Wine Analysis Home

Electrolyte contact with solution being tested

• To complete the electrical circuit of a pH meter the electrolyte solution of the reference electrode needs to make electrical contact with the solution being tested without the two solutions mixing to any significant extent.
  
  
• The most simple but crudest method is to employ a pin hole but with the disadvantage of a high loss rate of electrolyte and a high mixing rate.
  
  
• A common satisfactory method employed is to fit the reference electrode with a sintered, porous glass frit.
  
  The only disadvantage is the clogging of the frit when non filtered solutions with solids are frequently tested, with the resulting loss of function.
  
  
• Paper wedges or asbestos wicks sealed into glass were used as prototypes to the glass frit.
  
  
• By far the most satisfactory method is the combination electrode that employs a liquid sleeve junction that is able to be cleaned.
  
  These include manual cleaning or quick semi-automated cleaning.