Hi all
I am now working in an analytical lab with ~40yrs history, some of the chemicals are expired for more than 10 yrs, should I be using them? And wil it affect the results I get from them? Also if i want to throw them how should I treat them?
Whether you can use expired chemicals depends on how stable they are and if they are likely to have been contaminated or grown something nasty. For example personally I would not use out-of-date agar as it is an ideal growing medium for all kinds of bacteria. Some chemicals become dangerous when expired - for example picric acid becomes so explosive that one small bottle will require specialist removal and probably a controlled explosion to get rid of it. However, unopened, stable reagents like sodium chloride or some solvents will probably be OK. To dispose of out-of-date chemicals you need to know the disposal procedure for each one. This will be different in each case so don't assume you can throw them down the sink or in the trash. You can find this in the safety data information about each chemical. This should be supplied with new chemicals but probably for the old ones has long since been lost. You can look them up on the internet - the link below gives suggestions as to where to find them. Chemical producers and retailers often provide access via their websites.
http://www.ilpi.com/msds/index.html
This of course depends on what chemicals you are referring to and what they will be used for. Some chemicals are very stable and others unstable and very reactive. Check the MSD sheets and get information on each specific chemical. Silica sand for instance will last virtually forever. Derivatizing agents are very reactive and if that old need to be disposed of. Ethers can form peroxides on prolonged exposure to air which can become a potential fire/explosion hazard, especially when the ether is evaporated and the peroxides concentrate. Always wear appropriate PPE; gloves, eyes, skin protection when handling chemicals and use proper ventilation! Chlorinated solvents can slowly decompose and produce phosgene, a deadly poisonous gas. Open chlorinated solvents in a properly functioning fume hood. Many chemicals are hygroscopic and pick up moisture over time. In some cases they can be dried and made potentially usable. If the chemicals are standards by all means purchase fresh. If they appear usable they could be tested to detemine their purity or fitness for use but if the chemicals are inexpesnsive it would probably just be a lot easier to dispose of them and order new if needed. We should all do our part to help safeguard the environment. Be sure to check with your state and federal regulations regarding proper disposal of the old chemicals.
This depends on the nature and stability of the chemicals in question. I use salts like sodium hydrogen phosphate etc as old as me, that work fine. Enzymes on the other hand, can be problematic (we do have highly active alpha amylase that is probably 30 years old in the freezer.).
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