The microwave induced plasma with optical emission spectrometry (MIP-OES) in 23 elements determination in geological samples.

The article presents the optimisation, validation and application of the microwave induced plasma optical emission spectrometry (MIP-OES) dedicated for a routine determination of Ag, Al, B, Ba, Bi, Ca, Cd, Cr, Cu, Fe, Ga, In, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, Tl, Zn, in the geological samples. The three procedures of sample preparation has been proposed: sample digestion with the use of hydrofluoric acid for determination of total concentration of elements, extraction by aqua regia for determination of the quasi-total element concentration and extraction by hydrochloric acid solution to determine contents of the elements in acid leachable fraction. The detection limits were on the level 0.001-0.121 mg L(-1) (from 0.010-0.10 to 1.2-12 mg kg(-1) depend on the samples preparation procedure); the precision: 0.20-1.37%; accuracy 85-115% (for recovery for certified standards materials analysis and parallel analysis by independent analytical techniques: X-ray fluorescence (XRF) and flame absorption spectrometry (FAAS)). The conformity of the results obtained by MIP-OES analytical procedures with the results obtained by XRF and FAAS analysis allows to propose the procedures for studies of elemental composition of the fraction of the geological samples. Additionally, the MIP-OES technique is much less expensive than ICP techniques and much less time-consuming than AAS techniques.

Electron impact induced mass spectral study of 2- and 4-ethoxycarbonylalkylthio-5-bromo-6-methyluracils

Electron impact induced mass spectral fragmentation of ten new 2- and 4-ethoxycarbonylalkylthio-5-bromo-6-methyluracils have been investigated. Fragmentation pathways are proposed on the basis of accurate mass and B/E and B(2)/E linked scan spectra measurements. The data obtained create the basis for the distinction of isomers. Copyright 2000 John Wiley & Sons Ltd.