Unfortunately, this is the one element that simply can't be controlled. This leaves the 'human factor' (number 3). Inorganic Ventures has eliminated number 1 and greatly reduced number 2. A one year shelf life can only be justified.' - source Expiration DatesĪ standard's expiration date is dependent upon numbers 1, 2, and 3 above. NIST has reinforced this fact, stating, 'The limit on the validation period is due to transpiration of the solution. The cap circumference to volume ratio predicts a shelf life of up to one year. Inorganic Ventures purchases NIST SRMs that come packaged in 60 mL HDPE bottles. Some have a shelf life exceeding a decade. Typically, Inorganic Ventures stock items have an average shelf life of 2-4 years. Transpiration loss is linear with time.The shelf life can be accurately predicted from the ratio of the cap circumference to the surface area of the solution exposed just below the head space.There is no difference between the transpiration loss of water versus hydrochloric or nitric acid aqueous solutions.Transpiration loss occurs mainly around the cap circumference and not through the container walls.Closed but untaped 125mL bottles have a shelf life of 21 months.Closed but untaped 500 mL bottles have a shelf life of 4 years.Our studies, performed on our 500 mL and 125 mL LDPE bottles, showed the following: Figure 1 below provides a brief presentation of our transpiration data.įigure 1 - Transpiration Losses over Time: Inorganic Ventures's scientists have studied these losses over a period of several years. The entire chemical standard industry suffers from transpiration loss. All standards have a limited shelf lifeĪ standard's finite shelf life is caused by transpiration (number 2 above). Number 1 above has been eliminated in our facility.

Inorganic Ventures can state with certainty that there are no chemical stability problems that have not been solved. Our chemists have been checking and testing standards for almost 20 years. Inorganic Ventures manufactures single-element standards to be chemically stable indefinitely. A change greater than that uncertainty (☐.5% relative for our standards) means the standard has gone over (passed) its shelf life. Shelf Life is the amount of time that a properly packaged and stored standard will last without undergoing chemical or physical changes, remaining within the specified uncertainty. The shelf life of aqueous trace metals standards is dependent upon numbers 1 and 2 above. The 'human factor' while using the standard.The chemical stability of the standard.The integrity of an aqueous trace metals standard is dependent upon: This information will help you make the correct decisions when other suppliers throw misleading comments into the mix. This article provides you, the consumer, with the best definitions for shelf life and expiration date. and Christopher Gaines The FactsįACT: Shelf Life does NOT mean expiration date.įACT: A standard's expiration date should never exceed 1 year.įACT: A standard's expiration date and shelf life are two entirely different entities.Ĭhemical stability is only one of many factors involved in defining expiration date and shelf life.

How long do checks last before expiring