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

What locations on the sticks to make it balanced, Here's what is given: A....

Here's what is given: A. There are three 1 meter sticks B. There are four weights: Weight #1 = 1kg Weight #2 = 1.2kg Weight #3 = 1.5kg Weight #4 = 2kg The sticks don't hav

Op-amp as a subtractor, Op-amp as a Subtractor A fundamental differe...

Op-amp as a Subtractor A fundamental differential amplifier can be used as a subtractor as shown in figure (c) In this figure, all external resistors are equal in value, so

Organic or polymer solar cells , Organic & polymer solar cells are made fro...

Organic & polymer solar cells are made from thin films (typically 100nm) of organic semiconductor such as polymer and small molecule compounds like poly phenylene vinylene, copper

On what factors does the amount of optical rotation depend, Q. On what fact...

Q. On what factors does the amount of optical rotation depend? The amount of optical rotation relay on (a) Thickness of crystal (b) Density of the crystal or else concent

How does the laser printer works, Q. How does the laser printer works? ...

Q. How does the laser printer works? Answer:- When a text or else image is entered into the CPU it produces a series of varying voltages. This manages a LED (light emittin

Illustrate what is balanced field takeoff, Q. Illustrate what is balanced f...

Q. Illustrate what is balanced field takeoff? Answer:- A balanced field with admiration to aircraft takeoff performance refers to the minimum length of runway that will pe

Heat energy, how heat energy is liberated during respiration?

how heat energy is liberated during respiration?

Scientific activity, the factors which decide the broad area of scientific ...

the factors which decide the broad area of scientific activity ?

Explain p-type substance, P-Type Substance: When a small quantity of bo...

P-Type Substance: When a small quantity of boron or Indium (group III A elements ) is added to silicon or Germanium, holes are formed in it and it becomes good conductor of pos

Explain electrostatic potential energy, Two point changes q1 and q2 are pla...

Two point changes q1 and q2 are placed at a distance r from one another then electrostatic potential energy of two phase charge system will be kq 1 q 2 /r  . We take P.E. of two ch

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