point isoélectrique

Traductions

• anglais

  Date : 1984

  Définition

  The pH at which the positive and negative charges on the particles of a colloidal solution cancel each other so that the particles become electrically neutral. This condition is brought about by altering the original pH by addition of acids or alkalis to the solution.

  Note :

  The pH at which the isoelectric point occurs varies with the chemical nature of the particle; for example, it is about 6.0 (faintly acid) for glycine and near 10 (moderately alkaline) for lysine. At the isoelectric point, particles will not migrate in an electric field; the system becomes unstable, and coagulation or precipitation occurs, unless the change of pH is great enough to cause reversal of the charge by "jumping" the isoelectric point.

  Termes :

  1. isoelectric point
  2. iso-electric point