Improving the 90 mm Disk Oil & Grease Method Using the Horizon 5000 (EPA 1664B)

Importance of the Topic

Oil and grease analysis in wastewater is essential to protect aquatic ecosystems and prevent pipe blockages caused by hydrophobic residues. Accurate quantification ensures regulatory compliance and informed treatment decisions.

Objectives and Study Overview

The aim of this application note is to enhance the EPA 1664B 90 mm disk method for total n-hexane extractable material (HEM) determination by leveraging the Biotage Horizon 5000 automated extraction system and SPEED-VAP IV evaporation unit.

Methodology and Instrumentation

Samples are acidified to pH 2, spiked for performance checks, and processed via automated solid phase extraction on 90 mm disks. Automation minimizes manual steps and standardizes conditions.

Instrumentation:

• Biotage Horizon 5000 automated SPE system
• SPEED-VAP IV solvent evaporation system
• Pacific Premium 90 mm oil and grease disks and optional fast flow pre-filters
• Analytical balance and 105 mm aluminum weighing pans

Main Results and Discussion

Internal performance checks returned mean recoveries of 98.5% (SD 0.89), within the 83–101% acceptance range. Blank runs confirmed negligible contamination. The method detection limit was calculated at 0.336 mg/L, well below the 1.4 mg/L regulatory limit.

Benefits and Practical Applications

The optimized protocol reduces extraction time to 35 minutes and final volume to approximately 78 mL, enabling single-step evaporation and reducing solvent use and labor. This increases sample throughput and data consistency in routine lab operations.

Future Trends and Opportunities

Advancements in automation, real-time monitoring, and miniaturized extraction media will further streamline workflows. Expanding the method to other analyte classes and integrating with hyphenated detection techniques will broaden its industrial and environmental applications.

Conclusion

The improved 90 mm disk method using the Biotage Horizon 5000 and SPEED-VAP IV offers a rapid, reliable, and efficient solution for oil and grease quantification in wastewater, meeting EPA 1664B criteria with enhanced throughput and reduced manual intervention.

Reference

EPA Method 1664B Revision B: n-Hexane Extractable Material by Extraction and Gravimetry, 2010