Analysis of Arsine and Phosphine in Ethylene and Propylene Using the Agilent Arsine Phosphine GC/MS Analyzer with a High Efficiency Source

Significance of the Topic

Accurate detection of trace contaminants such as arsine and phosphine in polymer feedstocks is critical for maintaining catalyst performance in ethylene and propylene production. Even low parts-per-billion levels of these species can degrade metallocene catalysts, leading to unplanned downtimes and increased operational costs.

Objectives and Overview of the Study

This work demonstrates a robust gas chromatography/mass spectrometry (GC/MS) method for quantifying arsine and phosphine at single-digit ppb concentrations in ethylene and propylene matrices. The study evaluates signal stability, linearity, precision, and instrument detection limits over extended runs.

Methodology and Instrumentation Used

A dedicated Agilent Arsine Phosphine GC/MS analyzer (model G3440B with SP1 option 7890-0667) was configured with an Agilent 7890B GC and a 5977B Series GC/MSD equipped with a high efficiency source (HES) and self-cleaning ion source (SCIS). Thick film Select Olefins columns (120 m × 0.32 mm, 8 µm) provided excellent resolution of PH3, AsH3, H2S, and COS. Continuous hydrogen flow (150 µL/min) into the source minimized bleed effects and ensured stable response.

Main Results and Discussion

Calibration in ethylene and propylene matrices achieved strong linearity (R2 ≥ 0.9987) from 5 to 50 ppb. Over 300 injections spanning 4.5 days, relative standard deviations for all analytes remained below 6 %. Instrument detection limits ranged from 0.063 ppb (AsH3) to 0.715 ppb (PH3). Overlay of total ion chromatograms every 50th run confirmed consistent peak shape and retention time stability.

Advantages and Practical Applications of the Method

• High sensitivity at single-digit ppb levels enables early detection of catalyst poisons
• Long-term stability supports routine monitoring and quality control
• Inert flow path and continuous source cleaning reduce maintenance and downtime

Future Trends and Opportunities

Advances may include online integration for real-time process control, miniaturized detectors for at-line analysis, and coupling with advanced data analytics or machine learning to predict catalyst performance and optimize purification steps.

Conclusion

The Agilent Arsine Phosphine GC/MS analyzer with HES and SCIS delivers reliable, high-precision measurement of trace arsine and phosphine in olefin streams. The method’s sensitivity, stability, and ease of use make it well suited for petrochemical quality assurance and process monitoring.

References

• Smith Henry A and Quimby B Application Note 5991-6967EN Agilent Technologies Inc 2016