Two pipetting methods that can be used with pipettes
Pipette is a device for quantitative transfer of liquids. It has the advantages of flexible use, easy maintenance, small size, and convenient carrying. It is widely used in biology, chemistry, scientific research and other fields. The pipette needs daily maintenance during use, which can ensure the normal use of the instrument.
The basic points of pipette:
1. Note that the pipette, suction nozzle and liquid are at the same temperature.
2. Pay attention that the suction nozzle is tightly fitted on the connecting piece.
3. When aspirating liquid, the pipette is kept upright, and the suction nozzle is only a few millimeters below the liquid surface.
4. Pre-wash the liquid suction nozzle before liquid suction, that is, suction and release the liquid 5 times. This is especially important when transferring liquids that are viscous or have a density different from water.
5. Always use the thumb to control the button movement to ensure consistency.
Before pipetting, make sure that the pipette, pipette tip and liquid are at the same temperature. When sucking liquid, keep the pipette upright and insert the pipette tip 2-3 mm below the liquid surface. Before absorbing the liquid, you can suck and put the liquid several times to wet the suction nozzle (especially when you want to absorb a liquid with a viscosity or a density different from water). At this time, two pipetting methods can be adopted.
One is the forward pipetting method. Press the button with your thumb to the *stop point, and then slowly release the button to return to the origin. Then press the button to the stop point to discharge the liquid, pause for a while and continue to press the button to the second stop point to blow out the remaining liquid. Release the button after zui.
The second is the reverse pipetting method. This method is generally used to transfer high-viscosity liquids, biologically active liquids, easily foaming liquids or very small amounts of liquids. The principle is to suck in more liquid than the set range first, without blowing out the remaining liquid when transferring the liquid. First press the button to the second stop, then slowly release the button to the origin. Then press the button to the *stop point to discharge the liquid with the set range, continue to hold the button at the *stop point (don't press it down), remove the tip with residual liquid, and discard it.
The correct placement of the pipette: After use, you can hang it vertically 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.