Search results for "Analytical"
showing 10 items of 9586 documents
Some observations on the use of matrix modifiers in the determination of aluminum by electrothermal atomic absorption spectrophotometry
1989
Abstract Some evidence demonstrating that the use of matrix modifiers is necessary to obtain good calibration lines in the determination of aluminum by graphite furnace atomic absorption spectrophotometry is provided. It was found that the most sensitive results were obtained when Mg(NO 3 ) 2 was used instead of NH 4 H 2 PO 4 .
Determination of platinum and iridium in reforming catalysts by second derivative and absorptiometric spectrophotometry
1991
Investigations on the spectrophotometric determination of platinum as a complex formed by tin(II)chloride in hydrochloric acid are reported. The determination of platinum was found to be interfered with by iridium, because it also forms a complex with tin(II) chloride. The features of the derivative absorption spectrophotometry for the quantitative determination of platinum and iridium was also studied. The analytical application of the method for the determination of platinum and iridium in catalysts was investigated.
Some observations on the spectrophotometric determination of nitrite using ergonovine-p-dimethylaminobenzaldehyde
1991
Abstract The system ergonovine maleate-p-diethylaminobenzaldehyde in sulfuric acid media is applied to the kinetic-spectrophotometric determination of nitrite ions with competitive precision. The reaction rate is strongly enhanced by the presence of nitrite or ferric ions, being the nitrite in the “promoting” role of the reaction. Linear calibration plots are obtained for nitrite concentration ranges 0.3–2.4 ppm or 0.66–6 ppb. The influence of foreign compounds is also established.
Influence of Grain Size, Oxygen Stoichiometry, and Synthesis Conditions on the γ-Fe2O3 Vacancies Ordering and Lattice Parameters
2002
The soft chemistry method has been used to synthesize γ-Fe2O3 nanoparticles: various synthesis temperature were applied to obtain nanometric powders with crystallite size in the 9–14 nm range. Powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrophotometry, surface area measurements, and electron microscopy (TEM, SEM). It is clearly shown that these nanometric powders are very well crystallized as indicated by XRD and IR spectra which present substructural bands attributed to vacancies ordering (P4132). Based on these model materials and in the crystallite size range studied here, cell parameter appears to be not linked to crystallite size. It rat…
Direct radiofluorination of [18F]MH.MZ for 5-HT2A receptor molecular imaging with PET
2012
Imaging the serotonin 2A neuroreceptor with positron emission tomography has been carried out with [11C]MDL 100907 and [18F]altanserin for years. Recently, the MDL 100907 analogue [18F]MH.MZ was developed by combining the increased selectivity profile of MDL 100907 and the favourable radiophysical properties of fluorine-18. Here, we want to report the synthesis of [18F]MH.MZ via direct radiofluorination. Unfortunately, the direct radiofluorination did not have any significant benefits over the indirect labelling method. This is mainly because the precursor for the direct labelling approach is not completely stable and slowly decomposes. However, only one HPLC separation is necessary for the…
Current advancement in immunosensing of p53 tumor suppressor protein based on nanomaterials: Analytical approach
2017
Abstract The utility of detection of p53 in tomorrow's personalized health care field will mean early and accurate diagnosis of many types of cancers. This review is meant to provide an overview of the various types of immunosensors and immunoassay have been developed for determination of p53, along with significant advances over the last several years in related technologies. In addition, this review described: • Most frequently applied principles in immunoassay/immunosensing of p53. • The aspects of fabrication in the perspective of immunoassay/immunosensing applications. • The potential of various electrochemical, electrochemiluminescence immunosensors for the determination of p53 within…
Four color-measuring devices compared with a spectrophotometric reference system
2009
Abstract Objectives The objective of this study was to compare the L*C*h° color coordinates of dental color-measuring devices with those of a spectrophotometric reference system. Methods The International Commission on Illumination (CIE) L*C*h° color coordinates of ceramic samples, matching the colors of the VITA Linearguide, were recorded using four color-measuring devices (VITA Easyshade (A), VITA Easyshade compact (B), Degudent Shadepilot (C), X-Rite Shadevision (D)) and a spectrophotometric reference system under standardized test conditions. The intraclass correlation coefficients, regression lines with coefficients of determination, and mean deviations of the dental color-measuring de…
Hapten Design and Antibody Generation for Immunoanalysis of Spirotetramat and Spirotetramat-enol
2018
Spirotetramat - a tetramic acid insecticide - is rapidly metabolized or degraded to give spirotetramat-enol; so, common residue definitions include the sum of both compounds. In the present study, two spirotetramat-functionalized derivatives (haptens) have been designed to generate immunoreagents to these molecules for rapid immunochemical analysis. Haptens have been synthesized with alternative linker tethering sites and, for the first time, high-affinity antibodies have been generated with different specificities to these active principles. Two sensitive assays have been developed using the same antibody in different formats, and by using linker-site heterologous haptens, the selectivity …
Tropane-derived11C-labelled and18F-labelled DAT ligands
2013
Radiolabelling of cocaine-derived 3-phenyltropanes for dopamine transporter positron emission tomography with 18F and 11C is reviewed. Copyright © 2013 John Wiley & Sons, Ltd.
Investigations on the Steroidal Anti-Inflammatory Activity of Triterpenoids fromDiospyros leucomelas*
1995
Three triterpenes were isolated from Diospyros leucomelas and identified as betulin, betulinic acid, and ursolic acid. They showed anti-inflammatory activity in the carrageenan and serotonin paw edema tests and TPA and EPP ear edema tests. The blockade of their effects by progesterone, actinomycin D, and cycloheximide has served to determine the mechanism of action in relationship with that of glucocorticoids. Betulinic acid was the most affected and therefore a mode of action similar to these drugs may be postulated for it.