Effect of the type of organometallic iron and copper compounds on the determination of both metals in petroleum samples by flame atomic-absorption spectroscopy

Abstract

The effect of the type of organometallic iron or copper compounds on the value of the absorbance signals of these metals in an air-acetylene flame and for iron in a dinitrogen oxide-acetylene flame is reported. The determination of iron and copper in xylene solutions of the asphaltene and resinous petroleum fractions was carried out using various organometallic compounds of both metals as standards and by both the calibration graph and standard additions techniques. There are serious limitations to the direct flame atomic-absorption spectrometric methods, owing to transport interferences. In addition, with iron, there are matrix interferences caused by the structure of the petroleum samples being analysed and also owing to the various forms of iron present in these samples. It is recommended that determination of these elements in heavy petroleum fractions should be carried out by dry mineralisation and flame atomic-absorption spectrometric analysis of aqueous solutions.