Related Experiment Video
Updated: Jun 28, 2026
05:16
UV-Vis Spectroscopic Characterization of Nanomaterials in Aqueous Media
Published on: October 25, 2021
Kinetic analysis of second order reactions using UV-VIS spectroscopy
1Lehrstuhl für Allgemeine Chemie und Biochemie der Technischen Universität München, D-8050 Freising-Weihenstephan, Germany.
Talanta
|October 1, 1992
Summary
A novel spectroscopic kinetic analysis method simplifies complex reactions with multiple concentration variables. This technique successfully analyzes reaction systems without needing absorption coefficients, using only time-dependent data and initial concentrations.
Area of Science:
- Chemical Kinetics
- Spectroscopic Analysis
- Reaction Mechanism Studies
Background:
- Traditional kinetic analysis often struggles with reactions involving multiple independent concentration variables.
- Accurate determination of reaction parameters typically requires knowledge of species absorption coefficients.
Purpose of the Study:
- To introduce and validate a new spectroscopic kinetic analysis method for complex reaction systems.
- To demonstrate the method's applicability to reactions with two linearly independent concentration variables.
Main Methods:
- Development of a novel theoretical framework for spectroscopic kinetic analysis.
- Application of 'formal integration' and 'singular value decomposition' (SVD) for data evaluation.
- Utilized time-dependent spectroscopic measurements and initial concentrations.
Main Results:
- The new method provides satisfactory results for analyzing complex reaction systems.
- Demonstrated successful application to model reactions: A + Bk --> C + D and A + E --> F + G.
- Eliminated the need for absorption coefficients of reacting species during analysis.
Conclusions:
- The developed spectroscopic method offers a robust approach for kinetic analysis of complex reactions.
- The technique is efficient, requiring only time-dependent spectroscopic data and initial concentrations.
- This advancement simplifies the study of multi-step reaction mechanisms.
Related Concept Videos
01:02Ultraviolet and Visible (UV–Vis) Spectroscopy: Overview
Ultraviolet–visible (UV–visible or UV–Vis) spectroscopy is an analytical technique that investigates the interaction between matter and UV–Vis light within the electromagnetic spectrum. This method is widely used for its versatility, simplicity, and relatively quick data acquisition, making it valuable for both qualitative and quantitative analysis. When UV–Vis radiation passes through a material, molecules absorb light depending on the energy required for electronic transitions. As a result...
01:14UV–Vis Spectrometers
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell. Samples for...
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:09UV–Vis Spectroscopy: Beer–Lambert Law
The Beer-Lambert law describes the relationship between absorbance and concentration, which combines the principles established by scientists Johann Heinrich Lambert and August Beer. Lambert's law states that when light passes through a medium, the loss in intensity is directly proportional to the original intensity and the path length of the light. Beer's law proposed that the transmittance of a solution remains constant if the product of concentration and path length is constant. The modern...
01:30UV–Vis Spectrum
When light passes through a substance, a portion of the light is absorbed while the remaining light is reflected or transmitted. If the molecule absorbs light between the wavelengths of 180–400 nm range, the UV spectrum is obtained, and if it absorbs light in the 400–780 nm wavelength range, the visible spectrum is obtained.
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
01:29UV–Vis Spectroscopy: Woodward–Fieser Rules
UV–Visible absorption spectra of conjugated dienes arise from the lowest energy π → π* transitions. The light-absorbing part of the molecule is called the chromophore, and the substituents directly attached to the chromophore are called auxochromes. A strong correlation exists between the absorption maxima, λmax, and the structure of a conjugated π system. The Woodward–Fieser rules predict the value of λmax for a given structure by adding the contributions...