Hydrophilic PTFE syringe filter

Welch's syringe filters are designed for high quality and ease of use, offering excellent value for performance. Available in a variety of filter membrane materials and sizes, and custom configurations can also be made to meet specific customer requirements. Manufactured in a cleanroom environment, these filters ensure good batch-to-batch consistency. They are commonly used for sample preparation in HPLC/GC applications and quality control in industrial and laboratory settings.

Additionally, Welch offers sterile syringe filters with medical-grade polypropylene housings. These filters are injection-molded in a single-use design, offering high pressure resistance and sterilized by gamma radiation. They are free from DNases, RNases, pyrogens, and endotoxins, and come in easy-tear paper-plastic individual packaging.

Membrane Material Selection Guide

Nylon:

• Broad chemical compatibility, high mechanical and tensile strength.
• Ideal for a wide range of general laboratory applications.
• Since nylon binds protein, it is not recommended when high protein recovery is required.

PTFE:

• Excellent chemical resistance and inertness. 
• Commonly applicable for filtering biological samples, corrosive chemicals, and strong acids and bases. 
• Comes in hydrophobic and hydrophilic variants.

PVDF:

• Comes in hydrophobic and hydrophilic variants. 
• High chemical stability and thermal stability (~140 ℃). 
• Widely used in the production of biological drugs and vaccines for the purification and filtration of drugs.

CA:

• Ideally suited for biological analysis and aqueous solutions that require maximum protein recovery.
• Suitable for capturing and culturing microorganisms in water.
• High thermal stability (up to 180 ℃) and flow rate.
• Limited resistance to solvents and can degrade under acid or basic conditions.

GF:

• Good mechanical strength.
• Highly durable.
• Features large pore sizes, ideal for high particulate particles.
• Less effective for filtering fine particles.

PES:

• Fine chemical stability and thermal stability. Suitable for biomedical and pharmaceutical settings.
• Primarily used on mid-polar liquids and organic solvents.

MCE:

• Best for capturing and culturing microoranisms in the water and waste water industry.

PP:

• Commonly used for general laboratory filtration where high chemical resistance is not critical.

RC:

• Perfect choice for biomolecule solutions and other dissolved substances.

Filter Size Selection Guide

It is generally recommended to use a 13mm diameter syringe filter for sample volumes between 2-10 µL, a 25mm diameter filter for sample volumes between 11-100 µL, and a 33mm diameter filter for volumes exceeding 100 µL.

For samples that are more turbid or contain some particulate matter, pre-filter syringe filters are recommended.