Instrumentation of Fluorimetry & MCQs
INSTRUMENTATION
OF Fluorimetry
1.
Source of light:
In Fluorimetry there
are mainly three types of lamps are used
A.
Mercury vapour lamp :-
At high pressure
Mercury lamp give 350 nm to 734 nm region radiation.
At low pressure
Mercury vapour give addition line at 254 nm is used as source in filter type of
Fluorimetry.
B.
Xenon arc lamp :- It give a more
intensity radiation when compared to Mercury lamp.
C.
Tungsten lamp :- when molecule
are excited in visible region tungsten lamp are used.
2.
Filter and monochromator
In Fluorimetry there
are mainly two filter are present
1.
Primary filter :– absorbed visible
radiation and transmit uv radiation.
2.
Secondary filter :– absorbed uv
radiation and transmit visible radiation.
Mainly
two monochromator are used in flourimetry.
1.
Excitation monochromator :–
provide a suitable radiation for excited of molecule.
2.
Emission monochromator :–
Isolates only the radiation emitted by the flourescent molecule.
3.
Sample cell : sample cell are
cylindrical or quadrangular shape. The cell are made up of colour corrected
fused glass and pathlength is normally 10 mm or 1 cm.
4.
Detector :-
Mainly photovoltaic
cell, Photo multiplier tubes , Photo tube are used as detector.
Photo multiplier tubes
are the best and accurate.
5.
Instruments
- A. Single beam fluorimeter
- B. Double beam fluorimeter
- C. Spectroflourimeter
Here we discussed
Double beam Fluorimetry
Working
of double beam Fluorimetry:-
- The excitation radiation which
are produced by the 150W xenon lamp are chopped by the radiation fall on
excitation monochromator.
- A sector mirror is present
after the exit slit of excitation monochromator.
- During first rotation of
chopper, sector mirror reflect the beam to reference cell. During second
rotation of the chopper sector mirror open and radiation fall on sample
cell.
- Generally the radiation emitted
from the sample cell and reference cell are focused one after the
other on the entrance slit of emission monochromator or from front surface
mirror.
- Reference and sample beam are
focused on photomultiplier tube by passing through exit slit of emission
monochromator.
- Thus, the signal from
photomultiplier tube is measured in a photometer and recorder using
suitable readout system.
MCQ
1.
When molecules are excited in visible region which lamp is used ?
A. Hydrogen deturium
lamp
B. Xenon lamp
C. Tangustan lamp
C. Mercury lamp
Ans.
B
2.
Which filter are absorbed UV radiation and transmit visible radiation ?
A. Primary filter
B. Secondary filter
C. A and B
D. None of this
Ans.
B
3.
Which filter are absorbed visible radiation and transmit UV radiation ?
A. Primary filter
B. Secondary filter
C. A and B
D. All of the above
Ans.
A
4.
At low pressure Mercury lamp liner radiation wavelength is ?
A. 254 nm
B. 700 nm
C. 800 nm
D. 600 nm
Ans.
A
5.
Sample cell shape is
A. Cylindrical
B. Quadrangular
C. A and B
D. None of this
Ans.
C
6.
How many mm path length is sample cell ?
A. 10 mm
B. 20 mm
C. 30 mm
D. 40 mm
Ans.A
7.
During first rotation of chopper radiation beam is transmit through ?
A. Sample cell
B. Reference cell
C. A and B
D. None of this
Ans.
B
8.
During second rotation of chopper radiation beam is transmit through ?
A. Sample cell
B. Reference cell
C. A and B
D. None of this
Ans.
A
9.
Which detector are used in Fluorimetry?.
A. Photo voltaic cell
B. PMT
C. Photo tube
D. All of the above
Ans.
D
10.
Which are the varient of Fluorimetry instrument ?
A. Single beam
B. Double beam
C. Spectroflourimeter
D. All of the above
Ans.
D