Shim-pack Arata LC Columns

Significance of the Topic

The analysis of basic and acidic compounds as well as peptides under reversed-phase liquid chromatography is essential in pharmaceutical, environmental, and biochemical research. However, conventional C18 columns often face challenges such as poor peak shape for basic analytes, extended equilibration times in low ionic strength acidic mobile phases, and reliance on strong ion-pairing reagents that suppress mass spectrometric detection.

Objectives and Study Overview

This application note presents the development and performance evaluation of the Shim-pack Arata C18 column designed to deliver superior resolution and peak shape for a wide range of compounds. Key goals include demonstrating improved chromatographic behavior for basic and acidic small molecules, peptide separations using weak ion-pairing acid, and rapid column equilibration under mild mobile phase conditions.

Methodology and Instrumentation

• Column: Shim-pack Arata C18 (2.2 µm, 3.0 x 75 mm)
• Instrument: Nexera X2 MP with M30A standard flow cell
• Mobile Phase for small molecules: 0.1% formic acid in water and acetonitrile (70:30 v/v)
• Mobile Phase for peptides: 0.1% formic acid in water and 0.1% formic acid in acetonitrile
• Flow Rate: 0.4 mL per minute
• Column Temperature: 40 degrees Celsius
• Detection Wavelength: 254 nm for small molecules, 214 nm for peptides

Main Results and Discussion

• Basic and acidic small molecules: Excellent peak shapes for amitriptyline and benzoic acid achieved even with low ionic strength mobile phase.
• Peptide separation: Angiotensin displayed sharp, symmetrical peaks under isocratic conditions using only 0.1% formic acid, avoiding the use of trifluoroacetic acid and minimizing ion suppression in LC/MS analyses.
• Column equilibration: Shim-pack Arata reached stable retention times and symmetry factors for basic drugs within minutes, whereas typical ODS columns required significantly longer conditioning and still showed poor peak shape and variability.
• Symmetry factors remained close to unity under repeated equilibration cycles, demonstrating robust performance.

Benefits and Practical Applications

• Improved resolution and peak shape for basic compounds reduces need for buffer additives and strong ion-pairing reagents.
• Rapid equilibration increases sample throughput and reduces downtime in routine analysis.
• Compatibility with low ionic strength and formic acid mobile phases enhances MS sensitivity for pharmaceutical and bioanalytical applications.
• Enhanced peptide separations support proteomic workflows without compromising mass spectrometric detection.

Future Trends and Potential Applications

Advances in stationary phase chemistry, such as that demonstrated by Shim-pack Arata, point toward universal columns capable of handling diverse analyte chemistries without extensive method development. Future developments may focus on further reducing particle size, exploring novel surface chemistries to fine-tune selectivity, and integrating these columns into high throughput and microflow platforms. Emerging applications could include comprehensive multi-omics profiling and real-time process analytical technology in pharmaceutical manufacturing.

Conclusion

Shim-pack Arata C18 columns offer a significant enhancement in chromatographic performance for both small molecules and peptides. Their ability to deliver sharp peaks under mild mobile phase conditions and fast equilibration times addresses common limitations of traditional ODS columns. These characteristics make them valuable tools for laboratories seeking robust, high-resolution analysis with minimal method optimization.