Precise pipetting starts with the correct use of the pipette

single channel pipette


Correct use of pipettes includes the following steps:


1. Set the volume
The principle of range setting is from large to small, so when adjusting the volume, if you want to adjust the volume from a large volume to a small volume, such as 200μL to 100μL, then according to the normal adjustment method, rotate the adjustment knob counterclockwise to the required volume. You can;
However, if you want to adjust from small volume to large volume, you can first turn the adjustment knob clockwise to 1/4 of a turn that exceeds the target volume value, and then adjust to the set value, so that the spring can be completely released, the mechanical gap can be eliminated, and the mechanical gap can be eliminated. The set value is accurate to ensure the accuracy of the measurement and prolong the service life of the pipette.
It should be noted that during this process, do not turn the button out of the maximum range of the pipette, otherwise the internal mechanism will be stuck and the pipette will be damaged.

2. Install the pipette tip
In order to ensure a good seal, before installing the tip, choose a tip that is suitable for the range of the pipette.
The installation of the pipette tip adopts the rotary installation method. Hold the handle with the palm and four fingers, the index finger is close to the hook-like structure at the front, the thumb is placed on the control button, and the pipette is inserted vertically into the tip. Rotate half a turn or 180° clockwise, and tighten to ensure that there are no gaps, otherwise the reagent will leak. At this point, you need to be careful not to use too much force.
When putting the tip on the pipette, many people tap hard on the tip box a few times, which is a mistake, and the specific reasons are as follows:
① Under the action of impact, the tip may be deformed and affect the pipetting accuracy;
②The part of the pipette handle that contacts the tip will gradually become rough and difficult to ensure tightness after many times of strong friction, and in order to achieve good tightness, greater impact force is required, and the vicious cycle begins;
③ The handle of the small-scale pipette is relatively thin, and it is very likely to become a fishing hook under the constant impact of the damage;
④Sometimes the impact force is greater than the force that the pipette can withstand when it falls on the ground, and some precision parts in the pipette may be overwhelmed and strike at any time.

3. Rinse the pipette tip
Before pipetting, rinse the tip by aspirating the liquid a few times for accurate measurements, especially if you are picking up liquids that are viscous or have a density different from water.
For normal temperature samples, tip rinsing helps to improve accuracy; but for high temperature or low temperature samples, tip rinsing reduces the accuracy of operation, so do not rinse tips with high temperature or low temperature liquids, please pay special attention to users.

4. Precise pipetting
(1) Before pipetting, make sure that the pipette, pipette tip and liquid are at the same temperature. High or low temperature will affect the volume of liquid to be pipetted.
(2) When sucking liquid, keep the pipette in a vertical state, and immerse the pipette tip vertically 1-6mm below the liquid surface (depending on the capacity of the pipette gun): a pipette with a capacity of 0.1-10μL enters 1-2mm below the liquid surface; 2-200μL capacity pipettes enter 2-3mm below the liquid surface; 1-5mL capacity pipettes enter 3-6mm below the liquid surface. Too much or too little is not recommended. Too much extension will cause the outer wall of the pipette to be stained with too much solution, resulting in volume error during pipetting; too little extension will easily suck empty after the liquid level drops, causing the pipetting to be invalid.
(3) There are two methods for pipetting:
①Forward pipetting: press the button of the pipette to the first stop, gently release the button to the starting point to complete aspiration, lightly press the button to the first stop to remove the liquid; stop for a while, continue to press the button until The second stop, empty the liquid, release the button to return to the original point. If necessary, continue pipetting after changing the tip.
The forward pipetting method is suitable for lower density solutions.
②Reverse pipetting: Press the button of the pipette to the second stop point, and gently release the button to the starting point to complete the pipetting. Absorb more than the set volume of liquid, lightly press the button to the first stop point to remove the liquid, and the excess liquid remaining in the tip is discarded with the tip.
Reverse pipetting is suitable for viscous, volatile or bubble-prone solutions.
(4) Slowly take out the tip and wait for 1-3 seconds before the pipette removes the liquid; pause for 1 second below 1000μL; pause for 2-3 seconds for 5-10mL. Make sure there is no liquid on the outer walls of the tip.

5. Remove the suction head
Press the eject button to eject the tip.
After the pipette is used up, adjust it back to the maximum volume, so as not to compress the spring and cause the spring to fail to recover.
After use, it can be hung upright on the pipette rack, but be careful not to fall off. Never place the pipette horizontally or upside down when there is liquid in the pipette tip. Corrode the piston spring with rabbit liquid backflow.
Precautions:

1. It needs to be calibrated before use, usually once every three months. If it is used infrequently, it can be corrected once every six months. The calibration method can be calibrated by weighing, that is, 1mL of distilled water = 0.9982g at 20°C (one ten thousandth of an electronic analytical balance is required).
2. Select a pipette with a suitable range, and it is recommended that the pipetting range be within 35%-100% of the pipette range.
3. Be sure to use a tip that matches the pipette.
4. Do not turn the button out of the maximum or minimum range, otherwise the mechanical device will be stuck and the pipette will be damaged.
5. Do not tilt the pipette.
Some people think that proper inclination will help the suction to be clean and more flexible. This is absolutely wrong. The pipetting angle has a great influence on the accuracy. Make sure that the deviation from vertical cannot exceed 20° during suction or discharge, otherwise the accuracy will be affected.
6. It is strictly forbidden to use a pipette to mix the liquid.
7. When sucking the liquid, the thumb must be released slowly and steadily, and it is not allowed to release suddenly. If the liquid is sucked too fast, air bubbles will be generated, and the liquid will be immersed in the inside of the pipette and the internal components will be corroded.
8. The used tips cannot be mixed with new tips to avoid cross-contamination.
9. Regularly clean the outer wall of the single-channel pipette, you can use 95% alcohol or 60% isopropyl alcohol, then wipe with distilled water and dry naturally.
10. If the pipette needs to be disinfected, it can be irradiated with ultraviolet light, or wiped with 75% alcohol, and must not be close to the fire.
11. When storing the pipette, keep it upright, do not lay it flat. During the pipetting operation, it is inevitable that liquid will enter the inside of the pipette. In the state of laying flat, these liquids will remain on the piston and other components, which will contaminate the piston and even corrode the piston over time.

——

Print       Small   Middle   Big

PreviousAnalysis of the reasons for inverted culture after inoculation of microbial culture dishes
NextExperiment failed? Maybe the problem lies in the small pipette tips!

Products

——

Search

Yong Yue Medical Technology(Kunshan) Co.,Ltd Copyright © All rights reserved Privacy Policy   site map   sitemap.html