Class: BE-210
Group: W8
Members: Kartik Shah, Albert J. Lee, Paul Van Dorpe, Elizabeth Khaykin
Date: 4/30/97
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Abstract:
Determination of ion concentration is a widespread and crucial application in various fields, biological, ecological and industrial. In this laboratory experiment, comparative atomic spectroscopy between two methods of ion analysis, atomic absorbance and flame photometry, was conducted for the Group I alkali metal, potassium (K). The Atomic Absorption Spectrophotometer 4000 apparatus, constructed by Perkin-Elmer Corp., was used to atomize aqueous solutions of KCl by an air-acetylene flame, and to subject the free atoms to either absorption measurements by passing 766.5 NM monochromatic light through the samples or measuring emissions intensities brought about by thermal excitation. The linear working ranges for the absorbance and flame photometry of K+ ions have been found to be from 0 PPM to 6 PPM (A = 0.081(C + 0.252%)) and 10 PPM to 70 PPM (E = 0.0085(C + 1.5%)) respectively. Repeated trials have been performed to isolate and reaffirm these linear regions, defined by linear fits with R2 values of .99 or greater (linear fits of up to .9994 found for absorbance and .9964 found for flame photometry). It was determined that the proper method of ion analysis cannot be distinguished, being highly dependent upon the range of unknown concentrations in question. Both methods can provide very accurate results indicated by the error values above, depending on the situation.