Determination of Trace Elements in Rocks by Optical-Emission Spectroscopy

摘要

An emission spectrographic method has been developed for the estimation of twelve trace elements in geological rock specimens. The samples are thoroughly ground initially to a fine mesh and then mixed with pure conducting graphite powder in the ratio 1:3 by weight. Thirty milligrammes of the sample filled into the cavity of a 6.35 mm dia graphite electrode, is excited in oxygen atmosphere at 10 amperes d.c. The spectra of the samples and synthetic standards are recorded on an Ebert 3.4 m plane grating spectrograph using a 1200 grooves/mm grating in the wavelength region 280 to 340 nm (first order). A single set of standards is adequate to analyse rock samples belonging to any of the three types, acidic, basic or intermediate. Twelve trace elements such as Pb, Sn etc. are estimated in the concentration range between 5 and 500 ppM. (ERA citation 07:047494)