chemical shift


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chem·i·cal shift

dependence of the resonance frequency of a nucleus on the chemical binding of the atom or molecule in which it is contained. See: chemical shift artifact.

chemical shift

An MRI term for a variation in the nominal Larmor frequency for a particular isotope within the imaging volume. The amount of chemical shift is directly proportional to the strength of the magnetic field, and is specified in parts per million of the resonant frequency.
References in periodicals archive ?
TABLE 1; [sup.1]H NMR chemical shift ([delta]) data of pyrimethanil, HP/[beta]/CD, and pyrimethanil/HP-[beta]-CD inclusion complex.
The 1D NMR data of 2 (Table 1), recorded in DMSO-[d.sub.6], showed a signal for the conjugated carbonyl carbon (C-4) at a chemical shift lower than that of compound 1 ([[delta].sub.C] 173.7), which is suggestion for the absence of the sugar moiety at C-3.
Chemical shifts at 1.4~1.6 (peak c and peak d), 2.4 (peak b), and 4.1 ppm (peak e) can be assigned to the signal of independent methylene protons, carbonyl group adjacent to methylene protons, and oxygen atoms in acyloxy group adjacent to methylene protons in PCL unit, respectively.
1H chemical shifts were expressed in ppm relative to the solvent shift as chemical standard.
Meanwhile, two peaks at 4.14 ppm and 3.66 ppm chemical shift, representing lactate and ethanol respectively, were observed in the co-cultures.
The accuracy of soft tissue dimensional measurement can be affected by chemical shift resulting from fat and adipose tissue.
[49, 50] using perfluoroalkyl iodide involved in a halogen bonding system where secondary iodide invariably was found to give larger change in the F chemical shift than a primary iodide.
Table 3: [DELTA]i value of -[CH.sub.2] increased by the substituent group (X or Y) in X-[CH.sub.2]-Y Substituent group [DELTA]i Substituent group [DELTA]i -[CH.sub.3] 0.47 -CO-OR 1.55 -COR 17 -OCO-R 3.13 -Br 2 33 -[C.sub.6][H.sub.5] 1.85 -OR 2.36 where 0.23 is the basic number of -[CH.sub.2] protons, and [DELTA]i is the protonational chemical shift increase of -[CH.sub.2] protons.
The [sup.31]P NMR spectra of the other NaOH-EDTA soil extracts, which consist of four pairs of control and P-treated soils, contain signals in four diagnostic chemical shift regions, orthophosphate (6.5-5.3 ppm), orthophosphate monesters (5.3-2.6 ppm), orthophosphate diesters (2.0 to -1.0 ppm), and pyrophosphate (-4.5 to -5.5 ppm) (Fig.
They showed that the anumeric proton for [alpha]-naphthol glucoside has a chemical shift of [[delta].sub.H] 5.41 and [beta]-naphthol glucoside [[delta].sub.H] 5.18.
The spectra of original and ionoactivated ash samples exhibit broad resonance in the chemical shift range from -80 to -110 ppm.