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 CONFIDENTIALITY NOTICE: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential, proprietary, and/or privileged information protected by law. If you are not the intended recipient, you may not use, copy, or distribute this email message or its attachments. If you believe you have received this email message in error, please contact the sender by reply email and destroy all copies of the original message. -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of Bitting, Angela K. Sent: Wednesday, December 10, 2014 8:45 AM To: histonet@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. IMPORTANT WARNING: The information in this message (and the documents attached to it, if any) is confidential and may be legally privileged. It is intended solely for the addressee. Access to this message by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken, or omitted to be taken, in reliance on it is prohibited and may be unlawful. If you have received this message in error, please delete all electronic copies of this message (and the documents attached to it, if any), destroy any hard copies you may have created and notify me immediately by replying to this email. Thank you. Geisinger Health System utilizes an encryption process to safeguard Protected Health Information and other confidential data contained in external e-mail messages. If email is encrypted, the recipient will receive an e-mail instructing them to sign on to the Geisinger Health System Secure E-mail Message Center to retrieve the encrypted e-mail._______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
