GOH Lab Accumet AB15 pH Meter Oct 27, 2008
pH Meter Basic Operation Instructions (Ag/AgCl Reference Electrode)
First time users or anyone having problems should read the instrument and electrode manuals located in this Lab
· Electrode Set Up (Fisher liquid filled, mercury-free pH/ATC Epoxy Body, Combination Electrode13-620-631, pink collar)
· Electrode storage solution : Fisher SE 40-1
· Electrode filling Solution: Saturated KCl, Fisher SP 138
· When the electrode is in storage the fill hole needs to be closed. For measurements the fill holes needs to be open.
· The fill hole is located on the purple cap ring. Rotate the ring from the closed to the open position.
· Check the level of the internal filling solution (SE 138), it should be approximately 1 cm below the fill hole.
Samples need to be at a stable temperature.
Calibration:
· Check the calibration of the instrument using either the pH 4 and pH7 solutions. If check sample readings are wrong, refer to the manual p.29 (Standardization). Use at least 2 buffers, either pH 4 and 7 or pH 7 and 10.
Taking a Reading:
1. Make sure the electrode filling hole is open.
2. Immerse the electrode far enough into the solution to cover the sensing bulb and the reference junction (approx 2 cm). The level of the internal filling solution should always be greater than 3 cm above the level of the sample solution.
3. Swish the electrode in the solution, then hold the electrode still before recording the reading.
Cell Cleaning:
· Between samples, wash the electrode with a stream of RO or deionized water from a water bottle. Gently shake the cell to dislodge water droplets and tap the end with a clean piece of paper towel.
Cell Storage:
· Between samples readings, submerse the probe in the plastic beaker containing electrode storage solution. Never store a pH electrode in water.
· After use make sure the electrode is clean and then store it in the small sealable container that contains fresh storage solution. Close the electrode filling hole.