Method 1664, Revision B: n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry.
Get more information about the standard at EPA 1664B.
Facts about the EPA 1664B Test Method
EPA 1664 revision B is commonly used for the determination of oil and grease. The method EPA 1664B describes the determination of n-hexane extractable material in various waters (e.g. surface, saline, waste). When the extraction is followed by a clean-up step using silica-gel, just the non-polar substances are measured (oil). In contrast the content of oil and grease is measured when the clean-up step is omitted. The extraction (and clean-up) is followed by the evaporation of the solvent and the gravimetric determination of the contained oil (and grease). Due to the evaporation of the solvent during the sample preparation no hydrocarbons that volatilize at a temperature below 85°C.
While the ERACHECK is capable to additionally determine more volatile hydrocarbons, an excellent correlation between both methods can be reached, using a combined calibration method between the EPA 1664B and ASTM D7678.