Facile and highly efficient three-phase single drop microextraction in-line coupled with capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Direct immersion-single drop microextraction (DI-SDME) coupled with capillary electrophoresis (CE) is a powerful analytical technique.
• Analyzing trace analytes in complex matrices like human urine requires efficient sample preparation and enrichment.

Purpose of the Study:

• To develop and demonstrate a high-performance, user-friendly, in-line DI-SDME-CE method for analyzing nonsteroidal anti-inflammatory drugs (NSAIDs) in human urine.
• To optimize the DI-SDME-CE protocol for improved performance, including sample agitation and heating.

Main Methods:

• A three-phase DI-SDME technique was coupled with a commercial CE instrument without modification.
• Urine samples were acidified to pH 2, and acidic NSAIDs were extracted into a basic acceptor drop.
• Sample agitation and heating were employed to enhance extraction efficiency.

Main Results:

• The DI-SDME-CE method achieved significant enrichment factors (340-970-fold) for NSAIDs in urine within 10 minutes.
• High precision was observed with intraday and interday relative standard deviations (RSDs) of 0.8-2.4% and 1.1-3.6%, respectively.
• Low limits of detection (LODs) of 10-50 nM (2-10 µg/L) were obtained using CE/UV detection.

Conclusions:

• The developed in-line DI-SDME-CE method is a simple, automated, and effective technique for analyzing ionizable trace analytes in complex biological samples.
• This method offers excellent sample cleanup and enrichment, making it highly promising for routine analysis.