Isolation of acidic, neutral, and basic drugs from whole blood using a single mixed-mode solid-phase extraction...

Area of Science:

• Forensic Chemistry
• Analytical Chemistry
• Toxicology

Background:

• Accurate drug quantification in biological matrices is crucial for clinical and forensic toxicology.
• Existing methods for drug isolation from whole blood can be complex and time-consuming.
• Development of efficient extraction techniques is essential for reliable drug testing.

Purpose of the Study:

• To develop and validate a solid-phase extraction (SPE) procedure for isolating acidic, neutral, and basic drugs from whole blood.
• To optimize SPE conditions for selective drug elution and high recovery rates.
• To provide a robust method for drug analysis using gas chromatography.

Main Methods:

• Sonication of whole blood samples followed by dilution with phosphate buffer.
• Extraction of drugs using a mixed-mode bonded-phase silica column at pH 6.0, adjusted to pH 3.3.
• Selective elution of drugs using two distinct solvent fractions: acetone-chloroform and basic ethyl acetate.
• Analysis of eluted drug fractions by gas chromatography with a flame ionization detector.

Main Results:

• The developed SPE method successfully isolated acidic, neutral, and basic drugs from whole blood.
• Two distinct fractions allowed for the separation of different drug classes based on their pKa values.
• Absolute recoveries for all tested drugs exceeded 81% at a concentration of 2 µg/mL.
• Gas chromatography with flame ionization detection provided sensitive drug quantification.

Conclusions:

• The optimized SPE method provides an efficient and reliable approach for the simultaneous isolation of diverse drug types from whole blood.
• This method enhances drug analysis in toxicological investigations by offering high recovery and selectivity.
• The technique is suitable for routine drug screening and quantification in clinical and forensic settings.