Continuous and automated slug flow nanoextraction for rapid partition coefficient measurement

Area of Science:

• Analytical Chemistry
• Microfluidics
• Pharmaceutical Science

Background:

• Octanol-water partition coefficients (log Kow) are crucial for assessing compound lipophilicity in pharmaceutical and environmental applications.
• Traditional shake-flask methods for log Kow determination are time-consuming, labor-intensive, and require large sample volumes.

Purpose of the Study:

• To develop and validate an automated, microfluidic system for rapid log Kow determination.
• To significantly reduce sample and solvent consumption compared to conventional methods.

Main Methods:

• Utilized slug flow nanoextraction (SFNE) within a microfluidic chip for automated sample handling.
• Introduced 1 μL samples into a device that creates segmented 4 nL aqueous and octanol slugs, separated by a fluorous carrier fluid.
• Employed online UV absorbance detection for real-time concentration analysis and log Kow calculation.

Main Results:

• Successfully determined log Kow for seven pharmaceutical compounds using minimal sample (5 μL) and solvent (2.9 μL) volumes.
• Achieved rapid analysis, with complete measurements including calibration curves, completed in under 2 hours.
• Demonstrated the capability to toggle between aqueous plug and phase pair generation for online calibration.

Conclusions:

• The developed SFNE microfluidic system offers a highly efficient and automated approach for log Kow determination.
• This method presents a significant advancement over traditional techniques, enabling faster, more economical, and environmentally friendly lipophilicity assessments.