Maintenance of manual single channel pipettes
Why do pipettes need care and maintenance?
1. If it is not used for a long time, the range of the pipette should be adjusted to the maximum scale, so that the spring is in a relaxed state to protect the spring. Failure to pay attention to this point will easily cause the piston to fail to rebound.
2. If the pipette needs to be used every day, it is recommended to clean and calibrate it every three months. It can be washed with soapy water or sterilized ethanol, then washed with distilled water and dried naturally.
3. Steps for cleaning the pipette: (as follows)
(1) Disassemble the pipette according to the instructions.
(2) Check and wipe off dust and smudges.
(3) Wipe with 70% ethanol only. The nozzle connector and ejector can be soaked in soapy water or isopropyl alcohol solution for two hours. For models with replacement filter elements, the dirty filter element should be replaced in time to ensure the cleanliness of the cavity.
(4) Coat the piston, O-ring and spring with silicone oil (Vaseline without silicone oil is also available).
(5) Install and restore the pipette.
NOTE: Cleaned pipettes require calibration.
4. Calibration steps
4.1 Temperature requirements: Pipette calibration must be performed at room temperature (25+/-2℃).
4.2 Referring to the instructions for use of the pipette, different scales of 10000\5000\1000\200ul must be calibrated separately.
4.3 Remove the air bubbles in the pipette tip and select the scale to be calibrated.
4.4 Peel an empty container on an electronic balance with an accuracy of 0.1 mg.
4.5 Press the add key, add water to the empty container and weigh, and record the reading.
4.6 According to the national standard, the calibration of the pipette adopts the rule of "three-point test (100%, 50% and 10% of the maximum range), six times per point", and the supplier usually chooses two rules: one is simple calibration , that is, two-point test (100% and 10% of the maximum range), four times per point; the second is strict calibration, that is, three-point test (100%, 50% and 10% of the maximum range), ten times per point . Users select a rule according to their actual needs and enter the calculation link after completing the test. (Adjust according to the absolute difference between the average value and the actual value, and use a tool to tighten the spring buckle)
5. Before high temperature sterilization, make sure that the pipette can adapt to high temperature.
6. Do it by repeating the method of weighing distilled water several times.
7. Check whether there is liquid leakage when using. In the method, suck the liquid and place it vertically for a few seconds to see if the liquid level drops. If there is leakage, the reasons are roughly as follows:
1) Whether the gun head matches;
2) Whether the spring piston is normal;
3) If it is a volatile liquid (as is the case with many organic solvents), it may be a problem of saturated vapor pressure. You can aspirate the liquid a few times before pipetting.
