Precautions for the use of serological pipettes

Date:2021-12-02 16:02:37 Thursday

Summary:1. Before use: When using a pipette, first look at the pipette mark, accuracy level, and position of the scale mark. Before using the pipette, it should be rinsed with chromic acid lotion to remove the oil stains on the inner wall of the pipe. Then r......

1. Before use: When using a pipette, first look at the pipette mark, accuracy level, and position of the scale mark. Before using the pipette, it should be rinsed with chromic acid lotion to remove the oil stains on the inner wall of the pipe. Then rinse the remaining lotion with tap water, and then rinse with distilled water. There should be no water droplets on the inner wall of the pipette after washing. Before pipetting the solution, use filter paper to absorb the water inside and outside the end of the pipette, and then rinse the wall of the pipe with the solution to be piped 2 to 3 times to ensure that the concentration of the pipetted solution remains unchanged.
2. Aspiration: Use the thumb and middle finger of the right hand to pinch the upper end of the pipette, insert the lower mouth of the tube into the solution to be sucked, not too shallow or too deep, generally 10-20mm, too shallow will produce Aspirate and suck the solution into the ear wash ball to soil the solution. If it is too deep, too much solution will be attached to the outside of the tube. Take the ear-washing ball in your left hand, first press out the air in the ball, and then connect the tip of the ball to the upper mouth of the pipette, slowly loosen the flattened ear-washing ball so that the solution is sucked into the tube, first suck in 1 of the capacity of the tube /3 or so, use the index finger of your right hand to hold the mouth of the tube, take it out, hold it horizontally, and turn the tube so that the solution touches the part above the scale to replace the water on the inner wall, and then release the solution from the lower mouth of the tube and discard it. After repeated washing 3 times, you can draw the solution to above the mark, and immediately press the nozzle of the tube with the index finger of your right hand.
3. Adjust the liquid level: lift the pipette up to leave the liquid level, the end of the tube is still against the inner wall of the solution container, the tube body is kept upright, and the index finger is slightly relaxed (sometimes the pipette can be turned slightly) to make the solution in the tube slowly Flow out from the lower mouth until the bottom of the meniscus of the solution is tangent to the marking line, and immediately press the mouth of the tube with your index finger. Remove the tip of the drop against the wall, remove the pipette, and insert it into the container that holds the solution.
4. Release the solution: If the container that accepts the solution is an Erlenmeyer flask, tilt the Erlenmeyer flask by 30°, and the pipette should be upright. The lower end of the tube is close to the inner wall of the Erlenmeyer flask. Slightly loosen your index finger to allow the solution to slowly flow down the wall of the flask. , After all the solution has flowed, you need to wait 15s before taking out the pipette, so that part of the solution attached to the tube wall can flow out. If the pipette is not marked with the word "Blow", the solution remaining in the tip of the pipette cannot be blown out, because this part of the residual solution is not included in the calibrated volume of the pipette.
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