Extraction of Semi-volatile Organic Compounds in Drinking Water with NEW Atlantic® ReadyDisk DVB Solid Phase Extraction Disks in Compliance with EPA Method 525.3

Significance of the Topic

The reliable detection and quantification of semi-volatile organic compounds (SVOCs) in drinking water is critical for public health and regulatory compliance. EPA Method 525.3 refines earlier protocols, introducing specialized sorbent disks and updated preservation steps to improve sensitivity and accuracy in trace-level analysis.

Objectives and Overview

This study demonstrates the performance of Atlantic ReadyDisk DVB solid phase extraction (SPE) disks combined with a Biotage Horizon 5000 automated extractor for EPA Method 525.3 compliance. Key goals include verifying low background contamination, assessing spike recoveries and precision, and establishing method detection limits (MDLs).

Methodology and Instrumentation

Sample Preparation and Extraction:

• Water buffering to pH ~3.8 and addition of antioxidants (ascorbic acid, EDTA).
• Surrogate and standard spikes at defined levels (5 µg/L and 0.5 µg/L for MDL study).
• Automated conditioning, loading, washing, drying and elution on Biotage Horizon 5000.
• Concentration of combined eluates via XcelVap to ~0.9 mL, internal standard addition, final volume to 1 mL.

Instrumentation:

• Extraction: Biotage Horizon 5000.
• SPE Disk: Atlantic ReadyDisk DVB.
• Solvent Evaporation: XcelVap.
• Analysis: Agilent 6890 GC with 5975C Inert GC/MSD, Zebron ZB-Semi Volatiles column, consistent helium flow, splitless injection.

Results and Discussion

Laboratory reagent blanks (n=6) showed no detectable contamination. Laboratory fortified blanks (n=6) spiked at 5 µg/L yielded average recoveries between 70–130 % for nearly all 85 target SVOCs, with relative standard deviations (RSDs) below 10 % in most cases. Method detection limits (n=7) ranged from 0.01 to 1.45 µg/L based on standard deviation and t-factor calculations. Known unstable compounds (e.g., phorate, disulfoton, HCCPD) exhibited lower recoveries or higher RSD due to chemical instability in ethyl acetate or sensitivity to light/heat.

Benefits and Practical Application

The integrated SPE disk and automated extraction workflow provides:

• High throughput and reproducibility for drinking water monitoring.
• Robust control of background contamination and clear demonstration of method capability.
• Sensitivity meeting regulatory MDL requirements for diverse SVOCs.

Future Trends and Possibilities

Advancements may include:

• New sorbent chemistries for broader analyte coverage and enhanced selectivity.
• Miniaturized and on-site extraction platforms to reduce solvent use and improve turnaround.
• Coupling with high-resolution mass spectrometry for non-target screening of emerging contaminants.

Conclusion

The Atlantic ReadyDisk DVB SPE disks, in concert with automated extraction and GC/MS analysis, satisfy EPA Method 525.3 performance criteria for semi-volatile compounds in drinking water. The method offers reliable recoveries, low detection limits, and robust precision, supporting routine monitoring and compliance efforts.

Reference

• US EPA Method 525.3, Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column GC/MS, 2012.
• Gang Guo, Naiwen Jiang, Fengmao Liu, Yanli Bian, “Storage Stability of Organophosphorus Pesticide Residues in Peanut and Soya Bean Extracted Solutions,” R. Soc. Open Sci., 2018.