The Analysis Of Organic Carbon
May 10th, 2008 | by Muneeb Akhtar |
Introduction
All Organic Carbon (TOC) is a rapid method that analyzes for organic carbon and expresses the result as the amount of carbon found.It is not the suitable method specially with it it can not be detected the presences of organic carbons in a compound . Organic carbon analyzers operate by the determination of the amount of total carbon present in a sample aliquot. Total carbon consists of inorganic and organic carbon. The inorganic carbon, present as carbonate or bicarbonate ions, must be removed or quantified prior to the analysis of organic carbon.
Discussion
The process and the method used to remove inorganic carbon relies on acidification that converts all bicarbonate and carbonate ions to carbon dioxide that is then purged out of the sample using an inert gas. If the quantity of the inorganic carbons is desired it is purged into a detector, otherwise, it is vented to atmosphere. Once the inorganic carbon is removed the remaining organic carbon is oxidized to carbon dioxide that is purged by the inert gas into the detector.
Carbon Measurement Techniques
In about 1630 a Flemish scientist, Jan Baptista van Helmont found that when wood is burn a gas is produced which is known as carbon dioxide . He also discovered that air in which we breath is a combination of gases. In 1756, Joseph Black, performed many experiments and showed that carbon dioxide occurred in natural air and could be created from other compounds. In his research on magnesium carbonates Black invented the analytical balance and used it to measure carbon dioxide by Loss on Ignition (LOI). The LOI test, where samples are heated and reduction in mass is measured, is the first quantitative test for carbon.
Conclusion
Total Organic Carbon (TOC) analysis is an attempt to measure carbon contained in organic molecules and report results as a single value. The value obtained is dependent upon the oxidation technique and no single oxidation technique is adequate for every purpose. While high temperature catalytic oxidation (HTCO) seems better, the smaller sample volumes introduce sampling error. The slightly lower oxidation efficiency of chemical methods is offset by the ability to digest fairly large sample volumes. Thus, when HTCO and chemical oxidation results are compared, even though HTCO results trend higher than chemical oxidation the results always seem to lie within each others experimental error.For an analyzer it is must that he should take proper amount of chemicals for studies or analysis.But these organic carbon compounds exists in lower concentration studies .
If, however, they exist at lower concentrations then partial recovery is better than no detection at all and a chemical oxidation method should be used. Other factors such as catalyst fouling, blanks, and so forth also need to be considered
