Determination of Gamma-Hydroxy-Butyrate (GHB) in Biological Samples

Importance of the Topic

Gamma-Hydroxybutyrate (GHB) is a critical analyte in forensic toxicology due to its endogenous presence at low concentrations and its misuse as a recreational drug or date-rape agent. Accurate determination of GHB in biological matrices is essential for clinical diagnostics, forensic investigations, and toxicology screening.

Goals and Study Overview

This study presents a validated analytical procedure for the identification and quantification of GHB in serum, whole blood, vitreous humor, urine, and tissue homogenates. The primary objectives included establishing linearity over a relevant concentration range, minimizing matrix interferences, and demonstrating method robustness for routine forensic use.

Methodology and Instrumentation

Sample Preparation:

• Protein precipitation of 0.5 mL sample with acetonitrile/methanol.
• Centrifugation, drying under nitrogen, and derivatization with BSTFA+1% TMS at 70 °C for 20 minutes.

Chromatographic Analysis:

• Gas chromatography on a 25 m × 0.20 mm DB-5MS column, splitless injection, helium carrier.
• Oven program: 60 °C (1 min), 10 °C/min to 200 °C, then 200 °C/min to 280 °C.

Mass Spectrometry:

• Agilent 220 Quadrupole Ion Trap MS with EI source.
• Scan range 200–250 Da, narrow window for GHB and GHB-d6.

Instrumentation Used:

• Agilent 220 Quadrupole Ion Trap GC/MS system.
• Autosampler vials, microcentrifuge, nitrogen drying apparatus.

Key Results and Discussion

The assay exhibited excellent linearity from 10 to 200 µg/mL (R2 > 0.997). Limits of detection and quantitation were established at 5 µg/mL and 10 µg/mL, respectively. No significant carryover or interferences were observed in blank matrices. Ion ratios and retention times consistently met acceptance criteria, ensuring reliable identification.

Benefits and Practical Applications

• High selectivity and sensitivity reduce false positives and negatives.
• Robust against complex biological matrices.
• Applicable to multiple sample types encountered in forensic casework.
• Fast sample throughput supports high-volume laboratories.

Future Trends and Opportunities

Emerging developments such as tandem MS and high-resolution accurate mass spectrometry may further enhance specificity. Integration with automated sample preparation and data processing pipelines can improve laboratory efficiency. Expanded use in clinical studies may clarify endogenous GHB baseline levels and metabolic pathways.

Conclusion

The described GC-Ion Trap MS method provides a rapid, precise, and sensitive solution for GHB quantification in diverse biological specimens. Its validated performance supports forensic and clinical applications, offering confidence in detection at low concentration levels.

References

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