Brief Analysis on the Use of Trace Moisture Analyzer

　Regarding the use of laboratory instrument trace moisture analyzer, we have summarized 5 steps, namely instrument self-calibration, cleaning, drying and assembly of titration cell, reagent adjustment and blank current removal, laboratory instrument calibration, and the influence of blank current on measurement accuracy. The following is a detailed introduction for you.

　　1. Instrument self-calibration

　　Plug the power socket on the rear panel of the main unit into an AC 220V power supply, press the power switch, the LCD screen lights up, and the main unit is powered on. Press any key to enter the test interface, then press the electrolysis key, the instrument automatically counts, and the self-test begins:

　　1. Short-circuit the inner and outer electrodes of the electrolytic electrode socket, and the display will count quickly.

　　2. Short-circuit the two electrodes inside and outside the measuring electrode socket, the display screen will show excessive iodine and the numbers will stop counting.

　　3. Press the start button on the main unit, the numbers on the display will be reset to zero, and the buzzer will sound after about one minute. The display will prompt: Please connect the measuring electrodes.

　　If the above three conditions are met, it means the host is working normally.

　　2. Cleaning, drying and assembly of the titration cell

　　1. Before use, open all the glass openings of the titration cell. The titration cell, drying tube, sealing plug, and stirring rod can be cleaned with water, methanol, or acetone. The cathode chamber and measuring cell can be cleaned with methanol or acetone, but do not clean the electrode leads. (Note that the cathode chamber and measuring electrode must not be cleaned with water, otherwise it will cause measurement errors.) After cleaning, place in an oven at about 60C for 4 hours, and then let it cool naturally. (New electrolytic cells and electrodes generally do not need to be cleaned and can be used directly)

　　2. Put the color-changing silica gel into the drying tube (be careful not to put the powder in); put the silicone rubber pad into the injection stopper and screw in the fastening stud; carefully put the stirring bar into the titration cell; then evenly apply a thin layer of vacuum grease on the ground edges of the cathode chamber, measuring cell, drying tube, injection stopper, and sealing plug. Except for the drying tube and sealing plug of the cathode chamber, install the others in the corresponding positions and gently turn them a few times to make them seal better.

　　3. Use a dried funnel to inject about 100-120mL of electrolyte into the cathode chamber through the sealed port, and then use a funnel to inject electrolyte through the drying tube socket of the cathode chamber. The liquid levels of the cathode and anode chambers should be basically level. After completion, install the drying tube and sealing plug, and gently turn them a few times to make them better sealed (the electrolyte filling work should be carried out in a fume hood).

　　4. Place the titration cell on the electrolytic cell seat on the main unit, and then insert the measuring electrode plug and the electrolytic electrode plug on the cathode chamber into the measuring and electrolytic sockets respectively.

　　3. Adjustment of reagents and removal of blank current

　　Adjustment of reagents: Press the power switch, the LCD screen lights up and the power is turned on. Adjust the stirring speed control knob of the stirrer to make the electrolyte in the anode chamber form a vortex, but it cannot splash onto the pool wall. At this time, if the status shows over-iodine and prompts: Please inject an appropriate amount of pure water. Press the electrolysis button, use a 50ul injector to extract a certain amount of pure water (new reagents require about 20-50ul of pure water) and slowly inject it into the reagent through the injection cock. The color of the reagent slowly changes from dark brown to light yellow until the status changes to over-water. At this time, there will be a real-time electrolysis curve, and the display starts counting. At this time, take out the injector and wait for the instrument to automatically adjust the balance. The instrument status display is normal, and the alarm reaches a balanced state.

　　Clearing of blank current: If the electrolysis curve is relatively high or the measurement indication is unstable, it means that there is water on the wall of the titration cell. At this time, you can turn off the electrolysis, remove the titration cell, slowly tilt and rotate it so that the water on the cell wall is absorbed, and then press the electrolysis key to continue electrolysis. This step can be repeated several times, and the electrolysis curve will drop to a relatively low level. When the measurement signal is stable, the test can be carried out.

　　After the above operations, if the blank current (electrolysis curve) still cannot be reduced, it may be affected by the intrusion of moisture from the atmosphere or the ceramic filter plate in the cathode chamber adsorbing moisture.

　　At this time, check the sealing condition of the ground joint surface of the titration cell, whether the silica gel is ineffective, whether the hole of the silicone rubber pad in the injection plug is too large, and whether the cleaning and drying effect of the cathode chamber is good. Repeat the above operation after carrying out the corresponding treatment.

　　4. Instrument Calibration

　　When the instrument reaches the initial equilibrium point and is relatively stable, it can be calibrated with pure water (the electrolysis switch (7) should be pressed).

　　1. Use a 0.5?l micro syringe to draw 0.1?l of pure water to prepare for sample injection.

　　2. Press the Start button.

　　3. Inject 0.1 μl of pure water into the electrolyte in the anode chamber through the injection cock. Note that the needle tip should be inserted into the electrolyte and avoid contact with the cell wall or electrode. After injection, titration will start automatically.

　　4. If the buzzer sounds and the status is normal, it means that the electrolysis has reached the end point. The displayed result should be 100±10ug. Generally, it is calibrated 2 to 3 times. If the displayed number is within the error range, the sample can be measured.

　　5. The influence of blank current on measurement accuracy

　　When measuring the water content in a sample, in order to obtain high-precision data, we hope that the blank current is as small as possible. Generally, the measurement can be performed as long as the status prompt is normal. When there are special requirements for measurement accuracy or the water content in the sample to be measured is low, the electrolysis curve should be as low and stable as possible, and the measurement signal should be as stable as possible, which is beneficial for measuring low-content samples.

　　Through the introduction of the use of laboratory instrument trace moisture meter, we hope it can be helpful for our daily use and work.