GC, GC columns, Consumables
IndustriesEnergy & Chemicals
ManufacturerAgilent Technologies
New Specialized GC Columns for Petroleum Industry
Importance of Topic:
- Accurate gas and vapor analysis underpins quality control, environmental compliance and process optimization in petroleum operations.
- Stationary phase shedding can compromise sensitivity, reproducibility and damage detectors in porous layer open tubular (PLOT) columns.
- Trace sulfur detection is critical to prevent corrosion, catalyst poisoning and to meet stringent environmental regulations on fuel sulfur content.
Objectives and Overview:
- Introduce integrated particle trap PLOT (PLOT PT) columns that eliminate phase shedding while preserving selectivity and GC/MS compatibility.
- Present a new DB-Sulfur SCD GC column optimized for inertness and low bleed, enhancing stable, sensitive sulfur detection by sulfur chemiluminescence detection (SCD).
Methodology and Instrumentation:
- Baseline stability tests with flame ionization detector (FID) and mass spectrometer detector (MSD) over repeated temperature and pressure cycles to evaluate detector spikes.
- Selectivity studies comparing retention of light gases, solvents and C1–C4 hydrocarbons on PLOT PT vs standard PLOT columns.
- Lifetime tests: hundreds to thousands of methanol/water injections to assess retention index and plate count stability for PoraPLOT Q, PoraPLOT U, Al2O3, Molsieve 5A PT phases.
- Sulfur compound standards (ppb–ppm) analyzed on DB-Sulfur SCD columns by GC-SCD and FID, monitoring linearity, repeatability, sensitivity and detector tube fouling.
Used Instrumentation:
- Gas chromatographs equipped with capillary flow technology (CFT) splitters.
- Detectors: FID (300 °C), MSD (70 eV, transfer line up to 300 °C), sulfur chemiluminescence detector (SCD) with pulsed or continuous plasma.
- Columns: PLOT PT series (PoraPLOT, PoraBOND, HP-PLOT Q/U, Al2O3/KCl, Molsieve 5A PT) and Agilent J&W DB-Sulfur SCD (G3903-63001/63002/63003/63004).
Results and Discussion:
- PLOT PT columns showed no detector spikes under extreme cycling; FID baseline drift <5 pA, MSD noise <2 × 105 counts, enabling valve switching and GC-MS compatibility.
- Selectivity profiles of gases, solvents and C1–C4 hydrocarbons on PLOT PT were within manufacturing reproducibility compared to non-PT references.
- Lifetime testing (>350–1350 injections) revealed no change in retention index (ΔRI <1 unit) or separation performance across polymeric and inorganic PLOT PT phases.
- DB-Sulfur SCD columns delivered consistent response factors over 20+ injections with no sensitivity loss, SCD tube fouling or regeneration downtime for over six months of use.
- Trace sulfur standards (2–100 ppb on-column) achieved signal-to-noise >3, linearity R2 >0.998 and inter-day RSD <5 % for a range of mercaptans, sulfides, disulfides and thiophenes.
Benefits and Practical Applications:
- PLOT PT columns eliminate labor-intensive trap installations, reduce leak risks and enable reliable gas analysis in QA/QC, petrochemical process control and environmental monitoring.
- DB-Sulfur SCD columns provide robust, equimolar sulfur detection in natural gas odorant analysis, light petroleum liquids and process gas streams, minimizing maintenance costs and downtime.
Future Trends and Opportunities:
- Expansion of trap integration technology to other selective phases for trace VOC and process gas analysis.
- Development of high-throughput, automated sulfur detection workflows coupling DB-Sulfur SCD with multiport sampling systems.
- Integration with advanced data analytics and AI-driven method optimization for real-time process monitoring.
Conclusion:
- Integrated PLOT PT columns and DB-Sulfur SCD columns address key challenges in petroleum industry GC analysis by improving stability, sensitivity and reducing maintenance.
- These innovations support stringent quality, environmental and safety requirements while streamlining laboratory workflows.
References:
- ASTM D5623 – Standard Test Method for Sulfur in Light Petroleum Liquids by Sulfur Chemiluminescence Detection
- ASTM D5504 – Standard Test Method for Determination of Trace Sulfur Compounds in Natural Gas by GC-SCD
- Agilent Technologies Brochure 5991-2977EN – New Specialized GC Columns for the Petroleum Industry
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