High levels of TOC and inorganic carbon are detected in our lab distilled water. After disinfection of the system, I need to monitor the levels and wonder if the GCMS would be a practical tool.
GCMS against an internal Standard might be a reasonable way to detect TOC if all of your C compounds are volatile and the inorganics can be converted to e.g CO2 somehow (Neutralisation or oxidation).
You Need to convert the inorganic carbon to CO2 or some other form for detection by e.g. acidification or oxidation.
The main problem with GC is if the compounds are non-volatile (and therefore not visible on the GC). If you do an LCMS on a concentrated contaminated sample and you can identify the components you can find out if they "fly" on the GCMS. Carboxylic acids and amines tend to be problematic without derivatisation and are often not seen. Compounds of MW of upto ca 500-700 can often be seen higher MW compounds usually not).
If you have a high carbon Content, the classic way to do a sample like this is to burn everything completely to CO2, water and N2 and run a microanalysis but the carbon Levels are probably too low to do this.
Thanks for all the answers, everyone. It looks like a difficult problem without an automatic carbon analyzer. One of the professors has a Shimadzu 5050 or something like that. but I would have to wait for them to do a run for themselves.
many of the old toc analysers used a persulfate oxidation and quantitation of the resultant CO2 via IR
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