Target Based Screening of Environmental Water Samples using Deconvolution Reporting Software on an Agilent 5975 Series GC/MSD and the Creation of a New Screening Database

Significance of Topic

The European Water Framework Directive mandates comprehensive monitoring of organic pollutants in water. A rapid and reliable multiresidue screening is critical to assess water quality and support regulatory compliance. Target based screening enables efficient detection of known and emerging contaminants at trace levels.

Objectives and Study Overview

This study aimed to develop a cost effective GC/MSD screening method with deconvolution reporting software. Key goals included detection of VOCs and SVOCs in a single water extract, achieving detection limits near 0.1 ug/L, and building a flexible database of over 1,000 target compounds.

Methodology and Instrumentation

Sample preparation

• Internal standard added to 1 L water sample followed by two sequential liquid liquid extractions with dichloromethane under neutral and acid conditions
• Extracts combined, dried and concentrated to 1 mL for GC/MS analysis

Instrumentation and software

• Agilent 7890A GC with 5975C MSD and PTV inlet
• HP5-MS UI column with retention time locking using fluorene
• Cold splitless injection, EI full scan from m/z 35 to 566
• Deconvolution Reporting Software integrating ChemStation, AMDIS and NIST08

Main Results and Discussion

• Detection limits of 0.1 ug/L were met for diverse pesticides, PAHs and solvents
• Many compounds detected below 0.02 ug/L demonstrating high sensitivity
• Database includes 53 compounds not present in NIST08, ensuring comprehensive coverage
• DRS reduced data processing time, enabling 24 samples to be processed overnight

Benefits and Practical Applications

• Automated deconvolution cuts interpretation time and reduces false positives
• Customizable database supports evolving monitoring requirements
• Applicable to river water, effluent, groundwater, coastal and transitional waters as well as sediments
• Enables rapid response during pollution incidents and routine surveillance

Future Trends and Potential Applications

• Expansion of the target database with emerging contaminants and transformation products
• Integration with high resolution mass spectrometry and suspect screening workflows
• Application to other environmental matrices such as soil and biota
• Development of quantitative methods for priority pollutants identified via screening

Conclusion

The developed GC/MSD screening method with deconvolution reporting meets the stringent requirements of the Water Framework Directive. High sensitivity, broad compound coverage and reduced analysis time deliver a robust tool for water quality monitoring and regulatory compliance.

Reference

• Full listing of target database provided by National Laboratory Service