Analysis of Methyl-t-Butyl Ether (MTBE) and related impurities per ASTM test method D5441 using Zebron™ ZB-DHA-PONA Gas Chromatography Column

Significance of the Topic

Methyl tert-butyl ether (MTBE) is a key octane-enhancing gasoline additive whose purity critically affects engine performance and environmental compliance. Accurate detection of trace contaminants ensures fuel quality and regulatory adherence.

Objectives and Overview of the Study

This work compares the Zebron ZB-DHA-PONA GC column against three commercial alternatives (Restek Rtx-DHA-50, Supelco Petrocol-DH 50.2, Agilent HP-PONA) for ASTM D5441 analysis of MTBE and related impurities. The goal is to evaluate peak shape, separation efficiency, and resolution of mandated critical pairs.

Methodology and Instrumentation

• Column: Zebron ZB-DHA-PONA, 50 m × 0.20 mm ID × 0.50 µm, 100 % dimethylpolysiloxane phase.
• Instrument: GC-FID with helium carrier gas at 0.9 mL/min (constant flow).
• Injection: Pulse split 50:1 at 200 °C, 20 psi for 0.5 min; sample volume 0.5 µL; Zebron PLUS Z-Liner recommended.
• Oven program: 40 °C hold 13 min; ramp to 180 °C at 10 °C/min; hold 3 min.
• Comparative tests run under identical conditions for fair performance assessment.

Main Results and Discussion

• Zebron ZB-DHA-PONA delivers symmetric peaks for both polar and nonpolar impurities due to its advanced deactivated fused-silica surface and engineered self cross-linking stationary phase.
• Resolution between trans-2-pentene/tert-butanol reached 1.6 and between tert-butanol/cis-2-pentene reached 1.5, exceeding the ASTM D5441 minimum of 1.3.
• Competitor columns showed mixed results: Supelco achieved 2.1 for the first pair but only 0.8 for the second; Restek and Agilent gave moderate performance that did not match the overall balance of the Zebron column.

Benefits and Practical Applications

• Enables reliable quantification of C1–C4 alcohols, C4–C12 olefins, dimers, trimers, and ether isomers in MTBE.
• Low-bleed, high-resolution separations support high-throughput quality control in petrochemical and fuel laboratories.
• Minimizes retests and ensures compliance with fuel specifications, improving operational efficiency.

Future Trends and Potential Applications

• Development of tailored low-bleed phases for other fuel additives and complex hydrocarbon matrices.
• Coupling with mass spectrometry for enhanced structural identification of trace contaminants.
• Application of chemometric and automated method optimization tools to further enhance resolution and reduce analysis time.

Conclusion

The Zebron ZB-DHA-PONA column surpasses ASTM D5441 requirements for MTBE impurity profiling, offering outstanding peak symmetry and resolution. Its robust performance makes it an ideal choice for routine fuel quality assurance and regulatory testing.

Reference

Ramkumar Dhandapani, Zeshan Aqeel, Tim Nelson. Analysis of Methyl-t-Butyl Ether (MTBE) and Related Impurities per ASTM Test Method D5441 Using Zebron ZB-DHA-PONA GC Column. Phenomenex Application Note TN-2083.