U.S. EPA method 625.1 – New method and new instrumentation for semi-volatiles with SPE
By Biotage
US EPA method 625 is used to determine acidic, basic, and neutral semi-volatile organic compounds (SVOC) in municipal and industrial wastewater. Revision A of this method is applied to a total possible list of 364 compounds that include; polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, pesticides, phthalate esters, organophosphate esters, nitrosamines, halo ethers, aldehydes, ethers, ketones, anilines, pyridines, quinolones, aromatic nitro compounds, and phenols. The current method outlines an extraction procedure utilizing either liquid-liquid extraction (LLE) or continuous liquid-liquid extraction (CLLE), followed by sodium sulphate drying. While it is not specifically outlined in the method, solid phase extraction (SPE) may be utilized for sample preparation, provided the Alternate Testing Procedure (ATP) process is followed.
Solid phase extraction is a well-established technique for automating traditional acid-base-neutral LLE methods; however, the method typically involves a multi-pass procedure where the solutions must be passed through the extraction media following 2 separate pH adjustments. The work presented here demonstrates successful sample preparation using an automated, one-pass SPE system. In this configuration, all analytes of interest are extracted with a single pH adjustment. The success of the extraction is due to the use of a mixed mode SPE disk which contains several functionalities.
Literature number: P185.V.2
