US EPA 625 Method Validation Study for Automated SPE Disk Application

Reinventing Method Validation for Environmental Monitoring
Oral Presentation

Prepared by , A. Cannon, M. Ebitson

Contact Information:; 603-386-3654


US EPA method 625 is used to determine acidic, basic, and neutral semi-volatile organic compounds (SVOC) in municipal and industrial wastewater using GC-MS, in many cases for National Pollution Discharge Elimination System (NPDES) compliance. The most recent version of method 625, version 625.1 includes new language allowing the use of solid phase extraction. Additional requirements for laboratory validation with nine matrices optionally done at the vendor location or with a laboratory are required. This new language is also in several other new method versions, such as 608.3 and 624.1 to allow changes to the method and a re-validation procedure.
In this work we measured nine different wastewater-type matrices using the full suite of deuterated surrogates. Working with an accredited laboratory and the EPA Office of Science and Technology we were able to design a study and validate the method using an innovative solid phase extraction disk that requires one pass of the water rather than two passes with a pH adjustment to capture the full range of acid, base and neutral compounds. The performance of the various matrices in the study will be discussed and the advantages to an environmental laboratory will be outlined.