Full set of Notes with Fill-Ins - San Jose State University

Chem 155 Unit 8 Page 151 of 316Practical aspects of atomic spectroscopy:Sample introduction and plasma chemistry.Skoog chapters covered: 8C, 9AFlame or PlasmaMonochromatorAtomic EmissionfromHollowCathodeLampLight sourcefor absorptionmeasurementonly.Flame orPlasmaNebulizer /Spray ChamberAtomicAbsorptionand / orAtomicEmission inFlame/PlasmaMolecular gasDry solidsAerosolAnalytes inSolutionAbsorbance:⎡ P ⎤A = −Log⎢⎥ = ε b[C]⎢⎣PO⎥⎦Emission:C]= k(P − P )[OPMTPP 0In AAS and AES solutions of analytes are a. aerosolized, b. measured asthey race past the detector as a very dilute gas and in a flame or plasma.This a. very strongly dilutes the analyte and b. limits the time it spends infront of the detector. ---- Why is this tradeoff worthwhile?Intense and narrow emission and absorption bands makeatomic spectroscopy sensitive and selective compared tomost comparable solution methods.Page 151 of 316