Pasteur pipets are traditionally one of the most abused and misunderstood items of glassware in the student labs. The goal of this section is to teach you how to properly handle Pasteur pipets.
Re-use and disposal of the glass part of a Pasteur pipet
The glass in a Pasteur pipet costs only 5 cents. So, why not simply use it and throw it away?
First of all, it is always better to re-use something if possible, to help preserve our resources and the environment. Why have someone make another one if the one you have is perfectly okay, just a little dirty? Why add trash to the dumps if it is avoidable?
Second, "dirty" glassware in a chemistry lab is not only "dirty" it is "hazardous waste". The "dirt" on it is a chemical, and almost surely a hazardous chemical. Legally and morally you cannot place hazardous waste in the city dump, which is where the trash can contents end up.
We collect chemically dirty Pasteur pipets in a large plastic carboy which is on the back shelves of each labroom. A picture of one of these carboys is at the right. When full, this carboy is tagged and picked up for processing by EH&S (see the waste chemicals page). Most likely, it will be shipped to a site where it can safely be incinerated. Each pipet you put into the container burdens this expensive process.
What to do with a used Pasteur pipet
Clean it and re-use it. Do it immediately, before the chemical dries on the pipet and makes it impossible to clean.
How to do it:
If the above steps do not clean it, put the Pasteur pipet in the broken glassware hazardous waste container.
If a Pasteur pipet is broken and dirty, it goes in the broken glassware hazardous waste container
If a clean Pasteur pipet is broken, it goes in the broken clean glassware container on the floor by the trash cans.
How to use a Pasteur pipet and bulb
Pasteur pipets must be used in a vertical position. This means, up and down. Or nearly so, you are allowed to have it at an angle The bulb on top, the tip of the pipet pointed down. Here, let me show you:
| fill it like this: | hold it like this: | ||||||
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Never, I repeat NEVER, hold a filled pipet upside down. (If you must see one the wrong way, you can go to the wrong way to hold a Pasteur pipet.) Wrong is with the tip pointed up and the bulb down. If you hold it this way, the liquid runs into the bulb. If this happens:
Never lay a filled pipet down on it's side, as this practice allows the solvent run into the bulb (see the wrong way page again).
photo thanks to KJ
