Determination of carbide-forming metals, chromium and barium, by graphite furnace atomic absorption spectrometry using a tungsten coil platform

The use of a tungsten coil as a platform has been evaluated for the determination of carbide-forming metals, Cr and Ba. The methodology developed has been used for Cr and Ba determinations in HPS CRM, Trace Metals in Drinking Water, and NIST SRM 1643b, Trace Elements in Water. Good agreement was found between the results obtained and the certified values for Cr in both reference materials and for Ba in the NIST SRM. Barium results were approximately 14% lower than the certified results for the HPS CRM. This inaccuracy was ascribed to the presence of considerable amounts of Ca in this particular material. Precision of the measurements, 3 sigma relative standard deviation as percentage, were 2.5 and 5.8 for Cr and Ba, respectively. Characteristic masses, in picograms, were 1.70 for Cr and 19.0 for Ba. These results compare favorably with the literature values for Cr but not for Ba. (C) 2000 Elsevier Science B.V. All rights reserved.