My total organic carbon (TOC) results do not compare well with the results from an outside lab, what can I do?

Document ID

Document ID TE399

Published Date

Published Date 27/05/2017
Question
My total organic carbon (TOC) results do not compare well with the results from an outside lab, what can I do?
Summary
Hach Total Organic Carbon and outside lab results do not match
Answer
TOC results from an outside lab that uses an analysis method such as UV persulfate can differ from the Hach method for a couple of reasons. The UV persulfate method is often less efficient at digesting compounds than the colorimetric method and therefore can give lower results. Particles can also cause discrepancies, because the particles often settle out by the time the sample is measured at outside labs. When samples are first filtered before being split and sent to an outside lab, results tend to agree much more closely.