Evaluation Of Analytical Techniques Research Articles

Major and trace element geochemistry of the European Kupferschiefer – an evaluation of analytical techniques

Simple and rapid techniques are needed for routine quantitative chemical bulk-rock analyses of Kupferschiefer, a black shale containing variable amounts of silicates, base metal sulphides, carbonates and an organic content of up to 30 weight percent. In this study, WD-XRF, TXRF, and ICP-OES of acid- as well as peroxide-digested samples were tested as potential techniques based on their availability and adaptability to analyse major (Si, Ti, Al, Mg, Ca, Fe, K, but also Cu, Zn, Pb) and selected trace (Ag, As, Ba, Co, Mo, Ni, V) element concentrations. Because of the absence of a suitable reference material, a comparative study was undertaken using instrumental neutron activation analysis to ascertain the accuracy of different approaches. Our results suggest that data from ICP-OES were much higher in accuracy compared to INAA than those from WD-XRF and TXRF, independent of the digestion procedure. The choice of digestion procedure is reflected in low detection limits but an underestimation of Cu, Ag, Co, and V concentrations reported by ICP-OES relative to those obtained by INAA in the case of acid digestion and increased detection limits coupled with a loss of over 25% Ag relative to INAA for peroxide digestion. Supplementary material: Geochemical data, list of irradiation times and measured isotopes can be found at https://doi.org/10.6084/m9.figshare.c.4015507

Protein on Cloths: Evaluation of Analytical Techniques

Textile detergency studies require methods which can follow the removal and build-up of proteins on cloths. The suitability of X-ray fluorescence spectrometry (XRF), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectrometry (XPS), and nitrogen analysis for these studies was investigated by analyzing blood- and hemoglobin-stained cloths. Protein was measured via nitrogen by XRF, XPS, and the nitrogen analyzer and via an amide band by FT-IR. FT-IR was used with attenuated total reflection (ATR) and with photoacoustic spectrometry (PAS) as sampling techniques. A logarithmic relationship was found between the nitrogen content analyzed on the surface (XPS, XRF, and FT-IR) and in the bulk (N-analyzer). This result can be caused by the fact that the proteins in the cloths with a low quantity of blood or hemoglobin are located more on the outer layer of the cloth. With XRF, FT-IR/PAS, and XPS a significant difference could be detected between the 1% blood- and hemoglobin-stained cloths and a blank cloth, because protein is concentrated on the outer surface of the cloth. With FT-IR/ATR the 1% level can be detected when one is measuring at three different places. The measured surface areas of XRF, FT-IR/PAS, XPS, and FT-IR/ATR are about 37, 10, 5, and 0.2 mm in diameter, respectively. XRF proved to be the most suitable technique, giving a very fast indication of the amount of nitrogen on the outer micrometer layer of the cloths with an acceptable precision [relative standard deviation (RSD) 6%]. However quantitation is difficult due to the logarithmic relationship. XPS is also a valuable technique because protein on washed cloths is located mainly on the outer nanometer layer. The nitrogen analyzer is suitable for quantitative analysis of protein in the bulk sample. However more than 1% of the original blood stain (= 0.018% N) has to be present on the washed cloths.

Review Article Hyperspectral geological remote sensing: evaluation of analytical techniques

Abstract Improvements in optical remote sensing spectral resolution and increased data volumes necessitates the development of improved techniques for quantitative geological analysis. Laboratory spectral studies indicate that absorption band positions, depths and widths are correlated with diagnostic physicochemical mineral properties such as composition and abundance. Most current analytical techniques are incapable of providing comprehensive quantitative analysis of hyperspectral geological remote sensing data. Factors which must be considered for hyperspectral remote sensing campaigns include spectral resolution, analytical technique, band pass positions and spatial resolution. In many cases the volume of data required to address specific issues can be reduced through intelligent selection of band passes and analytical techniques.

A review of fluorescence spectroscopic methods for oil spill source identification

Abstract A review and evaluation of analytical techniques and methods for oil spill source identification by fluorescence spectroscopy is presented. The subject is discussed within the context of a three dimensional system which permits the reader to readily visualize and comprehend the many diverse approaches incorporated into the reviewed methods. The three dimensional system utilizes the three interdependent variables inherent to fluorescence spectroscopy, i.e., excitation wavelength, emission wavelength and fluorescence intensity, and portrays the fluorescence characteristics of petroleum oils as “total fluorescence spectra”; that are analogous to topographic maps of mountainous regions. Spectral information, derived by each of the methods, is discussed in terms of appropriate portions of such total spectra.