1. When using the dropper, squeeze the rubber nipple with your finger to expel the air from the dropper, then extend the dropper into the reagent bottle, release your finger, and the reagent will be inhaled.
2. The dropper after taking the liquid should keep the rubber head on the top, do not lay it flat or upside down, to prevent the solution from flowing back and corroding the rubber head.
3. When adding liquid dropwise, it should be suspended above the beaker, do not touch the beaker wall, so as not to contaminate the dropper or cause contamination of the reagent.
4. Do not put the dropper on the test stand or other places, so as not to contaminate the dropper.
5. Rinse the used dropper immediately with clean water for reuse.
6. It is strictly forbidden to use the uncleaned dropper to absorb other reagents (the dropper on the dropper bottle should not be washed with water).