The analysis of carbohydrates is one of the important issues in biological/clinical diagnoses since carbohydrates play important roles in biological functions.Among various techniques for analyzing carbohydrates, capillary electrophoresis (CE) is advantageous because it provides a rapid analysis with a low consumption of the sample.In conventional CE of carbohydrates, however, a troublesome derivatization is often required for the detection and/or separation since many carbohydrates have no UV absorbance and no charge.To overcome this drawback, we focused on the affinity CE (ACE) analysis using aryl boronic acids which form complexes with cis-diol compounds like most carbohydrates.In a background solution (BGS) containing aryl boronic acids, the complexation provides the variations of both the wavelength of the absorption maximum and apparent electrophoretic mobility of the complex from those of native carbohydrates, resulting in both the label-free detection and selective separation of carbohydrates [1].