The Shimadzu TOC-L with autosampler is capable of five different measurements on filtered samples in solution: Total Carbon (TC), Inorganic Carbon (IC), Total Organic Carbon (TOC) , Non-Purgeable Organic Carbon (NPOC) and TN. The instrument is PC controlled.
TC: Sample is combusted or decomposed to CO2 in a column filled with oxidation catalyst that resides within a furnace heated to 680C. The carrier gas containing the combustion product flows through the IC reaction vessel and is cooled and dried by a dehumidifier. It is then sent into a sample cell set in a non-dispersive infrared gas analyzer.
IC: Sample is introduced into the IC reactor vessel which contains an acidified solution and carrier gas flowing in the form of tiny bubbles. Only the IC component of the sample is decomposed to CO2. IC concentration is then determined using the same procedure as TC concentration described above.
TOC: TOC concentration is determined by subtracting the IC concentration from the TC concentration.
NPOC: Sample is acidified and sparged with high purity air, eliminating the IC component. Sample is then injected onto the column and combusted to CO2.
The CO2 is detected by a non-dispersive infared gas analyzer which outputs a detection signal (analog) which generates a peak. The area of the peak is proportional to the carbon component of the sample and concentration can be calculated by comparing to standard solution.
TN: After thermal decomposition in the furnace, nitrogen is determined with a chemiluminescence detector.
