Sensitive determination of nonsteroidal anti-inflammatory drugs using 3-phase direct immersion single drop microextraction in-line coupled with capillary electrophoresis

Abstract

A direct immersion (DI)-single drop microextraction (SDME) in the 3-phase mode was in-line coupled with capillary electrophoresis to improve the detection sensitivity for weakly acidic nonsteroidal anti-inflammatory drugs, such as ketoprofen, ibuprofen, and naproxen in solution. The acidic analytes in an acidified sample donor solution were extracted into a basic acceptor drop covered with a thin organic layer attached to the tip of a separation capillary. Due to the small dimensions of the acceptor and the organic phases, quite high enrichment factors of 1,600-2,600 were obtained from a 10-min DI-SDME at 25°C with stirring. The limits of detections obtained by monitoring the absorbance at 214 nm were about 0.9-3 nM.