Meeting the Korean Method ES 04607.1 for Naphthalene (나프탈렌) with Static and Dynamic Headspace GC/MS

Importance of the Topic

Accurate measurement of naphthalene in drinking water is critical due to its potential health risks and regulatory limits imposed by environmental authorities. The Korean Standard Method ES 04607.1 specifies stringent criteria for quantitation limits and calibration performance, driving the need for reliable analytical workflows.

Study Objectives and Overview

This study assesses the performance of the Teledyne Tekmar HT3 Automated Static and Dynamic Headspace Vial Sampler coupled to GC/MS to meet the requirements of Korean Method ES 04607.1. Key goals include:

• Achieving a minimum quantitation limit (MQL) below 3 ppb for naphthalene in water
• Demonstrating a calibration curve with correlation coefficient (r²) > 0.98 and RSD of response factors < 25 %
• Comparing static (loop) versus dynamic (trap) headspace techniques under both full‐scan and selected ion monitoring (SIM) modes

Methodology and Instrumentation

Sample Preparation:

• 10 mL deionized water + 3 g NaCl per vial
• Internal standard: 10 µL of 2 ppm chlorobenzene-d5
• Calibration levels: 0, 1, 5, 10, 50, 100 ppb naphthalene

Headspace Conditions:

• Static loop mode: sample equilibration at 60 °C, mixing for 5 min, transfer at 180 °C, loop fill at 7 psig
• Dynamic trap mode: sample at 45 °C, trap sweep at 0 °C, desorb at 260 °C, bake at 265 °C

GC/MS Parameters:

• Column: Agilent DB-624UI, 20 m × 0.18 mm ID, 1 µm film, He carrier at 0.9 mL/min
• Oven program: 35 °C (3 min) → 13 °C/min to 85 °C → 25 °C/min to 225 °C (1 min)
• MS: scan 35–270 m/z or SIM at 128 m/z for naphthalene, 117 m/z for IS

Main Results and Discussion

Static Headspace SIM:

• MQL (Rf method): 1.1 ppb, RSD 5.3 %, r² = 0.9993
• MQL (linear calibration): 1.1 ppb

Dynamic Headspace Full Scan:

• MQL (Rf method): 0.7 ppb, RSD 22.7 %, r² = 0.9884
• MQL (linear calibration): 0.6 ppb

Dynamic Headspace SIM:

• MQL (Rf method): 0.7 ppb, RSD 22.7 %, r² = 0.9884
• MQL (linear calibration): 0.6 ppb

All modes achieved MQLs well below the 3 ppb requirement, and calibration criteria were satisfied.

Benefits and Practical Applications

The combined static and dynamic headspace GC/MS approach offers:

• Robust sensitivity to detect low-ppb levels of naphthalene
• Flexible operation for different sample matrix requirements
• Compliance with regulatory standards for routine drinking water analysis

Future Trends and Applications

Emerging developments may include:

• Integration of high-resolution mass spectrometry for improved selectivity
• Automated sample preparation and direct coupling to online monitoring systems
• Advanced data analytics and chemometric methods for rapid quality control

Conclusion

The Teledyne Tekmar HT3 headspace sampler, combined with GC/MS in both static and dynamic modes, reliably fulfills the Korean Method ES 04607.1 requirements for naphthalene analysis in drinking water. Both MQL and calibration performance exceed regulatory thresholds, demonstrating a robust solution for environmental laboratories.

Reference

Roger Bardsley, "Meeting the Korean Method ES 04607.1 for Naphthalene with Static and Dynamic Headspace GC/MS," Teledyne Tekmar Application Note.