Shim-pack Arata LC column

Importance of the Topic

The analysis of basic and acidic compounds by reversed-phase liquid chromatography is often hampered by peak tailing, poor resolution and lengthy equilibration when using conventional C18 columns under low–ionic-strength acidic conditions. Shim-pack Arata columns address these challenges through a novel surface chemistry that suppresses unwanted silanol interactions, improving data quality and throughput in pharmaceutical, environmental and biochemical laboratories.

Objectives and Overview of the Study

This whitepaper introduces the Shim-pack Arata column series and demonstrates its performance advantages. Key goals include:

• Evaluating peak shape and symmetry for mixtures of basic and acidic drugs under 0.1% formic or phosphoric acid mobile phases.
• Assessing equilibration speed and retention stability for impurity control applications.
• Testing method transfer consistency across different column dimensions and particle sizes.
• Validating lot-to-lot reproducibility and peptide analysis performance including recovery and equilibration behavior.

Methodology and Instrumentation

A range of Shim-pack Arata C18 columns (2.2 µm and 5 µm particle sizes; various ID/length formats) were compared with standard ODS and hybrid C18 columns. Typical analytical setups comprised:

• LC system: Shimadzu Nexera X2 with SPD-20A or M30A detectors.
• Mobile phases: 0.1% formic or phosphoric acid in water (A) and in acetonitrile (B); peptide analyses used formic acid gradients.
• Flow rates: 0.2–1.0 mL/min depending on column format.
• Column temperatures held at 40 °C; UV detection at 210–254 nm.
• Gradient programs tailored for small molecules, peptide digests and impurity profiling.

Key Results and Discussion

• Peak Symmetry and Resolution: Under low-ionic acidic conditions, Shim-pack Arata columns produced remarkably sharp, symmetric peaks for both basic (e.g., histamine H1 antagonists) and acidic drugs, outperforming hybrid and conventional ODS columns.
• Rapid Equilibration: Retention times and peak areas of basic drugs and impurities stabilized within 30 minutes on Arata columns, whereas typical ODS columns required several hours.
• Method Transfer: Selectivity factors (α) and retention factors (k) remained consistent when transferring methods between 5 µm and 2.2 µm Arata columns of different dimensions, enabling faster UHPLC assays with up to 4× shorter run times and 5× less solvent consumption.
• Lot-to-Lot Reproducibility: Multiple lots of Arata C18 material exhibited minimal variation in retention and peak symmetry for test probes (uracil, amitriptyline, benzoic acid) under strict QC conditions.
• Peptide Analysis: The Arata Peptide C18 column achieved excellent peptide peak shapes and stable retention after only 30 minutes of equilibration in 0.1% formic acid, compared to prolonged conditioning on conventional ODS. Recovery tests with myoglobin digest showed ~2–3× greater total peak area versus core-shell C18 and C8 columns.

Benefits and Practical Applications

• Eliminates the need for ion-pairing additives in LC/MS workflows for basic compounds.
• Enhances quantitative reliability in pharmaceutical impurity profiling and method validation.
• Facilitates rapid method development and transfer between HPLC and UHPLC platforms.
• Reduces column conditioning time and solvent usage while preserving resolution.
• Supports high-throughput peptide quantitation in bioanalysis without extensive pre-conditioning.

Future Trends and Potential Uses

The proprietary end-capping and surface treatment of Shim-pack Arata columns position them for expanding roles in bioanalytical and proteomic LC/MS applications, therapeutic antibody monitoring, metabolomics and high-throughput screening. Ongoing developments may further extend useful pH range, enhance compatibility with 100% aqueous mobile phases and integrate seamlessly with emerging UHPLC-MS technologies.

Conclusion

Shim-pack Arata LC columns deliver unmatched peak shape, rapid equilibration, seamless method transfer and excellent reproducibility for both small molecule and peptide analyses under challenging acidic conditions. Their deployment can streamline routine QC, bioanalytical assays and research workflows by improving data quality, reducing solvent waste and accelerating turnaround times.