Accurate Quantitative13C NMR Spectroscopy:  Repeatability over Time of Site-Specific13C Isotope Ratio Determination

2007 ◽  
Vol 79 (21) ◽  
pp. 8266-8269 ◽  
Author(s):  
Elsa Caytan ◽  
Eliot P. Botosoa ◽  
Virginie Silvestre ◽  
Richard J. Robins ◽  
Serge Akoka ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Isotope Ratio ◽  
Ratio Determination ◽  
Quantitative13c Nmr ◽  
Over Time

Improved three‐filament thermal ionization mass spectrometry ion source for isotope ratio determination of two samples

2020 ◽  
Vol 34 (8) ◽  
Author(s):  
Adrian Pacek ◽  
Tomasz Pieńkos ◽  
Maciej Czarnacki ◽  
Stanisław Hałas ◽  
Andrzej Pelc
Keyword(s):  
Mass Spectrometry ◽  
Isotope Ratio ◽  
Thermal Ionization Mass Spectrometry ◽  
Ion Source ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Two Samples ◽  
Ratio Determination ◽  
Thermal Ionization Mass

scholarly journals Isotopic variations of copper at the protein fraction level in neuronal human cells exposed in vitro to uranium

The Analyst ◽  
2019 ◽  
Vol 144 (20) ◽  
pp. 5928-5933 ◽  
Author(s):  
Eduardo Paredes ◽  
Véronique Malard ◽  
Claude Vidaud ◽  
Emilie Avazeri ◽  
Richard Ortega ◽  
...  
Keyword(s):  
Cell Line ◽  
Protein Fraction ◽  
Isotope Ratio ◽  
Human Cells ◽  
Protein Fractions ◽  
Ratio Determination ◽  
Isotopic Variations

Accurate isotope ratio determination was downscaled to the level of metal-containing protein fractions obtained from cell line lysates.

Absolute isotope ratio determination of a natural boron standard

1969 ◽  
Vol 2 (1) ◽  
pp. 15-23 ◽  
Author(s):  
P.J. De Bièvre ◽  
G.H. Debus
Keyword(s):  
Isotope Ratio ◽  
Ratio Determination

Geomedical application of copper isotope ratios: change of δ65Cu in xenograft model of human cancers

2020 ◽  
Author(s):  
Gabriella Kiss ◽  
Enikő Vetlényi ◽  
Lívia Varga ◽  
Ildikó Krencz ◽  
Titanilla Dankó ◽  
...  
Keyword(s):  
Isotope Ratio ◽  
Copper Concentration ◽  
Tumour Growth ◽  
Isotope Ratios ◽  
Tumour Tissue ◽  
Tumour Mass ◽  
Copper Isotope ◽  
Essential Information ◽  
Mass Spectrometric Measurement ◽  
Ratio Determination

<p>In geosciences, high precision isotope ratio determination provides essential information about processes in geological systems. Novel ambitions evolve closer to biological applications. Copper is an essential metal for human body taking part of several cellular processes (e.g. respiratory chain, enzyme function, iron metabolism, elimination of reactive oxygen species, cell signalling pathways etc). However, the disorder of copper homeostasis causes serious diseases like Wilson disease (Cu accumulation in liver caused by genetical disorder) and it could also promote tumour growth by supporting angiogenesis and metastasis formation [Denoyer et al., 2015]. Despite numerous experiments, focusing on copper concentration determination in different tumour tissues (e.g. breast, lung cancer, etc.) hoping to assist in tumour diagnosis, the results are not convincing enough. However, previous studies on hepatocellular cancer and oral squamous cell carcinoma showed that tumour tissue appears to be relatively enriched in <sup>65</sup>Cu compared to normal tissue whereas the δ<sup>65</sup>Cu in blood of tumorous patient decreased according to data obtained from control population [Balter et al., 2015, Lobo et al., 2017]. Our main aim is to elaborate a method to understand better the change in <sup>63</sup>Cu/<sup>65</sup>Cu stable isotope ratio during tumour growth. In this approach, we present our first results on copper isotope ratio determination in a xenograft mouse model. Our model was established in SCID (severe combined immunodeficiency disease) mice by injecting human cancer cells (1x10<sup>7</sup> cells) subcutaneously. After the tumour reached approximately 2-3 cm diameter, the tumour mass was cut it in small, equal pieces and transplanted further into 10 mice increasing the experimental set-up homogeneity. All the animals were sacrificed by cardiac puncture under deep terminal anaesthesia within four weeks. Tumour and organs were removed by ceramic knife then were frozen with liquid nitrogen and stored at -80°C. We measured the copper concentration and δ<sup>65</sup>Cu in the tumour tissue, blood, liver, kidney and brain. A clean laboratory ambience was chosen to perform the sample preparation processes decreasing the environmental contamination. Separation of copper from other biologically essential element (Na, Mg, Fe, Zn) interfering the copper isotope measurement is a serious condition of the preparation [Lauwens et al., 2017]. Effects of sodium (<sup>23</sup>Na<sup>40</sup>Ar<sup>+</sup>) and magnesium (<sup>25</sup>Mg<sup>40</sup>Ar<sup>+</sup>) on copper isotope ratio were solved by choosing not the peak center but the interference-free plateau. Our measurements have been carried out on a Thermo Neptune PLUS multicollector mass spectrometer equipped with 9 moveable Faraday detectors, 3 amplifiers with a resistance of 10<sup>13</sup> Ohm, and 6 amplifiers with a resistance of 10<sup>11</sup> Ohm, in wet plasma conditions. The mass spectrometric measurement of the copper isotope ratio is doped either with Ni or Ga reference material which have a well-known isotope ratios.</p><p> </p><p>References:</p><p>Balter V. et al. PNAS 2015; 112: 982−985.</p><p>Denoyer D. et al. Metallomics 2015; 7: 1459−76.</p><p>Lauwens S. et al. J. Anal. At. Spectrom. 2017; 32: 597−608.</p><p>Lobo L. et al. Talanta 2017; 165: 92−97.</p>

Isotope ratio determination of antimony from the transient signal of trimethylstibine by GC-MC-ICP-MS and GC-ICP-TOF-MS

2003 ◽  
Vol 18 (9) ◽  
pp. 1001 ◽  
Author(s):  
Silvia Wehmeier ◽  
Rob Ellam ◽  
J�rg Feldmann
Keyword(s):  
Isotope Ratio ◽  
Transient Signal ◽  
Icp Ms ◽  
Ratio Determination ◽  
Tof Ms

Inappropriate tail corrections can cause large inaccuracy in isotope ratio determination by MC-ICP-MS

2001 ◽  
Vol 16 (10) ◽  
pp. 1121-1125 ◽  
Author(s):  
Matthew Thirlwall
Keyword(s):  
Isotope Ratio ◽  
Icp Ms ◽  
Ratio Determination
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