Topics - Polarization
Polarization has a number of meanings but, in chromatography, it usually refers to the condition of the electrodes used in an electrical conductivity detector. If two electrodes are immersed in a conducting liquid and a DC (direct current) potential is applied to the electrodes, ions are neutralized at the electrode surface and deposits are formed. These deposits may consist simply of bubbles of hydrogen and oxygen, metals if inorganic salts are present, or, with organic salts, organic acids or bases. These deposits interfere with the performance of the detector and the electrodes are said to have become ‘polarized’. This problem is solved by employing AC (alternating current) potential to the electrode which continually reverses the electrolytic effect and, thus, prevents deposits and polarization.