An instrument that measures the
amount of light that passes through
(is transmitted through) a sample.
Uses a type of light to detect
molecules in a solution
Light is a type of energy, and
the energy is reported as
waveleng...
 Ultraviolet (UV) Spectrophotometers.
Uses ultraviolet light of wave lengths
from 200 nm to 350 nm.
 Visible (VIS) Ligh...
R O Y G B I V
 Shines a beam of light on a sample.
 The molecules in the sample interact
with the light waves in of 3 ways:
Absorb th...
Blue molecules absorb the other
colors of visible light.
Blue molecules are blue because
they reflect blue light.
 Consider blue molecules, all the
wavelengths of light are absorbed,
except for the blue ones.
 The blue wavelengths are...
 Molecules are whatever color of
light that they do not absorb.
 Green molecules appear green
because they absorb most
w...
 The spectrophotometer measures
the amount of light transmitted
through the sample
(Transmittance).
 By using an equatio...
 The concentration of an unknown
sample can be determined by
comparing the absorbance data to
standards of known concentr...
 Inner parts
Lamp
Prism or grating that direct
light of a specific wavelength.
 Visible spectrophotometer
Contains a tungsten lamp that
produces wwhhiittee lliightght.
 Ultraviolet
spectrophotometer...
 Outer parts:
Sample Holder
Display
Knobs or buttons used to calibrate the
spec to measure the designated molecule.
Wavel...
 Visible Spectrophotometer
White light hits the prism or
grating, it is split into the
colors of the rainbow (Visible
Sp...
 The wavelength of light
produced by the tungsten lamp
range from about 350 nm (Violet
light) to 700 nm (red light).
 Th...
 The detector measures the
amount of light being
transmitted by the sample and
reports that value directly (%
transmittan...
A = 2 – log10%T
 After collecting data for your
concentration an absorption
spectrum graph is created.
 These can be used when
attemptin...
The absorbance spectrum is a
graph of a sample’s absorbance
at different wavelengths.
The spectrophotometer can
measure the amount of absorbance
or
lack of absorbance of different
colored light for a given
mo...
 The concentration of molecules
in a solution affects the
solution’s absorbance.
 Remember [ ] is a ratio – when we
chan...
 Determines the presence and
concentrations of samples.
 Determines the purity of a
sample.
 Look at the change of
samp...
A. Measure the absorbance of standards
containing known concentrations of the
analyte
B. Plot a standard curve with absorb...
spectrophotometer
spectrophotometer
spectrophotometer
spectrophotometer
spectrophotometer
spectrophotometer
spectrophotometer
spectrophotometer
Upcoming SlideShare
Loading in …5
×

spectrophotometer

1,371
-1

Published on

0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
1,371
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
118
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

spectrophotometer

  1. 1. An instrument that measures the amount of light that passes through (is transmitted through) a sample.
  2. 2. Uses a type of light to detect molecules in a solution Light is a type of energy, and the energy is reported as wavelengths, in nanometers (nm).
  3. 3.  Ultraviolet (UV) Spectrophotometers. Uses ultraviolet light of wave lengths from 200 nm to 350 nm.  Visible (VIS) Light Spectrum Spectrophotometers. Uses visible light (white light) of wave lengths from 350 nm to 700 nm.
  4. 4. R O Y G B I V
  5. 5.  Shines a beam of light on a sample.  The molecules in the sample interact with the light waves in of 3 ways: Absorb the energy Reflect the energy Transmit the energy between and through the atoms and molecules of the sample.
  6. 6. Blue molecules absorb the other colors of visible light. Blue molecules are blue because they reflect blue light.
  7. 7.  Consider blue molecules, all the wavelengths of light are absorbed, except for the blue ones.  The blue wavelengths are transmitted or reflected off the molecules. If these blue wavelengths hit a detector (such as in the spectrophotometer or the nerve cells in your eye), they appear blue.
  8. 8.  Molecules are whatever color of light that they do not absorb.  Green molecules appear green because they absorb most wavelengths of visible light, except the green wavelengths.
  9. 9.  The spectrophotometer measures the amount of light transmitted through the sample (Transmittance).  By using an equation (Beers law), it converts the transmittance data to an absorbance value. What kind of data is this?
  10. 10.  The concentration of an unknown sample can be determined by comparing the absorbance data to standards of known concentration.  The data generated with the set of known standards is called a standard curve.
  11. 11.  Inner parts Lamp Prism or grating that direct light of a specific wavelength.
  12. 12.  Visible spectrophotometer Contains a tungsten lamp that produces wwhhiittee lliightght.  Ultraviolet spectrophotometer Contains a deuterium lamp that produces light in the UV light part of the spectrum.
  13. 13.  Outer parts: Sample Holder Display Knobs or buttons used to calibrate the spec to measure the designated molecule. Wavelength Selection
  14. 14.  Visible Spectrophotometer White light hits the prism or grating, it is split into the colors of the rainbow (Visible Spectrum). The wavelength knob rotates the prism/grating, directing different color of light toward the sample.
  15. 15.  The wavelength of light produced by the tungsten lamp range from about 350 nm (Violet light) to 700 nm (red light).  The molecules in the sample either absorb or Transmit the light energy of one wavelength or another.
  16. 16.  The detector measures the amount of light being transmitted by the sample and reports that value directly (% transmittance) or converts it to the amount of light absorbed in absorbance units (au) using Beers Law.
  17. 17. A = 2 – log10%T
  18. 18.  After collecting data for your concentration an absorption spectrum graph is created.  These can be used when attempting to identify unknown substances (e.g. CSI)
  19. 19. The absorbance spectrum is a graph of a sample’s absorbance at different wavelengths.
  20. 20. The spectrophotometer can measure the amount of absorbance or lack of absorbance of different colored light for a given molecule.
  21. 21.  The concentration of molecules in a solution affects the solution’s absorbance.  Remember [ ] is a ratio – when we change one number – it affects the ratio If there are more molecules in one solution than in another, than there are more molecules to absorb the light.
  22. 22.  Determines the presence and concentrations of samples.  Determines the purity of a sample.  Look at the change of samples over time.
  23. 23. A. Measure the absorbance of standards containing known concentrations of the analyte B. Plot a standard curve with absorbance on the X axis and analyte concentration on the Y axis C. Measure the absorbance of the unknown(s) D. Determine the concentration of material of interest in the unknowns based on the standard curve
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×