Kanji Tsujii

The determination of arsenic by non-dispersive atomic fluorescence spectrometry with a gas sampling technique

Abstract Non-dispersive atomic fluorescence measurements of arsenic with a gas sampling technique have been investigated. Arsenic is converted to arsine in a mixed acid medium containing iodide, tin(II) and zinc powder, and is atomized in a hydrogen-argon-entrained air flame. A microwave-excited (2450 MHz) electrodeless arsenic discharge lamp, a solar-blind photomultiplier, and a lock-in amplifier are used. The detection limit of arsenic is 2 ng and the linear working range covers nearly three decades of concentration.

Improvements in the non-dispersive atomic fluorescence spectrometric determination of arsenic and antimony by a hydride generation technique

Abstract A sodium borohydride reduction, with subsequent atomization in a small argon—hydrogen—entrained air flame has been developed for the determination of arsenic and antimony by non-dispersive atomic fluorescence spectrometry. The proposed method increases the signal level and decreases the noise level in the system. The detection limits for arsenic and antimony are 0.05 ng and 0.1 ng, respectively. The analytical working curves are linear over about four decades of concentration from the detection limits. The consumption rates of hydrogen and argon are comparatively low, while the speed of hydride evolution is improved; a peak measurement requires less than 40 s. The technique has been applied to the determination of arsenic in steel samples.

Determination of antimony depth profiles in semiconductor silicon by chemical etching and nondispersive atomic fluorescence spectrometry with hydride generation

Abstract After the silicon has been anodized, the silica film formed is removed by dilute hydrofluoric acid, and the antimony in the etching solution determined by nondispersive atomic fluorescence spectrometry. The amount of silicon removed is measured in the etching solution by inductively-coupled plasma atomic emission spectrometry. Down to 10 18 atoms Sb cm -3 can be determined at sectioning intervals of 50 nm.

Depth profiles of arsenic in semiconductor silicon by chemical etching and non-dispersive atomic fluorescence spectrometry with hydride generation

Abstract An improved non-dispersive atomic fluorescence spectrometric determination of arsenic by sodium tetrahydroborate reduction is described. A new burner on which a small argon-hydrogen-entrained air flame can be maintained at a low hydrogen flow rate (0.15 1 min -1 ) is reported. The detection limit ( S N = 2) is 10 pg of arsenic, and the analytical working curve is linear over four decades of concentration from the detection limit. The system is applied to depth profiling of arsenic in silicon slices. The silicon is anodized, the silica film is removed by hydrofluoric acid and the arsenic in the etching solution determined. The depth of silicon removed is measured by determining the silicon content in the etching solution by inductively-coupled plasma atomic emission spectrometry. The method permits determinations of ⩾10 18 atoms As cm -3 in 30-nm sections of a silicon slice with a diameter of 5.1 cm.

Determination of cadmium, zinc, and lead by non-dispersive atomic fluorescence spectrometry with a new graphite furnace atomizer

Abstract A new graphite furnace atomizer has been developed and applied to the determination of cadmium, zinc, and lead by non-dispersive atomic fluorescence spectrometry. A solar-blind photomultiplier, a lock-in amplifier, and microwave-excited electrodeless discharge lamps are used. The detection limits for cadmium, zinc, and lead in the non-dispersive atomic fluorescence mode are 1·10 −13 g, 2·10 −13 g, and 2·10 −11 g, respectively, which are 20-, 10-, and 2-fold better than those in the atomic absorption mode. The analytical working curves are linear over about three decades of concentration from the detection limits.

Indirect determination of phosphorus by non-dispersive atomic fluorescence spectrometry of antimony

Abstract Phosphate is converted to molybdoantimonylphosphoric acid, which is reduced and extracted into isobutyl acetate. The extracted material is atomized in a graphite furnace and antimony determined by non-dispersive atomic fluorescence spectrometry. The detection limit is 2 ng of phosphorus, limited by the reagent blank, and the linear analytical range covers three decades of concentration up to 2 μg. The technique is applied to the determination of phosphorus in a phosphosilicate glass film deposited on a silicon wafer.

Evaluation of new high-frequency discharge lamps for atomic absorption and atomic fluorescence spectrometry of cadmium, lead and zinc

Abstract High-frequency discharge lamps with a hollow electrode are successfully utilized as the spectral line sources for atomic absorption and atomic fluorescence spectrometry of cadmium, lead and zinc. The sensitivities for atomic absorption spectrometry are superior to those obtained with commercially available hollow-cathode lamps by factors of 1.5 (Cd), 1.4 (Pb) and l.6 (Zn). Detection limits for non-dispersive atomic fluorescence spectrometry with graphite furnace atomization are 1 × 10 -13 g (Cd), 3 × 10 -11 g (Pb) and 2 × 10 -13 g (Zn). The linear analytical range covers over four (Cd, Zn) and three (Pb) decades of concentration above the detection limits.