ORP ELECTRODE VERIFICATION PROCEDURE


DIRECTIONS:

1. FILL BEAKER WITH DISTILLED OR DEIONIZED WATER TO USE FOR
   RINSING THE ELECTRODE.
2. FILL ANOTHER BEAKER WITH 1/2 OZ. OF PH 7 BUFFER.
     2.1 TO THIS BEAKER ADD THE AMOUNT OF QUINHYDRONE THAT
         STAYS ON ABOUT 1/4" OF WOOD APPLICATOR.
     2.2 STIR QUINHYDRONE INTO BUFFER.
     2.3 A SMALL AMOUNT OF QUINHYDRONE MUST REMAIN
         UNDISSOLVED. IF ALL DISSOLVES, ADD A SMALL AMOUNT
         AND STIR. REPEAT AS NECESSARY UNTIL A SMALL AMOUNT
         OF QUINHYDRONE REMAINS UNDISSOLVED.
3. FILL ANOTHER BEAKER WITH 1/2 OZ. OF PH 4 BUFFER.
     3.1 REPEAT STEPS 2.1 THRU 2.3
4. RINSE THE ORP ELECTRODE AND PAT DRY WITH SOFT TISSUE.
     4.1 PUT IT IN THE BEAKER FILLED WITH THE 7
         BUFFER/QUINHYDRONE MIXTURE, STIR ELECTRODE GENTLY
         AND LET IT REST AGAINST SIDE OF BEAKER.
     4.2 ALLOW READING TO STABILIZE 30 TO 60 SECONDS-RECORD
         THE READING.
     4.3 THE READING SHOULD BE 90MV PLUS OR MINUS 15
5. RINSE ELECTRODE AND PAT DRY WITH SOFT TISSUE.
     5.1 PUT IT IN THE BEAKER FILLED WITH THE 4
         BUFFER/QUINHYDRONE MIXTURE, STIR ELECTRODE GENTLY
         AND LET IT REST AGAINST SIDE OF BEAKER.
     5.2 ALLOW READING TO STABILIZE 30 TO 60 SECONDS-RECORD
         THE READING
     5.3 THE READING SHOULD BE BETWEEN 170MV AND 185MV ABOVE
         THE READING IN THE 7 BUFFER MIXTURE.
6. IF A SHORT SPAN IS FOUND, LESS THAN 170MV CHANGE BETWEEN 7
   AND 4 BUFFERS. THE PLATINUM SURFACE MAY BE COATED. THE
   COATING MUST BE REMOVED BY ONE OF FOLLOWING WAYS.
     6.1 WIPE SURFACE WITH CLEAN AND SOFT CLOTH OR TISSUE.
     6.2 SOAK ELECTRODE IN CHEMICAL KNOWN TO DISSOLVE
         SUSPECTED COATING.
     6.3 VERY GENTLY POLISH SURFACE WITH 600 GRADE WET
         SILICONE CARBIDE PAPER.
     6.4 AFTER CLEANING LET ELECTRODE SOAK IN ONE OF
         CALIBRATING SOLUTIONS FOR ABOUT FIVE MINUTES.
7. THE BUFFER/QUINHYDRONE MIXTURES SHOULD BE FRESHLY MADE
   EACH TIME THE ELECTRODES ARE CALIBRATED. DO NOT STORE THE
   MIXTURES OR USE AFTER ABOUT 2 HOURS AS THEIR VALUE WILL
   CHANGE WITH TIME.