New approach for understanding the fundamental chemistry of the oxidative sample digestion in spectrochemical analysis |
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Authors: | Jorge Yáñez Claudio Sandoval Héctor D Mansilla Dulasiri Amarasiriwardena |
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Institution: | 1. Faculty of Chemical Sciences, Department of Analytical &2. Inorganic Chemistry, University of Concepción, Concepción, Chile;3. School of Natural Science, Hampshire College, Amherst, Massachusetts, USA |
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Abstract: | The process known as “wet digestion” is widely used in analytical chemistry as the most common way of dissolving solid samples for elemental spectrochemical analysis. Wet digestion involves the use of oxidizing reagents and acids–mainly HNO3, H2O2, H2SO4, HClO4, and other complementary acid reagents such as HF, HCl, or their mixtures. Wet digestion has become popular and attractive to users in part owing to the application of modern equipment with new technologies such as temperature-controlled heating blocks, microwave systems, and automated digestion systems, among others. Nonetheless, the use of modern, sophisticated instruments does not change the physical and chemical foundations of the classic chemical process. Until now, simplified equations have been used to explain this process. However, fundamental chemical mechanisms and thermodynamic concepts have been commonly left aside. In this work, the acid digestion of samples has been approached based on the chemical reactions, detailing the role and the effect of main reagents and intermediaries. The reactions that can occur during the digestion process have been specified considering the fundamental thermodynamic properties of the reagents used, especially the oxidizing reagents HNO3 and H2O2. This article will be a beneficial resource for students, instructors, and professionals alike. |
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Keywords: | Fundamentals sample digestion HNO3 H2O2 spectrochemical analysis tutorial |
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