Methods of stoichiography in geochemistry and mineralogy

Reported is a novel reference-free technique, based on stoichiography, for the molecular and phase analysis of complex mixtures with unknown compositions. The concept of stoichiography is based on the stoichiometry of mass transfer of the constituents in transient, homogeneous and heterogeneous phase transformation processes. The technique utilizes both the separation of components according to their differential dissolution characteristics as well as the dynamics of the changes in stoichiometry. The detailed study of the dissolution processes has been made possible by the use of a specially designed instrumental system, termed a Stoichiograph, which consists of a high sensitive inductively coupled plasma atomic emission spectrometer as the detector–analyzer. Fundamentals, methodology, and instrumentation of the technique are discussed and its application for the phase analysis of multielement-multiphase samples such as minerals, aerosols, and archaeological materials is demonstrated.