Expiration Policy and TCT

The expiration of Inorganic Ventures certified reference materials (CRMs) packaged using Transpiration Control Technology (TCT) is determined by specific information provided in Section 11.0 of the product Certificate of Analysis:

Certification Issue Date – the date upon which the product is certified

Lot Expiration Date – the date upon which the entire lot (batch) of product expires. This expiration date is not specific to a container, location, or storage condition, and applies equally to all of the product currently in existence.

Period of Validity – this defines the expiration of specific containers of the product. Therefore, different containers of the same lot (batch) of product can have unique Periods of Validity.

The Certification Issue Date and Lot Expiration Date cannot vary; these dates are assigned by Inorganic Ventures when the product is certified. In contrast, the Period of Validity depends upon when the sealed TCT bag is first opened, and is therefore defined by the actions of the product user.

The policy outlined above addresses the three factors that can affect the certified values of a CRM: chemical stability, transpiration, and human errors associated with laboratory use. Chemical stability is demonstrated through long term stability studies, and is represented, at a minimum, by the period of time defined by the Certification Issue Date and the Lot Expiration Date. Transpiration is controlled by the TCT packaging, and does not affect the CRM or its expiration as long as the product remains in the sealed TCT bag. The Period of Validity primarily addresses the human error factor and to a lesser extent the transpiration that will occur after opening the sealed TCT bag. Once the sealed TCT bag is opened, the product in that specific container is valid for one year (i.e., the Period of Validity) when stored and used under normal laboratory conditions.

Supplementary information regarding both TCT and the expiration of CRMs is available on the our website ( and, and technical assistance is always available for additional questions or concerns.