beer s law and spectrophotometry l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Beer’s Law and Spectrophotometry PowerPoint Presentation
Download Presentation
Beer’s Law and Spectrophotometry

Loading in 2 Seconds...

play fullscreen
1 / 6

Beer’s Law and Spectrophotometry - PowerPoint PPT Presentation


  • 683 Views
  • Uploaded on

Tristan Ursell APh 162 California Institute of Technology. Beer’s Law and Spectrophotometry . Two-fold: - Relates concentration to the optical measurement of ‘absorbance’ - combined with spectrophotometry can be used to distinguish and compare different molecules in

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Beer’s Law and Spectrophotometry' - Sophia


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
beer s law and spectrophotometry

Tristan Ursell APh 162

California Institute of Technology

Beer’s Law and Spectrophotometry

uses of beer s law

Two-fold:

- Relates concentration to the optical measurement

of ‘absorbance’

- combined with spectrophotometry can be used to

distinguish and compare different molecules in

solution

Uses of Beer’s Law:

conceptual basis of beer s law
Conceptual Basis of Beer’s Law
  • - Light of a particular wavelength enters the ‘sample’.
  • Light scatters from particles in solution (no momentum change) reducing light transmission
  • - Light is absorbed by molecules/particles (momentum
  • change) and remitted at different wavelengths, reducing light transmission
a little more in depth
A little more In-depth:

Beer’s Law is stated in a way to make certain quantities easy to compare and interpret.

Parameters:

l – sample pathlength (usually 1cm)

c – concentration (mol/vol)

– molar absorption coefficient ( )

I – light intensity (W/m^2)

when can i use beer s law
When can I use Beer’s Law?

Rule of Thumb: A<1 for accurate results

Only at low concentrations, where the absorbance is linear (single scattering event):