I’ve been reviewing a number of resources on how to keep glassware clean, and I’m putting the info up here. I will update later after I can see how it went.
Dirty glassware is a fiasco waiting to happen. First of all, it can prove a risk to the lab, with tiny amounts of chemicals setting off dangerous reactions. Second, it will definitely mess up experiments to have contaminants in the glassware.
- Detergents – standard dishwashing liquid is suggested by some, but others say one should use a specialty chemical detergent like Liquinox. Some use Chromic acid cleaning solution.
- Hydrochloric acid (dilute to 1% or less for soaking)
- Ethanol and acetone
- Brushes. Sigma’s got quite a range of brushes for glassware and believe me, you will be using them all.
- Basins – you will need several to let items stand or soak (do NOT soak different kinds of contaminants together).
- Containers for toxic wash material – such as the aforementioned Ethanol and Acetate
Preparation – what needs to be cleaned?
Pretty much everything. If you are performing precision chemical tests, it is in fact a good idea to soak glassware that’s just arrived in 1% hydrochloric overnight before cleaning it, before use.
Water: deionized or no?
Deionized water is the gold standard for washing stuff, but it is expensive. So you have to clear it with the brass before doing so.
By rights, this should be filed under “what can possibly go wrong?” Yet the very nature of these things – volatile – is why they are used. They can follow a decent wash of water, then evaporate and leave nothing behind. Glassware is clean and ready to use.
Assemble the different items that need cleaning and separate them according to contamination. They usually fall into the following categories, with their own cleaning requirements:
- Water soluble solutions: 3-4 times with (deionized) water
- Water insoluble solutions: 2-3 times with ethanol or acetone, 3-4 times with deionized water.
- Strong acids: Drain, then wash with copious amounts of tap water. Then 3-4 times with (deionized) water
- Strong bases. Drain, then wash with copious amounts of tap water. Then 3-4 times with (deionized) water
- Weak acids. 3-4 times with (deionized) water
- Weak bases. 3-4 times with (deionized) water
Do not dry with a towel or paper, as that may scratch and leave residue. Air dry. It is okay to use an oven, but NOT if you are using acetone or ethanol (fumes build up). Also not if you are using calibrated glassware – measuring cylinders etc. The heat can cause them to distort and wreck the calibration.
It’d be worth working on a non-autoclave way of sterilizing such cylinders.