Validation of EPA method 521 Using a Triple Quad Mass Spectrometer

Oral Presentation

Prepared by K. Tadigo1, C. Marvin2, R. Honnold2, C. Grady1
1 - Eurofins Eaton Analytical, 750 Royal Oaks Drive, Monrovia, CA, 91016, United States
2 - Agilent Technologies, 2850 Centerville Road, Wilmington, DE, 19808, United States

Contact Information:; 626-386-1100


Nitrosamines are an important disinfection byproduct, particularly for reused water. USEPA is considering the possible regulation of nitrosamines in drinking water due to the prevalence of occurrence in the UCMR 2 monitoring from 2005-2008. Nitrosamines are traditionally measured using EPA method 521, a solid phase extraction method followed by ion trap detection with chemical ionization. The instrumentation has been phased out, and thus, if EPA elects to regulate nitrosamines, it will be necessary to use an alternative detection method. In this study, we evaluated the use of a GC-QQQ system with EI detection as a simpler approach to detection. Because the front end (extraction) process was not changed, USEPA indicated they would be willing to evaluate method modifications as a "mini ATP" study. We performed an LCMRL determination for nitrosamines in a single laboratory using the GC-QQQ based method and also analyzed the extracts via method 521 as written.The GC-QQQ method outperformed method 521 in terms of sensitivity and speed (sub ppt MRLs and run times that were ~1/3 of the 521 run times). The next steps will be to repeat the extract analysis in two other laboratories and to perform analysis of a number of samples by both methods for direct comparison. The final method and data package will be submitted to USEPA for consideration as a new method for nitrosamines in drinking water in the event that a regulation is proposed.