Precautions for using a pen type pH meter
(1) Waterproof pen pH meters can be calibrated using two point or three point calibration. Firstly, a pH of 7.00 needs to be calibrated. Then, based on the pH value and accuracy requirements of the measured solution, a pH of 4.00 or 10.01 needs to be calibrated. If three-point calibration is selected, a reading of * * * can be obtained within the full range. During automatic calibration, the instrument will automatically recognize the calibration solution, but if the standard solution is inaccurate, it will cause calibration errors; If the calibration solution is greater than or less than the standard value (4.00, 7.00, or 10.01) by one pH value, the instrument will display CAL and END symbols, indicating that calibration cannot be performed.
(2) The number of instrument calibration cycles depends on the measured solution, electrode performance, and accuracy requirements for the measurement. When measuring with high precision (≤ ± 0.03pH), calibration should be carried out in a timely manner. Generally, when measuring with high precision (≤ ± 0.1pH), it can be used continuously for a week or more after one calibration, or the electrode can be inserted into a calibration solution close to the pH value of the measured solution before use. If the error exceeds your accuracy requirements, recalibration is necessary. The instrument must be recalibrated in the following situations: (a) electrodes that have not been used for a long time or newly replaced electrodes. (b) After measuring the concentration of acid (pH 12). (c) After measuring solutions containing fluoride and more concentrated organic solutions. (d) When the CAL symbol appears on the instrument LCD screen, it indicates the need for calibration. This is a reminder function set by the built-in chip of the instrument, but this function does not include all situations that require recalibration.
(3) The planar bulb and liquid interface of the pH composite electrode must be kept in a moist condition to maintain an activated state and undergo normal testing. If the pH electrode is dried for a long time, abnormal situations such as slow response and poor accuracy may occur. Therefore, at the bottom of the electrode cap at the front end of the PH100 waterproof pen pH meter, there is a water storage sponge. Users must always keep the sponge moist. When the sponge is dry, an appropriate amount of pH 4.00 standard solution can be added dropwise (do not let the solution flow out), and the electrode cap should be tightly covered to keep the pH electrode in an activated state under wet conditions.
(4) PH electrodes that have not been used for a long time may have dried. Before use, they should be soaked in a 3.3mol/L KCl solution for several hours (3.3mol/L KCl solution preparation: weigh 25g KCl, dissolve in pure water and dilute to 100ml), or a dedicated electrode soaking solution can be purchased.
(5) The waterproof pen pH meter carrying case is equipped with three bottles of pH correction solutions (one bottle each for pH 4.00, pH 7.00, and pH 0.01). These three bottles of different colored correction solutions contain anti mold agents, so they can be stored for a long time at ambient temperature without spoilage (shelf life of one year). After multiple uses and inaccuracies, users can purchase the same standard solution from the instrument distributor or our factory's business office. This standard solution is very convenient to use and store.
(6) The sensitive glass bulb at the front end of the pH electrode should not come into contact with hard objects. Any damage or scratching will cause the electrode to fail. Clean the electrodes with pure water before and after measurement to ensure measurement accuracy. After measuring in a viscous sample, the electrode needs to be rinsed repeatedly with pure water to remove the sample sticking to the glass film, or cleaned with a suitable solvent first and then washed with pure water to remove the solvent.
