Catalog Number - 65318-05P-2

Zx Similars C18™ is a traditional reversed-phase HPLC stationary phase manufactured on high-purity Type-B spherical silica with a fully endcapped octadecyl (C18) bonded phase. Designed as a cost-effective alternative to Agilent Zorbax® C18 columns, it offers comparable chromatographic behavior for USP L1 methods while providing the strong hydrophobic retention, reproducibility, and broad applicability expected from a conventional C18 stationary phase.

65318-05P-2 is a 50 mm x 2.1 mm ID narrow-bore analytical column packed with 3 µm Zx Similars C18 particles. The short 50 mm length is optimized for rapid analyses and reduced solvent consumption, while the 2.1 mm ID format is particularly well suited for LC-MS applications. The 3 µm particle size delivers significantly higher efficiency and improved peak capacity than traditional 5 µm columns, although it generates increased operating pressure. Typical operating flow rates are approximately 0.2–0.3 mL/min and require an HPLC or LC-MS system capable of reliable low-flow operation with low-volume plumbing and flow cells.

This USP L1 column is ideal for hydrophobic and neutral compounds requiring strong reversed-phase retention. Its narrow-bore design, low-flow operation, and fast analysis capability make it a popular choice for LC-MS methods, pharmaceutical analysis, long-chain fatty acid separations, and high-sensitivity analytical workflows requiring chromatographic behavior similar to Agilent Zorbax® C18 columns.

Key Benefits

• Type-B spherical silica stationary phase

• Suitable alternative for USP L1 methods

• Comparable selectivity to Agilent Zorbax® C18 columns

• Narrow-bore format ideal for LC-MS applications

• Fast analysis with 50 mm column length

• Higher efficiency than comparable 5 µm columns

• Reduced solvent consumption

• End-capped C18 bonded phase

Typical Applications

• USP L1 methods

• LC-MS analysis

• Reversed-phase HPLC

• Pharmaceutical analysis

• Long-chain fatty acid analysis

• Quality control testing

• Fast analytical separations

• Method transfer and validation

Specifications

• Product Type: HPLC Column

• Stationary Phase: Zx Similars C18

• USP Classification: L1

• Particle Size: 3 µm

• Particle Type: Type-B Spherical Silica

• Bonded Phase: C18 (Octadecyl)

• Endcapped: Yes

• Column Dimensions: 2.1 mm ID x 50 mm

• Length: 50 mm

• Recommended Flow Rate: 0.2–0.3 mL/min

• Brand: Cogent

Important Notes

• Designed for reversed-phase chromatography

• Narrow-bore format optimized for LC-MS applications

• Requires an HPLC or LC-MS system capable of reliable low-flow operation

• Higher efficiency than comparable 5 µm columns

• Increased operating pressure compared to larger particle sizes

• Reduced solvent consumption compared to 4.6 mm ID columns

• Excellent alternative for many USP L1 methods

• Ideal for high-throughput LC-MS workflows

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