Analysis of Oxalic Acid Leachates of Geologic Materials by Inductively Coupled Plasma-Atomic Emission Spectroscopy

The introduction of induction coupled plasma-atomic emission spectroscopy (ICP-AES) has satisfied, to a large degree, the requirement for a higher quality data-generating technique. The methods used in exploration geochemistry include many partial or selective digestion techniques that can readily be adapted to ICP-AES analysis. Extensive and highly significant new information cannot only be added to a mineral's evaluation by providing associated trace metals previously overlooked or unobtainable because of detection limits, but also suggests a degree of differentiation of mineral fractions and their ability to scavenge trace metals from other sources. Oxalic acid leaching of soils and stream sediments has long been recognized as a method for dissolving secondary Fe and Mn oxides. Modifications in the digestive procedure to produce solutions compatible with ICP-AES instrumentation have not only significantly reduced analytical time and increased precision over previously used instrumental methods, but have also provided a technique that allows for greater geochemical interpretation.