Absorbance spectrophotometer , Physics

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.

Posted Date: 10/15/2012 5:43:56 AM | Location : United States







Related Discussions:- Absorbance spectrophotometer , Assignment Help, Ask Question on Absorbance spectrophotometer , Get Answer, Expert's Help, Absorbance spectrophotometer Discussions

Write discussion on Absorbance spectrophotometer
Your posts are moderated
Related Questions
WHY Surface tension increases when an highly soluble SUBSTANCE is dissolved in water WHILE IT DECREASES WHEN an weakly soluble substance is dissolved in water

A radiation of 500nm is incident on a metal surface whose work function is 3ev.why do we not observe the phenomenon of photoelecric effect? Ans) we do not observe the phenomenon

Motion of an object in a straight line is called one dimensional motion. The location of a particle in one dimensional motion can be explained by only one variable (say x). For a p

if acceleration vs time graph is given then how to calculate displacement

Determine the amount of heat transfer required to convert 200 g(0.200kg) of ice to vapor if the initial temperature of the ice is25 degrees C and the final temperature is 100 degre

what is necol prism and give construction and working

A 2400-kg satellite is in a circular orbit around a planet. The satellite travels with a constant speed of 6.67x10 3 m/s. What is the acceleration of the satellite? Determine the m

A circuit which employs a DIRECT CURRENT source has a branch which has a capacitor.  After the circuit has reached a steady state, what is the magnitude of the current in the c

A force of 25 N is applied vertically at the end of a wrench handle that is 45 cm long to tighten a bolt in the clockwise direction. What torque is required by the bolt to keep the

Get an expression for the fringe width in the interference pattern due to Young's double slit.