Product: Aquili pH electrode Attack BNC
Dispatch and storage:
All electrodes are individually tested before delivery.
Storage in dry conditions, 10 °C to 30 °C.
In temperatures below -15 °C the electrodes may fracture due to freezing of buffer and electrolyte.
Provide frost-proof packaging for long distance dispatch.
The electrodes have a cap. A sponge soaked with a special liquid is fitted in the cap. This liquid prevents the sensor element from drying out.
Calibration and measurement
Remove the cap for calibration and measurement. Dry stored pH electrodes must be immersed in water for 24 hours prior to use, otherwise strong drift will occur.
When the cap is not used, the electrode must be stored in a KCl solution, e.g. 3-molar, or buffer solution.
Do not place in distilled water.
Each new electrode must be calibrated. For pH electrodes, two-point calibration is necessary. Standard buffer solution must be used.
Note the manufacturer's calibration instructions. If no instructions are available, proceed as follows:
- The first calibration must be carried out with a buffer solution equivalent to the electrode zero (E0). This is usually pH 7.
- To calibrate, immerse the sensor in buffer solution pH 7 (for electrode with E0 = pH 7).
- With automatic temperature compensation the temperature sensor must also be immersed in the buffer solution, otherwise set "temperature" button to "measuring temperature". With "Zero" button (asymmetry potential AP), set indication to buffer solution value.
- Rinse electrode with distilled water and immerse in the second buffer solution, e.g. pH 4.
- With "gradient" button (mV / pH) set indication to the value of the second buffer solution. The pH measuring instrument is then compatible with the new electrode.
- The frequency of calibration or checking the measuring electrode depends on the application conditions (dirt, chemical build-up).
It is necessary to clean the sensor before calibration. The following agents may be used:
- For fatty or oily product, tenside cleaner.
- For calcium deposit and metal hydroxide coating, dilute hydrochloric acid (3%).
- For sulphide deposit (e.g. effluent treatment applications), a cleansing mixture of dilute hydrochloric acid (3%) and thiourea (commercial).
- For material with protein content (food industry applications) a cleansing mixture of dilute hydrochloric acid (3%) and pepsin (commercial).
- As a regeneration solution for very sluggish pH electrodes, a mixture of nitric acid (10%) and ammonium fluoride (50 WI).
When using strongly acid or alkaline solutions, note protection regulations. After cleaning all parts, rinse thoroughly with deionised water.
Electrodes must be installed with an angle of max. 80° to the vertical. This refers also to the calibration of electrodes.
Ensure that the black semi-conductor layer between the copper wire and the polyethylene insulation is completely insulated. If the semi-conductor sleeve is not removed, a shunt occurs at the measuring electrode. This means that either no gradient or only reduced gradient is available.
Quality certificate for electrochemical sensors:
Your electrochemical sensor has been manufactured with the greatest care and observation of all technical rules. Before leaving our factory, your electrode has individually passed a stringent test on our computerised inspection unit and the main results are printed on the certificate.