Matters needing attention when using the dropper

When dripping, the dropper should be kept perpendicular to the top of the container, avoid tilting, avoid standing upside down, and do not extend into the container or touch the container wall. Except for absorbing the solution, the tip of the tube should not touch other utensils to avoid contamination by impurities. Don't do it for two. 　　

The ordinary dropper needs to be cleaned when it is used up, while the special dropper cannot be cleaned and needs to be used for special purpose. Just put it back into the original reagent bottle when it is used up.