The syringe filter is a pre-filter membrane added before the normal filter membrane, which serves to protect the microporous filter membrane. The filter membranes are made of chemically inert materials and are resistant to most solvents. The membrane's rigidity and large specific surface area structure provide a small retention capacity and low resistance, so the syringe filter can maintain a high throughput even when processing difficult to filter samples.
It is suitable for the filtration of small quantities of samples in the laboratory. It has a low adsorption to the sample, thus ensuring the maximum recovery of small quantities or high value samples. The filter housing is made of polypropylene, ultrasonically welded and adhesive-free, thus not contaminating the sample. Syringe filters are good for protecting the column and chromatographic system from contamination, and can also improve the sensitivity and accuracy of analytical results. They are widely used in drug analysis, food testing, environmental monitoring, protein removal and sterility testing.
The syringe filter consists of a graduated syringe and a filter head, which contains filter membranes with different characteristics and can be selected according to the experimental requirements. Today, HAWACH will discuss the five main type of filter membranes used in syringe filter.
Mixed cellulose ester syringe filters are naturally hydrophilic and are used for aqueous solvent filtration, for particle filtration removal, biochemical analysis filtration (protein retention) and are particularly suitable for aqueous sample preparation and solvent filtration for HPLC.
PES syringe filters are specially designed filtration units for the filtration of media, culture solutions, serum solutions, nutrient solutions, growth hormones and other solutions requiring special handling in the laboratory. These filters have been certified for bacterial filtration capacity, residual volume, and protein recovery. Another application for polyethersulfone (PES) syringe filters is the filtration of mobile phases and samples in ion chromatography.
Nylon syringe filters are used in a wide range of analytical processes. Nylon filters are suitable for the filtration of aqueous and organic solvents, e.g. for sample preparation in liquid phase and gas chromatography. They are characterised by high throughput, low solubility and good mechanical strength. The good physical properties of nylon can meet the needs of a wide range of testing conditions.
PVDF syringe filters have a much lower protein binding rate than MCE, PTFE and other membranes and are particularly suitable for filtration and decontamination of biological samples with low resistance and high filtration speed. It is compatible with a wide range of organic solvents, has good oxidation and heat resistance and is suitable for filtration of most media. It’s widely used in gas and vapour filtration, high temperature liquid filtration, tissue culture media, additives and other sterilisation filtration, solvent and chemical material purification filtration.
PTFE is a chemically stable filter membrane for filtering organic solvents, gases, and strong acid and alkaline solutions. It’s widely used in chemical, pharmaceutical, environmental protection, electronics, food, energy and other fields, it can filter almost all organic solutions.
Syringe filters are very versatile and can be used in many areas, liquid and gas phase sample preparation; environmental testing; routine QC testing; removal of protein precipitates; dissolution assays and many more. Whether it is for storage or for access, be sure to pay attention to bagged and sealed storage, and ensure that gloves and tools are clean when accessing them; cross contamination is a difficult, difficult thing to address.