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SPECTROFLUORIMETRY

INSTRUMENTATION

Trainer: Chandramouli R

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A generalized Spectrophotometry

consists of:

Source of radiation

A sample cell

PhotodetectorRead out device

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A generalized Fluorimeter/

Spectrofluorimeterconsists of: Source of radiation

A primary filter / excitation Monochromator

A sample cell

A secondary filter / emission Monochromator

Photodetector

Read out device

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FILTER FLUORIMETER

Secondary filterPrimary filter

AbsorbsVisible

radiation

and

transmits

UV

radiation

AbsorbsUV

radiation

and

transmits

Visible

radiation

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SPECTRO FLUORIMETER

Secondary / Emission

Monochromator

Primary / Excitation

Monochromator

Provides a

suitable

radiation for

excitation of

molecule

Isolates only

the radiation

emitted by the

fluorescent

molecule

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BLOCK DIAGRAM

Source of

lightPrimary filter /

MonochromatorSAMPLE Secondary filter /

Monochromator

DETECTOREmitted

radiation

from source

Specific

wavelength

of radiation

Resultant

luminescence

Radiation

emitted by the

fluorescent

molecule

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Flourimeter over Filter

Flourimeter

Spectroflourimeter can measure the

spectral distribution of Flourescenceemission (emission spectrum)

And

the variation in emission spectral radiancewith excitation wavelength (excitationspectrum)

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INSTRUMENTATION

Source of radiation

A primary filter / excitation monochromator

A sample cell A secondary filter / emission monochromator

Detectors

Read out device

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INSTRUMENTATION

Source of radiation

A primary filter / excitation monochromator

A sample cell A secondary filter / emission monochromator

Detectors

Read out device

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Source of light

Source of light should emit a radiation

over a continuous region and be of

adequate intensity and stability Mercury vapour lamp Xenon arc lamp

Tungsten lamp

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INSTRUMENTATION

Source of radiation

A primary filter / excitation monochromator

A sample cell A secondary filter / emission monochromator

Photodetector

Read out device

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Filters and Monochromators

Primary filter/Monochromator selects specificbands or wavelengths of radiation from the sourceand directs them through the sample in the samplecell

Secondary filter/Monochromator Resultantluminescence from primary filter/monochromator isisolated by the secondary filter or emissionmonochromator and directed to the photodetector

which measures the power of the emitted radiation.

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INSTRUMENTATION

Source of radiation

A primary filter / excitation monochromator

A sample cell A secondary filter / emission monochromator

Detectors

Read out device

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Sample cells

Cylindrical /Quadrangular in shape Path length 10mm or 1cm

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amp e ce s con

Types :1. Right angle method (90)

2. Frontal method (37)

3. Rotating cell method

sample

Monochromatic excitation light90

sample

Monochromatic excitation light

37

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Detectors

Photovoltaic cell Phototubes Photomultiplier tubes BEST &

ACCURATE

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PHOTOVOLTAIC CELL /

BARRIER LAYER CELL

A Steel support (positive contact)

B SeleniumSemiconductor layer

C Metallic Layer coated

with silver or gold

D Negative contact

E Metallic spray coating to

protect from corrosion

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PHOTO TUBES / PHOTO

EMISSIVE CELLS

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PHOTO MULTIPLIER TUBE

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PHOTO MULTIPLIER TUBE