Ph And Ise Mode Settings; Buffer Group And Automatic Buffer Recognition - Thermo Scientific Orion Versa Star Pro User Manual

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Appendix A Channel Specific Settings and Features
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130 Orion Versa Star Pro Meter User Manual

pH and ISE Mode Settings

Buffer Group and Automatic Buffer Recognition

Versa Star Pro meters with pH, pH/ISE and pH/LogR modules are capable of automatically
recognizing pH 1.68, 4.01, 7.00, 10.01 and 12.46 buffers; pH 1.68, 4.01, 6.86, and 9.18 buffers;
or up to six custom buffers during a pH calibration, depending on the pH buffer set that is
selected in the setup menu. During a calibration, the meter uses the selected buffer set and the
raw mV reading of the pH electrode in the buffer to recognize and display the buffer value at the
measured temperature. The raw mV reading of the pH electrode in the buffer must be within
one pH unit (± 59 mV) of the buffer's theoretical mV value for the meter to recognize the buffer.
USA Buffer Set
pH
mV range
Buffer
1.68 +256 to +374 mV
4.01 +119 to +236 mV
7.00 -59 to +59 mV
10.01 -236 to -119 mV
12.46 -264 to -382 mV
Testing a pH Electrode for Automatic Buffer Recognition
Use the following procedure to verify that the raw mV reading of the pH electrode is within one
pH unit (± 59 mV) from the theoretical mV reading of the pH buffer, and therefore verify that the
pH electrode in use is capable of performing automatic buffer recognition.
1. Prepare the pH electrode according to the electrode user manual. Set the meter measure
mode to mV.
2. Rinse the pH electrode with distilled water, blot it dry with a lint-free tissue and place the
pH electrode into a pH 4.01 buffer at approximately 25 °C.
3. Wait for the measurement to stabilize and record the mV value of the pH 4.01 buffer when
the measurement is stable.
4. Remove the pH electrode from the pH 4.01 buffer.
5. Rinse the pH electrode with distilled water, blot it dry with a lint-free tissue and place the
pH electrode into a pH 7.00 buffer at approximately 25 °C.
6. Wait for the measurement to stabilize and record the mV value of the pH 7.00 buffer when
the measurement is stable.
7. The mV reading of the pH electrode in pH 4 buffer should be +119 to +236 mV and in pH 7
buffer should be -59 to +59 mV. If the mV readings are in the correct ranges, the pH
electrode is capable of performing automatic buffer recognition. If the mV readings are not
in the correct ranges, manually enter the pH buffer values during a pH calibration.
DIN Buffer Set
pH
mV range
Buffer
1.68 +256 to +374 mV
4.01 +119 to +236 mV
6.86 -51 to +67 mV
9.18 -70 to -188 mV
Custom Buffer Set
Entered pH mV range (based on
Buffer Value entered pH value)
1 buffer value Theoretical ± 59 mV
st
2 buffer value Theoretical ± 59 mV
nd
3 buffer value Theoretical ± 59 mV
rd
4 buffer value Theoretical ± 59 mV
th
5 buffer value Theoretical ± 59 mV
th
6 buffer value Theoretical ± 59 mV
th
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