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Improved Sampling Technique for Powdered Samples for Emission Spectrometric Analysis

Volume 31, Number 5 (Oct. 1977) Page 473-473

Kapoor, S.K.; Singh, I.D.; Gupta, P.L.


For elemental analysis of solids by emission spectrometric methods, powdered samples commonly diluted by mixing with pure graphite/carbon powder are analyzed after loading into the electrode cavity directly as the powder or after pelleting. Several variations of the method have been proposed from time to time to improve the sensitivity, precision, and accuracy of the results. The proportionate dilution with graphite/carbon powder or other salts works satisfactorily for small dilutions only and fails for higher dilutions. In this communication, we propose a method for analysis of powdered samples, e.g., catalysts, dust, or rocks, by making a fine suspension of the solid powder in N-300 or equivalent motor oil base stocks (free from metallic contaminants, additives, etc.) and analyzing the suspension as a "liquid" sample using the rotating disc-arrangement commonly used for handling fluid samples. As the matrix almost always remains essentially constant - principally base oil - the method is more precise and is applicable to practically all types of powdered samples including heterogeneous materials like coal, petroleum coke, or surface deposits.