Meeting the Korean Method ES 04601.2 for 1,4- Dioxane (1,4-다이옥산-헤드스페이스/기체크로마토그래피- 질량분석법) with Static Headspace GC/MS

Significance of the Topic

1,4-Dioxane is a widely recognized drinking water contaminant classified as a probable human carcinogen. Regulatory frameworks, such as the Korean Method ES 04601.2, mandate highly sensitive detection with a minimum quantitation limit below 1 ppb. Achieving reliable trace-level analysis is critical for public health protection and compliance with environmental standards.

Objectives and Study Overview

This study demonstrates the application of static headspace GC/MS to meet the Korean Method ES 04601.2 requirements for 1,4-dioxane in drinking water. Key aims include:

• Establishing a calibration curve with correlation coefficient (r²) ≥ 0.98.
• Achieving a minimum quantitation limit (MQL) below 1 ppb.
• Maintaining relative standard deviation (RSD) of response factors ≤ 25%.

Methodology and Instrumentation

A static headspace sampler (Teledyne Tekmar HT3) was used alongside an Agilent 7890B GC coupled to a 5977A mass spectrometer. Standards were prepared by spiking 5 mL deionized water with 100 µL of a 1 ppm 1,4-dioxane-d8 internal standard, then adding varying volumes of a 1 ppm 1,4-dioxane stock to produce calibration levels from 1 to 50 ppb. Analytical conditions included:

• Headspace equilibration: 85 °C, 20 min, loop fill at 12 psig.
• GC column: Agilent DB-624UI (20 m × 0.18 mm, 1 µm) at 1.0 mL/min He.
• Oven program: 36 °C for 7 min, ramp at 20 °C/min to 200 °C.
• MS detection: Scan 35–270 m/z; SIM ions 96.00, 88.00, 64.00, 58.00, 46.00, 43.00 m/z.

Main Results and Discussion

The calibration exhibited excellent linearity (r² = 0.9991). The RSD of the response factor for 1,4-dioxane was 15.4%, well below the 25% threshold. Calculated MQL values were:

• Based on RSD: 0.57 ppb.
• Based on linear calibration: 0.47 ppb.

These results exceed the method requirements, confirming reliable quantitation at sub-ppb levels.

Benefits and Practical Applications

This static headspace GC/MS approach delivers robust, high-throughput monitoring of 1,4-dioxane in drinking water. Key advantages include:

• Automation via the HT3 sampler, reducing manual handling and improving reproducibility.
• Low detection limits supporting stringent regulatory compliance.
• Minimal sample preparation and solvent use, enhancing laboratory efficiency.

Instrumentation Used

• Teledyne Tekmar HT3 Automated Static Headspace Sampler
• Agilent 7890B Gas Chromatograph
• Agilent 5977A Mass Spectrometer

Future Trends and Applications

Ongoing advancements may include integration of two-dimensional GC for improved separation of complex matrices and adoption of higher-resolution mass analyzers to enhance selectivity. Miniaturized headspace devices and ambient sampling techniques could further streamline trace contaminant monitoring in water.

Conclusion

The presented static headspace GC/MS method successfully meets and surpasses the Korean Method ES 04601.2 criteria for 1,4-dioxane analysis in drinking water. The high linearity, low MQL, and acceptable precision demonstrate its suitability for routine environmental monitoring.

References

No additional literature references were provided in the original application note.