Thermo Fisher Scientific pHScan BNC - Manual (Page 2)

Waterproof pHScan BNC
Microprocessor-based Pocket pH Tester
Connecting your electrode:
To connect the tester to your electrode, align the
posts of the tester's BNC connector with the slots
on the electrode connector. Push together and twist
the electrode connector 1/2 turn until it clicks into
place.
Calibration:
Calibration should be done regularly, typically
every day that the tester is used. You can calibrate
up to three point. Choose buffer sets as described
above right.
1. Press ON/OFF button to switch unit on.
2. Dip electrode about 2 cm into buffer.
3. Press CAL button to enter Calibrate (CAL)
mode. 'CAL' flashes on the display. Then a
pH value close to pH buffer value will flash
repeatedly.
4. After at least 3 minutes, press
the HOLD/CON button to confirm
calibration. The display will show
'CO' and then switch to the buffer
value reading.
5. Repeat with other buffers if
necessary. Rinse electrode in tap
water before dipping into next buffer.
Calibration Troubleshooting:
Failure to press HOLD/CON to
confirm calibration (step 4 above).
Pressing the CAL button will resume
measuring mode but will not enter
the calibration value.
Insufficient sampling time. If the
tester does not have a long enough
exposure to the buffer, a stable
calibration point will not be reached.
Wait at least 3 minutes before
pressing HOLD/CON.
Failure to re-hydrate the electrode. A
dry electrode will give fluctuating
reading while it re-hydrates in a buffer,
causing errors.
Buffer Set selections:
To choose USA (pH 4.01, 7.00, 10.01) or NIST
(pH 4.01, 6.86, 9.18) buffers:
1. With tester off, hold HOLD/CON key while
pressing ON/OFF key.
2. Press HOLD/CON key again.
3. Press CAL key to toggle between USA and NIST
buffer sets.
4. Press HOLD/CON to confirm.
pH Testing:
1. Remove cap or storage bottle from the
electrode and press the ON/OFF button to
switch tester on.
2. Dip the electrode about 2 cm into the test
solution. Stir once and let the reading stabilize.
3. Note the pH or press HOLD/CON button to
freeze the reading. Press HOLD/CON again to
release the reading.
4. Press ON/OFF to turn off tester. If you do not
press a button for 8.5 minutes the tester will
automatically shut off to conserve batteries.
Instrument Maintenance:
• Rinse the electrode with tap water or electrode
storage solution after each measurement.
• Periodic soaks in warm pH 4 buffer will help
remove contaminants.
• When finished using electrode, fill electrode cap
with tap water or electrode storage solution and
replace cap.