Capillary Gel Electrophoresis

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Capillary Gel Electrophoresis

Method Introduction

Capillary gel electrophoresis (cGE) is a high-resolution and automated variation of the SDS-PAGE technique. SDS-PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis) is a technique used to separate proteins based on their molecular weight. It works by denaturing proteins with SDS, which coats them with a negative charge and unfolds them, allowing them to be separated in a gel under an electric field. The separation is primarily based on size, with smaller proteins migrating faster through the gel. In general, electrophoresis is a separation technique based on the migration of charged molecules in response to an electric field toward the electrode of opposite charge. It is performed mainly in polyacrylamide gels. In cGE, the gel is located inside a capillary through which the sample components must migrate. The larger the molecular weight, the longer the migration time. A detection system, mainly UV or fluorescence detection, detects and quantifies the migrating species. Molecular weight is determined in reference to a standard.

Applications

Capillary gel electrophoresis (cGE) allows for the qualitative and quantitative analysis of the molecular weight of protein aggregates and fragments.

Compared to conventional SDS-PAGE, cGE allows for much higher resolution, faster sample analysis, and a lower detection limit. Moreover, automation makes cGE attractive during formulation development, stability studies, and forced degradation studies.

If required, we can update SDS-PAGE to cGE for our customers.

Quality and Biosafety Level

We provide all our analytical services with the highest quality standards. Experienced scientists carry out each project, and a scientific reviewer comprehensively checks every report or data presentation.

We offer this technology with the following quality and biosafety levels:

R&D level

We offer this method under R&D. Our GRP system assures the highest-quality research standards.

Up to biosafety level 1

This method can be applied to proteins, nucleic acids, and most viral vectors, including AAVs and more.

Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis and Capillary Gel Electrophoresis Frequently Asked Questions (FAQs)

  • Capillary gel electrophoresis is a high-resolution, automated technique that separates biomolecules—such as proteins and fragments—based on size. It is an advanced alternative to traditional SDS-PAGE, with faster run times, lower sample volumes, and higher detection sensitivity. 

  • While both techniques separate proteins based on size using polyacrylamide gels and SDS, cGE is performed within a capillary rather than a slab gel. This allows for automation, higher resolution, better reproducibility, and more efficient quantification—especially useful in high-throughput or regulated environments. 

  • SDS-PAGE (Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis) is a widely used protein separation method that denatures proteins and separates them by molecular weight. It’s commonly used in protein purity checks, expression analysis, and comparative studies across many stages of biopharmaceutical development. 

  • cGE is ideal when higher resolution, automation, or precise quantification is required—especially for formulation development, forced degradation, or stability studies. SDS-PAGE is preferred for routine visual assessment or when cost-effectiveness is a primary concern. 

  • Yes. Coriolis Pharma offers both SDS-PAGE and cGE as part of its analytical services. We can upgrade your analytical method from SDS-PAGE to cGE if needed to enhance resolution and reproducibility. 

  • cGE is suitable for proteins, peptides, fragments, and protein aggregates. It can also be applied to some nucleic acids and viral vector components under biosafety level 1 (BSL-1) conditions. 

  • cGE enables precise detection and quantification of protein degradation products and aggregates, making it ideal for comparing formulation conditions, tracking stability over time, and performing stress testing under ICH guidelines. 

  • Capillary gel electrophoresis typically uses UV or fluorescence-based detection to monitor the migration of protein species through the capillary and calculate their molecular weight in reference to standards. 

  • Yes. One of the major advantages of cGE is the minimal sample volume required. This is particularly beneficial when working with high-value or limited-quantity biopharmaceutical products. 

Analytical Method Development, Qualification and Validation

For common sample types, we can often apply standardized methods with little setup effort. However, when needed, our experienced analytical experts create or optimize custom methods tailored to your active pharmaceutical ingredient, product type and development phase.

Method Development

Our method development approach tailors sample preparation, method settings and data analysis to the needs of your project and sample.

We include representative samples and, where available, suitable reference standards and stressed/degraded materials, allowing our analytical scientists to design a highly suitable, stability-indicating, robust and repeatable method. Upon request, we will compile a detailed description of the method for your records.

Method Qualification

Method qualification is the initial assessment of an analytical procedure’s performance to show its suitability for its intended purpose.

During method qualification, our analytical scientists perform documented testing demonstrating that the analytical procedure meets criteria in several categories. Criteria may include factors such as repeatability, specificity and robustness. We compile a qualification plan and report, including all relevant data.

Method Validation

Under GMP conditions, method validation confirms that an analytical procedure’s performance suits its intended purpose. Depending on the method’s scope, a broad range of method characteristics, such as specificity, accuracy, precision, limit of detection/limit of quantification (LOD/LOQ), linearity and range, is considered.

During method validation, our analytical scientists perform documented testing demonstrating that the analytical procedure consistently produces a result that meets the predetermined acceptance criteria. We compile a validation plan and report that includes all relevant data.

Depending on the development phase, a fit-for-purpose validation approach can be offered, adjusting the validation required efforts in a phase-appropriate way to meet the method’s needs.

Method Verification

Compendial method verification confirms that a compendial method (e.g., from Ph. Eur. or USP) is suitable and reliable for its intended purpose under the specific conditions of the laboratory.

Unlike full method validation, compendial method verification is often considered a partial validation since the method has already undergone extensive testing and validation during its inclusion in the compendium. The extent of method verification depends on the type of method.

During method verification, our analytical scientists perform documented testing demonstrating that the developed analytical method performs adequately for the specific product or matrix being tested and within the specific laboratory where the method will be employed.

Talk to Our Experts or Request a Quote

Our expert team is ready to answer your questions and guide you to the services best suited to your program’s modality, stage and challenge. If your needs are well-defined, we’ll begin the quotation process.

Description

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Aggregate analytics – Overview Analytical ultracentrifugation (SV-AUC / SE-AUC) Asymmetrical flow field-flow fractionation (AF4) Capillary gel electrophoresis (cGE) Dynamic light scattering (DLS) High-performance size-exclusion chromatography (HP-SEC) Hollow fiber flow field-flow fractionation (HF5) Liquid chromatography coupled mass spectrometry (LC-MS) Nephelometry/Turbidity SDS-PAGE Ultra-high-performance size-exclusion chromatography (UP-SEC)