Organic carbon measurement

Ogura and Hanya [62-65] investigated the components of the ultraviolet absorption in an attempt to devise a useful method for oceanic dissolved organic carbon measurements. They concluded that while the method might have limited application in coastal waters, most of the absorption in oceanic waters was due to the inorganic components, principally nitrate and bromide ions. 

A separate and independent injection loop dispenses the sample for non-purgeable organic carbon measurements. 

Unattended operation possible, loop-sampler option autosampler printer, option inorganic, carbon, purgeable carbon, total carbon and total organic carbon measurements possible... 

This is a fully automated system capable of determining between lpg L 1 and 300pg L 1 total organic carbon. It is equipped with a 36-place autosampler, microprocessor and printer. Total organic carbon measurements down to 40pg L 1 have been achieved at a coefficient of variation of 16.3%. 

Fig. 12.2Apparatus layout and flow diagram for dissolved organic carbon measurement Source Reproduced with permission from Blackwell Science Publishers Ltd [39]... 

The problems associated with sampling particulate organic C in the atmosphere crudely parallel those with sampling nitrates. However, the very large number of carbonaceous species, the range of vapor pressures involved, and the ubiquitous nature of carbon severely complicate development of improved sampling techniques based on total (or organic) carbon measurements. 

The sum of EC and OM contributes another 20-27% (at urban sites) and 18-24% (rural) to the PM mass, with OM dominating EC at most sites. Like in the case of SIA, differences between rural and urban sites appear modest which is probably caused by a considerable natural (biogenic) input. A study by ten Brink et al. [13] on the presence of 14C in PM filter samples revealed that at least 64% of the organic carbon measured at an urban Dutch site was contemporary (i.e. emissions from biogenic material and biomass wood combustion). 

Xu, B., T. Yao, X. Liu, and N. Wang. 2006. Elemental and organic carbon measurements with a two-step heating-gas chromatography system in snow samples from the Tibetan Plateau. Ann. Glaciol. 43 257-262. 

COMPARATIVE DIGESTION EFFICIENCIES (% SAMPLE DECOMPOSITION) AS DETERMINED BY RESIDUAL TOC-TOTAL ORGANIC CARBON MEASUREMENTS... 

The concentrations of reactive organic carbon for the model were 20% of the total organic carbon measured in the cores. This percentage was... 

Aqueous organic carbon analyzers helped revolutionize humic studies during the last decade. Not only could organic carbon measurements be made quickly and accurately on any water sample, but organic carbon analysis, used as a monitoring detector like conductivity and fluorescence, opened a new dimension in experimental design and approaches. In conjunction with other methods, the amount and distribution of humic substances in water in relation to other carbon-containing compounds could be determined. 

Kuster, W. C., Jobson, B. T., Karl, T., Riemer, D., Apel, E., Goldan, P. D., and Fehsenfeld, F. C., Intercomparison of volatile organic carbon measurement techniques and data at La Porte during the TexAQS2000 Air QuaUty Study, Environ. Sci. TechnoL, 38, 221-228, 2004. 

The amount of initial organic carbon then is the sum of the preserved organic carbon (measured as TOC) and the metabolized organic carbon (determined from the sulfur content with stoichiometric correction for the sulfate reduction process). Furthermore, the diffusive loss has to be taken into account. With a... 

Fig. 1. Carbon isotopic values of coexisting carbonate and organic carbon measured in bulk samples of Phanerozoic and Precambrian sedimentary rocks, for the Precambrian represented by data from 100 fossiliferous cherts and shales shown as average values for groups of samples from 50-Ma-long intervals (Strauss and Moore, 1992).

Fig. 2. Carbon isotopic values (with error bars) of individual Precambrian microfossils from single stratigraphic horizons of three geologic units measured by ion microprobe mass spectrometry compared with those of the carbonate and total organic carbon measured in bulk samples of the same geologic units. Values plotted for carbonate and total organic carbon are from Strauss and Moore (1992) for microfossils from the Bitter Springs and Gunflint Formations, from House et al (2000) and those for microfossils from the Dresser Formation, from Ueno et al. (2001).

G. Visco, F. Bellanti, L. Campanella, T. Mazzella, and V. Nobili. Optimization of a photochemical sensor for total organic carbon measurement. Ann. Chim., 95(3—4) 185-198, 2005. 

The herbicide bentazon (3-isopropyl-2,l,3-benzo-thiadiazin-4-one-2,2-dioxide) is efficiently converted to give near quantitative yield of sulphur as sulphate ion and carbon as carbon dioxide dissolved and particulate organic carbon measurements also support nearly complete mineralization [35]. 

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