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Characterization of solid standards prepared by freeze‐drying
Author(s) -
Dang T. A.,
Lunk H.J.,
Roychowdhury S.,
Frisk T. A.,
Bard T. J.
Publication year - 2010
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3145
Subject(s) - sublimation (psychology) , homogeneity (statistics) , tungsten , analytical chemistry (journal) , doping , dopant , homogeneous , chemistry , glow discharge , materials science , metallurgy , chromatography , optoelectronics , thermodynamics , plasma , psychology , statistics , mathematics , physics , quantum mechanics , psychotherapist
Abstract Solid standards prepared by freeze‐drying consistently showed a high degree of homogeneity. The freezing process, completed in fractions of a second, preserves the original homogeneous distribution of the dopants, and the subsequent sublimation step would minimize any disturbance. Compared to those prepared by conventional methods such as blending and spiking, freeze‐dried standards exhibited superior lateral distribution and better uniform depth distribution. There is, however, a concentration constraint for achieving homogeneity. At 5% doping, segregation was observed in both lateral and depth distribution. Many tungsten standards doped with 10–28 elements ranging from 10 to 200 ppm were successfully prepared and used as controls for a number of analytical techniques including glow discharge mass spectrometry (GDMS) and d.c.‐arc optical emission spectroscopy (OES). Copyright © 2009 John Wiley & Sons, Ltd.