When I try to measure total carbon for instance 100 ppm benzene in water solution I get very low ppm content. Only around 30 ppm.
What could be reason? is there any protocol how to perform TC, or TOC measurement of BTEX compounds in water?
Check TOC analyzer is compatible with 100ppm and also check injection sample properly pass through the Detector.
Dear Patrik Sobolčiak,
TOC of 100 ppm of benzene is 94.7 ppm. Therefore, you must read TOC value around 94.7 ppm for 100 ppm of benzene. Otherwise, there may be a malfunction in the system, a blockage or an error in the calibration line, etc.
TOC analysis of BTEX was reported in this paper, which may guide you.
Article Photochemical Treatment of Benzene, Toluene, Ethylbenzene, a...
King regards
Dear Erdal:
When you measure the TOC of benzene solutions by the so-called "npTOC" method ("non-purgeable TOC") the sample will be stripped subsequently to acidification for TIC removal. During this stripping step, you will also lose a reasonable part of the volatile benzene. This might explain the results lower than expected. For benzene solutions, the "difference method" is working more properly: In a first run, the total carbon is determined in a sample which is not acidified and not stripped prior to measurement of the so-called "total carbon", TC, (the sum of TIC and TOC) after incineration. In the second run, the sample is acidified and stripped, but not incinerated, and only the CO2 content of the stripping gas is measured which represents the TIC ("total inorganic carbon"). The TOC is calculated by subtracting the TIC from the TC (see e.g. https://shimadzu.com.au/sites/default/files/TOC_POC-Determination_News_03_2008_en.pdf). As with all differences, this method is prone to errors when the TOC is small in comparison to the TIC.
I hope, this answer is helpful.
Best regards,
Holger
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