A rapid method for separation and identification of microcystins using capillary electrophoresis and time-of-flight mass spectrometry

Abstract

This paper demonstrates a method for the rapid separation and identification of four microcystin (MC) variants commonly found in aquatic environments. The procedure utilizes capillary electrophoresis (CE) coupled to UV absorbance and time-of-flight mass spectrometric (TOF-MS) detectors. All four analytes were effectively separated within 6min using phosphate buffer in 50-μm ID capillaries with an applied electric field of 400V/cm. The separation of the individual compounds was optimized through the adjustment of buffer, pH, and β-cyclodextrin content. Ultimately it was determined that, at a sufficiently high pH, all 4 compounds could be separated without the need for added cyclodextrins. The results provided accurate molecular information, assisting in the determination of compound identity. The method was then applied to environmental samples using solid phase extraction for isolation and pre-concentration. The results were comparable to those obtained by LC/MS, but with a shorter run time and lower sample and eluent consumption.

Keywords: Capillary electrophoresis; Cyclodextrin; Mass spectrometry; Microcystin.