140um Dextran Gel Filtration Fillers TopGF G-25M

140 μm Dextran Gel Filtration Media G-25 M

SHBC TopGF G-25 M is a medium-grade dextran gel filtration medium with a nominal particle size of 140 μm.

It is designed for protein desalting, buffer exchange and removal of salts or other low-molecular-weight substances from antibodies, antigens, enzymes and protein conjugates.

TopGF G-25 M is suitable for immunoassay development, biomolecule preparation and scalable biotechnology production.

TopGF G-25 M Technical Specifications

Size-Exclusion Separation Principle

TopGF G-25 M separates molecules according to their effective molecular size.

Large biomolecules are excluded from most internal pores and pass through the column first. Salts, free dyes and other small molecules enter the pores and elute later.

The target protein does not need to bind to the matrix, allowing rapid group separation and buffer exchange. G-25 media are primarily used for desalting and group separation rather than high-resolution protein fractionation.

Key Advantages of TopGF G-25 M

• Cross-linked dextran matrix

• Nominal 140 μm particle size

• Medium particle-size grade

• Rapid protein desalting

• Efficient buffer exchange

• Removal of low-molecular-weight impurities

• Separation without ligand binding

• Good balance between flow and resolution

• Suitable for laboratory and production columns

• Available for bulk manufacturing supply

Why Choose the 140 μm Medium Grade?

The medium particle grade provides a practical balance between separation efficiency and liquid flow.

Compared with coarse media, TopGF G-25 M may provide:

• Better group-separation resolution

• More uniform packed beds

• Improved separation of proteins from small molecules

• Suitable flow for laboratory and process columns

• Flexible use from development to scale-up

The optimum grade should be selected according to column size, sample volume, required resolution and processing speed.

Immunoassay Manufacturing Applications

Antibody Desalting

TopGF G-25 M can be evaluated for removing salts and small buffer components from antibody preparations.

Typical applications include:

• Desalting after antibody purification

• Removal of ammonium sulfate

• Removal of reducing agents

• Removal of small reaction by-products

• Preparation before antibody conjugation

• Preparation before magnetic-bead coupling

Antibody Buffer Exchange

Antibodies can be transferred into a selected assay, storage or coupling buffer before:

• Epoxy magnetic-bead coupling

• Carboxyl magnetic-bead coupling

• Fluorescent labeling

• Enzyme conjugation

• Biotinylation

• Chemiluminescent reagent preparation

• Immunoassay formulation

Antigen and Protein Preparation

TopGF G-25 M can also be used for:

• Antigen buffer exchange

• Recombinant protein desalting

• Enzyme formulation

• Protein cleanup

• Sample preparation before chromatography

• Removal of low-molecular-weight additives

Removal of Free Labeling Reagents

TopGF G-25 M may be evaluated for separating labeled proteins from smaller unreacted reagents, including:

• Free fluorescent dyes

• Free biotin reagents

• Unreacted NHS esters

• Small coupling reagents

• Reducing agents

• Buffer salts

G-25-type media are commonly used to separate labeled proteins from unreacted low-molecular-weight dyes and to transfer biomolecules into a new buffer.

Application performance should be validated according to the molecular size of the target biomolecule and impurity.

Suitable Samples

TopGF G-25 M can be evaluated with:

• Monoclonal antibodies

• Polyclonal antibodies

• Recombinant proteins

• Diagnostic antigens

• Enzymes

• Protein conjugates

• Labeled antibodies

• Labeled antigens

• Other water-soluble biomolecules

Performance depends on molecular size, sample concentration, viscosity and operating conditions.

General Operating Workflow

1. Hydrate the Medium

Hydrate the dry medium completely using purified water or the selected buffer.

Allow sufficient time for uniform swelling before packing.

2. Prepare the Slurry

Mix the hydrated medium gently to form a uniform slurry.

Avoid excessive air bubbles and particle damage.

3. Pack the Column

Transfer the slurry into a suitable chromatography column and allow the bed to settle evenly.

Avoid cracks, channels and trapped air.

4. Equilibrate the Column

Wash the packed bed with the target buffer until the outlet conditions are stable.

5. Load the Sample

Apply the sample evenly onto the column without disturbing the bed surface.

6. Elute the Biomolecule

Elute with the target buffer. Larger biomolecules normally elute before salts and other small molecules.

