Catalog Number - 65308-25P

Zx Similars C8™ Octyl is a traditional reversed-phase HPLC stationary phase manufactured on high-purity Type-B spherical silica with a fully endcapped octyl (C8) bonded phase. Designed as a cost-effective alternative to Agilent Zorbax® C8 columns, it offers comparable chromatographic behavior for USP L7 methods while providing the moderate hydrophobic retention, reproducibility, and reliability expected from a conventional C8 stationary phase. Compared to C18 columns, C8 phases generally provide reduced retention and faster elution of hydrophobic analytes.

65308-25P is a 250 mm x 4.6 mm ID analytical column packed with 3 µm Zx Similars C8 particles. The extended 250 mm length provides increased theoretical plate counts and enhanced resolving power for impurity profiling, complex sample matrices, and challenging separations where maximum resolution is required. The 3 µm particle size delivers higher efficiency and improved peak capacity compared to traditional 5 µm columns, while generating increased operating pressure that should be considered during method development. Typical operating flow rates are approximately 1.0–2.0 mL/min on HPLC systems capable of supporting elevated backpressure.

This USP L7 column is ideal for hydrophobic and neutral compounds when less retention is desired than a comparable C18 phase. Common applications include pharmaceutical analysis, long-chain fatty acid separations, impurity testing, method development, and quality control laboratories requiring chromatographic behavior similar to Agilent Zorbax® C8 columns.

Key Benefits

• Type-B spherical silica stationary phase

• Suitable alternative for USP L7 methods

• Comparable selectivity to Agilent Zorbax® C8 columns

• Increased resolution from 250 mm column length

• Higher efficiency than comparable 5 µm columns

• Lower retention than C18 columns

• Excellent for hydrophobic and neutral compounds

• End-capped C8 bonded phase

Typical Applications

• USP L7 methods

• Reversed-phase HPLC

• Pharmaceutical analysis

• Impurity profiling

• Method development

• Long-chain fatty acid analysis

• Quality control testing

• Method transfer and validation

Specifications

• Product Type: HPLC Column

• Stationary Phase: Zx Similars C8 Octyl

• USP Classification: L7

• Particle Size: 3 µm

• Particle Type: Type-B Spherical Silica

• Bonded Phase: C8 (Octyl)

• Endcapped: Yes

• Column Dimensions: 4.6 mm ID x 250 mm

• Length: 250 mm

• Recommended Flow Rate: 1.0–2.0 mL/min

• Brand: Cogent

Important Notes

• Designed for reversed-phase chromatography

• Longer column length provides increased resolving power

• Higher efficiency than comparable 5 µm columns

• Increased operating pressure compared to larger particle sizes

• Compatible with HPLC systems capable of handling elevated backpressure

• Provides less retention than comparable C18 stationary phases

• Excellent alternative for many USP L7 methods

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