EPA Method 1664B was developed for measuring oil and grease in wastewater with Hexane Extractable Material (HEM) concentrations ranging from 5 to 1000 mg/L. However, samples containing high oil and grease content (> 500 mg/L HEM) are challenging to extract and therefore the method allows for a smaller sample to be collected. To run reduced sample volumes, laboratories must be able to demonstrate the ability to meet the method detection limit (MDL) require