Molekülabsorptionsspektrometrie bei elektrothermischer verdampfung in einer graphitrohrküvette: Teil 7. Untersuchung der erdalkali-halogen-molekülabsorptionen,bestimmung von Fluorid- und Chloridspuren durch die molekülabsorption von MgF- und MgCl-molekülen

(Molecular absorption spectrometry with electrothermal volatilization in a graphite tube. Part 7. A study of molecular absorption of alkaline earth halides and determination of traces of fluoride and chloride based on molecular absorption of MgF and MgCl moleculesv)The molecular absorption of alkaline earth halides, generated by volatilization in a normal graphite tube, is reported. Intense absorption bands were found only with MgF and MgCl molecules. These molecules are used for the determination of fluoride and chloride, respectively. Fluoride can be determined at 268.3 nm or 358.2 nm; for 10-μl injections, the linear ranges are, respectively, 0–6 μg ml^-1 and 0–35 μg ml^-1, with sensitivities (0.01 absorbance) of 2.4 ng and 7.5 ng. Chloride can be determined at 376.3 nm; response is linear up to 15 μg ml^-1, with a sensitivity of 5.8 ng if copper ions are added. Optimal conditions, interferences and mechanisms are discussed.