ng/mL for THC-OH, and 7 to 500 ng/mL for THC-COOH. Automated sample handling ensures consistent recoveries, minimal carryover, and reproducible chromatographic performance.

Benefits and practical applications

• Reduced hands-on time and minimized operator variability through full automation
• High throughput suitable for forensic, clinical, and research laboratories
• Wide calibration ranges enable both low-level detection and high-concentration analyses
• Modular design allows future expansion to additional analytes or alternative detection methods

Future trends and potential applications

Future developments may focus on coupling automated workflows with liquid chromatography–mass spectrometry for enhanced polar metabolite analysis, continuous on-line extraction systems for real-time monitoring, and seamless integration with laboratory information management systems. Expanding the method to include emerging synthetic cannabinoids and therapeutic metabolites will meet evolving analytical challenges.

Conclusion

The GERSTEL THC Solution offers a comprehensive, automated platform for reliable quantification of THC and its major metabolites in blood serum. By combining SPE, evaporation, silylation, and GC/MS analysis in a single workflow, it delivers high throughput, consistent data quality, and flexible upgrade paths for expanding laboratory requirements.

References

No external references provided.