1. Before use: When using a sterile serological pipette, first check the pipette mark, accuracy level, and the position of the scale mark.

2. Liquid absorption: Hold the upper end of the pipette with the thumb and middle finger of the right hand, insert the lower mouth of the pipette into the solution to be absorbed, do not insert too shallow or too deep, generally 10~20mm, too shallow will produce Suction air, suck the solution into the ear washing ball to make the solution dirty, if it is too deep, there will be too much solution attached to the outside of the tube. Take the ear wash ball in your left hand, connect it to the upper mouth of the tube, and slowly inhale the solution. First, inhale about 1/3 of the capacity of the tube, press the tube opening with the index finger of your right hand, take it out, hold it horizontally, and turn the tube to make the solution come into contact with it. Above the scale to replace the water on the inner wall, then release the solution from the lower opening of the tube and discard it. After repeated washing in this way for 3 times, the solution can be absorbed to about 5mm above the scale, and immediately press the tube mouth with the index finger of the right hand .

3. Adjust the liquid level: Lift the pipette up to leave the liquid surface, wipe off the liquid on the outer wall of the pipette with filter paper, and put the end of the pipe against the inner wall of the solution container, keep the pipe body vertical, and slightly relax the index finger Let the solution in the tube flow out slowly from the lower opening until the bottom of the meniscus of the solution is tangent to the marking line, and immediately press the tube opening with your index finger. Remove the droplet against the wall, remove the pipette, and insert it into the vessel receiving the solution.

4. Release the solution: If the vessel receiving the solution is a conical flask, the conical flask should be tilted at 30°, the disposable pipette should be kept vertical, and the lower end of the tube should be close to the inner wall of the conical flask. Slowly flow down, when the liquid level drops to the liquid discharge head and the tube touches the inner wall of the bottle for about 15 seconds, then remove the pipette. The small amount of solution remaining at the end of the tube cannot be forced out by external force, because it has been considered in the calibration The volume of solution retained at the end.