Analysis of methamphetamine in urine by GC/MS coupled with solid-phase dispersive extraction and solid-phase...

Area of Science:

• Forensic Toxicology
• Analytical Chemistry
• Sample Preparation

Background:

• Accurate quantification of methamphetamine (MA) in biological samples is crucial for clinical and forensic toxicology.
• Existing methods for MA analysis often involve complex extraction and derivatization steps, impacting efficiency and turnaround time.
• Development of streamlined analytical procedures is essential for timely detection of MA in urine.

Purpose of the Study:

• To develop and validate a novel solid-phase dispersive extraction (SPDE) and solid-phase derivatization method for methamphetamine (MA) in urine.
• To improve the efficiency and sensitivity of MA analysis using gas chromatography/mass spectrometry (GC/MS).
• To enable simultaneous extraction, cleanup, and derivatization on a single solid-phase material.

Main Methods:

• Utilized a solid-phase gel (Oasis® HLB) for simultaneous extraction and trifluoroacetic acid (TFA) derivatization of MA from urine samples.
• Employed N-Methylbenzylamine (NMe-BA) as a surrogate standard during the SPDE process.
• Analyzed the TFA derivative of MA using gas chromatography/mass spectrometry (GC/MS).

Main Results:

• Achieved a limit of detection (LOD) of 0.002 µg/mL and a limit of quantification (LOQ) of 0.01 µg/mL for MA.
• Demonstrated high average recovery rates (97.6-100.1%) and acceptable repeatability (5.6-10.7%) and intermediate precision (10.1-11.4%).
• The method facilitated continuous extraction, cleanup, and derivatization on the same solid-phase, simplifying the workflow.

Conclusions:

• The developed method offers an efficient, rapid, and sensitive approach for the analysis of urinary MA.
• This integrated solid-phase pretreatment technique enhances accuracy and ease of MA detection in toxicological screening.
• The SPDE and solid-phase derivatization strategy provides a robust platform for routine analysis of methamphetamine in urine samples.