How to use pipettes and precautions!
A complete pipetting cycle includes the steps of tip installation-volume setting-aspiration and dispensing-removal of the tip. Each step has operating specifications that need to be followed.
1. Suction head installation
For single-channel pipettes, insert the pipette tip vertically into the pipette tip, press lightly and turn it slightly from left to right to tighten;
For a multi-channel pipette, align the first channel of the pipette with the first tip, insert it at an angle, and shake it back and forth to tighten it.
Do not repeatedly hit the pipette to ensure the air-tightness of the tip. Assembling the tip in this way for a long time will cause the parts of the pipette to loosen due to strong impact, and even cause the knob to adjust the scale to get stuck.
2. Capacity setting
When adjusting from a large volume to a small volume, you can rotate it counterclockwise to the scale; when adjusting from a small volume to a large volume, you can adjust the set volume clockwise first, and then return to the set volume to ensure the best accuracy.
Do not turn the adjusting knob out of the measuring range, otherwise the mechanical device in the pipette will be damaged.
3. Suction and discharge
Press the button of the aspiration pipette to the first position, release the button, and perform aspiration. Remember not to be too fast, otherwise the liquid will enter the tip too quickly and the liquid will be sucked into the pipette.
Discharge Close to the container wall, first press to the first level, pause for a while, and then press to the second level to drain the remaining liquid.
● Aspirate liquid vertically.
● For 5ml and 10ml pipettes, the tip needs to be immersed in the liquid surface 5mm, suck the liquid slowly, after reaching the predetermined volume, pause under the liquid surface for 3 seconds, and then leave the liquid surface.
● Slowly release the controller when aspirating liquid, otherwise the liquid will enter the tip too quickly and the liquid will be sucked into the pipette
● When sucking volatile liquid, you need to rinse the suction head 4-6 times to saturate the steam in the sleeve chamber to avoid liquid leakage.
4. The correct placement of the pipette
After use, you can hang it upright on the pipette holder, but be careful not to fall off. When there is liquid in the pipette tip, do not place the pipette horizontally or upside down to prevent the liquid from flowing back and corroding the piston spring.
If not in use, adjust the range of the pipette gun to the maximum scale, so that the spring is in a relaxed state to protect the spring.
5. Common mistakes
1) When assembling the tip, repeatedly hitting the pipette tip makes it difficult to remove the tip and even damages the pipette.
2) When aspirating liquid, the pipette tilts, resulting in inaccurate pipetting, and the liquid easily enters the pipette handle.
3) When aspirating liquid, quickly release the thumb, which will force the liquid to form a turbulent state, and the liquid will directly flush into the pipette.
4) Press directly to the second level to aspirate liquid (should follow the above standard method).
5) Use a large-range pipette to pipette small volumes of samples (a pipette with a suitable range should be selected).
6) Lay the pipette with residual liquid tips flat (the pipette should be hung on the pipette rack).
