Detailed use and maintenance of lead ion electrode
Instructions for the use of lead ion electrodes Technical indicators:
Measuring range: (10-1-10-7) mol / L lead ion concentration Temperature range: (5-35) degree PH value of sample: (4-6) PH
Ionic strength regulator: a small amount of potassium nitrate powder activation solution: 10-3mol / L lead nitrate
Reference electrode: 217 double salt bridge reference electrode (the second section of salt bridge is filled with saturated potassium nitrate)
Steps for usage:
1. Combine the lead ion electrode with the reference electrode and use a magnetic stirrer to clean the electrode potential in deionized water. For example, when the temperature of the solution is 25 degrees, the cleaning potential is generally around 250mv. If the temperature of the solution is lower than 25 degrees, the potential value should be appropriately reduced.
2. After the electrode is cleaned, the electrode should be calibrated, and the electrode potential should be tested from dilute to concentrated in two or more lead ion standard solutions with different concentrations and recorded. According to the recorded mv value and ppb value (negative logarithm value of lead ion concentration), draw a standard curve of electrode "mv-ppb".
3. Use the electrode to measure the sample, record the measured mv value, read the corresponding ppb value on the standard curve diagram, and then calculate the lead ion concentration of the sample.
Electrode storage:
1. After use, clean the electrode potential with deionized water to about 250mv as soon as possible, and then use the filter paper to absorb the moisture on the surface of the electrode, put on the protective cover and put it back in the packaging box to store it dry.
2. The electrode should be stored in a dry and ventilated normal pressure room with a relative humidity of (5-45) degrees not more than 85%, and the air should not contain corrosive gases.
Precautions:
1. During measurement, the measuring end of the electrode should be fully immersed in the measured solution. The level of the external reference solution of the matching reference electrode must be higher than the level of the external measured solution.
2. In order to ensure the measurement accuracy, the temperature, ionic strength, stirring speed and other conditions should be consistent during electrode calibration and measurement.
3. When changing the sample for measurement, the indicator electrode and reference electrode should be washed thoroughly with deionized water, and then the residual water traces on the electrode should be gently blotted with filter paper, and then the electrode should be immersed in the next sample for measurement. Samples are contaminated with each other.
4. The PH value of the sample should be kept within the (4-6) PH range. Before using the electrode, you should consult as many documents as possible or use recognized standard measurement methods (such as national standards) to ensure correct use.
5. The lead ion electrode plug part should always be kept clean and dry to avoid rust and pollution.
6. The lead ion electrode should avoid rubbing and strong vibration during use.
7. It is not recommended to wipe the electrode directly with gauze or roll paper, as this may cause damage to the sensitive diaphragm.
8. Problems related to electrode calibration:
a. The lead ion standard solution is generally (2-5) concentrations, and the concentration value of the standard solution increases / decreases 10 times in sequence.
b. The more standard solutions used in electrode calibration, the higher the accuracy of the standard curve.
c. The concentration range of the standard solution used should include the potassium ion concentration value of the tested sample.
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