Fig. 3 Electropherograms of As species at different pH values using the operating conditions of 25 kV, 30°C (verticle axis in mV). Separation column, 720-mm by 50-µm i.d. fused capillary tube; support electrolyte chromate buffer 5 mmol L^-1 with 0.5 mmol L^-1 EOF; . Peak "x" was not identified during the analysis