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Theoretical calculation of the characteristic mass in graphite furnace atomic absorption spectrometry

1986; Elsevier BV; Volume: 41; Issue: 10 Linguagem: Inglês

10.1016/0584-8547(86)80125-2

1873-3565

Б. В. Львов, В. Г. Николаев, Erik Norman, L.K. Polzik, M. Mojica,

Ion-surface interactions and analysis

A comparison is made of calculated and experimental values of the characteristic mass, mXXX for 40 elements atomized in standard graphite tubes using integrated absorbance signals. The theoretical calculation involved a simplified model of vapor diffusion from the tube center toward their ends for a furnace isothermal both in time and over its length. For 30 elements measured under STPF conditions, the mean value of mo calmo exp was found to be 0.90 with a standard deviation of 0.25. Of the 10 elements vaporized from the furnace wall, the discrepancy is less than a factor of 2 for Ca, Mo, V and Yb, reaching a factor of 3–10 for Ba, Er, Eu, Si, Sr and Ti. These discrepancies may be accounted for by the formation of the thermostable gaseous carbides and monocyanides. Pretreatment of tubes with yttrium compounds in order to inhibit carbide formation turned out to be only partially efficient. On the whole, the results obtained support the possibility of developing an absolute method of AA analysis based on the STPF technique.