Electro-Chemical Devices (ECD) SMS22 - Manual (Page 25)

3. Allow the sensors and a thermometer to equilibrate for at least 10 minutes
4. Verify the displayed temperature agrees with the thermometer
5. If not, then adjust the temperature of the sulfide sensor to agree with the thermometer in the
Configure/Trim Menu → °C/°F & temp cal → 1 Trim °C menu. (see section 3.2.3 above)
6. Repeat in the 2 Trim °C menu, for the pH sensor.
This calibration was performed in the factory calibration but it is advisable to perform a temperature
check every 2-3 months.
4.2.2 pH SENSOR
The PHS10 pH sensor was calibrated with pH 7.0 and pH 10.0 buffers at the factory before shipping.
Periodically verify the displayed pH agrees with the actual pH.
4.2.2.1 Single Point Calibration (Standardization)
If the displayed pH value deviates by more than 0.2pH from the sample pH then the pH sensor should
be recalibrated,
1. Switch the SMS-22 Analyzer to CALIBRATE Mode
2. Remove the PHS10 pH sensor from the flow cell and place it in a beaker of pH7 buffer.
3. Scroll up to the Ch2 Buffer Menu (see Section 3.3.3 above)
4. ENTER the Menu and ENTER the 1 pH 7.00 pH line
5. When the mV reading has stabilized SAVE the reading (MENU SELECT
▼)
6. It is recommended to proceed down to the 2 pH 10.00 pH screen, the slope calibration (Section
4.2.2.2 below)
Alternatively the reading could be STANDARDIZED on line to agree with a laboratory determined pH
value for the sample solution. The SMS-22 must be switched to CALIBRATE mode with sample in the
flow cell or the sensor must be removed from the flow cell and placed in a beaker of the sample.
1. Switch the SMS-22 Analyzer to CALIBRATE Mode with untreated sample in the flow cell
2. Scroll up to the Ch2 Buffer Menu (see Section 3.3.3 above)
3. ENTER the Menu and ENTER the 1 pH 7.00 pH line
4. Adjust the pH value to the value determined by the laboratory measurement
5. When the mV reading has stabilized SAVE the reading (MENU SELECT
▼)
6. Return to HOME screen (CALIBRATE▼)
4.2.2.2 Two Point Calibration
1. Switch the SMS-22 Analyzer to CALIBRATE Mode
2. Remove the PHS10 pH sensor from the flow cell and place it in a beaker of pH 7.00 Calibration
Buffer.
3. Scroll up to the Channel 2 Buffer Menu and ENTER the menu by pressing both horizontal
CALIBRATE keys, ◄ CALIBRATE ► (See section 3.3.3 above)
SMS-22 Page 16