Performance of four mixed-mode solid-phase extraction columns applied to basic drugs in urine

Area of Science:

• Analytical Chemistry
• Forensic Toxicology
• Pharmacology

Background:

• Accurate extraction of basic drugs from biological matrices is crucial for toxicological and clinical analysis.
• Solid-phase extraction (SPE) is a common technique for sample preparation in drug analysis.
• Evaluating different SPE column chemistries is essential for optimizing method performance.

Purpose of the Study:

• To compare the performance of four different mixed-mode cation exchange solid-phase extraction (SPE) columns.
• To assess the efficiency of these columns in extracting a panel of basic drugs from urine samples.
• To provide insights for selecting the most suitable SPE column for basic drug analysis.

Main Methods:

• Four mixed-mode cation exchange SPE columns (Isolute HCX-3, ABN, Bond Elut Certify, Oasis MCX) were evaluated.
• Urine samples spiked with a range of basic drugs were processed using each SPE column.
• Extracted analytes were analyzed using High-Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD).

Main Results:

• All four tested SPE columns achieved average drug recoveries ranging from 68.5% to 92.1%.
• With a single exception, all studied basic drugs exhibited recovery rates exceeding 50% across all column types.
• The studied drugs included amphetamine, fentanyl, methadone, olanzapine, sertraline, and zopiclone, among others.

Conclusions:

• Mixed-mode cation exchange SPE columns generally perform well for the extraction of basic drugs from urine.
• The choice of SPE column may be influenced by practical considerations such as cost and availability, in addition to recovery rates.
• Further optimization may be needed depending on specific drug targets and matrix complexities.