Determination of cocaine in human plasma by selective solid-phase extraction using an aptamer-based sorbent

Area of Science:

• Biochemistry
• Analytical Chemistry
• Materials Science

Background:

• Solid-phase extraction (SPE) is crucial for isolating analytes from complex matrices like plasma.
• Developing highly selective extraction materials is essential for accurate toxicological and clinical analyses.
• Aptamers offer unique molecular recognition capabilities for targeted analyte capture.

Purpose of the Study:

• To synthesize and characterize a novel aptamer-based solid-phase extraction (SPE) sorbent.
• To evaluate the sorbent's efficiency and selectivity for cocaine extraction from human plasma.
• To establish a reliable method for cocaine quantification in biological samples.

Main Methods:

• Immobilization of anti-cocaine aptamers onto CNBr-activated Sepharose to create an oligosorbent.
• Development of an extraction procedure in both pure media and human plasma.
• Determination of sorbent capacity and cocaine extraction recovery rates.
• Assessment of interfering compound retention and limit of detection.

Main Results:

• The aptamer-based oligosorbent demonstrated specific retention of cocaine.
• High extraction recovery (close to 90%) was achieved for cocaine from human plasma.
• Interfering compounds, problematic for standard SPE, were not retained, improving selectivity.
• An estimated limit of detection of 0.1 microg mL(-1) was established for plasma samples.

Conclusions:

• A highly selective aptamer-based SPE sorbent was successfully developed for cocaine extraction.
• This novel oligosorbent enables fast, reliable, and sensitive quantification of cocaine in human plasma.
• The aptamer approach significantly enhances selectivity compared to conventional SPE methods.