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Atomic Absorption Terry A. Ring Chemical Engineering University of Utah E= -13.6 eV Z2/n2 Photo absorption/emision Atomic Absorption Lamps are Special • Cathode with receptacle for material • Vapor of Material to be analyzed • Vapor Excited by plasma • Light of particular wavelength Aerosol Flow • Burner Fuel (& oxidizer) mixed with aerosol of sample • Sample asperated into burner • Flame ionizes Sample Intensity vs Wavelength in AA • Light Source • Absorbance • Monochromatic • Detector Analysis • Absorption of Light • Electrons are excited • Light Intensity on detector is less Graphite furnace AA Other AA’s • • • • • • Flame Spark Arc Plasma Laser X-ray Atomic Emission Spectroscopy • Flame is used to generated Atoms with excited electrons and ions • Light is filtered in spectrometer to give Intensity vs wavelength Spectrometer • Emitted Light • Broken into different color components – Prism – Grating X-ray Fluorescence • Two Steps – Absorption of X-ray • Elimination of electron for k or L shell – Collapse of M shell electron to fill hole • Light emission (xray) Potential X-ray Emissions • From K shell hole – K, K, K, – Zeeman Effect - 1, 2, 3 • From L shell hole – L, L, L, Generation of X-rays • High Voltage Electrons • Electron Scattering • Electron Absorption – X-ray photo ionization XRF • Energy-dispersive XRF • Wavelengthdispersive XRF XRF Detectors • Energy-dispersive XRF – Semiconductor • Wavelength dispersive XRF – Scintilation Counter XRF Analysis • Samples can be in any form – Solid – Powder – Liquid
