Absorption of the solution of the pipette
Put the tip of the lower end of the washed pipe into the liquid level about 1 cm below, do not extend too deep, in order to avoid excessive solution adherence on the outer wall of the pipe mouth, and do not extend too shallow, in order to avoid inhaling air when the liquid level drops. The left-hand holds the ear wash ball, after extruding the air in it, connects it to the orifice of the pipette, slowly relaxes the ear wash ball, so that the solution is inhaled into the pipette.
At this time, attention should be paid to the position of the liquid level rising in the pipette. When the liquid level in the pipe exceeds the marked line, remove the ear wash ball, and quickly press the pipe mouth with the right index finger, let the pipette leave the liquid level, and vertically make the tip of the pipe lean on the inner wall of the container, slightly relax the index finger, let the liquid level drop slowly. When the lowest point of the meniscus of the liquid level is tangent to the marked line, press the pipe mouth tightly, so that the liquid level no longer sucks out.
Effusion of pipette
The pipette is a measuring instrument used to accurately remove a certain volume of solution. The pipette is only used to measure the volume of the solution it emits. It is a slender glass tube with a large expansion in the middle. The lower end is pointed mouth, and the upper neck is inscribed with a marking line, which is a mark of the exact volume removed. Therefore, we must pay attention to whether the operation method is correct. The following are the specific methods of operation:
Carefully remove the pipette and put it into the receiving container (in this process, the liquid in the pipe should not leak out). Make the tip of the pipette lean against the inner wall of the receiving container, keep the pipette vertical and accept the inclination of the container, lift the index finger of the right hand, let the liquid flow freely, wait about 15 seconds to remove the pipette. Note that a small amount of liquid remaining at the tip can not be blown out by external force (except for the word “blowing” on the pipette).
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