Derivative absorption spectra

Mantini A R, Marzocchi M P and Smulevich G 1989 Raman excitation profiles and second-derivative absorption spectra of beta-carotene J. Chem. Phys. 91 85-91... 

Because of peak overlappings in the first- and second-derivative spectra, conventional spectrophotometry cannot be applied satisfactorily for quantitative analysis, and the interpretation cannot be resolved by the zero-crossing technique. A chemometric approach improves precision and predictability, e.g., by the application of classical least sqnares (CLS), principal component regression (PCR), partial least squares (PLS), and iterative target transformation factor analysis (ITTFA), appropriate interpretations were found from the direct and first- and second-derivative absorption spectra. When five colorant combinations of sixteen mixtures of colorants from commercial food products were evaluated, the results were compared by the application of different chemometric approaches. The ITTFA analysis offered better precision than CLS, PCR, and PLS, and calibrations based on first-derivative data provided some advantages for all four methods. ... 

Fig. 3.44 Second-derivative absorption spectra oflOpM 4-hydroxytamoxifen in DMPC liposomes at different lipid concentrations. The nominal concentration of DM PC in suspensions was 0 (curve 0), 21 (1), 28 (2), 42 (3),...

The spectral shifts of the iron complexes of transferrins occurring upon modification of amino groups were particularly prominent with succinylated derivatives. Absorption spectra in the visible range for succinylated chicken ovotransferrin are seen in Fig. 17. The changes were a shift in the maximum from 465 mp to shorter wavelengths, and an increase in absorption at approximately 400 mp. Similar but slightly different spectral shifts have been obtained by treatment of metal free transferrins with hydrogen peroxide (82) (Komatsu and Feeney, 1966 un-... 

Fig. 3.5. Derived absorption spectra of the (001) face. The solid and dotted curves were obtained from the corresponding curves of Fig. 3.4 by Kramers-Kronig analyses. The projection of the two molecules of the unit cell onto the (001) plane is shown. Reprinted with permission from Clark et al. (63). Copyright 1970, American Institute of Physics.

Nordal and Kanstad have derived absorption spectra by photothermal radiometry (PTR), a technique whereby the absorption of amplitude-modulated light causes pulsating surface temperatures and hence a pulsed thermal reradiation. Applications of this technique to biological materials such as blood and leaves have been demonstrated. 

Figure 7.15. Typical second-derivative absorption spectra of gaseous samples. A Spectrum of an automobile exhaust. B Spectrum of 14 ppm benzene. Spectra courtesy of Lear Siegler Inc., Environmental Technology Division, Englewood, Colorado.

Absorption Spectroscopy. Second derivative absorption spectra were recorded using a Perkin-Elmer Model 554 absorption spectrophotometer. Film samples were analysed by transmission on optically transparent quartz flats. 

TABLE 1. The 4th derivative absorption spectra components of chtoroplasts from control and chilling temperature treated cucumber leaves... 

Fig. 4. Powder line shapes in continuous wave (CW) ESR (derivative absorption spectra) and echo-detected ESR (absorption spectra), (a) Rhombic g-tensor. (b) Axial g-tensor. (c) Axial hyperfine coupling tensor with dominating isotropic contribution.

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