TOC is measured in a Rock-Eval 6 analyser of Vinci Technologies.

Sample preparation: The sample (approximately 40g) is crushed in a mortar and sieved in a 50 mesh (250μm) sieve. After that it is placed for 12 hours in an oven at 40^o C. 50 – 70 mg of dried sample is placed in a RE6 crucible. First the sample is pyrolised (300^oC for 2 minutes and then temperature increase with a rate of 25^oC/min until 650^oC) and then oxidized (from 300^oC until 850^oC with a rate of 20^oC/min and remaining time in 850^oC for 5min). Rock-Eval 6 is calibrated with “IFP 160000” calibration standard of Vinci Technologies (IFP 160000 standard’s TOC= 3.28% (+-0.14)). Alternatively TOC determination is conducted using LECO analyser. Requires sample pre-treatment to remove carbonates. It is accomplished by treating a pre-weighted amount of sample with concentrated HCl (10% vol.) at 80oC, followed by distilled water washing to remove water soluble salts (chlorides) and remaining HCl.