Quantitative Fluorescence Analysis

Quantitative analysis starts with Eq. (8.15) which gives the true total fluorescence flux of the sample relative to the flux of incident radiation. However, the true fluorescence is experimentally only rarely accessible, and questions of analytical interest are among others how much of / tot is emerging from the sample, how is the emerging part distributed between front and back surface, how are the parts related to the concentration of the fluorophore, how can multicomponent systems be analyzed, how is the fluorescence disturbed by interactions between fluorophore and substrate, how the fluorescence is decaying with time. 

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The most recent petrographic method used to characterize coal macerals is quantitative fluorescence analysis. In this method the macerals are excited by incident ultraviolet light and the spectrum of the resulting fluorescent light is used to characterize the macerals. This technique has led to the discovery of new macerals (18), the quantitative discrimination between certain macerals in a given coal (19), and the correlation of the fluorescence properties of macerals to the rank, and technological properties of coal (20-22). 

Fluorescence images at the start and end of the micro-bead zone reveal that within only a short distance after entering the micro-bead bed, fluorescence is observed, whereas there is no fluorescence before [162], A quantitative fluorescence analysis confirms this visual observation. 

Li X, Li PC (2005) Microfluidic selection and retention of a single cardiac myocyte, on-chip dye loading, cell contraction by chemical stimulation, and quantitative fluorescent analysis of intracellular calcium. Anal Chem 77(14) 4315 322... 

Liang, Y., Baker, M. E, Gilmore, D. A., and Denton, M. B. (1996a). Evaluation of commercial silica gel HPTLC plates for quantitative fluorescence analysis. J. Planar Chromatogr.—Mod. TLC 9 247-253. 

PANCHOLY S.K. and LYND J.Q. 1972. Quantitative fluorescence analysis of soil lipase activity. Soil Biology and Biochemistry, 4, 257-259. 

Over the last seventeen year s the Analytical center at our Institute amassed the actual material on the application of XRF method to the quantitative determination of some major (Mg, Al, P, S, Cl, K, Ti, Mn, Fe) and trace (V, Cr, Co, Ni, Zn, Rb, Sr, Y, Zr, Nb, Mo, Ba, La, Ce, Pb, Th, U) element contents [1, 2]. This paper presents the specific features of developed techniques for the determination of 25 element contents in different types of rocks using new Biaiker Pioneer automated spectrometer connected to Intel Pentium IV. The special features of X-ray fluorescence analysis application to the determination of analyzed elements in various types of rocks are presented. The softwai e of this new X-ray spectrometer allows to choose optimal calibration equations and the coefficients for accounting for line overlaps by Equant program and to make a mathematic processing of the calibration ai ray of CRMs measured by the Loader program. 

In Total Reflection X-Ray Fluorescence Analysis (TXRF), the sutface of a solid specimen is exposed to an X-ray beam in grazing geometry. The angle of incidence is kept below the critical angle for total reflection, which is determined by the electron density in the specimen surface layer, and is on the order of mrad. With total reflection, only a few nm of the surface layer are penetrated by the X rays, and the surface is excited to emit characteristic X-ray fluorescence radiation. The energy spectrum recorded by the detector contains quantitative information about the elemental composition and, especially, the trace impurity content of the surface, e.g., semiconductor wafers. TXRF requires a specular surface of the specimen with regard to the primary X-ray light. 

Three techniques involving the use of X-ray emission to obtain quantitative elemental analysis of materials are described in this chapter. They are X-Ray Fluorescence, XRF, Total Reflection X-Ray Fluorescence, TXRF, and Particle-Induced X-Ray Emission, PIXE. XRF and TXRF use laboratory X-ray tubes to excite the emission. PIXE uses high-energy ions from a particle accelerator. 

X-Ray Fluorescence analysis (XRF) is a well-established instrumental technique for quantitative analysis of the composition of solids. It is basically a bulk evaluation method, its analytical depth being determined by the penetration depth of the impinging X-ray radiation and the escape depth of the characteristic fluorescence quanta. Sensitivities in the ppma range are obtained, and the analysis of the emitted radiation is mosdy performed using crystal spectrometers, i.e., by wavelength-dispersive spectroscopy. XRF is applied to a wide range of materials, among them metals, alloys, minerals, and ceramics. 

