IA Ch 13,14

What are the specs of a deuterium/hydrogen lamp?
Range: 160-800nm
Effective range 190-400nm
Excited atoms by electrical discharge cause photon
What are the specs of a tungsten filament lamp?
Range: 350-2500nm
Eff Rang 350-800nm
Blackbody emitter
What are the specs of a Xenon arc lamp lamp?
Range 200-1000nm
Eff Range: 200-800nm
How do losses occur regarding the cuvette?
Losses occur from reflection and scattering
What is the effect of slit width on peak height?
Radiant power is proportional to (slitwidth)^2
What are the assumptions made by Beer’s Law?
1)A monochromatic beam of light transversing a sample of absorbing molecules loses it intensity exponentially
2)Absorption changes as a fcn of frequency and wavelength
3)Absorption is proportional to conc. (All sp. abs equally)
4)Absorbing substances do not interact w/ ea. other or interfere w/ ea. other’s absorption properties
Define absorption
Promotion of compound to higher energy state w/o relaxation
What are limitations on Beer’s Law?

Instrumental deviations

-Stray radiation/light

-polychromatic radiation/light

-mismatched cells


Chemical deviations

-High analyte or low analyte concentrations

-Changes to refractive index of the solvent