Further Development of Spiking Thermal Desorption Tubes using GERSTEL Tube Spiking System and TD3.5+

Significance of the Topic

Thermal desorption (TD) tube spiking enables accurate quantitation of volatile and semi-volatile organic compounds in environmental and industrial air monitoring. Automating the spiking process enhances reproducibility, reduces human error, and streamlines workflows in laboratories handling complex samples.

Objectives and Study Overview

This study aimed to evaluate the feasibility and performance of the GERSTEL Tube Spiking System (TSS) combined with an automated GERSTEL TD3.5+ unit for liquid spiking semi-volatile organic compounds (SVOCs) onto 3.5-inch Tenax TD tubes. Collaboration between Anatune Ltd and the UK Health and Safety Laboratory (HSL) assessed reproducibility, precision, and bias across two platforms: GC-FID at HSL and GC-MSD at Anatune.

Methodology and Instrumentation

The automated protocol employed 5 μL liquid spikes of a multi-analyte SVOC standard onto Tenax tubes via the GERSTEL MPS RoboticPro with Universal Syringe Module. Spiked tubes were split between HSL and Anatune for parallel analysis. Key instrument settings at Anatune included splitless desorption on TD3.5+ with CIS 4 inlet in solvent vent mode, transfer temperature 280 °C, desorption from 30 °C to 260 °C, and cryostatic cooling via CCD2. Chromatographic separation used a DB-5 column with mass spectrometer in SIM mode. HSL performed GC-FID analysis under comparable conditions for cross-evaluation.

Key Results and Discussion

Precision was assessed as relative standard deviation (%RSD) over eight replicates. Anatune data showed %RSD below 7% for most analytes, except lauric acid at 43% attributed to chromatographic challenges of the polar acid. HSL GC-FID results consistently achieved %RSD below 6% across all compounds. Approximate accuracy (bias) relative to theoretical loads ranged from 1.9% to 5.6%, demonstrating acceptable agreement without formal recovery experiments. Differences between GC-FID and GC-MSD quantitation were noted, highlighting method-specific factors.

Benefits and Practical Applications

• Automated liquid spiking covers a broad analyte range from toluene to high molecular weight phthalates.
• Integration of TSS and TD3.5+ supports end-to-end automation, reducing manual handling and potential contamination.
• High reproducibility and low bias enable reliable quantitative analysis for environmental monitoring or industrial quality control.

Future Trends and Opportunities

Further developments may include validation of recovery and bias through formal experiments, expansion to other sorbent materials, and integration with advanced detectors. Coupling with high-resolution mass spectrometry or comprehensive two-dimensional GC could broaden compound coverage. Machine learning algorithms for data processing may optimize quantitation and identification.

Conclusion

The GERSTEL Tube Spiking System combined with TD3.5+ efficiently automates SVOC loading on thermal desorption tubes, delivering precise and accurate results across two analytical platforms. This integrated workflow enhances laboratory throughput and data quality for routine environmental and industrial applications.

References

1 Anatune Ltd technical note AS201 on GERSTEL Tube Spiking System
2 GERSTEL TD3.5+ user manual
3 Health and Safety Laboratory internal report on GC-FID analysis