Csilibrsition. Quantitative binding analysis requires knowing the concentration of FLPEP, which can be determined for a stock solution of FLPEP by absorption spectroscopy. The quenching by the antibody is essentially quantitative, and the relative amounts of free and bound ligand are calculated from the relative fluorescence intensity. 

G. R. Lachance and F. Claisse, Quantitative X-Ray Fluorescence Analysis, Theory and Application, John Wiley Sons, Ltd, Chichester (1998). 

R. Tertian and F. Claise, Principles of Quantitative X-Ray Fluorescence Analysis, Heyden Sons, London (1982). 

X-ray fluorescence analysis is a nondestructive method to analyze rubber materials qualitatively and quantitatively. It is used for the identification as well as for the determination of the concentration of all elements from fluorine through the remainder of the periodic table in their various combinations. X-rays of high intensity irradiate the solid, powder, or liquid specimen. Hence, the elements in the specimen emit X-ray fluorescence radiation of wavelengths characteristic to each element. By reflection from an analyzing crystal, this radiation is dispersed into characteristic spectral lines. The position and intensity of these lines are measured. 

Fei He, Van Espen PJ (1991) General aspects for quantitative energy dispersive X-ray fluorescence analysis based on fundamental parameters. Anal Chem 63 2237... 

Quantitative fluorescence imaging techniques and FLIM in particular are becoming increasingly important in biological and biomedical sciences. Knowledge of instrumentation and data analysis is required to avoid misinterpretation of the experimental results and to exploit the wealth of information provided by these techniques. 

Zheng, J. (2006). Spectroscopy-based quantitative fluorescence resonance energy transfer analysis. Methods Mol. Biol. 337, 65-77. 

Measurement of blue and green fluorescence of NADH and FAD in living tissues Quantitative fluorescent cytochemistry Using permeable fluorogenic substrates of enzymes, specific inhibitors, and kinetic analysis... 

Tertain, R. Claisse, F. "Principles of Quantitative X-ray Fluorescence Analysis", Heyden London, 1982. 

Figura, P.M. 1987. Standardless quantitative X- ray fluorescence analysis using stored calibration constants. American Laboratory, 19(2), 156-164.

Optical examination of etched polished surfaces or small particles can often identify compounds or different minerals hy shape, color, optical properties, and the response to various etching attempts. A semi-quantitative elemental analysis can he used for elements with atomic number greater than four by SEM equipped with X-ray fluorescence and various electron detectors. The electron probe microanalyzer and Auer microprobe also provide elemental analysis of small areas. The secondary ion mass spectroscope, laser microprobe mass analyzer, and Raman microprobe analyzer can identify elements, compounds, and molecules. Electron diffraction patterns can be obtained with the TEM to determine which crystalline compounds are present. Ferrography is used for the identification of wear particles in lubricating oils. 

Similar to the analytical procedure for trace analysis in high purity GaAs wafers after matrix separation, discussed previously,52 the volatilization of Ga and As has been performed via their chlorides in a stream of aqua regia vapours (at 210 °C) using nitrogen as the carrier gas for trace/matrix separation.58 The recoveries of Cr, Mn, Fe, Ni, Co, Cu, Zn, Ag, Cd, Ba and Pb determined after a nearly quantitative volatilization of matrix elements (99.8 %) were found to be between 94 and 101 % (except for Ag and Cr with 80 %). The concentrations of impurities measured by ICP-DRC-MS (Elan 6100 DRC, PerkinElmer Sciex) after matrix separation were compared with ICP-SFMS (Element 2, Thermo Fisher Scientific) and total reflection X-ray fluorescence analysis (TXRF Phillips). The limits of detection obtained for trace elements in GaAs were in the low ngg-1 range and below.58... 

J. M. Adams and J. R. Allen, Quantitative X-ray fluorescence analysis of geological matrices using PLS regression. Analyst, 123, 1998, 537-541. 

Purity of the product was ascertained by quantitative X-ray fluorescence analysis for chlorine and mercury, which showed satisfactory agreement with calculated values. Compounds containing both mercury and chlorine are difficult to analyze by classical wet analytical procedures. 

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