Principles of Self-Modulating Derivative Optical Spectroscopy

Bonfiglioli, G.; Brovetto, P.

doi:10.1364/ao.3.001417

Cited by 72 publications

(10 citation statements)

References 6 publications

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“…Simplified least-squares method for the calculation of second derivative absorption spectra Historically, second derivative electronic absorption spectra have been obtained either with electronic differentiators (Martin, 1957;Green and O'Haver, 1974) or with wavelength modulators (Bonfiglioli and Brovetto, 1964;Williams and Hager, 1970). With the increased availability of microprocessor-controlled spectrophotometers, it is now possible to record an absorption spectrum in a computerreadable format, and to calculate the second derivative with use of numerical methods such as the simplified leastsquares method of Savitzky and Golay (1964) or by differentiation in the Fourier domain (Kauppinen et al, 1981b;Moffat, 1984, 1987;Mantsch et al, 1988).…”

Section: Quantitative Analysis Of Direct and Second Derivative Electronic Absorption Spectramentioning

confidence: 99%

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

Horvath

Copeland

Makinen

1999

Biophysical Journal

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The electronic absorption spectrum of solubilized beef heart cytochrome c oxidase was analyzed in the 400-500 nm region to identify the origin of doublet features appearing in the second derivative spectrum associated with ferrocytochrome a. This doublet, centered near 22,600 cm(-1), was observed in the direct absorption spectrum of the a(2+)a(3)(3+).HCOO(-) form of the enzyme at cryogenic temperatures. Since evidence for this doublet at room temperature is obtained only on the basis of the second derivative spectrum, a novel mathematical approach was developed to analyze the resolving power of second derivative spectroscopy as a function of parameterization of spectral data. Within the mathematical limits defined for resolving spectral features, it was demonstrated that the integrated intensity of the doublet feature near 450 nm associated with ferrocytochrome a is independent of the ligand and oxidation state of cytochrome a(3). Furthermore, the doublet features, also observed in cytochrome c oxidase from Paracoccus denitrificans, were similarly associated with the heme A component and were correspondingly independent of the ligand and oxidation state of the heme A(3) chromophore. The doublet features are attributed to lifting of the degeneracy of the x and y polarized components of the B state of the heme A chromophore associated with the Soret transition.

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Section: Quantitative Analysis Of Direct and Second Derivative Electronic Absorption Spectramentioning

confidence: 99%

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

Horvath

Copeland

Makinen

1999

Biophysical Journal

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“…Chromium is well known to be more interference-prone than the other three elements (8,9). Even here, when the single-slot head was used, only phosphoric acid interfered by more than 1% at the lower acid concentration.…”

Section: Iwaflementioning

confidence: 75%

Acid interferences in atomic absorption spectrometry

Barnett¹

1972

Anal. Chem.

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A study was made of the interferences caused by five mineral acids with the determination of copper, chromium, manganese, and nickel by atomic absorption. Variations in acid concentration, flame type, and flame stoichiometry were examined. Significantly smaller interferences were found than had been previously reported, probably because of differences in burner design. The use of a lean air-acetylene flame on a single-slot head produced the fewest and smallest interferences. Shifting to a nitrous oxide-acetylene flame, often recommended as a means of reducing interferences, frequently increased them. FLAME SPECTROMETRY offers a rapid, accurate method for the determination of metallic elements. One potential problem, widely discussed in the literature, is the extent and severity of analytical interferences.Recent reports ( I , 2) attracted our attention because they reported interferences which were larger than our experience indicated should exist. The elements involved were common-Cu, Cr, Mn, and Ni-and the interfering substances were mineral acids at frequently encountered concentrations. The original objective of the study, thus, was to see if the reported observations applied to the burner we use. Subsequently, it was decided to extend the study to include the nitrous oxide-acetylene flame. It is well known (3) that use of the nitrous oxide-acetylene flame eliminates many interferences which are present in an air-acetylene flame. Some workers (4-6), however, have noted interferences peculiar to the nitrous oxide-acetylene flame.The work reported in this study, while not purporting to explore all the possible permutations, has attempted to examine some of the more obvious variables. The intent was to ascertain what experimental conditions would provide the most interference-free environment for determining these four elements in the presence of five commonly employed mineral acids. EXPERIMENTALThe instrumentation employed for this study consisted of a Perkin-Elmer Model 403 atomic absorption spectrophotometer equipped with its standard burner, single-element Intensitron hollow cathode lamps, and a TR-1 typewriter readout. This combination is especially suited to experiments of this type where a large amount of data must be recorded.The instrument produces data in digital form eliminating the need to interpret strip chart recordings and the TR-1 can be programmed to log these data directly in convenient, tabular form.

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“…Two separate photomultipliers would ease both the optical and electronic de~ign, 18 • 22 but at the expense of an imperfect matching of the spectral responses.…”

Section: -6-mentioning

confidence: 99%

Wavelength modulation spectroscopy of semiconductors

Zucca

1971

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Principles of Self-Modulating Derivative Optical Spectroscopy

Cited by 72 publications

References 6 publications

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

Acid interferences in atomic absorption spectrometry

Wavelength modulation spectroscopy of semiconductors

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