[Histonet] RE: shelf life

[Morken, Timothy]

Angela most of these "shelf life" dates are just the length of time a vendor is willing to be responsible for the reagent. It's mostly a financial decision, not chemical deterioration. They just don't want to be responsible for chemicals for too long. So that is why you see variations in shelf life or expiration dates for the same chemical from different vendors.

We generally give any solution we make up a 6-month shelf life unless we know from validations that is it is shorter. We make up solutions in amounts that will be used up before that date so we never have expired reagents around. That's easier than always having to inventory for expired reagents. 

To justify your dating you can use published dates from various vendors (ie, datasheets, expirations on the bottle, etc).

For chemicals that do not state expiration dates I actually asked the question and got a written reply (via their website) from Fisher that states liquid chemicals are good for 3 years and dry chemicals for 5 years unless stated on the bottle. I put that letter in our manual as documentation on how we arrived at our in-house expiration dating. 

Tim Morken
Supervisor, Histology, Electron Microscopy and Neuromuscular Special Studies
UC San Francisco Medical Center
San Francisco, CA

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-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Bitting, Angela K.
Sent: Wednesday, December 10, 2014 8:45 AM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] shelf life

We are being inspected soon and I'm trying to check the labels on all of my chemicals.  How do I determine the expiration date of a 1N HCl solution I prepared in house.  I went on line and a commercially available 1N HCl solution has a 36 month shelf life according to the vendor's web site. I don't know how they arrived at that. I know concentrated HCl has an indefinite shelf life, but a 5 year retest date appears on the COA. It's confusing to me.
Any help would be appreciated.



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