Jiangxi online ph meter

1. The principle of the online pH meter Jiangxi online pH meter measures the potential difference in the solution of the working battery composed of the electrode and the reference electrode, and uses the linear relationship between the pH value of the solution to be measured and the potential of the working battery , And then converted to pH unit value by the ammeter to realize the measurement.　　2. Maintenance of the online pH meter 　　 1. Storage of the pH meter Glass electrode storage When the pH meter is not in use for a short period of time, it can be fully immersed in distilled water or 1×10-4 hydrochloric acid solution. However, if it is not used for a long time, it should be left dry and should not be soaked with washing liquid or other water-absorbent reagents.　　2. Cleaning of the pH glass electrode 　　 The contamination of the glass electrode bulb may increase the response time of the electrode. You can use CCl4 or soap to wipe off the dirt, and then immerse in distilled water for a whole day and night to continue using it. When the pollution is serious, it can be immersed in 5% HF solution for 10-20 minutes, rinsed off with water immediately, and then immersed in 0.1N HCl solution for a whole day and night before continuing to use.　　3. Treatment of glass electrode aging 　　The aging of glass electrode is related to the gradual change of the glue layer structure. The old electrode has a slow response, high membrane resistance and low slope. Etching off the outer adhesive layer with hydrofluoric acid often improves electrode performance. If this method can be used to regularly remove the inner and outer layers of glue, the life of the electrode is almost unlimited. 4. Storage of silver for reference electrode-the best storage solution for silver chloride electrode is saturated potassium chloride solution. High concentration potassium chloride solution can prevent silver chloride from precipitating at the liquid junction and keep the liquid junction in operation state. This method is also suitable for storage of composite electrodes, which is also a feature of Jiangxi online pH meter.　　　　 3. Common problems and solutions of online pH meter 　　1 The same sample, the pH value of the two measurements is different? 　　 Temperature change or the sample itself has a chemical reaction, will cause the pH value to change. Therefore, the temperature should be kept as consistent as possible and chemical reactions should be avoided.　　2 The same sample is measured on two pH meters at the same time, and the readings are inconsistent? 　　 Because the calibration conditions of the two pH meters are different (such as calibration at different times), the measured values u200bu200bare different. Therefore, it is necessary to calibrate the pH meter at the same time with the same buffer, and then measure at the same time.　　3 Why the buffer solution has deteriorated within the validity period and cannot be used? 　　The validity period of the buffer solution refers to the shelf life in the unopened state of use. Once opened and used, the buffer solution is more prone to deterioration due to the action of various molds in the air.　　Attention: The used buffer solution must not be poured back into the original bottle! 　　4 How often does the electrode need to be calibrated? 　　The calibration frequency of the electrode depends on the specific conditions such as the use, maintenance, sample properties and measurement accuracy of the electrode. It is recommended to calibrate once a day, and the longest should not exceed once a week. It must be calibrated before replacing the electrode and not using it for a long time.　　5 How to maintain the pH electrode? After using the electrode for a period of time, if you find that the slope becomes low and the response speed slows down, you can try the following methods: 　　① If the measurement sample contains protein, you can clean the electrode membrane with pepsin/hydrochloric acid lotion.　　② If the measurement sample is oily/organic liquid, it can be washed with acetone or ethanol.　　③If you find that the junction of the electrode becomes dirty and black, you can clean the junction with a mercaptan cleaning solution.　　④Activate the electrode film. Activation method: soak the electrode in regeneration solution for 30 seconds, then soak in 3mol/L KCl solution for 5 hours. 6 The sample temperature is 10°C, at this time the meter displays the pH value at 10°C or 25°C? 　　 acidity meter displays the pH value of the solution at the current temperature, if it is measured at 10°C, the meter displays the solution 10°C If you need to get a pH of 25°C, you must increase/decrease the temperature of the solution to 25°C before measuring. The temperature compensation of the pH meter refers to the compensation of the temperature's influence on the pH electrode, but it cannot compensate the pH value at any temperature to 25°C.　　7 Why is the electrode displayed as 7.02 after it is calibrated in the pH 7.00 buffer? 　　 At this time, the buffer temperature is about 20°C. Since the pH value of the buffer will change slightly with temperature changes, 7.00 is only the value of the buffer at 25°C, and the value of the buffer at 20°C should be 7.02. The pH meter can automatically compensate for the effect of temperature on the buffer to ensure measurement accuracy.