Hanna Instruments HI 4101 - Manual (Page 29)

9
•
If sensor has been stored or shipped dry, it should be
“conditioned” by soaking the pH/reference assem-
bly 1 hour or more in one of the pH test solutions.
•
Avoid touching the pH glass with your fingers.
•
Attention: The pH/reference assembly is fragile!
Support the upper portion of the internal cell while
immersing the glass and reference assembly. A tall
narrow container with weighted bottom is best. The
pH test solution should cover the bottom of the large
black ban.
Test: Connect the BNC connector on the electrode cable to a
pH/mV (mV or ORP mode) meter. Carefully immerse
the sensor assembly into one of the buffers. When the
measurment stabilizes record the mV generated. Rinse
sensor tip in deionized water and dab dry between
buffers to prevent solution carry-over. Do not rub the
glass. Take a measurement in the second buffer and
record mV. Pay attention to minus sign if present.
Calculate the difference in mV between the two solutions.
Example of typical values:
HI 4000-47- 7 -90.2 mV
HI 4000-47-4 80.66 mV
Difference 170.8 mV= 80.6-(-90.2)
A calculated value equal or greater than 160 mV is ac-
ceptable for ambient temperatures between 20° and 25°C.
1) Remove glass internal from sensor body and perform
inner electrode check. (See section VIII).
2) Install membrane on the outer probe body. Use twee-
zers provided and avoid touching working area of
membrane with your fingers as skin oil will change
the hydrophobic properties. Discard the paper back-
ing (blue) found between white PTFE membranes.
Hold membrane at corner with tweezers and drape
over lower opening of outer probe body.
IX. IX. IX. IX. IX. Electrode Preparation Electrode Preparation Electrode Preparation Electrode Preparation Electrode Preparation