The Different Ways Expiration Dates can be Defined or Constrained

Interview conducted by Mychealla RiceJul 27 2016

Dr Brian Alexander, Vice President, Technical Operations at Inorganic Ventures, talks to AZoM about the different ways expiration dates can be defined or constrained.

Can you give a brief introduction about Inorganic Ventures and the work you do?

Inorganic Ventures manufactures certified reference materials (CRM), which are used for analytical testing in such varied industries as environmental, pharmaceutical, mining, research, etc. My role in the company includes overseeing technical operations related to the manufacturing, testing, and certification of our products.

Please can you explain the difference between shelf life and expiration dates?

We define the shelf-life of a certified reference material as the amount of time that a properly packaged and stored CRM will last without undergoing chemical or physical changes that could change the certified value(s). The expiration date represents the end of the shelf-life period.

How do you define a products expiration date?

The expiration date of a CRM is defined by research that studies the stability of the product over time. The data from these studies allows us to characterize the shelf-life of a CRM, and that information is used to assign expiration dates for any given batch or lot of product.

What factors affect shelf life and expiration dates?

There are three key factors that can affect the shelf-life and expiration date for the certified reference materials we manufacture. The first factor is chemical stability, which is essentially indefinite for a well-designed product. The second factor is human error, the everyday mistakes that all people can experience. The third factor is transpiration, or water vapor transmission as it is described in some industries. Transpiration describes the loss of water vapor from a closed container, and for plastic bottles the loss of water can be significant. As a result of transpiration, the amount of water in a closed plastic container will decrease, and the chemical concentrations in the solution that remains will increase, which can potentially compromise the accuracy of a CRM.

What role does human error play in shelf life and expiration dates?

Human error can significantly affect the shelf-life and expiration of a certified reference material, and examples include contamination of the CRM or improper storage. Unfortunately, human errors are not always clearly evident and can be difficult to identify, particularly for some analytical methods. However, the likelihood of human errors compromising a CRM can be minimized by following the instructions for use and storage that are provided with the product.

Why is human error a dangerous factor when it comes to expiration dates?

Human error is a concern because it can be difficult to identify and characterize. The frequently unpredictable nature of human errors presents a challenge when assigning expiration dates, as a single action or the cumulative effect of many different actions can all compromise a CRM. The best approach is to follow well-defined laboratory practices and follow the CRM manufacturer’s instructions regarding handling and storage.

How can Inorganic Ventures guarantee a products one-year expiration date?

The one-year expiration date is the amount of time that a customer can use a CRM before the factors of human error and/or transpiration may have compromised the certified value(s). It doesn’t mean that the certified values have been compromised, but rather that it is reasonable to expect that they may no longer be accurate, even if the CRM has been stored and handled appropriately.

What constraints do expiration dates face? How does this impact a manufacturer?

One constraint on expiration dates for CRM manufactured by Inorganic Ventures is the design of the product, which primarily affects chemical stability. The goal is indefinite chemical stability, and this has been achieved for the vast majority of our products. The other constraints on expiration dates, human error and transpiration, are addressed by providing technical information and guidance to the consumer, thereby allowing them to take appropriate measures to ensure confidence in their testing results.

Where can our readers go to find out more?

Inorganic Ventures provides numerous technical resources on our website related to the topics discussed here. Additional information regarding chemical stability, shelf-life and expiration dates can be found in our Guide and Papers section (https://www.inorganicventures.com/guides-and-papers). Detailed information about transpiration and its effects is provided in our Transpiration Control Technology (TCT) section (https://www.inorganicventures.com/tct). Additionally, free technical assistance is also available via email or phone for specific inquiries or questions (https://www.inorganicventures.com/webform/contact-us).  

About Dr. Brian Alexander

Dr. Brian Alexander is an earth scientist specializing in geochemistry. His research has focused trace metal analysis using ICP techniques and rare earth element studies of natural waters and chemical sediments. Today, Dr. Alexander is the Vice President, Technical Operations at Inorganic Ventures.