Headspace solid-phase microextraction of cannabinoids in human head hair samples.

Area of Science:

• Forensic Toxicology
• Analytical Chemistry
• Pharmacology

Background:

• Cannabinoid detection in biological matrices is crucial for forensic and clinical toxicology.
• Human head hair analysis offers a long-term window for detecting drug use.
• Existing methods for cannabinoid analysis in hair can be time-consuming and complex.

Purpose of the Study:

• To develop and validate a fast, precise analytical method for detecting key cannabinoids in human head hair.
• To establish reliable quantification limits and accuracy for cannabinoid analysis in hair samples.
• To assess the method's utility in identifying frequent marijuana use among clinical populations.

Main Methods:

• External decontamination of hair samples with petroleum ether.
• Alkaline digestion followed by headspace solid-phase microextraction (HS-SPME) for cannabinoid extraction.
• Gas Chromatography-Mass Spectrometry (GC-MS) in Selected Ion Monitoring (SIM) mode for detection and quantification.

Main Results:

• Achieved low limits of quantification (LOQ) of 0.07 ng/mg and limits of detection (LOD) of 0.12 ng/mg for all studied cannabinoids.
• Demonstrated high accuracy (r >0.98) across the calibration range (0.12–12 ng/mg) using weighted least squares linear regression.
• Successfully detected cannabinoids in hair samples from volunteers reporting frequent marijuana use (≥10 times/week).

Conclusions:

• The optimized method is simple, rapid, and precise for cannabinoid analysis in human head hair.
• The validated method provides accurate quantification, suitable for forensic and clinical applications.
• This hair analysis technique can effectively identify individuals with a history of frequent marijuana consumption.