What Are Filter Tips?
Filter tips are pipette tips that incorporate a filter within them. They are designed to prevent the liquid or vapor of the sample from entering the pipette body during aspiration, thereby preventing cross-contamination between different samples. The filters, typically made of polyethylene, are hydrophobic, allowing air but not liquids to pass through.
Applications of Filter Tips
Filter tips are essential when handling samples that could contaminate the pipette or in assays susceptible to cross-contamination, such as those involving radioisotopes or DNA and RNA for PCR assays. They are particularly useful for working with volatile, radioactive, corrosive materials, and biohazards like pathogenic microorganisms or genetically modified organisms.
Features of Filter Tips
The filters in filter tips are usually made from materials like high-density polyethylene, hydrophobic polypropylene, or ultra-high molecular weight polyethylene, among others. These filters are effective at preventing over-aspiration of liquid into the pipette body and stopping aerosols from entering the tip cone. Filter tips can be self-sealing to block liquids upon contact or non-self-sealing, both types aiding in preventing cross-contamination.
Choosing the Right Filter Tip
- Purpose of Use: Determine the specific application for the filter tip, considering factors like sample concentration, analysis, purification, or particle removal.
- Nature of the Sample: Choose based on the sample’s physical properties, such as whether it’s a liquid or gas, its viscosity, and its pH level.
- Material: The material of the filter tip, which commonly includes polypropylene, cellulose, PTFE (Teflon), and nylon, should be compatible with the sample.
- Size and Pore Size: Ensure the filter tip and the filter’s pore sizes are appropriate for the size of the particles or molecules in the sample.
- Flow Rate and Throughput: Select based on the required sample flow rate and throughput, with larger throughput needs necessitating larger tips.
- Maintenance and Cost Efficiency: Consider the ease of cleaning, replacing, and the overall cost-effectiveness, balancing the performance against the budget.
- Regulation and Safety: Ensure compliance with safety and quality standards relevant to the specific industry or application.