Stabilization of urinary THC solutions with a simple non-ionic surfactant

Area of Science:

• Analytical Chemistry
• Forensic Toxicology

Background:

• Urinary solutions containing Delta-9-tetrahydrocannabinol (THC) metabolites are prone to adsorptive loss.
• Specialized handling and storage are often required to maintain analyte integrity.

Purpose of the Study:

• To investigate the efficacy of a non-ionic surfactant, Tergitol, in stabilizing urinary THC metabolite solutions.
• To reduce the need for complex storage and handling procedures.

Main Methods:

• Addition of Tergitol surfactant to urinary THC metabolite solutions at varying concentrations, including up to 20 times the critical micelle concentration (CMC).
• Assessment of analytical process interference by the surfactant.
• Evaluation of adsorptive loss mitigation under diverse storage (refrigerated, frozen) and handling (glass, plastic, low pH) conditions.
• Comparison of analyte concentrations and stability over 49 weeks with and without surfactant using gas chromatography-mass spectrometry.

Main Results:

• Tergitol addition, even at two times CMC, effectively mitigated adsorptive loss of THC analytes across various conditions.
• Micellar solubilization by the surfactant increased assayed THC concentrations by an average of 10% (range 3-20%).
• Solutions with surfactant remained stable for 49 weeks, while those without failed within 21 weeks.

Conclusions:

• Non-ionic surfactant addition is a simple and effective method to enhance the accuracy and precision of urinary THC metabolite quantification.
• Tergitol mitigates adsorptive losses during storage and handling, improving the reliability of gas chromatography-mass spectrometry results.