Colorimeter and Flame Photometry Principle and Uses

Colorimeter Principle


In the colorimeter
technique, a particular reagent is utilized which responds with the particular
segment to colorimeter structure shaded complex. In a pencil of light is
permitted to go through a shaded arrangement some measure of light saw to
corresponding to the idea of the arrangement. The convergence of the solute or
shading and the separation of the way of light is known as bear’s law.


     
                     
  A=abc
Where
     
    = Absorbance
     
    = Nature of solution
     
    = Distance of the path of light
     
    = Concentration
The photodetector system,
however, can only measure the transmitted lights. If the scale
of the photometric electrometric colorimeter is in, it should
be first be converted to absorbance before using the value for the calculation
of the concentration of the unknown.

As Beer’s law shows the immediate connection among absorbance and focuses the transmittance perusing is
first changed over to be absorbance scale for setting up the standard bend.

Uses Of Colorimeter

Colorimeter use in
emergency clinics and labs for the estimation of biochemical examples like the
serum, plasma, cerebrospinal liquid, an
d pee. They are additionally utilized by
the nourishment business and assembling of painting and textline organization.
Component Of Photometer

1. Light Source  

This provides radiant
energy. Tungsten lamp is used for the UV range and lower visible.
2. Monochromatic Filter

These systems provide
the desired quality of light by using filters or grits. The latter provides a
narrow spectrum of light. The grits have partially replaced
the prism because they are expensive. The complementary filter is used to
expand the particularity and affectability of optical estimations, the particular
nature of light is permitted to enter the shaded arrangement.



The quality of
the light-regulated by monochromator in case of the spectrometer,
which allows one to select a specific wavelength of light to pass through to
test solution. In the common stage, an electrical photometer refers to
colorimeters or spectrophotometer. The colorimeter use filter while
spectrometer use prism or grit that yields a single
selected wavelength of light.
3. Slit

The light emerging from
the monochrometer is than pass through a narrow slit that improves the quality
of light by choosing a single wavelength. This is found in all
spectrophotometers.
4. Cuvette
The cuvette holds the solution whose absorbance is to be measured the cuvette must be optically
transparent, scruple clean, devoid of any scratch, and free from contamination.
The cuvette is either round like a test tube or rectangular.

The optical path
within the cuvette is always” 1cm “. Glass cuvettes are utilized in
noticeable range colorimetry or spectrophotometry while quartz or silica cells
are utilized for UV radiation. This is because glass observes lights. 
Special
plastic cuvettes are known available which are specially used for calorimetry.

Some the production gives a characteristic of the cuvette which ought to be by the imprint given on the colorimeter. Clearing of the cuvette
must be done with lens paper or soft tissue paper. Never clean the cuvette with
chronic acid, use only mildly good quality detergent.
Flame Photometry

The two important
electrolytes of the body sodium and potassium are conveniently and accurately
analyzed by flame photometry or flame emission photometry. The request for the
analysis of sodium and potassium is most often a stat procedure where the speed
and the accuracy of the operation is critical.


Flame photometry meets this
requirement. In addition to Na and K flame photometer also analyze the
concentration of lithium(Li). Lithium is used in therapy does for some mental
patients and the level to be maintained in the serum is critical.



The recent introduction of the ion-selective electrode will eventually replace the flame
photometer. The ion-selective electrode is more accurate and relatively simpler
to use.

Principle of Flame Photometry

Several elements like
Na, K, Ca, Li AND Cs(The earth metal) when place in the heat of flame become
excited and emit light of a specific wavelength which is characteristics while
they return to their ground state. The amount of light emitted is proportional
to the number of excited atoms present or in other words concentration of the
elements in solution.

Quantization of the emitted light is done by the
photodetector system. 
The various elements
that can be radically analyzed by flame emission photometry only sodium and
potassium routinely done. Li only occasionally does on special request from
mental hospitals. Analysis of Ca by flame emission photometry is not every
popular as it requires a high temperature to volatilize(2000-2500 degree
Celcius) the element as compared to Na and K(1500).

The specific wavelength
for the clinically significant element is sodium(589 nm or yellow),
potassium(1404 nm or violet and 767 nm or red), and Lithium (671 nm or red). By
setting appropriate monochromators and corresponding, photocells for each
element to be analyzed, the concentration of different elements can be
determined simultaneously from the same flame. As the absorption maxima are
wide apart for sodium(589nm) and potassium(766nm).


Siple filters are required
as monochromators to provide specific wavelengths. The flame is the light
source for flame emission photometry. It is burnt with a mixture of propane and
butane. The aqueous specimen is sprayed into flame as a fine mist by means of a
nebulizer or aerosol.

Components of Flame Emission Photometry

1. Nebulizer – This helps to spray the specimen into the
burner. It is usually of the scent type. Whereby a forced stream of air passes
over a capillary tube that dips into the test solution.
2. Flame – The flame generates heat that volatilizes the
element that becomes luminous when it returns to the ground state. The most
common gas mixture that provides an optimum temperature for the routine
determination of sodium and potassium is propane, Butane, or natural gas.



The mixture of the fuel gas and air in the right proportions is ignited which
provides the flame. The purpose of the flame is to generate heat and
volatilizes the elements that become luminous when they return to the ground
state.
3. Monochromators – These devices increase the specificity of
the analysis. Simple filters are used that yield 589nm for Na and 767 nm for K.
These are not complementary, filters against the color of the flame. Along with
the monochromator filters, a heat filter is placed between the flame and monochromator
filter to stop the passage of heat.



The monochromator screen out the wavelength
of light except the specific one emitted by the element analyzed to separate the monochromator is used or each element analyzed. 
4. Photo Detector
– 
The photodetector system
quantifies the emitted light by converting it into an electrical impulse which
is eventually transmitted to the readout galvanometer.

Procedure Of Photometer


1.    
Dilution of the specimen
and std (1:200) if the internal std is to be used, specimen and std are dilute
with the internal std solution. The instrument may be provided with a combined
automated dilution and feeding system this saves time in dilution. In most
laboratories of developing countries, manual dilution is done.
2.    
Turn off the electrical
connection to the flame photometer. Permit it to balance out for a couple of
moments. Ignite the flame by pressing the ignition button on the instrument
panel.
3.    
Put the deionizer water
under the inlet tube. Water will be sucked in at a specific rate.
4.    
Replace the water with
the std solution and set the level for sodium and potassium.
5.    
Put the dilution
specimen and take the reading.
6.    
Run the quality control
sera occasionally to check the validity of the results
7.    
To run off machine,
first, close the gas value.

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