Controlling Transpiration

David contacted Paul having heard about our Transpiration Controlled Technology (TCT). He wanted to know more about this technology, as his background in inorganic analysis involves developing reference methods of trace analysis. As such, his organization gives a lot of attention to measurement uncertainty and transpiration.

	RE: Controlling Transpiration Dear David, Thanks for contacting Inorganic Ventures. TCT is a patented technology we have developed and perfected to increase the shelf life of our standards. Your concerns about transpiration are our concerns as well (influence upon uncertainty), and we are glad to learn that other laboratories recognize the problem. I have not seen or heard any mention of this problem by other standard manufacturers. Your interest and concern about this matter is most reassuring to us. The treatment of transpiration is a topic I have explored for some time. It is an error that we refer to as a "systematic" error. We find that dealing with random errors is much easier than systematic errors and we tend to attempt to eliminate systematic errors. Unfortunately, transpiration is an error that we cannot control after the CRM leaves our facility. However we continue to look at ways to address this problem. We believe that the problem of transpiration can be 1) described, 2) defined, and 3) estimated. However, how does the user actually determine how much of a change in their certified value has occurred with their CRM during use at any specified time? In theory, a user could have multiple bottles of the same type of CRM in use, and each could exhibit different transpiration losses. See the Container Transpiration section of our Reliable Measurements guide to learn more about our transpiration studies.     Paul R. Gaines, Ph.D. Serving you in chemistry