Thermo Scientific
ROSS Ultra, ROSS Ultra Triode and ROSS pH Electrodes
|
11
Thermo Scientific Orion
5. Place the electrode into the buffer. When the reading is stable,
set the meter to the pH value of the buffer at the measured
temperature. Refer to the meter user guide for a detailed
procedure.
Table 1
provides pH buffer values at various
temperatures.
6. Proceed to the
pH Measurement
section.
Two Buffer Calibration
This procedure is recommended for precise measurements.
1. Select two buffers that bracket the expected sample pH. The first
buffer should be near the electrode isopotential point (pH 7) and
the second should be near the expected sample pH (pH 4 or pH
10). Buffers should be one to four pH units apart.
2. The buffers should be at same temperature as the sample. If the
buffers and samples are at varying temperatures, temperature
compensation is recommended.
3. Rinse the electrode first with distilled water and then with the first
buffer.
4. Place the electrode into the first buffer. When the reading is
stable, set the meter to the pH value of the buffer at the measured
temperature. Refer to the meter user guide for a detailed
procedure.
Table 1
provides pH values at various temperatures.
5. Rinse the electrode first with distilled water and then with the
second buffer.
6. Place the electrode into the second buffer. When the reading
is stable, set the meter to the pH value of the buffer at the
measured temperature. Refer to the meter user guide for a
detailed procedure.
Table 1
provides pH buffer values at various
temperatures.
Nominal
Buffer
Value at
25 °C
Temperature
0°C
5°C
10°C
20°C
30°C
40°C
50°C
60°C
70°C
80°C
90°C
1.68
1.67 1.67 1.67 1.68 1.68 1.69 1.71 1.72 1.74 1.77 1.79
4.01
4.00 4.00 4.00 4.00 4.02 4.03 4.06 4.09 4.12 4.16 4.21
6.86
6.98 6.95 6.92 6.87 6.85 4.03 6.83 6.84 6.85 6.86 6.88
7.00
7.11 7.08 7.06 7.01 6.98 6.97 6.96 6.97 6.99 7.03 7.08
9.18
9.46 9.40 9.33 9.23 9.14 9.07 9.01 8.96 8.92 8.89 8.85
10.01 10.32 10.25 10.18 10.06 9.97 9.89 9.83 9.79 9.78 9.78 9.80
12.46 13.47 13.24 13.03 12.64 12.29 11.99 11.73 11.50 11.30 11.13 11.98
Table 1: pH Values of Buffers at Various Temperatures
