Validation of a new ASTM method for the Determination of Total Nitrogen and Total Phosphate using Alkaline Persulfate Digestion followed by Ion Chromatography

Changing the Paradigm for Water Pollution Monitoring
Oral Presentation

Prepared by R. Jack1, T. Patten2, J. Rohrer1
1 - Thermo Fisher Scientific, 490 lakeside Dr., Sunnyvale, CA, 94085, United States
2 - Inter Mountain Labs, 1673 Terra Ave., Sheridan, WY, 82801, United States

Contact Information:; 408-481-4227


This talk will briefly discuss the validation of a new method for the determination of total nitrogen, total kjeldahl nitrogen by calculation and total phosphate. The method uses an alkaline persulfate digestion followed by ion chromatography with suppressed conductivity detection. The digestion step is well established and approved by standard methods, however, the combination with ion chromatography has been demonstrated in the literature but not gone through a rigorous validation process. Thus the goal of this work. This method has preliminary approval based on a single lab study and tested against POTW domestic waste and brackish waters. In addition, the method shows equivalent performance between the same digestion but a different colorimetric determinative step. Using the ASTM validation process we will show the results from more than 10 matrices and more than 10 participating laboratories including universities, government testing labs, utilities and private companies.