Chemical standards and expiration dates

[BRT549]

One of my duties is running the QC laboratory, and I need some help on determining whether to throw away several thousand dollars of elemental standards due to the expiration date. I did a purge of our analytical standards in 2007, and was throwing away stuff from the 70's and 80's. Now most of the stock is expiring again, and we haven't even opened alot of standards. Most of the online information about expiring standards has been posted by chemical supply houses that have an obvious bias. We are an agricultural chemicals manufacturer, and go through enough of the main elements (N, P, K, Fe, Mg, etc) to stay in date. It's mainly the oddball elements that we do once in a while, like the TCLP list, Be, Si, Cr, and Pt. Are there some elements that expire much faster than others, such as Hg?

 

[MiketheEngineer]

They have been around since the dawn of time... go figure..

 

[MortenA]

Mike,

Chemicals undergoes reaction, and some are even radioactive and may decay into something else.

Best regards

Morten

 

[BRT549]

I appreciate your responses, but I think we're thinking of two different things. In the case of a bottle of elemental standard, the expiration date is based on transpiration of water out of the poly bottle or vaporization of a volatile element like Hg or I.

I think the way I'll get around this issue is to get some multi-element standards that I can use for several analysis. Rather than single-element standards that I would use only once in a while, I think I'll burn through the multi-element standards before they hit their expiration date.

 

[MiketheEngineer]

You can't possibly expect a decent answer from a structural engineer with a question like this - do you??

My wife throws out milk the day of expiration - when in actuality it is still good?? Her excuse - the g-kids - who can and do drink and eat everything in sight - including dirt on occasion!!

These are guidelines provided by the mfg. - to CYA themselves!!