Yes, it is possible to measure COD in solid samples...For this purpose a modification of the open reflux method is described in the literature: oxidant at high concentration (1.2 N) and volume (20 mL) and titrimetric end-point...For more information, please contact me privately...

The open reflux method (standard methods) is suitable for sludge samples.

Maybe, this paper can help you:

Determination of chemical oxygen demand in heterogeneous solid or semisolid samples using a novel method combining solid dilutions as a preparation step followed by optimized closed reflux and colorimetric measurement.

http://www.ncbi.nlm.nih.gov/pubmed/22762259

Or also this discussion in Linkedin:

https://www.linkedin.com/groups/COD-analysis-in-solid-material-1962574.S.89864148

Nicolas

I have one query to you. We are doing the COD for sea water samples of conductivity in the rage of 50 to 70, 000 micro Siemen by hack method(Closed reflux). I put mercuric sulfate to reduce the interference by chloride. Even the results are much varying. Do you have some comments?

Thank you Mohammad for attaching the article we published in Analytical Chemistry about the solid dilutions method. After some years working with the classical method, thought for waters, with high uncertainty results, now with solid dilutions we obtain narrow confidence intervals. We are proud of this development work and I recommend try it.

can someone write us here, a step-by-step method of determining COD of solid (powder)?