title: Studies in atomic-fluorescence spectroscopy-VII Fluorescence and analytical characteristics of arsenic, with a microwave excited electrodeless discharge tube as source.
abstract: The construction of an electrodeless arsenic discharge tube and its use for atomic-fluorescence studies is described. Cool nitrogen-hydrogen and argon-hydrogen diffusion flames as well as normal premixed flames are considered as atom reservoirs and the atomic-fluorescence emission at 15 different wavelengths is evaluated. The diffusion flames give the largest emission signals at arsenic concentrations below 200 ppm, but show a premature curvature at higher concentrations because of the presence of an abnormally high density of arsenic atoms. Above 200 ppm of arsenic, the premixed air-acetylene flame is superior. The limit of detection at 1890 A is 0.2 ppm of arsenic in the nitrogen-hydrogen diffusion flame and 1.0 ppm in the airacetylene flame. A long path-length diffusion flame is also particularly useful in atomic-absorption measurements because it absorbs very little radiation in the far ultraviolet region and gives an abundance of arsenic atoms.
authors.affiliation: Chemistry Department, Imperial College, London, S.W.7., U.K.
authors.forename: R M
authors.initials: RM
authors.lastname: Dagnall
authors.forename: K C
authors.initials: KC
authors.lastname: Thompson
authors.forename: T S
authors.initials: TS
authors.lastname: West