Evaluation of Mg and Mn determination in water and plants using continuum source tungsten coil atomic fluorescence spectrometry

A procedure for Mg and Mn determination in contaminated fresh water and plant materials by tungsten coil atomic fluorescence spectrometry (WCAFS) is described in this work. A commercial tungsten coil was used as atomizer and housed in a lab made glass cell. This cell especially developed for fluorescence measurements was equipped with three quartz windows, arranged in a T-shape configuration, which enables the passage of radiation from a 300 W Xe arc lamp, used as excitation source, and also the atomic fluorescence radiation. Using an appropriate heating program, free atoms are generated on the atomizer and excited by the Xe radiation source. Finally, simultaneous fluorescence signals for Mg and Mn are obtained. After optical alignment and optimization, detection limits (99.7% confidence level) were estimated as 0.06 mg L− 1 for Mg (λ = 285.2 nm) and 0.1 mg L− 1 for manganese (λ = 403.1 nm), with linear dynamic ranges of 0.2-2.0 and 0.25-10 mg L− 1 for Mg and Mn, respectively. The developed procedure was successfully applied to Mg determination in water samples and certified reference materials of plants. Interferences caused by high concentrations of concomitants were critical for Mn determination in plant materials. On the other hand, the Mn LOD was suitable for contaminated water analysis according to maximum concentration limits established by Brazilian environmental and health legislations.