Glass Fibre Filters
Multi-range pH testing
Indicator strips for fast pH measurement across multiple ranges, including universal and comparator papers
Johnson Test Papers glass fibre filters are prepared from 100% borosilicate glass microfibres. They are chemically resistant towards most organic and inorganic solvents (except HF) as well as high strength acids and alkaline solutions. Glass microfibre filters can also resist temperatures up to 500°C. They find uses where extremely fine filtration and high loading capacities are essential.
| Grade | Whatman Equivalent |
Speed | Thickness (mm) | Retension Rate (%) | Weight (g/m2) | Filtration Speed (Sec) | Air Permeability | Max Operating Temperature (oC) |
|---|---|---|---|---|---|---|---|---|
| 50A + | GFA | Fast, High Load | 0.29 | 99.993 | 56 | 19 | 33 | 500 |
| 50B + | GFB | Medium - Fast, Very High Load | 1 | 99.993 | 140 | 44 | 11 | 500 |
| 50C + | GFC | Medium - Fast, Very High Load | 0.28 | 99.995 | 54 | 25 | 54 | 500 |