Critical study of the determination of tin by electrothermal atomic-absorption spectrometry using resonance and non-resonance lines

The 235.48 nm non-resonance line of tin gives a sensitivity for AAS determination equal to that given by the most sensitive resonance line. Vaporization from a platform improves some twofold the sensitivities of all lines investigated. The atomization temperature has only slight influence on the relative sensitivities given by the non-resonance tin lines studied. Phosphoric acid shows a rather peculiar interference pattern, low concentrations (0.05%) depressing the signal, but high concentrations (1%) enhancing it. Contrary to expectation, the resonance and non-resonance lines are affected to the same extent by phosphoric acid. Platform-vaporization does not change the interference pattern of phosphoric acid. Calibration can be done by injecting various volumes of a single standard solution onto a platform coated with tantalum carbide. This method yields calibration graphs that are just as linear as those obtained with identical volume of standards of various concentrations. Some suggestions are made for further improvement of the analytical potential of non-resonance lines.