Measurement of zeta-potential of microalgae by electrophoresis

摘要

Migration velocities of microalgae Chlorella pyrenoidosa with a unicellular diameter of 4.4 micrometer ad density of 1.04 X 10~3 kg/m~3 were measured in a fused silica capillary tube with inner diameter of 100 micrometer under the electric field strength of 20kV/m by changing the solution pH from 4 to 8. The measurement was carried by vertical capillary electrophoresis, in which the gravitational settling of microalgae onto the capillary wall does not occur. Detection of the microalgae was performedat 210nm wavelength for its maximum absorption, whose validity was confirmed by the measurement at 680nm wavelength for detecting chlorophyll. The electrophoretic velocity was obtained by subtracting the electro-osmotic flow and settling velocities fromthe migration velocity. The zeta-potentials calculated from the electrophoretic velocities were negative in the range of pH4 to pH8 and decreased with increasing pH.