1.1 Methods
Note:
1. The photometric determination of Suspended Solids is based on a gravimetric method.
In a lab this is usually done by evaporation of the filter residue of a filtrated water
sample in an oven at 103°C – 105°C and weighing of the dried residue.
2. When higher accuracy is required perform a gravimetric determination of a water
sample. The result can be used to calibrate the photometer with the same water sample.
3. The estimated detection limit is 20 mg/L TSS.
4. Collect water samples in clean plastic or glass bottles and analyse the water sample as
soon as possible. It is possible to store the sample at 4°C for 7 days. Before measurement
warm up the sample to the temperature at collection time.
5. Interferences:
• Air bubbles interfere and can be removed by swirling the vial gently.
• Colour interferes if light is absorbed at 660 nm.
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