a. Pipette is a commonly used instrument for measuring liquid in biochemical experiments. According to different needs, it is divided into different scales, such as 10mL, 5mL, 2mL, 0.5mL, 0.1mL and so on. First select a pipette with a scale close to it according to the volume of the solution to be weighed (Note: the volume of the pipette must be greater than or equal to the volume to be weighed).

b. Observe the arrangement of pipette scale numbers, pay attention to observe whether the scale is from top to bottom or bottom to top, and find 0 scale value.

c. Hold the earball in one hand and the pipette in the other.

First, insert the pipette into the liquid surface about 1 cm, pinch the suction bulb to discharge the gas, then plug the upper port of the pipette, slowly relax the suction bulb, and observe the rise of the liquid surface. When the liquid level rises by a certain distance above the zero mark, remove the suction bulb and hold the upper port of the pipette with the index finger of the hand holding the pipette (remember not to use your thumb).

d. Hold the ear bulb and put down the ear bulb, take the filter paper and wipe the liquid on the outer wall of the pipette clean; pick up the reagent bottle, the reagent bottle is required to be at 45 ° to the table, the pipette head contacts the bottle wall and is perpendicular to the table , Slowly relax the index finger to make the liquid level slowly drop to zero. Be careful not to drop the liquid level too fast.

e. When moving to another container, a hand-held container is also required. The container is at 45 ° to the tabletop. The pipette head contacts the wall and is perpendicular to the tabletop. Relax the index finger and release the volume to be removed.

f. When it is required to release all the liquid of the selected pipette, pay attention to whether the pipette needs to be blown. Generally, a pipette less than 1 ml (including 1 ml), when the full volume needs to be released, use an ear bulb to blow out the remaining solution in the tube, so that it is the required volume. When the pipette with a volume of 1 ml or more releases all of its solution, there is no need to blow, just the pipette head against the wall. After all the pipette head is placed, it stays for about 15 seconds. At this time, a part of the solution remains in the pipe head and becomes dead volume. Blowing in will exceed the required volume.

g. After use, the pipette should be cleaned in time, taking care to avoid mixing and contaminating the reagents.