Determination of VOCs in water using the new Anatune VOC Analyser

Importance of the topic

Monitoring volatile organic compounds (VOCs) in drinking and wastewater is critical for public health, regulatory compliance and environmental protection. Static headspace GC-MS is a well-established approach, but conventional workflows often involve manual sample handling, limiting throughput and introducing variability. The development of automated systems seeks to overcome these challenges by enhancing reproducibility, reducing analyst time and increasing sample capacity.

Objectives and overview

The primary aim of this study was to demonstrate full automation of VOC quantification in water using the new Anatune VOC Analyser. Key goals included integration of auto-spiking of internal standards, rapid GC-MS analysis, high sample throughput and robust performance metrics in compliance with typical laboratory requirements.

Methodology

• Sample preparation consisted of combining 15 ml of water with sodium sulfate in 20 ml vials.
• Samples were incubated at elevated temperature for 17 minutes before headspace extraction.
• One milliliter of headspace was injected into the GC-MS for each analysis.
• A six-point calibration in spring water covered analyte concentrations from 0.1 to 20 μg/L, with internal standards fixed at 30 μg/L.

Instrumentation used

The automated workflow was achieved with:

• Anatune VOC Analyser incorporating a Gerstel MPS Dual Head (2.5 ml and 100 μl syringes).
• Agilent 7890B gas chromatograph with DB-624 column (30 m×0.25 mm×1.4 μm) and a 14 minute cycle (9.08 minute run time).
• Agilent MSD 5977 in EI mode operated in SIM/Scan using two ions per analyte.
• 240-position sample tray and Maestro software for Prep Ahead scheduling.
• MassHunter and Maestro software for data acquisition and auto-spiking control.

Main results and discussion

• Linearity was excellent for all 58 target compounds with R² values above 0.995 and up to 0.999 after internal standard correction.
• Limits of detection (LODs) in spring water were generally below 0.1 μg/L; for chloroethane and bromomethane the transition from the 5975 to the 5977 MSD improved sensitivity by factors of 3 and 1.6, respectively.
• Background levels for key analytes remained at or below 0.1 μg/L under controlled conditions.
• Reproducibility tests on six replicates at 4 μg/L and 16 μg/L yielded CVs below 10% and recoveries between 92% and 107%.
• Throughput of the system allowed 97 injections per 24 hours (14 minutes per cycle), demonstrating high laboratory efficiency.

Benefits and practical applications

Automation of headspace GC-MS analysis offers:

• Enhanced reproducibility via auto-spiking of internal standards.
• Significant reduction of manual handling steps and associated errors.
• High throughput suitable for routine QA/QC of drinking water and environmental monitoring.
• Rapid turnaround with sub-15 minute cycle times.

Future trends and opportunities

Further work may focus on extending the method to additional analytes such as vinyl chloride, assessing robustness across diverse real-world water matrices and conducting long-term stability studies. Implementation of positive-pressure clean laboratories could further reduce background interference. Continued software enhancements and integration with laboratory information management systems (LIMS) will support fully digital workflows.

Conclusion

The Anatune VOC Analyser combined with Gerstel MPS automation and Agilent GC-MS provides a powerful, fully automated solution for VOC analysis in water. It delivers high sensitivity, excellent linearity, strong reproducibility and throughput suitable for routine environmental monitoring.