Separation of Morpholine, N-Methylmorpholine and N-Methylmorpholine-N-oxide by Indirect UV Absorption Capillary Electrophoresis

Abstract

A UV absorption bipolar capillary electrophoresis system was built on the basis of on-column detection. As an application of capillary electrophoresis, analysis of inorganic anions such as Cl^-, SO₄^2- and SO₃^- is demonstrated. The separation of morpholine (M), N-methylmorpholine (NMM) and N-methylmorpholine-N-oxide (NMMO) using indirect UV absorption technique is discussed as well. Chromate buffer of 10mM was used to provide absorption of the mobile phase additive in indirect detection and precise pH control of the carrier electrolyte. The effect of buffer pH on the separation of M, NMM and NMMO is illustrated.