Absorbance spectrophotometer , Physics

Assignment Help:

Absorbance spectrophotometer:

A schematic diagram of a simple instrument that is used to measure the absorption of visible light is shown in Figure below.

1116_absorbance spectrophotometer.png

When studying a compound in solution by spectrophotometry, you put it in a sample holder called a cuvette and place it in the spectrophotometer.  Light of a particular wavelength passes through the solution inside the cuvette and the amount of light transmitted (passed through the solution-Transmittance) or absorbed (Absorbance) by the solution is measured by a light meter. While a spectrophotometer can display measurements as either transmittance or absorbance, in biological applications we are usually interested in the absorbance of a given sample.

Because other compounds in a solution (or the solvent itself) may absorb the same wavelengths as the compound being analyzed, we compare the absorbance of our test solution to a reference blank.  Ideally, the reference blank should contain everything found in the sample solution except the substance you are trying to analyze or measure. For instance, in today's lab exercise you will be measuring the absorbance of a dye, bromphenol blue that was dissolved in water. The reference blank in this case would be water alone.

The amount of light transmitted through a solution is referred to as transmittance (T). The transmittance is defined as the ratio of the light energy transmitted through the sample (I) to the energy transmitted through the reference blank (I0). Since the compound being tested is not present in the reference blank, the transmittance of the reference blank is defined as 100%T.


Related Discussions:- Absorbance spectrophotometer

Compton effect, Compton effect (A.H. Compton; 1923) An effect which de...

Compton effect (A.H. Compton; 1923) An effect which demonstrates that photons (the quantum of electromagnetic radiation) contains momentum. At a stationary particle, a photon

Tunnels through the earth, Q. Tunnels through the Earth Assume a straig...

Q. Tunnels through the Earth Assume a straight tunnel is cut from the surface of the earth to the opposite side through the centre. The object is going down the tunnel and a

Calculate drg process of equilibrium , In the following dissociation reacti...

In the following dissociation reaction, A 2 (g) is 42.7 % dissociated at equilibrium at 64.8 o C , and 1 bar pressure. A 2 (g)  ↔  2A Calculate D r G o for this proce

Calculate static resistance, give examples for how to calculate static resi...

give examples for how to calculate static resistance.

Mathematical expression for dispersive power, Arrive at the mathematical ex...

Arrive at the mathematical expression for dispersive power of the material of a prism in terms of angle of deviation. Determine the critical angle for the material of refractiv

Friction, why friction is called a necessery evil?

why friction is called a necessery evil?

Explain reaction is exothermic and entropy , A chemical reaction is known t...

A chemical reaction is known to occur spontaneously under standard conditions. Which of the following statements is/are true (more than one answer may be selected): A    The to

ELECTROSTATIC ., two insulated charged copper spheres A and B of identical ...

two insulated charged copper spheres A and B of identical size have charge q and -3q respectably .when they are brought in contact with each other and then separated,what are the n

Amperes law, The line integral of the magnetic flux about a closed curve is...

The line integral of the magnetic flux about a closed curve is proportional to the algebraic total of electric currents passing through that closed curve; or, in differential form,

A simple model of the earth and moon, A simple model of the earth and moon ...

A simple model of the earth and moon The earth can be shown by an orange or other round object stuck on a piece of bamboo or a meat skewer. A piece of bent wire or knitting nee

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd