Different methods of on-line preconcentration in the electrophoretic determination of amines, amino acids, and steroid hormones

Abstract

The scope and limitations of various types of on-line preconcentration for ionogenic and neutral analytes, i.e., catecholamines, amino acids and, steroid hormones, under the conditions of capillary zone electrophoresis and micellar electrokinetic chromatography are examined. The preconcentration factors of the studied analytes were found to be influenced by pH of the buffer solution and the origin and composition of the samples.