Gravimetric analysis samples require filters to be weighed both before and after sampling to determine the amount of contaminate collected. Zefon match-weighed cassettes eliminate the need of weighing filters before sampling by providing 2 filters which are matched in weight. The top filter collects particulate and the bottom filter serves as a control. After sampling, both filters are weighed and the difference in weight equals the amount of contaminate collected.
Zefon uses the most advanced microbalance equipment and technology available to produce premium quality weighed cassettes. Our process includes manufacturing under strict environmental controls to ensure weight reproducibility and numerous quality checks to ensure consistent weights. The end result is a quality product at a competitive price.
The weight tolerance of match weighed filters references the maximum difference in weight from the test (top) filter and the control (bottom) filter. For example, a stated tolerance of 50μg means that the control filter may differ in weight no more than 50μg from the test filter. This is important to know during post sample weighing as the weight tolerance of the 2 filters needs to be considered when calculating results.
During manufacture, filters with matched weights (within the given tolerance) are inserted into the cassette in random order. Thus, it is possible for the control filter to weigh more than the test filter before sampling (within the given tolerance). If the control filter still weighs more after sampling, a sample likely was not collected. Please check your equipment for proper operation and pump flow.
- Weight matching tolerance: ±20 μg for PVC Filters and ±50 μg for MCE Filters
- Choice of 2 or 3 piece cassette housing
- Available in both 25mm and 37mm diameter cassette housings
- Labels with serial numbers placed on each cassette
- Easy Filter Type Identification:
Red colored band indicates a PVC Filters
Blue colored band indicates MCE Filters
- Preloaded - ready to use
- Leak Free Design