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

NMR Spectrometers: Resolution and Error Correction01:14

NMR Spectrometers: Resolution and Error Correction

When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
Aliasing01:18

Aliasing

Accurate signal sampling and reconstruction are crucial in various signal-processing applications. A time-domain signal's spectrum can be revealed using its Fourier transform. When this signal is sampled at a specific frequency, it results in multiple scaled replicas of the original spectrum in the frequency domain. The spacing of these replicas is determined by the sampling frequency.
If the sampling frequency is below the Nyquist rate, these replicas overlap, preventing the original signal...
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations01:08

IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations

Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single stretching vibration...
¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
¹³C NMR: ¹H–¹³C Decoupling01:04

¹³C NMR: ¹H–¹³C Decoupling

The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
IR Frequency Region: X–H Stretching01:24

IR Frequency Region: X–H Stretching

In IR spectroscopy, signals produced by the X−H bonds (such as C−H, O−H, or N−H) can be observed in the frequency range of  2700–4000 cm–1. The C−H stretching vibration forms sharp bands in the region 2850–3000 cm–1. The presence of the O−H stretching vibration leads to the forming of an absorption band in the frequency range 3650–3200 cm−1. At the same time, N−H stretching can be confirmed by absorption bands in the 3500–3100 cm−1 range. Even though both O−H and N−H bonds vibrate at a similar...

You might also read

Related Articles

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

Sort by
Same author

Novel Dual Soft Drug Strategy Enables Development of Topical Androgen Receptor Antagonists with Enhanced Efficacy and Optimized Safety for Androgenetic Alopecia.

Journal of medicinal chemistry·2026
Same author

Decoupling Adsorption and Dissociation of Sulfur on Single-Atom Alloys for Robust CO/CO<sub>2</sub> Methanation.

Small (Weinheim an der Bergstrasse, Germany)·2026
Same author

Structure-Guided Discovery of Neuroprotective Kromycin-Type Macrolides from <i>Streptomyces narbonensis</i> sp.

Journal of natural products·2026
Same author

Development and validation of LC-MS/MS methods for the quantification of TMS-007, a member of the SMTP congeners, in rat plasma and brain: application to a preclinical pharmacokinetic study.

Analytical methods : advancing methods and applications·2026
Same author

Expression and function of miR-218-5p in the pathogenesis of postpartum depression.

Psychiatric genetics·2026
Same author

New nonacyclic duclauxin derivatives with potent anti-influenza activities from Antarctic fungus Penicillium sp. CPCC 401065.

Bioorganic chemistry·2026

Related Experiment Video

Updated: Jun 19, 2026

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements
08:54

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements

Published on: May 1, 2017

Tailoring noise frequency spectrum to improve NIR determinations.

Shaofei Xie1, Bingren Xiang, Liyan Yu

  • 1Center for Instrumental Analysis, China Pharmaceutical University, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing, China.

Talanta
|October 20, 2009
PubMed
Summary

A new chemometric method improves near-infrared spectroscopy (NIR) analysis by modifying noise frequencies. This technique enhances quantitative determination of low-concentration samples, overcoming limitations of standard filtering methods.

More Related Videos

Using MazeSuite and Functional Near Infrared Spectroscopy to Study Learning in Spatial Navigation
20:12

Using MazeSuite and Functional Near Infrared Spectroscopy to Study Learning in Spatial Navigation

Published on: October 8, 2011

Related Experiment Videos

Last Updated: Jun 19, 2026

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements
08:54

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements

Published on: May 1, 2017

Using MazeSuite and Functional Near Infrared Spectroscopy to Study Learning in Spatial Navigation
20:12

Using MazeSuite and Functional Near Infrared Spectroscopy to Study Learning in Spatial Navigation

Published on: October 8, 2011

Area of Science:

  • Analytical Chemistry
  • Spectroscopy
  • Chemometrics

Background:

  • Near-infrared spectroscopy (NIR) suffers from high background noise and weak signals due to overtones and combinations.
  • This noise complicates quantitative analysis, especially for samples with low analyte concentrations.
  • Conventional filtering methods, like single or consecutive Savitzky-Golay filters, offer limited improvement for NIR data.

Purpose of the Study:

  • To develop a novel chemometric approach to enhance NIR spectral data quality.
  • To improve the accuracy of quantitative determinations for low-concentration samples in NIR spectroscopy.
  • To address the limitations of existing filtering techniques in handling NIR spectral noise.

Main Methods:

  • A chemometric method involving multiplication of a Savitzky-Golay filtered NIR spectrum with a reference spectrum containing thermal noise.
  • This multiplication is performed before applying a second Savitzky-Golay filter.
  • The technique modifies the noise frequency spectrum, shifting it towards higher frequencies for improved filtering.

Main Results:

  • The proposed multiplication-based noise modification significantly improves NIR spectral data quality compared to standard filtering.
  • The second Savitzky-Golay filter effectively removes the shifted noise components, leading to better signal-to-noise ratio.
  • Validation using simulated and measured NIR datasets confirmed the effectiveness of the technique for quantitative analysis.

Conclusions:

  • The developed noise frequency spectrum tailoring technique offers a substantial improvement for NIR determinations.
  • This method is particularly beneficial for applications requiring precise quantitative analysis of low-concentration samples.
  • The approach is expected to find widespread adoption in challenging quantitative NIR spectroscopy applications.