CC LEC Flashcards
lamps for visible and near infrared
TUNGSTEN OR TUNGSTEN IODIDE
lamps for visible and near infrared
TUNGSTEN OR TUNGSTEN IODIDE
Incandescent light (nm)
400nm - 700nm
lamps required for work in U.V. range
Deuterium or mercury-arc
Range of mercury arc
160 - 375nm
Purpose of Components Monochromator
▶ Promote spectral isolation
▶ Isolate a single wavelength of light
▶ Provides increased sensitivity & specificity
Types of Components Monochromator
▶ Colored glass filters
▶ Prisms
▶ Diffraction gratings
Measures the success of the monochromator
Bandpass/Bandwidth
Defines the width of the segment of the spectrum that will be isolated by the monochromator
Bandpass/Bandwidth
for work in the visible light range
Glass Cuvette
for work in the UV range
Quartz or fused silica
are cheaper but light refraction and distortion occur
Round cuvets
have less light refraction but usually more costly
Square cuvette
to convert the transmitted light into an
equivalent amount of electrical energy
Photodetectors
to convert the electrical signal from the detector to a usable form
Read out device
checked by using special filters with known peak transmission
wavelength accuracy
verifies that the wavelength indicated on the dial is what is being passed through the monochromator.
wavelength accuracy
▶ is any wavelength of light reaching the detector, outside the range of
wavelengths being transmitted by the monochromator.
stray light
Causes insensitivity and linearity issues
stray light
Made by reading the absorbance of a set of standard solutions (obtained commercially) at specified wavelength(s)
linearity
photons of energy traveling in waves
Electromagnetic Radiation
The energy of EMR is ____________ to wavelength.
inversely proportional
The energy of EMR is ____________ to wavelength.
inversely proportional
States the relationship between the absorption of light by a solution and the concentration of the material in the solution.
Beer’s law
use a filter to produce light of one wavelength
Simple photometer/colorimeter
Spectrophotometers differ from photometers in that they use ________ to form monochromatic light.
prisms or diffraction gratings
Spectrophotometers differ from photometers in that they use prisms or diffraction gratings to form monochromatic light.
light source
monochromators
sample cell/cuvette
photodetector
display read-out device
Components of simple photometer
Lamp
Filter
cuvet
photocell
meter
based on the mathematical relationship between solute concentration & light absorbance
spectroscopy
