Polyethylene is probably the most used plastic material in daily life and its accurate analysis is of importance. In this communication the chemical structure of polyethylenes is studied in detail using conventional analytical pyrolysis (Py-GC/MS), bulk stable isotopic analysis (IRMS) and pyrolysis compound specific stable isotopic analysis (Py-CSIA) to measure stable isotope proportions (δ(13)...

Since the early days of geochemical isotope ratio mass spectrometry there has always been the problem of cross contamination, i.e. the contamination of the sample gas with traces of reference gas (and vice versa) in a dual inlet system and the analyzer itself. This was attributable to valve leakages and could be corrected for. In modern leak-free machines this problem still influences the measu...

Compound-specific isotope analysis (CSIA) by isotope ratio mass spectrometry (IRMS) following on-line combustion (C) of compounds separated by gas chromatography (GC) is a relatively young analytical method. Due to its ability to measure isotope distribution at natural abundance level with great accuracy and high precision, GC-C-IRMS has increasingly become the method of choice in authenticity ...

Weanalysed CN red system (∼8000 Å) andC2 Swan system (∼4700 Å) to know carbon isotope ratios (12C/13C) for carbon stars in the Galactic halo, named CH stars. The isotope ratios are obtained for 6 CH stars by the curve-of-growth analysis of the isolated 12CN and 13CN lines. In this analysis, we compared directly 12CN and 13CN lines of similar intensities (iso-intensity method), and the resulting...

We analyzed the C i lines associated with the damped Lyα system observed at zabs = 1.15 in the spectrum of HE 0515–4414 to derive the C/C ratio. The spectrum was obtained by means of the UV-Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT). The obtained lower limit C/C > 80 (2σ C.L.) shows for the first time that the abundance of C in the extragalactic intervening clouds ...