Materials: 

Fisher Scientific AB15 Accumet Basic pH Meter

pH Standards

Unknown Buffers



Method: 



1. Calibrated pH Meter using 7 and 10 standards by following the SOP for calibration.

 

2. Received unknowns and immersed probe in tube 1, tube 2, and tube 3. After immersing probe each time the buffer was immediately capped, and the probe was rinsed and blotted using a Chemwipe.



3. Re-calibrated pH meter with standard 7 and retested each unknown twice.



Data and Results: 



Tube #              1st pH           2nd pH           3rd pH

Tube 1                7.31               7.16                 7.27

Tube 2                11.6               11.4                 11.51

Tube 3               7.49               7.25                7.34 



Class Averages: 

Tube 1               7.05

Tube 2               11.63

Tube 3               7.35

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Discussion and Conclusion: 



Since I was working alone I deviated from the written procedure by adding additional readings. I questioned my calibration after my first reading which is why I re-calibrated and then read each again two more times.