CESI 8000 Plus High Performance Separation-ESI Module

Significance of the Topic

High-performance separation of charged and polar molecules is essential in metabolomics, proteomics and biopharmaceutical analysis. Integrating capillary electrophoresis (CE) with electrospray ionization (ESI) enhances sensitivity, resolution and depth of characterization while minimizing sample consumption. The CESI 8000 Plus module represents a key technological advance for laboratories seeking to expand the analytical reach of mass spectrometry (MS).

Study Objectives and Overview

This application note introduces the CESI 8000 Plus High Performance Separation-ESI Module and demonstrates its capability to:

• Enable high-resolution separation of polar metabolites, peptides, proteoforms and intact protein complexes.
• Consume minute sample volumes (≤50 nL per injection) with extraordinary sensitivity.
• Eliminate ion suppression bias and increase proteome/metabolome coverage.
• Accelerate throughput via multi-segment injection (MSI), achieving up to 10× faster sample analysis.

Methodology and Used Instrumentation

The CESI 8000 Plus couples low-flow CE separation with a proprietary OptiMS sprayer for ESI within a single cartridge.

• Separation flows: 10–350 nL/min, generating ultra-fine electrospray under ~1.25 kV.
• OptiMS cartridges: bare fused silica or neutral hydrophilic capillaries (30 µm ID × 90 cm).
• Sample introduction: nanoVials (validated at 5 µL, demonstrated at 1 µL).
• Detection modes: CESI-MS with connectivity to SCIEX, Thermo, Bruker, Waters and other MS platforms; stand-alone CE with UV/VIS, PDA or LIF detectors.
• Software: intuitive pre-loaded methods, visual guidance for sample loading and real-time tracking of injections.

Main Results and Discussion

Performance benchmarks and application examples include:

• Intact protein separation: 100-fold sample reduction and superior resolution compared to LC for high-mass analytes.
• Proteoform analysis: high-quality spectra of monoclonal antibodies (200 fmol) revealing primary sequence, glycosylation and PTMs.
• Metabolomic profiling: cesium increased peptide identifications from 100 ng yeast mitochondrial extracts and baseline separation of sugar‐phosphate isomers such as citrate/isocitrate.
• MSI throughput: sequential injections separated by 60 s background electrolyte allow multiple analyses from <1 µL total sample.

Benefits and Practical Applications

The CESI 8000 Plus delivers:

• Ultra-low sample consumption ideal for limited or precious materials (subcellular fractions, needle biopsies, CTCs, FFPE).
• Enhanced sensitivity and reduced ion suppression, improving detection of low‐abundance species.
• High-resolution separation of chiral compounds and isobaric PTMs, facilitating detailed biochemical studies.
• Modular connectivity for seamless switching between CE-MS, nanoLC-MS and stand-alone CE assays.
• Robust, plug-and-spray design with minimal equilibration and carry-over, suitable for routine QA/QC and research workflows.

Future Trends and Applications

Emerging developments and potential uses include:

• Integration with high-throughput proteomics and metabolomics pipelines driven by AI-based data analysis.
• Expanded use in biosimilarity assessment and biopharma QC for complex biologics and ADCs.
• Advanced chiral separations leveraging CE front ends for cost-effective enantiomeric purity testing.
• Coupling with novel detectors and real-time feedback control to further enhance separation performance.
• Miniaturization and microfluidic integration for point-of-care and field applications.

Conclusion

The CESI 8000 Plus High Performance Separation-ESI Module advances CE-MS technology by combining ultra-low flow, high resolution and ease of use. It facilitates deeper characterization of small molecules, peptides and proteins with minimal sample input and high throughput, making it an indispensable tool for modern analytical and biopharmaceutical laboratories.

Reference

1. Kelly RT, Page JS, Zhao R, Qian W, Mottaz HM, Tang K, Smith RD. Anal. Chem. 2008, 80, 143–149.
2. Schmidt A, Karas M, Dulks T. J. Am. Soc. Mass Spectrom. 2003, 14, 492–500.