CP-Sil 8 CB

CP-Sil 8 CB Column

Standard Polysiloxane GC Columns

Agilent J&W CP-Sil 8 CB is a versatile (5%-phenyl)-methylpolysiloxane GC column designed as a more selective alternative to CP-Sil 5 CB. By incorporating 5% phenyl groups into the dimethylpolysiloxane backbone, CP-Sil 8 CB offers slightly increased polarity—providing improved separation of aromatic compounds, semi-volatiles, and complex hydrocarbon mixtures. This balanced selectivity makes it an excellent column for general-purpose use and an ideal starting point for method development across a broad range of GC applications.

Equivalent to USP phases G27 and G36, CP-Sil 8 CB supports compendial and regulatory methods that require these selectivity classes. Laboratories benefit from outstanding batch-to-batch reproducibility, high column efficiencies, and predictable retention behavior—ensuring dependable performance across instruments, methods, and analytical environments.

For demanding applications and elevated temperature programs, CP-Sil 8 CB is also available in Agilent’s UltiMetal format. UltiMetal-coated stainless steel columns provide maximum thermal robustness and durability, making them recommended for rugged environments such as process monitoring, portable GC systems, and field-based analytical instruments. These columns maintain excellent inertness and stability even under highly aggressive conditions.

Key Definitions â–¸
(5%-Phenyl)-Methylpolysiloxane Phase
A stationary phase containing 5% phenyl substitution, giving the column slightly increased polarity compared to 100% dimethylpolysiloxane. This enhances separation of aromatic compounds, semi-volatiles, and complex hydrocarbon mixtures—ideal for method development.
USP Phase G27 & G36
Two United States Pharmacopeia classifications describing stationary phases appropriate for specific regulated GC applications. CP-Sil 8 CB matches both categories, enabling use in compendial, pharmaceutical, and quality-control methods requiring these selectivities.
Column Efficiency
A measure of how sharply a column separates analytes, commonly expressed in theoretical plates. CP-Sil 8 CB delivers very high efficiencies, producing narrow peaks, strong resolution, and reliable quantitation across complex mixtures.
Column-to-Column Reproducibility
The consistency of chromatographic performance across different manufacturing batches. CP-Sil 8 CB is engineered for excellent reproducibility, ensuring consistent retention, peak shape, and selectivity across replacements and multi-instrument labs.
UltiMetal Deactivated Stainless Steel
A rugged, high-temperature–compatible GC column format using deactivated stainless steel tubing. UltiMetal columns provide superior durability in harsh conditions, making them ideal for process monitoring, portable GC systems, and applications involving extreme thermal cycling.
Frequently Asked Questions â–¸
How does CP-Sil 8 CB differ from CP-Sil 5 CB?
CP-Sil 8 CB contains 5% phenyl substitution, giving it slightly higher polarity and improved selectivity for aromatic compounds, semi-volatiles, and complex hydrocarbon mixtures. CP-Sil 5 CB is fully nonpolar, whereas CP-Sil 8 CB offers enhanced pattern recognition and is often preferred for method development.
What applications are best suited for CP-Sil 8 CB columns?
CP-Sil 8 CB is ideal for separating aromatic compounds, semi-volatile organics, petrochemical fractions, environmental contaminants, flavor and fragrance components, and complex industrial mixtures. Its balanced polarity makes it a strong choice for both routine analysis and early-stage method development.
Is CP-Sil 8 CB compatible with USP methods?
Yes. CP-Sil 8 CB matches USP phases G27 and G36, making it suitable for validated and compendial workflows that require these stationary phase categories for regulatory or pharmaceutical testing.
When should I choose the UltiMetal version of CP-Sil 8 CB?
Choose UltiMetal when operating at very high temperatures, working with portable or process GC systems, or analyzing complex matrices that may stress fused silica columns. UltiMetal's rugged, deactivated stainless-steel tubing withstands harsh environments and aggressive thermal cycling while maintaining excellent inertness.
Does CP-Sil 8 CB offer high column efficiency?
Yes. CP-Sil 8 CB consistently delivers very high efficiencies, producing narrow peak widths, excellent resolution, and strong quantitative accuracy across diverse sample types. Its reproducibility makes it particularly reliable for multi-instrument labs and method validation.