NS30 Validated Automated Method for Liquid-Liquid Extraction of Epichlorohydrin from Water using GC/MS

Significance of the Topic

Epichlorohydrin is a key intermediate in plastics, polymers and water‐treatment resin manufacture. Its potential to leach from epoxy‐coated pipes or water‐treatment processes poses a risk to drinking water quality. The World Health Organization has set a provisional guideline limit of 0.4 µg/L for epichlorohydrin in drinking water, driving the need for sensitive, accurate and high‐throughput analytical methods.

Objectives and Overview of the Study

This study aimed to develop and validate an automated liquid–liquid extraction (LLE) protocol for epichlorohydrin in water using a GERSTEL MultiPurpose Sampler (MPS) coupled to GC/MS. The goals were to improve reproducibility, reduce solvent consumption and enable unattended, high‐throughput sample preparation.

Methodology

A 9 mL aliquot of deionized water was spiked across a calibration range of 0.2–10 µg/L epichlorohydrin. Extraction was carried out by adding 300 µL dichloromethane (DCM) in a high‐recovery vial, followed by automated vortex mixing (60 s) and centrifugation (90 s at 4 500 rpm). A 100 µL portion of the DCM layer was transferred to a GC vial for analysis. The complete preparation of six samples required under 21 minutes, with batch centrifugation optimized for throughput.

Used Instrumentation

• GERSTEL Dual‐Head MultiPurpose Sampler (MPS)
• GERSTEL mVORX automated vortex mixer
• Anatune CF‐200 centrifuge
• Anatune 9.5 mL high‐recovery vials
• Agilent 6890 GC coupled to 5975 MS detector

Main Results and Discussion

The high‐recovery vial design allowed a reduction of extraction solvent volume from 1 000 µL to 300 µL, enhancing sensitivity. Epichlorohydrin was detected by SIM at m/z 57 with a retention time of ~2.399 min. Calibration over 0.2–10 µg/L was linear (R² = 0.9997). Method validation at 8 µg/L yielded recovery of 103.6% with 4.7% RSD, a substantial improvement over the previous manual method (13% RSD).

Benefits and Practical Application

The automated protocol delivers higher reproducibility, lower detection limits and reduced solvent consumption (three‐fold decrease). It enables unattended operation, increasing laboratory throughput and reducing analyst exposure to chlorinated solvents. These improvements support regulatory compliance and cost‐effective monitoring of drinking water quality.

Future Trends and Opportunities

Further integration of automation with advanced sample‐introduction techniques and miniaturized extraction formats could enhance sensitivity and reduce solvent use further. Coupling with high‐resolution MS or alternative detectors may expand selectivity for multi‐analyte screening. Application of remote monitoring and digital workflow integration will drive real‐time water quality surveillance.

Conclusion

The automated LLE‐GC/MS method for epichlorohydrin provides robust, reproducible and high‐throughput analysis with improved sensitivity and reduced solvent use. Validation results meet NS30 criteria for drinking water testing, demonstrating its suitability for routine environmental monitoring and laboratory efficiency.

References

1 WHO/SDE/WSH/03.04/94 Epichlorohydrin in Drinking Water, World Health Organization, 2004.