The stable carbon isotope compositions of tetrols, erythritol and threitol were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Using four tetrols with various delta(13)C values derivatized by methylboronic acid, the carbon isotope analysis method achieved excellent reproducibility and high accuracy. There was no carbon isotopic fractionation during the ...

Swart, P.K., 1983. Carbon and oxygen isotope fractionation in scleractinian corals: a review. Earth-Sci. Rev., 19: 51-80. The present theories on the fractionation of stable isotopes in scleractinian corals are critically discussed in the light of data available on primary productivity, respiration and stable isotope chemistry. These data support a model of fractionation in which the carbon and...

RATIONALE Isotope analysis of wood is an important tool in dendrochronology and ecophysiology. Prior to mass spectrometry analysis, wood must be homogenized, and a convenient method involves a ball mill capable of milling samples directly in sample tubes. However, sample-tube plastic can contaminate wood during milling, which could lead to biological misinterpretations. METHODS We tested poss...

The synthesis of a unique isotope engineered system, double-wall carbon nanotubes with natural carbon outer and highly 13C enriched inner walls, is reported from isotope enriched fullerenes encapsulated in single-wall carbon nanotubes (SWCNTs). The material allows the observation of the D line of the highly defect-free inner tubes that can be related to a curvature induced enhancement of the el...

The origin of the carbon atoms in CO2 respired by leaves in the dark of several plant species has been studied using 13C/12C stable isotopes. This study was conducted using an open gas exchange system for isotope labeling that was coupled to an elemental analyzer and further linked to an isotope ratio mass spectrometer (EA-IRMS) or coupled to a gas chromatography-combustion-isotope ratio mass s...

Chlorinated ethenes are among the most frequently detected groundwater contaminants in industrially developed countries. Although their degradation pathways have been understood, assessing the progress of natural attenuation of chlorinated ethenes still remains a challenge. Chlorinated ethenes undergo sequential reductive dechlorination under anoxic conditions; hence, the presence of less chlor...

Detailed carbon isotope records have water enriched in i•C into the deep North Atlantic been obtained from benthic foraminifera in the during glacial periods alters the carbon isotopic North Atlantic (CHN 82 Sta 24 Core 4PC, 42øN, 32øW, signal of Atlantic cores relative to the global 3427 m, 244 kyr) and central equatorial Pacific mean [Streeter and Shackleton, 1979; Duplessy et (KNR 73 Sta 4 C...

285 The global carbon cycle is the biogeochemical engine at the heart of acid–base and redox processes in the oceans and atmosphere. It constitutes the most fundamental way in which the biosphere shapes the chemistry of our planet. Studying the behaviour of the carbon cycle during times past, however, presents unique challenges. On geological timescales, the CO2 emitted from volcanoes and the w...

The paper describes a novel approach to investigating Wilms' tumour (nephroblastoma) biology at the atomic level. Isotope Ratio Mass Spectrometry (IRMS) was used to directly assess the isotope ratios of nitrogen and carbon in 84 Wilms' tumour tissue samples from 28 cases representing the histological spectrum of nephroblastoma. Marked differences in nitrogen and carbon isotope ratios were found...

The determination of compound-specific stable isotope ratios is a promising new tool to assess biodegradation of organic compounds in groundwater. In this study, the occurrence of carbon isotope fractionation during dechlorination of tetrachloroethene (PCE) to ethene was evaluated in a PCE-contaminated aquifer and in a microcosm that was based on aquifer material from the site. In the microcosm...