Determination of N-Nitrosamines by USEPA Method 521 Using Triple Quadrupole Mass Spectrometry

Poster Presentation

Prepared by B. Prakash, W. Lipps, T. Ogura, R. Kitano, N. Lock, L. Chambers
Shimadzu Scientific Instruments, 7102 Riverwood Drive, Columbia, MD, 21046, United States

Contact Information:; 410-910-0903


Research indicates that N-nitrosamines are formed during chlorination of finished drinking water. These compounds are classified as possible human carcinogens by the International Agency for Research on Cancer (IARC), and were detected in about 25% of the drinking water systems monitored in the Unregulated Contaminant Monitoring Rule 2 (UCMR2).

Detection and quantitation of N-nitrosamines for contaminant monitoring require using USEPA Method 521 (2004) employing an ion trap MS with chemical ionization (CI). Method 521 was originally developed using ion trap MS, and all of the validation data presented in the method are based on this technique, but unfortunately, ion trap mass spectrometers are no longer available. A new method is needed.

This poster describes the development of a Multiple Reaction Monitoring (MRM) instrument method using a commercially available triple quadrupole GC-MS/MS for detection and quantitation of N-nitrosamines after extraction as described by USEPA Method 521. GC-MS/MS in MRM mode produces significant improvements in selectivity and specificity, as well as dramatically lower detection limits than single quadrupole GC/MS, especially in complex matrices producing background interferences. This poster presents final instrument configuration and operating conditions, as well as instrument validation results including LCMRL, and precision & accuracy as evaluated using spiked samples at various concentration levels. Use of the CI technique compared to electron impact ionization is also discussed.

Abstract submission information
Methodology: 12. Gas Chromatography/Tandem Mass Spectrometry
Application: H. Environmental
Primary Focus: Application
Keywords: 252. Tandem Mass Spec, 70. Environmental, 76. Environmental, Water, 100. GC-MS