For samples containing particles larger than 50μm, a pre-filtration or homogenization step is required.
For samples containing particles larger than 50μm, a pre-filtration or homogenization step is required. For biochemical oxygen demand (BOD) analysis, a simple pre-filtration step is required. MANTECH has a Sample Filtering Guide for PeCOD® Analysis. For chemical oxygen demand (COD) analysis, no filtering required as we recommend a homogenizer that gets all particles to a 1micron size. MANTECH recommends:
PRO200 Homogenizer with SS Probe – This is our base model and setup can be used within 5ml-50ml tubes with sample piece size of 10mm or less or liquid base sample up to 100ml. (MANTECH part number: PCH-4000-197)
PRO250 Homogenizer with SS Probe – When there is a more viscous/thick or larger solid sample piece over 10mm, our 20mm X 115mm SS Probe would be needed. This homogenizer & probe setup can cover 50ml-500ml tubes/beakers. Other probes can be used with this Homogenizer for even larger volumes. (MANTECH part number: PCH-4000-198)
Homogenization can be automated using the autosampler arm and in our online analyzer.
For pulp and paper and wastewater applications, MANTECH recommends using a 35um polyethylene (PE) syringe filter. These filters can contribute trace amounts of organics, which are negligible for wastewater applications. For drinking and source water applications it’s important to use a filter that does not contribute organics to the filtered sample. One of MANTECH’s research partners has recommended a 0.45um polyether sulfone (PES) filter; however, other filter types may also be acceptable, if no organics are contributed by the filter. Since these applications traditionally see less particulates, having a smaller pore size filter hasn’t shown an impact on the PeCOD® results.
You can check our sample preparation videos using a filtration kit and homogenizer here.