Isotopes cellulose

Raw ingredients and cooked recipes were analyzed for stable isotopes of carbon (Abonyi 1993). To our knowledge, no one has determined if there are differences in the stable isotope values of raw and cooked foods, however Hastorf and DeNiro (1985) did compare plant remains that were heated to those that had not been heated. They found no significant difference in isotope values due to heating. Marino and DeNiro (1987) studied the effects ofheating (boiling and roasting) on several types of plants to determine if cellulose... 

Marino, B.D. and DeNiro, M.J. 1987 Isotopic analysis of archaeobotanicals to reconstruct past climates Effects of activities associated with food preparation on carbon, hydrogen and oxygen isotope ratios of plant cellulose. Journal of Archaeological Science 14 537-548. 

Marino, B.D. and McElroy, M.B. 1991 Isotopic composition of atmospheric COj inferred from carbon in C, plant cellulose. Nature 349 127-131. 

Ramesh, R., Bhattacharya, S.K. and Gopalan, K. 1986 Stable isotope systematics in tree cellulose as palaeoenvironmental indicators—a review. Journal of the Geological Society of India 27 154-167. 

Stuiver, M. and Braziunas, T.F. 1987 Tree cellulose C/ C isotope ratios and climatic change. Nature 328 58-60. 

Epstein, S., Thompson, P. and Yapp, C. J. 1977 Oxygen and hydrogen isotopic ratios in plant cellulose. Science 198 1209-1215. 

Sternberg, L.O., DeNiro, M.J. and Johnson, H.B. 1984 Isotope ratios of cellulose from plants having different photosynthetic pathways. Plant Physiology 74 557-561. 

Saurer M, I Robertson, R Siegwolf, M Leuenberger (1998) Oxygen isotope analysis of cellulose an interlaboratory comparison. Anal Chem 70 2074-2080. 

Non-quantitative sample preparation, e.g., conversion to C02 provides two opportunities for bias. First, if the sample is a pure substance, such as methane or cellulose, isotopic fractionation can take place. Correction, using the stable isotope ratio 13C/12C, is possible provided the initial 13C concentration is... 

For more than 80 years, tree-ring data have been used to make inferences about past climatic variation. In general, the characteristic most often used has been the variations in widths of the annual growth rings. However, during the past decade other properties, such as cell density (measured by x-ray densiometric techniques), relative widths of early and late wood, and isotopic composition of the cellulose have been used to infer past environmental conditions. It is the isotopic composition that is of interest here. 

Epstein and Yapp [4] state "it is obviously necessary to calibrate more specifically the relationship between 6(D) records in cellulose nitrate from tree-ring records and known climatic records. This can probably be done best by the analysis of tree rings from widely different, well-documented environments. Such data will allow the comparison of a large variety of trees and determine the versatility of using the isotopic method for climatic temperature determination". We concur with this statement as long as "from the same population" is inserted. 

But isotope fractionation at climatic temperatures is a function of the frequencies of the chemical bonds [16]. We quote from Herzberg [19] as follows "One would expect the -C-H bond to have essentially the same electronic structure and therefore the same force constant in different molecules, and similarly for other bonds. This is indeed observed". For the -C-H bonds the vibrational frequencies in lignin and in cellulose are almost equal, but in fact differ by 6 percent [19] because cellulose is a multiple alcohol (H-C-0-H)n and lignin is a polymer containing... 

The carbon-carbon bond linkage In cellulose Is 1.541 A and in the aromatic groups of lignin is 1.395 A, a difference of 10 percent [20]. Therefore the presence of lignin, containing 75 percent carbon [18] of which 60 percent is aromatic, may affect the carbon isotope ratio by 10% x 75% x 60% x 25%, or about 1 percent, by variation from its average concentration of 25 percent. 

The component typically analyzed in plants is cellulose, which is the major structural carbohydrate in plants (Epstein et al. 1976, 1977). Cellulose contains 70% carbon-bound hydrogen, which is isotopically non-exchangeable and 30% of exchangeable hydrogen in the form of hydroxyl groups (Epstein et al. 1976 Yapp and Epstein 1982). The hydroxyl-hydrogen readily exchanges with the enviromnen-tal water and its D/H ratio is not a useful indicator of the D/H ratio of the water used by the plants. 

DeNiro MJ, Epstein S (1979) Relationship between the oxygen isotope ratios of terrestrial plant cellulose, carbon dioxide and water. Science 204 51-53 DeNiro MJ, Epstein S (1981) Isotopic composition of cellulose from aquatic organisms. Geochim Cosmochim Acta 45 1885-1894... 

Epstein S, Yapp CJ, Hall JH (1976) The determination of the D/H ratio of non-exchangeable hydrogen in cellulose extracted from aquatic and land plants. Earth Planet Sci Lett 30 241-251 Epstein S, Thompson P, Yapp CJ (1977) Oxygen and hydrogen isotopic ratios in plant cellulose. Science 198 1209-1215... 

To broaden the scope of his interests, he spent another year as a postdoctoral fellow in the Physics Department of Pennsylvania State University, working on the X-ray analysis of biological compounds. Equipped with an exceptionally broad and multidisciplinary education and experience, he proceeded to The Ohio State University, Columbus, Ohio, to work with Professor M. L. Wolfrom. His initial job was to investigate the ignition of cellulose nitrate, a project left over from World War II. In Fred s hands, this project was turned into an isotopic investigation of the biosynthesis and degradation of cellulose. At this time, there was very little known about the preparation of specifically labeled sugars, let alone the biosynthesis of... 

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