Automated Solid Phase Extraction and Gas Chromatography-Mass Spectrometry Analysis of Tap Water Samples According to EN 16693:2015 for Organochlorine Pesticides

Importance of the Topic

The monitoring of organochlorine pesticides in tap water is crucial due to their persistence, toxicity, and potential to bioaccumulate in ecosystems and humans. European legislation such as the Water Framework Directive sets stringent limits for these priority substances to ensure water safety and environmental protection.

Objectives and Study Overview

This application note demonstrates an automated disk based solid phase extraction (SPE) method followed by gas chromatography mass spectrometry (GC MS) analysis of 21 organochlorine pesticides in whole tap water samples. The procedure follows European Standard EN 16693 2015 as adopted under the Water Framework Directive, aiming to assess method performance in terms of recovery, precision, and compliance with acceptance criteria.

Methodology and Sample Preparation

A one liter tap water sample was spiked with 200 nanograms per liter of target pesticides and 500 nanograms per liter of mass labelled internal standards. An Atlantic DVB SPE disk was conditioned with hexane, acetone, and water using the SPE DEX 5000 automated extractor. The sample was loaded at 100 milliliters per minute, washed with reagent water, air dried, and eluted sequentially with acetone and hexane. The combined eluate was dried over a DryDisk membrane and concentrated to one milliliter using the XcelVap system under a nitrogen ramp at 60 degrees Celsius.

Applied Instrumentation

• SPE DEX 5000 Automated Extractor
• XcelVap Evaporation Concentration System
• SDS 101 Solvent Drying System with DryDisk Membrane
• Atlantic DVB SPE Disk
• TRACE GC 1300 with PTV Inlet
• ISQ LT Single Quadrupole Mass Spectrometer
• TriPlus RSH Autosampler
• Rxi 5 ms Capillary Column with 30 meter length and 0.25 millimeter inner diameter

Main Results and Discussion

Recoveries for all 21 pesticides ranged between 97 and 116 percent with relative standard deviations below 4 percent. All results met the EN 16693 acceptance criteria of 70 to 120 percent recovery. A blank tap water sample showed no detectable target compounds. The total automated SPE extraction time was 38 minutes per sample, enabling efficient throughput.

Benefits and Practical Applications

The automated disk based SPE approach delivers consistent recoveries, minimal solvent usage, and reduced manual handling. Integration with GC MS ensures sensitive and selective quantification of priority substances. This workflow supports routine monitoring laboratories in meeting regulatory requirements under the Water Framework Directive.

Future Trends and Applications

Advances in disk based SPE materials and inline concentration techniques may further reduce analysis time and solvent consumption. Coupling with high resolution mass spectrometry could enhance detection limits and expand screening to emerging contaminants. Automation and digital integration will streamline data management and compliance reporting.

Conclusion

The automated SPE disk method coupled with GC MS provides a robust and efficient solution for the analysis of organochlorine pesticides in tap water. The procedure complies with EN 16693 2015, offering high recoveries, precision, and throughput for environmental monitoring.

Reference

• Directive 2013 39 EU of the European Parliament and of the Council
• European Standard EN 16693 2015 Solid phase extraction and GC MS determination of organochlorine pesticides in water