7. Collect and Evaluate

Collect the protein-containing fraction and evaluate:

• Protein concentration

• Conductivity

• Recovery

• Buffer composition

• Purity

• Biological activity

• Immunoassay performance

Factors Affecting Desalting Performance

Important factors include:

• Sample volume

• Bed volume

• Column dimensions

• Packed-bed quality

• Flow rate

• Sample viscosity

• Protein concentration

• Molecular-size difference

• Buffer composition

• Fraction collection volume

The sample-to-bed-volume ratio is particularly important for balancing separation efficiency, recovery and sample dilution.

Column Packing Recommendations

For consistent performance:

• Hydrate the medium completely.

• Prepare a uniform slurry.

• Remove trapped air before packing.

• Maintain a level bed surface.

• Avoid excessive bed compression.

• Prevent the packed bed from drying.

• Confirm stable flow before loading samples.

• Inspect the column for cracks or channels.

Process Scale-Up

When transferring the process from laboratory to production, maintain consistent:

• Bed height

• Sample-to-bed-volume ratio

• Linear flow velocity

• Buffer composition

• Sample concentration

• Fraction collection strategy

• Cleaning procedure

• Product acceptance criteria

TopGF G-25 M can be evaluated for batch processing and packed-column purification at different production scales.

TopGF G-25 M vs. TopGF G-25 C

Choose G-25 M when balanced flow and separation efficiency are required. Choose G-25 C when rapid processing and lower flow resistance are the main priorities.

TopGF G-25 M vs. Dialysis

Quality Control for Bulk Production

Recommended evaluation items include:

• Particle-size consistency

• Swelling consistency

• Packed-bed uniformity

• Flow performance

• Desalting efficiency

• Protein recovery

• Conductivity reduction

• Sample dilution

• Lot-to-lot consistency

• Storage stability

Why Choose SHBC TopGF G-25 M?

• Nominal 140 μm medium-grade particles

• Cross-linked dextran matrix

• Designed for desalting and buffer exchange

• Suitable for antibodies, antigens and proteins

• Supports immunoassay reagent development

• Samples available for evaluation

• Stable batch manufacturing

• Bulk packaging options

• Scalable production supply

• Technical support for grade selection

Storage and Handling

Store TopGF G-25 M according to the product label and technical documentation.

Recommended practices:

• Keep unused dry medium tightly sealed.

• Protect from moisture and contamination.

• Use clean water, buffers and equipment.

• Avoid strong mechanical damage to hydrated beads.

• Do not allow the packed column to dry.

• Use a validated storage solution for hydrated media.

• Review the SDS before use.

Frequently Asked Questions

What is TopGF G-25 M?

TopGF G-25 M is a medium-grade cross-linked dextran gel filtration medium used for desalting and buffer exchange.

What is its particle size?

The nominal particle size is 140 μm.

What is the main application?

Its main applications are antibody and protein desalting, buffer exchange and removal of low-molecular-weight substances.

Can it purify antibodies directly?

It can desalt antibodies and replace their buffer. It is not a substitute for affinity chromatography used for selective antibody capture.

Can it be used before magnetic-bead coupling?

Yes. It can be evaluated for transferring antibodies or proteins into a compatible coupling buffer.

Can it remove free fluorescent dyes?

It may remove free dye when the dye is sufficiently smaller than the labeled protein. Each labeling system should be validated.

Can it remove salts from proteins?

Yes. Under suitable column conditions, proteins elute before salts and other small molecules.

Is TopGF G-25 M suitable for high-resolution fractionation?

It is primarily designed for group separation, desalting and buffer exchange rather than analytical protein fractionation.

What is the difference between G-25 M and G-25 C?

G-25 M has smaller particles and typically provides better separation efficiency. G-25 C has larger particles and generally supports faster flow.

Is process optimization required?

Yes. Sample volume, bed volume, flow rate, buffer and fraction collection should be optimized for each application.

Can SHBC supply bulk quantities?

Yes. SHBC supports sample evaluation and bulk supply for research laboratories, immunoassay developers and biotechnology manufacturers.

Request TopGF G-25 M Samples

Contact Shanghai SanYu Biotechnology Co., Ltd. for samples, technical documentation and bulk quotations.

Please provide:

• Target biomolecule

• Current buffer

• Required new buffer

• Sample volume

• Protein concentration

• Column dimensions

• Required processing capacity

• Estimated annual demand

TopGF G-25 M is supplied for research and process development. Customers should validate the medium for their final manufacturing or diagnostic application.