When performing oil-in-water testing two parameters are distinguished:
Total Petroleum Hydrocarbon (TPH) is defined as all matter that is extractable from an acidified sample by an cyclic aliphatic hydrocarbon. The extracted sample is filtrated over Florisil® (synthetic magnesium silicate) to remove all polar substances (e.g. vegetable oils). Total Oil and Grease (TOG) on the other hand still contains all polar substances because the sample is directly measured after the extraction without a filtration step.
This filtration step can be performed by a lab technician using manually prepared clean-up column filled with Florisil.
The ERACHECK series offers the possibility to automatize this filtration step by using cartridges that are plugged into the inlet of the analyzer. The sample is now filtrated automatically before it is pumped into the measurement cell.