Use of an internal reference in13C chemical shift measurements
作者:
D. G. de Kowalewski,
C. de Los Santos,
E. Marceca,
期刊:
Magnetic Resonance in Chemistry
(WILEY Available online 1990)
卷期:
Volume 28,
issue 1
页码: 1-4
ISSN:0749-1581
年代: 1990
DOI:10.1002/mrc.1260280102
出版商: John Wiley&Sons, Ltd.
关键词: Internal reference;13C chemical shift measurement
数据来源: WILEY
摘要:
AbstractThe use of the nominal value of the chemical shift of the solvent to calibrate the spectrometer in13C NMR spectroscopy was found to introduce errors due to the effect which the solute has on the solvent. In addition, hexamethyldisiloxane (HM) is proposed as an internal standard; owing to its high boiling point it is easier to manipulate than tetramethylsilane (TMS) and it is therefore possible to prepare solutions of known concentrations. In order to convert the data obtained with this standard to the TMS scale, the chemical shift of HM was determined in 16 solvents using cyclohexane as external standard in a spherical cell (5% w/w concentration of HM) as a function of the solvent factorg2. Comparing these results with a similar plot obtained previously for TMS by other workers, it is possible to convert one type of data to the other by a simple linear expression.
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