A Unified Method for the Analysis of Monocyclic Aromatice Solvents Using the 8860 GC System and On-Board Data Processing

Significance of the Topic

Determination of monocyclic aromatic solvent purity is crucial for quality control in chemical and petrochemical industries. It ensures compliance with regulatory standards, guarantees product performance, and prevents contamination in downstream processes.

Study Objectives and Overview

This application note presents a unified gas chromatography method for simultaneous analysis of 26 monocyclic aromatic solvents and selected nonaromatic impurities using the Agilent 8860 GC and onboard data processing. Two carrier gases, helium and nitrogen, were evaluated to simplify routine quality assurance workflows without external software.

Methodology and Instrumentation

The study employed an Agilent 8860 GC equipped with a split/splitless inlet and an FID detector, using an Agilent J&W HP-INNOWax column (60 m × 0.32 mm, 0.5 μm). Two methods were developed:

• Helium Carrier Gas: constant flow at 2.1 mL/min, oven program from 60 °C (10 min) then 5 °C/min to 150 °C (10 min)
• Nitrogen Carrier Gas: constant flow at 1.5 mL/min, extended initial hold at 65 °C (23 min), ramp to 150 °C, then postrun at 220 °C (5 min)

Data acquisition and processing were executed via the Agilent Browser Interface and DA Express onboard.

Main Results and Discussion

Baseline resolution was achieved for most of the 26 compounds with helium, except partial overlap of p-ethyltoluene and m-ethyltoluene. Using nitrogen, comparable separation quality was maintained with longer run times and a postrun step to clear high-boiling impurities. System stability was confirmed by nine consecutive injections, yielding retention time RSDs ≤0.03% and area RSDs ≤2.06%. Purity assessments for toluene, ethylbenzene, o-xylene, p-xylene, and styrene demonstrated >99% target analyte with minimal impurities, following Effective Carbon Number correction.

Advantages and Practical Applications

The unified method streamlines analysis by:

• Eliminating the need for external chromatography software
• Supporting both helium and nitrogen carriers based on local availability
• Providing on-board integration, calibration, and reporting
• Ensuring high throughput and reproducible results for QA/QC environments

Future Trends and Opportunities

Integration of onboard data processing with automated decision-making and remote monitoring can further enhance laboratory efficiency. Expanding the method to cover mixed xylenes and higher-boiling byproducts or coupling with mass spectrometry could broaden application scope.

Conclusion

The Agilent 8860 GC combined with the Browser Interface and DA Express delivers a robust, user-friendly approach for monocyclic aromatic solvent purity analysis. The dual-carrier gas capability accommodates diverse laboratory resources while maintaining high accuracy and precision.

References

1. ASTM D7504-15e1 Standard Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography and Effective Carbon Number, ASTM International, 2015.
2. Agilent Technologies Application Note 5988-3741EN A Unified Gas Chromatography Method for Aromatic Solvent Analysis.
3. Agilent Technologies Application Note 5988-9278EN A Unified Method for the Analysis of Aromatic Solvent Using the Agilent 6820 Gas Chromatography System.