Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Proton (¹H) NMR: Chemical Shift01:07

Proton (¹H) NMR: Chemical Shift

Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
Absorption signals of all the protium nuclei in a...
Chemical Shift: Internal References and Solvent Effects01:17

Chemical Shift: Internal References and Solvent Effects

In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)01:20

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
NMR Spectroscopy: Chemical Shift Overview01:15

NMR Spectroscopy: Chemical Shift Overview

The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
For instance, the proton...
¹H NMR Chemical Shift Equivalence: Homotopic and Heterotopic Protons01:03

¹H NMR Chemical Shift Equivalence: Homotopic and Heterotopic Protons

Protons in identical electronic environments within a molecule are chemically equivalent and have the same chemical shift. The replacement test is a useful tool to identify chemical equivalence and predict NMR spectra. A substituent replaces each of the protons being examined and the resulting molecules are compared. If the same molecule is obtained, the protons are equivalent or homotopic. Replacement of any hydrogens in ethane by chlorine yields chloroethane because all six protons are...
NMR and Mass Spectroscopy of Carboxylic Acids01:30

NMR and Mass Spectroscopy of Carboxylic Acids

In ¹H NMR spectroscopy, acidic protons (–COOH) of carboxylic acids are highly deshielded and absorb far downfield, at around 9–12 ppm. The chemical shift value depends on the concentration and solvent used.
While α protons of carboxylic acids absorb at 2–2.5 ppm, β protons absorb further upfield.
Carboxylic acids are easily identified by dissolving them in deuterium oxide, which results in a rapid exchange of the acidic protons with deuterium. This leads to the disappearance of the acidic...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Editorial: The rise of postmortem imaging in forensic radiology and paleoradiology.

Frontiers in radiology·2026
Same author

Attenuating trauma- and cocaine-related intrusions by blocking memory reconsolidation with minocycline: protocol for a transdiagnostic randomized controlled trial.

European journal of psychotraumatology·2026
Same author

The effect of longitudinal loading under weight-bearing conditions on ballistic long bone fracture patterns - an experimental study on porcine femora.

International journal of legal medicine·2026
Same author

Advancing forensic medicine through AI-based injury detection: innovation as the catalyst for forensic 3D avatars and translation as the pathway toward courtroom-grade digital twins.

Forensic science, medicine, and pathology·2026
Same author

Stereotactic rodent-to-human approximation of the mesencephalic cuneiform nucleus to guide deep brain stimulation.

Brain stimulation·2026
Same author

Forensic 3D avatars - AI-assisted injury detection and interactive digital-twin visualization.

Forensic science, medicine, and pathology·2026

Related Experiment Video

Updated: Jun 2, 2026

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery
08:08

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

Published on: May 11, 2011

In Situ pH Determination Using 1H-MRS Acetate Chemical Shift for Noninvasive Postmortem Examinations.

Sabina Frese1,2, Dominic Gascho1,3, Michael J Thali1

  • 1Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland.

NMR in Biomedicine
|June 1, 2026
PubMed
Summary
This summary is machine-generated.

Postmortem magnetic resonance spectroscopy can now determine brain pH noninvasively. This new method using acetate (Ace) in proton magnetic resonance spectroscopy (¹H-MRS) aids forensic investigations.

Keywords:
MRSpostmortemvirtopsyvirtual autopsy

More Related Videos

Metabolomic Analysis of Rat Brain by High Resolution Nuclear Magnetic Resonance Spectroscopy of Tissue Extracts
09:01

Metabolomic Analysis of Rat Brain by High Resolution Nuclear Magnetic Resonance Spectroscopy of Tissue Extracts

Published on: September 21, 2014

Assessing Hepatic Metabolic Changes During Progressive Colonization of Germ-free Mouse by 1H NMR Spectroscopy
07:54

Assessing Hepatic Metabolic Changes During Progressive Colonization of Germ-free Mouse by 1H NMR Spectroscopy

Published on: December 15, 2011

Related Experiment Videos

Last Updated: Jun 2, 2026

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery
08:08

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

Published on: May 11, 2011

Metabolomic Analysis of Rat Brain by High Resolution Nuclear Magnetic Resonance Spectroscopy of Tissue Extracts
09:01

Metabolomic Analysis of Rat Brain by High Resolution Nuclear Magnetic Resonance Spectroscopy of Tissue Extracts

Published on: September 21, 2014

Assessing Hepatic Metabolic Changes During Progressive Colonization of Germ-free Mouse by 1H NMR Spectroscopy
07:54

Assessing Hepatic Metabolic Changes During Progressive Colonization of Germ-free Mouse by 1H NMR Spectroscopy

Published on: December 15, 2011

Area of Science:

  • Forensic Science
  • Biochemistry
  • Medical Imaging

Background:

  • Noninvasive postmortem brain pH determination is crucial for forensic investigations.
  • While temperature assessment is established, pH determination using ¹H-MRS remains underexplored.
  • Brain pH is linked to the cause of death, making its assessment valuable.

Purpose of the Study:

  • To investigate the feasibility of in situ brain pH determination using postmortem ¹H-MRS.
  • To establish a method based on the chemical shift difference between myo-inositol and acetate.
  • To validate the accuracy of the developed method against traditional pH measurements.

Main Methods:

  • Evaluated LCModel-based fitting strategies using simulated postmortem brain ¹H-MRS spectra.
  • Optimized fitting by allowing flexibility in acetate chemical shift determination.
  • Analyzed in situ MRS data from 58 decedents and validated against homogenized tissue samples.

Main Results:

  • Optimal fitting strategy identified by simulations.
  • Robust detection of low postmortem brain pH values achieved.
  • Validated ¹H-MRS derived pH values against homogenized brain tissue samples.

Conclusions:

  • Acetate-based ¹H-MRS is feasible for noninvasive in situ postmortem brain pH assessment.
  • This method shows potential for enhancing forensic investigations.
  • Further research can refine this technique for broader forensic applications.