A THIN-WALLED METALLIC HOLLOW-CATHODE AS AN ATOMIZER FOR ZEEMAN ATOMIC-ABSORPTION SPECTROMETRY

A new kind of glow discharge atomizer, a thin-walled metallic hollow c athode (TMHC) combined with Zeeman atomic absorption spectrometry usin g high frequency modulated light polarization (ZAAS-HFM), is studied. A theoretically suggested, and experimentally confirmed, model of the atom confinement in the TMHC yields the appearance of the diffusion tr aps for atoms at both ends of the cathode, which increases the residen ce time of the analyte atoms in the analysis volume. The high atomizat ion efficiency in the glow discharge atomizer (caused by the ionic-the rmal mechanism of sputtering) and the high selectivity of ZAAS-HFM are demonstrated in the analysis of complex matrix samples such as whole blood and urine. The analytical system TMHC + ZAAS-HFM is characterize d by low detection limits, which are comparable to those of graphite f urnace atomic absorption spectrometry (GFAAS). Owing to its rather low average power consumption (30-50 W) the TMHC can be used in a portabl e and mobile spectrometer, and is therefore suitable for the in situ a nalysis of various sample materials. (C) 1998 Elsevier Science B.V.