Absorption spectrophotometric analysis

Atomic absorption spectrophotometric analysis and kinetic analysis of wild-type 1,2-a-D-mannosidase were performed. Concentrations of Ca2+ were determined by atomic absorption spectrophotometric analysis. The purified recombinant wild type 1,2-a-D-mannosidase almost completely did not contain Ca2+. Other divalent metal cations including Mg2+, Mn2+, Co2+, Cu2+, and Zn2+ were also not detected. 

Preconcentration of metals from water samples prior to atomic absorption spectrophotometric analysis increases the sensitivity of the analytical technique. It is only necessary when the level of metal required to be determined in the unconcentrated sample is below that which can be confidently measured by direct aspiration. 

This chapter deals with the origin, nature, and measurement of the spectra of molecules arising from the absorption of near-ultraviolet and visible radiation and the dependence of the spectra on molecular structure, reactivity, and interactions with the environment. In addition, the instrumentation employed to obtain the spectra and the techniques used in absorption spectrophotometric analysis are discussed. 

Absorption spectrophotometric analysis procedures have been developed for a number of environmental species. For water contaminants alone, these include procedures for the determination of arsenic, boron, bromide ion, cyanide, fluoride, nitrate, phenols, phosphate, selenium, sUica, sulfide, surfactants, and tannin and lignin. A typical such procedure is the spectrophotometric determination of phenol in water by the reaction with 4-aminoantipyrene... 

Pyrochemical reprocessing using molten salts has the potential to recover actinides from spent nuclear fuels [1,2], Since some fission products of rare earth elements have large neutron capture cross-sections, separating them from actinides is desirable. In order to control the separation performance, monitoring the concentration of each element is important. Absorption spectrophotometric analysis is superior to determine the solute concentration and hence its application is examined. 

While the control resins were deep red in color due to the presence of soluble porphyrin complexes, the methacrylate resins obtained after removal of the polyethylene-supported catalysts varied from light yellow to nearly water-white (APHA < 25). UV-Vis spectrophotometric analysis of the yellow resins indicated an absorption signal for the cobalt porphyrin complex Soret band (wavelength of cobalt(ll) porphyrin species appears at -415 nm free porphyrin ligand is formd at -423 tun). Resin samples that visttally appear as water-white show little or no porphyrin species present in the spectrum. Measured catalyst activity and PDl of the polyethylene-supported porphyrin complexes are in the expected range for soluble porphyrin CCT catalysts (PDl = M /Mn - 1.2- 2.0)." The screening resrrlts clearly... 

Stabilisers are usually determined by a time-consuming extraction from the polymer, followed by an IR or UV spectrophotometric measurement on the extract. Most stabilisers are complex aromatic compounds which exhibit intense UV absorption and therefore should show luminescence in many cases. The fluorescence emission spectra of Irgafos 168 and its phosphate degradation product, recorded in hexane at an excitation wavelength of 270 nm, are not spectrally distinct. However, the fluorescence quantum yield of the phosphate greatly exceeds that of the phosphite and this difference may enable quantitation of the phosphate concentration [150]. The application of emission spectroscopy to additive analysis was illustrated for Nonox Cl (/V./V -di-/i-naphthyl-p-phcnylene-diamine) [149] with fluorescence ex/em peaks at 392/490 nm and phosphorescence ex/em at 382/516 nm. Parker and Barnes [151] have reported the use of fluorescence for the determination of V-phenyl-l-naphthylamine and N-phenyl-2-naphthylamine in extracted vulcanised rubber. While pine tar and other additives in the rubber seriously interfered with the absorption spectrophotometric method this was not the case with the fluoromet-ric method. 

A spectrophotometer is a combination of spectrometer and photometer. A photometer is an instrument which is used for the production of light of selected colour or wavelength. The spectrometry involves the determination of the light absorptive capacity of a chemical. So spectrophotometric analysis provides a significant method of determining minute quantities of a substance. 

Therefore, it is difficult or impossible to relate the ash obtained from a food with its salts system, and low values are obtained for certain mineral elements by analysis of the ash compared to direct analysis of the intact food. Titrimetric, colorimetric, polarographic, flame photometric and atomic absorption spectrophotometric techniques are frequently used to analyse for the various mineral constituents however, the quantitative estimation of... 

Inorganic expl materials have also proven to he amenable to IR spectroscopic analysis. An IR spectrophotometric analysis method for carbon monoxide, carbon dioxide, nitric oxide, nitrous oxide and nitrogen dioxide produced in vacuum stability tests of expls stored together with polymeric materials has been developed (Ref 60). Structural properties, as elucidated by IR absorption, of a variety of new perfluorinated and halofluorinated covalent perchlorates are reported in Ref 42. Characterization of the products of the pyrot reaction of silicon and red lead in oxygen... 

AOAC. 1984b. Tin in food Atomic absorption spectrophotometric method. In AOAC official methods of analysis, 474. 

Cold vapor atomic absorption spectrophotometric method is applicable only for the mercury analysis. The principle of this method is described below. 

Maguire, R.J. and Tkacz, R.J. (1983) Analysis of butyltin compounds by gas chromatography. Comparison of flame photometric and atomic absorption spectrophotometric detectors./. Chromatogr., 268, 99-101. 

Apparatus For sample digestion, use the microwave apparatus as described for Apparatus in the Arsenic test (above). For sample analysis, see Apparatus for Method I in the Atomic Absorption Spectrophotometric Graphite Furnace Method under Lead Limit Test, Appendix IIIB. 

Limitations in colorimetric and atomic absorption spectrophotometric measures have prompted development of alternative methods of transition metal analysis. One example is the use of ion exchange chromatography to assess transition metals in serum and whole blood, a method developed by the company Dionex. While identification of transition metal complexes can also be made on the basis of symmetry (Laporte mle) or spin selection rule or analysis of charge transfer spectra, one of the most significant methods is on the basis of magnetism. The... 

The spectrum thus obtained enables the technique to be used as a classical method of spectrophotometric analysis, in which specific absorption wavelengths of organic compounds are employed to determine concentrations of the target analytes. 

Official Methods of Analysis of AOAC International, 17th edn. Rev 1, AOAC International, Gaithersburg, MD, USA, Official Method 973.34. Cadmium in Food - Atomic Absorption Spectrophotometric Method (2002)... 

Chloramine (Chloramide, Monochloramine). ClNHj, mw 51.48, N 27.2% a colorl liq or crysts, mp —66°, decoipps above the mp (Refs 2 8). It has an IR absorption peak at 2430A which can be used for spectrophotometric analysis (Ref 3). It is unstable at room temp except in aq soln, so it is stored and handled in this form (Ref 4) CA Registry No 10599-90-3... 

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