Capillary electrophoresis (CE) provides high-resolution, label-free quantification of protein expression and purity in small volumes. We use CE (including CE-SDS and cIEF modes) to quantify expression levels, detect fragmentation/aggregation, and assess charge variants.

​
How It Works

Proteins are separated in a narrow capillary under an electric field by size (CE-SDS, denaturing) or by isoelectric point (cIEF, native-like). Eluting species are detected by on-capillary UV absorbance (typically 214/280 nm). Peak area is proportional to protein mass, enabling titer and purity quantification against standards.

​
Applications

Expression Quantification

Estimate expression titer from crude lysates or purified material via calibrated peak areas.

Purity & Aggregation

Resolve monomer, fragments, and aggregates to quantify product quality.

Charge Variant Profiling

Characterize acidic/basic variants and batch-to-batch heterogeneity (cIEF).

Rapid Variant Screening

Compare expression outcomes across constructs, hosts, or conditions.

​
Performance & Notes

  • Linear quant range with appropriate standards; low-µg/mL sensitivity in CE-SDS.
  • Compatible with small sample volumes (≤10–20 µL); moderate throughput.
  • Denaturing CE-SDS reports size distribution; cIEF reports charge isoforms.
  • Detergents/salts should match method; sample cleanup may be required for crude matrices.

​
Integration

CE complements split-GFP and dye-based assays by providing orthogonal, high-resolution quantification and quality attributes (purity, fragments, charge variants) in protein expression workflows.