Comparative sensitivities of flame atomic absorption spectrophotometry (AAS) and molecular absorption spectrophotometry (MAS)

A sensitivity comparison was made between conventional atomic absorption spectrophotometry (AAS) and conventional molecular absorption spectrophotometry (MAS) for the serum trace metals, copper, iron, and zinc. The sensitivity aspect considered was absorbances was obtained for concentrations in the solutions analyzed using unit lightpaths of 1 cm and 10 cm for MAS and AAS, respectively. A distinction was made between procedural sensitivity and measurement sensitivity where the latter represents molar absorptivity. Some was given to the concepts of procedural sensitization by concentration of the analyte through the use of lyophilization, extraction or ashing. The misuse of data obtained with scale expanders is described as a commonly occurring phenomenon of both AAS and MAS and a source of confusion in the understanding of measurement sensitivity.