The membrane filters produced by the Spanish Teknokroma company feature good quality, high purity and excellent batch-to-batch reproducibility. In the range of products offered by the company there can also be found syringe filters as well as membrane filters used in the analytical practice and they are recommended for sample and chromatographic eluent filtration, as well.
Syringe filters
In the polypropylene house of the syringe filters a membrane filter with 13 or 25 mm is fitted. For an easy identification, the type of the membrane is indicated by the color of the plastic filter body. Conventional glass (with luer plug) or plastic syringes can be fitted to the filters. The Teknokroma syringe filters are available in resealable plastic boxes, 100 pieces/box.
Low-volume syringe filters
For the filtration of the sample volumes of less than 1 ml, the use of low-volume syringe filters are recommended. In the polypropylene house a 4 mm (Nylon, PTFE, PVDF) membrane filter is fitted. A conventional glass (with luer plug) or plastic syringe can be fitted to the filter.
Membrane types and their characteristics:
Nylon 66
- hydrophilic membrane
- filtration rate: fast
- strong protein binding capacity
- solvent compatibility: “weak” organic solvents (alcohols, acetonitrile), aqueous solutions, base solutions, THF
- not recommended for: strong acids, halogenated hydrocarbons
- use: for general filtration and filtration of HPLC and dissolution samples
PTFE (poly(tetrafluoroethylene))
- hydrophobic membrane
- filtration rate: medium
- low dissolution, best solvent resistance
- solvent compatibility: “strong” organic solvents, strong acids, strong alkalis, chlorinated hydrocarbons
- not recommended for: aqueous solutions
- use: for organic solvents, general filtration and filtration of HPLC samples
M. E. Cellulose (mixed cellulose ester, nitrate and acetate)
- hydrophilic membrane
- filtration rate: medium
- solvent compatibility: aqueous solutions, ”weak” base solutions, hydrocarbons
- not recommended for: ”strong” organic solvents, strong acids, strong bases
- used for the filtration of aqueous solutions, biological samples and HPLC and dissolution samples
PVDF (poly(vinylidene fluoride))
- hydrophilic membrane
- filtration rate: medium
- low dissolution
- weak protein binding capacity
- solvent compatibility: aqueous and organic solutions, weak base solutions, hydrocarbons, halogenated hydrocarbons
- not recommended for: strong acids, strong bases, ketones, ethers
- used for the filtration of aqueous solutions, proteins, peptides, biological samples, HPLC and dissolution samples
| Code | Pore size[μm] | Diameter[mm] | Color |
| Membrane: Nylon 66 | |||
| TR-200100 | 0.45 | 25 | green |
| TR-200101 | 0.20 | 25 | light green |
| TR-200500 | 0.45 | 13 | green |
| TR-200501 | 0.20 | 13 | light green |
| Membrane: PTFE | |||
| TR-200102 | 0.45 | 25 | blue |
| TR-200103 | 0.20 | 25 | light blue |
| TR-200502 | 0.45 | 13 | blue |
| TR-200503 | 0.20 | 13 | light blue |
| Membrane: M. E. Cellulose | |||
| TR-200104 | 0.45 | 25 | yellow |
| TR-200105 | 0.20 | 25 | light yellow |
| TR-200504 | 0.45 | 13 | yellow |
| TR-200505 | 0.20 | 13 | light yellow |
| Membrane: PVDF | |||
| TR-200106 | 0.45 | 25 | red |
| TR-200107 | 0.20 | 25 | light red |
| TR-200506 | 0.45 | 13 | red |
| TR-200507 | 0.20 | 13 | light red |
