The First Rule of Isotope Dilution Club is that We Do Talk about Isotope Dilution Club

Collaborative Efforts to Improve Environmental Monitoring
Oral Presentation

Prepared by H. McCarty, M. Alpizar, K. Roberts
General Dynamics Information Technology, 6361 Walker Lane, Alexandria, VA, 22310, United States

Contact Information: [email protected]; 703-254-0093


Isotope dilution is a long-established analytical technique used in many disciplines. EPA began employing isotope dilution in some of its methods in the late 1970s and the Office of Water continues to use the technique to improve the accuracy and precision of methods for volatile organics, semivolatile organics, dioxins and furans, PCBs, and other organic pollutants. Other EPA programs have included isotope dilution in methods for metals and other pollutants. The recent focus on PFAS has led to the development of methods from various sources that employ isotope dilution quantitation as a means to overcome some of the challenges faced when extracting and analyzing samples for this broad and complex category of pollutants. However, despite the long history of its use, many data reviewers and data users have only a limited understanding of the theory and practice of the technique, leading to misunderstandings and misinterpretations, as well as rejection of otherwise useful data for many projects. In this presentation we will examine the basics of isotope dilution and critical aspects of its application, as well as provide advice to data users dealing with methods that involve this quantitation technique.