Analysis of archaeological samples and local clays using ICP-AES, TG-DTG and FTIR techniques.
The spectrochemical and thermal analysis of different archaeological samples as bricks, terra-cotta and local clays were carried out. The concentration of major and minor elements of samples was determined by sequential inductively coupled plasma atomic emission spectrometry. The method was tested by determining Si, Al, Fe, Ca, Mg, Mn, Pb, Cu, Zn, Ti, Na and K in the standard solutions and reference material GXR-4. The precision of the determination (relative standard deviation) ranged from 0.4 to 1.54%. The clay minerals are the main materials for the production of bricks and terra-cotta figures. Thermogravimetric (TG) and differential (TG-DTG) analysis and Fourier transform infrared spectrometry (FTIR) methods can be used for the study of characteristic reactions, associated with the course of the heating. The TG-DTG curves were obtained in the temperature range 25-900 degrees C, and the dynamic experiment was carried out in the air and nitrogen atmosphere. The infrared evolved gas analysis was performed using FTIR in the dynamic nitrogen atmosphere.
Revisitation of the matrix effects in inductively coupled plasma atomic emission spectrometry: the key role of the spray chamber
The level of matrix effects observed in ICP-AES linked to a change in the matrix concentration is usually low, with the matrix being either the major element or a reagent such as an acid. However, the magnitude of the matrix effects depends on the ICP operating conditions. Under so-called robust conditions,i.e., high power and low carrier gas flow rate, matrix effects resulting from a change in the plasma conditions, i.e., temperature, electron number density and spatial distribution of the various species, are minimized to the same extent, regardless of the element and line. Robust conditions can be verified by using the ratio of an ionic line intensity to an atomic line intensity, the Mg II/Mg I ratio being commonly used. The remaining depressive effect is assigned to the sample introduction system, and it can be demonstrated that the effect occurs during aerosol transport and filtering. This phenomenon emphasizes the key role of the spray chamber in the matrix effects.
Researches on Structural Factor Involvement in Oral Tribology
This study is focused on two ceramic materials, D.SING (Ivoclar) and VM13 (emphasis the VITA TN), frequently used in restorative dentistry practice and it comes to complete a full set of results obtained by the authors over several years of research on oral tribology with main influence on oral health. In this way there are involved more specific structural aspects of dental restorative ceramic materials quality as is shown in [1].