Thermo Scientific
ROSS Ultra, ROSS Ultra Triode and ROSS pH Electrodes
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Thermo Scientific Orion
ROSS Ultra pH/ATC Triode Electrodes
The ROSS Ultra Triode electrode operating temperature range is 0
to 100°C and the temperature accuracy is ±1°C at 2 minutes when
immersed at least 2 inches in solution. The temperature equilibration
due to the rate of heat transfer can take up to 2 minutes in a stirred,
aqueous solution.
ROSS Electrode Operation with
Orion
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pH/LogR Meters
When ROSS electrodes are used with Orion
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pH/LogR
Meters, enhanced temperature compensation is achieved without
the need of a separate ATC probe. Using LogR technology, the
temperature of the solution is measured through the resistance value of
the pH electrode’s sensing bulb.
Each ROSS pH electrode must be calibrated for temperature before
a pH measurement is performed using LogR technology. Refer to the
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pH/LogR meter user guide for details. For maximum
precision, a three point temperature calibration is recommended. Do
not perform a one point temperature calibration if measured solutions
will be below 20°C. The following tables illustrate the expected
pH compensation error for one, two and three point temperature
calibrations. The accuracy values are valid only when the temperature
calibration is performed within the stated temperature range. The
higher temperature range data will apply to measurements made above
that temperature range, provided that calibration points are within 20°C
of each other. When highly accurate pH results are desired, a separate
ATC probe is recommended.
One Point Temperature Calibration
Electrode
Average
Temp. Error
20-30°C
Average
Temp. Error
30-50°C
Average
pH Error
20-30°C
Average
pH Error
30-50°C
8202BN
0.13
0.07
0.002
0.001
8203BN
0.24
0.17
0.003
0.002
8235BN
0.91
0.95
0.011
0.011
8256BN
0.09
0.10
0.001
0.001
Two Point Temperature Calibration
Electrode
Average
temp. error
0-25°C
Average
temp. error
20-40°C
Average
pH error
0-25°C
Average
pH error
20-40°C
8202BN
0.13
0.07
0.002
0.001
8203BN
0.24
0.17
0.003
0.002
8235BN
0.91
0.95
0.011
0.011
8256BN
0.09
0.10
0.001
0.001
