Choosing the Best Syringe Filters for Biological Sample Filtration

Agilent Captiva Premium PES syringe filters are evaluated and compared to other suppliers’ PES and PVDF syringe filters for the risk of losing protein during filtration. Captiva Premium PES syringe filters demonstrate low protein binding with excellent recovery for biological samples, especially for ‘sticky’ proteins at low concentrations. In addition, an assessment of filter extractables on LC/MS shows that Captiva Premium PES syringe filters provide excellent chemical cleanliness and do not introduce observable chemical contamination through the filtration process. Introduction Filter filtration is a common method for preparing and sterilizing biological samples to remove impurities and micro-organisms. However, using syringe filters could cause loss of significant amounts of biological materials due to unwanted protein binding with the membrane or introduce unexpected interferences to the samples from the syringe filter. Therefore, low protein binding and cleanliness are important features of a syringe filter’s performance. Polyethersulfone (PES) and polyvinylidene fluoride (PVDF) membranes are typically used for biological sample filtration and are claimed to provide very low protein binding. In this study, PES and PVDF membranes were evaluated and compared. A group of common proteins was used for the protein binding evaluations, including BSA, myoglobin, ovalbumin, cytochrome C, and thyroglobulin. After protein samples were filtered through syringe filters, the protein samples were evaluated using HPLC/UV by comparing samples with or without filtration for their monomer, dimer, or aggregates peaks. In addition, syringe filter cleanliness was evaluated by filtering membrane-compatible solutions and monitoring the filtrate with LC/MS under positive and negative modes.