The Shape of Analytical Curves in Zeeman Atomic Absorption Spectroscopy. II. Theoretical Analysis and Experimental Evidence for Absorption Maximum in the Analytical Curve

Abstract

The analysis of the shape of analytical curves in Zeeman atomic absorption spectroscopy has been extended toward higher concentrations. Nonlinearity in the conventional atomic absorption signal due to stray light or nonlinear electronic response causes both theoretically calculated and experimental analytical curves in Zeeman atomic absorption to go through a maximum at a certain concentration. The height and the position of the maximum depend on the magnetic system used, the strength of the magnetic field and the amount of nonlinearity. In all magnetic systems the maximum attainable absorbance is enhanced by increasing the magnetic field strength and decreasing the amount of nonlinearity. Over the normal concentration range a maximum in the Zeeman atomic absorption analytical curve only occurs under the extreme conditions of a very weak magnetic field and strong nonlinearity. Ultimately, however, all Zeeman atomic absorption analytical curves pass through a maximum unless the optics and electronics are perfect. For practical systems strong ac modulated magnetic fields are to be preferred over dc magnetic fields.