Question

A. Sketch an instrument for fluorescence spectroscopy (block diagram). Be sure to label the different parts of the instrument and use the most common geometry for this instrument. B. Explain why the instrument has two wavelength selectors. C. Explain why the instrument you sketched will not work for UV/VIS absorption measurements.

Answer 1

Answers

A) Instrument for fluorescence spectroscopy is spectrofluorometer .it also called fluorescence spectrometer or photoluminescence spectrometer.

Block Diagram of fluorescence spectrometer Light intensity detecton Source Excitation monochromato on Beam Seperator Sample Emissions monochromatog Photo multiplied tube Detector

In fluorescence spectroscopy a beam with wavelength between 180-800 nm pass through a sample solution in a cuvette. we measure the emitted light from the sample.

B)  In fluorescence spectrometer there are 2 wavelength selectors. one is for the excitation beam and other is for emission beam.

C) fluorescence spectrometer will not work for uv/visible absorption measurements.it has mainly 2 reasons.

1. uv/vis absorbance use light in uv range (10-400nm) and measure how much light of given wavelength pass through the sample.

in fluorescence spectrometer wavelength of light used to excite molecule and then measure for fluorescence at a longer wavelength.

2. light detector in absorbance spectroscopy is in line with light path and sample.

in fluorescence spectrometer light source and detector are in 900 to each other with respect to sample.