TSS and VSS: Filters standardisation

  An accurate measure of the Suspended Solid requires a careful standardisation of the filters that was performed as follows:

• preventive three cycles of washing and drying in oven at 90 °C
• three cycles of drying at 105 °C and overnight in desiccator
• after each cycle, weighting by analytical (0.01 mg sensitivity) balance

  A 10% of outlier filters (exceeding an established SD on successive weighting) were individuated and eliminated