The characteristics of a capillary discharge lamp, developed as a spectral source for the measurement of sulphur, phosphorus, selenium, and arsenic concentrations by flame atomic absorption spectroscopy, have been determined. Atomic spectral lines for each of the elements were produced when flowing mixtures of helium and vapor of the element, or a compound of the element, were passed through a quartz capillary discharge tube. Absorbance-concentration relationships, together with analytical sensitivities and detection limits, were obtained for sulphur, phosphorus, selenium, and arsenic with the use of a modified flame atomic absorption spectrophotometer, the optical system of which was purged with argon when necessary. The capillary discharge lamp readings were compared with measurements made under similar operating conditions with selenium and arsenic hollow cathode lamps. The capillary discharge lamp results were also compared with those obtained by other workers using electrodeless discharge lamps, modified hollow cathode lamps, and controlled temperature-gradient lamps. It was evident that the capillary discharge lamp possesses performance characteristics which make it potentially suitable as a spectral source for atomic absorption spectroscopy. Sensitivities and detection limits obtained with the use of this novel lamp were similar to those reported for other spectral sources.
