16 May 2011

Fluorescence Spectroscopy


THEORETICAL CONSIDERATION
1. Molecular fluorescence is the optical emanation from molecules with the intention of be inflicted with been excited to privileged energy levels by captivation of electromagnetic radiation.
2.The foremost benefit of fluorescence detection compared to captivation measurements is the greater sensitivity
Achievable since the fluorescence indicate has in opinion a zip background.
3. Analytical applications include a) quantitative measurements of molecules in solution and 2) fluorescence Detection in liquid chromatography.
Transitions linking molecular electronic energy levels:

Instrumentation
A predictable fluorimeter contains an excitation source, sample cell, fluorescence detector.
Molecules in solution are ordinarily excited by uv light and the excitation source is ordinarily a deuterium or xenon lamp. Broad-band excitation light from a lamp passes through a monochromator, which passes single a selected wavelength. The fluorescence is single by a further monochromator and detected by a photomultiplier tube. Scanning the excitation monochromator gives the excitation spectrum and scanning the fluorescence monochromator gives the fluorescence spectrum. Simple instruments now and again aid single a bandpass filter to excellent the excitation wavelength.

fluorometer schematic












Single-molecule fluorescence spectroscopy in (bio)catalysis



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