> ## Documentation Index
> Fetch the complete documentation index at: https://docs.adaptyvbio.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Capillary Electrophoresis (CE)

> Capillary electrophoresis for quantitative analysis of protein expression, purity, and heterogeneity

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

<CardGroup cols={2}>
  <Card title="Expression Quantification" icon="chart-bar">
    Estimate expression titer from crude lysates or purified material via calibrated peak areas.
  </Card>

  <Card title="Purity & Aggregation" icon="circle-check">
    Resolve monomer, fragments, and aggregates to quantify product quality.
  </Card>

  <Card title="Charge Variant Profiling" icon="flask">
    Characterize acidic/basic variants and batch-to-batch heterogeneity (cIEF).
  </Card>

  <Card title="Rapid Variant Screening" icon="gauge">
    Compare expression outcomes across constructs, hosts, or conditions.
  </Card>
</CardGroup>

## 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.