Precautions for maintenance of pipettes

1. If not used for a long time, adjust the range of the pipette gun to the maximum scale, so that the spring is in a relaxed state to protect the spring. Failure to pay attention to this point can easily cause the piston to not rebound.

2. If the pipette needs to be used every day, it is recommended to clean and calibrate it every three months. Soap water or disinfected ethanol can be used, and then distilled water can be used to clean and air dry.

3. Steps for cleaning the pipette: (Follow the steps below)

(1) Disassemble the pipette according to the instructions.

(2) Check and wipe off dust and stains.

(3) Only 70% ethanol can be used for wiping, and the nozzle connection and ejector can be soaked in soapy water or isopropanol solution for two hours. For models with replaceable filter elements, it is necessary to replace the dirty filter element in a timely manner to ensure the cleanliness of the chamber.

(4) Apply silicone oil to the piston, O-ring, and spring (even without silicone oil or petroleum jelly).

(5) Install and restore the pipette.

Attention: The cleaned pipette needs to be calibrated.

4. Calibration steps

4.1 Temperature requirements: The calibration of the pipette must be carried out at room temperature (25+/-2 ℃).

4.2 According to the instructions for using the pipette, different scales of 10000 5000 1000 200ul must be calibrated separately.

4.3 Remove the bubbles from the pipette and select the scale that needs to be calibrated.

4.4 Place an empty container on an electronic balance with an accuracy of 0.1 milligrams for peeling.

4.5 Press the add liquid button, add water to an empty container, weigh, and record the reading.

4.6 According to the national standard, the calibration of the pipette adopts the rule of "three point testing (100%, 50%, and 10% of the maximum range), six times per point", while suppliers usually choose two rules: one is simple calibration, which means two point testing (100% and 10% of the maximum range), four times per point; The second is strict calibration, which means three point testing (100%, 50%, and 10% of the maximum range), with ten tests per point. Users choose a rule based on their actual needs to complete the testing and enter the calculation phase. (Adjust according to the absolute difference between the average value and the actual value, and use tools to tighten the spring buckle)

5. Before high-temperature disinfection, it is necessary to ensure that the pipette can adapt to high temperatures.

6. Repeat the method of weighing distilled water several times.

7. Check for any leakage during use. Method: Suck in the liquid and place it vertically in the air for a few seconds to see if the liquid level drops. If there is a leakage, there are generally several reasons:

1) Whether the gun head matches;

2) Whether the spring piston is normal;

3) If it is a volatile liquid (as many organic solvents do), it may be a problem of saturated vapor pressure. You can aspirate and release the liquid several times before transferring it.