Inter-laboratory validation study for the analysis of nitrosamine in drinking water using GC-MS/MS

Topics in Drinking Water
Oral Presentation

Prepared by , C. Marvin

Contact Information: [email protected]; 302-636-8421


Nitrosamines are a group of disinfection byproducts frequently detected in finished drinking water and of concern to the U.S. Environmental Protection Agency and the Office of Drinking Water (EPA ODW). The EPA developed Method 521 in 2004 to provide procedures for the determination of trace level analysis of seven nitrosamines in finished drinking water by solid-phase extraction and chemical ionization tandem mass spectrometry (MS/MS). With the Ion Trap GC/MS systems being obsolete, migration to GC-MS/MS systems was necessary and have provided significant improvements in speed and sensitivity. This work demonstrates an enhanced GC-MS/MS method to allow for monitoring at levels below the current lowest concentration minimum reporting level (LCMRL) set in the EPA method 521. The improved GC-MS/MS method included the optimization of two additional nitrosamines, N-Nitrosomorpholine (NMOR) and N-Nitrosodimethylphenylamine (NDPhA). Three laboratories collaborated to produce the LCMRL and performance data required for an Alternate Test Procedure method update. Analytical performance was also verified through the determination of LCMRL using independently extracted samples. Results from these laboratories are compared to evaluate method feasibility and reproducibility.