Absorption Spectra of Mixtures

Fig. 21. IR absorption spectra of mixture 2 CoO - Nb205 - 10 NH4HF2, treated at 170X1 (1), 225X1 (2), 250X1 (3), 350X1 (4) 400X1 (5) and 900°C (6). Reproduced from [129], A. I. Agulyansky, E. L. Tikhomirova, V. T. Kalinnikov, Zh. Neorg. Khim. 32 (1987) 2079, Copyright 1987, with permission of Nauka (Russian Academy of Sciences) publishing.

UV/VIS-absorption spectra of mixtures with fatty acids Morphology of mixtures with fatty acids Electron diffraction of 34 and 35... 

An investigation of the infra-red spectra of mixtures of nitric acid and acetic anhydride supports these conclusions. The concentration of nitronium ions, measured by the absorption band at 2380 cm, was... 

Nitric oxide and OF2 inflame on contact emission and absorption spectra of the flame have been studied (24). Oxygen difluoride oxidizes SO2 to SO, but under the influence of uv kradiation it forms sulfuryl fluoride [2699-79-8] SO2F2, and pyrosulfuryl fluoride [37240-33-8] S20 F2 (25). Photolysis of SO —OF2 mixtures yields the peroxy compound FSO2OOF [13997-94-9] (25,26). 

Fig. 14-17. Infrared absorption spectra of liquid carbon tetrachloride, CCU, carbon disulfide, CSt, and a mixture of the two.

The above considerations will be illustrated by the simultaneous determination of manganese and chromium in steel and other ferro-alloys. The absorption spectra of 0.001 M permanganate and dichromate ions in 1M sulphuric acid, determined with a spectrophotometer and against 1M sulphuric acid in the reference cell, are shown in Fig. 17.20. For permanganate, the absorption maximum is at 545 nm, and a small correction must be applied for dichromate absorption. Similarly the peak dichromate absorption is at 440 nm, at which permanganate only absorbs weakly. Absorbances for these two ions, individually and in mixtures, obey Beer s Law provided the concentration of sulphuric acid is at least 0.5M. Iron(III), nickel, cobalt, and vanadium absorb at 425 nm and 545 nm, and should be absent or corrections must be made. 

This exercise provides the opportunity of examining the absorption spectra of typical aromatic hydrocarbons and of investigating the possibility of analysing mixtures of hydrocarbons by ultraviolet spectrophotometry. 

FIGURE 5. Absorption spectra of solvated electrons in DMSO/H20 mixtures 0,0.20,0.28,0.43,0.72,0.93 and l.Omole fraction DMSO. To fit into the Figure, the data for pure water have been multiplied by a factor of 0.65 relative to the others. These spectra represent the short-lived solvated electron band only, the longer-lived 600nm band and UV bands having been substracted from the observed absorbances. Reproduced by permission of the authors from Reference 30. 

Only a few quantitative data are available on copolymerization of methacrylates. Direct determination of the cross-propagation constants is readily achieved in living polymer systems whenever the absorption spectra of the two propagating species are different. Unfortunately, this is not the case in the methacrylate series. A new approach to this problem was developed by Muller 43). A mixture of two monomers is copolymerized, the reaction is interrupted at various times, and the concentrations of the residual monomers are determined as functions of time. The pertinent differential equations include 4 constants ku, k12, k21, and k22. Since kn and k22 were independently determined, the remaining cross-propagation constants are obtained by computer fitting the experimental conversion curves to the calculated ones. 

Figure 3. Absorption spectra of Au seed particles (S), UV-irradiation of the mixture of [Au(0)] + [AgN03] (Al) after lOinin, (A2) after ISinin and (A3) after prolonged time. Condition for gold seed TX-lOO (10 M) and HAuCfi (5.0 X 10 M), of which the final concentration of Au(III) ion remains 5.0 x 10 M. For Al and A2, [Au] = 1.67 x 10 and [AgNOs] = 3.33 X 10 M. (Reprinted from Ref [35], 2001, with permission from American Chemical Society.)...

Fig. 10. Absorption spectra of aqueous solutions of [PtiNHalsClJCCIOJa and K4[Os(CN)6]. Left-hand curve separate solutions right-hand curve mixture. The broken curve gives the difference between the two spectra and corresponds to Os(IIFPt(IV) MMCT (after data in Ref. [62])...

These procedures were further extended to tris(acetylacetonato)technetium(III) [24]. In an acetonitrile solution of Tc(acac)3, the absorbances at the characteristic absorption maxima at 348,375,505 and 535 nm decreased with time, while an increase in the absorbance at 272 nm corresponded to an increase of free acetylacetone liberated during the substitution reaction. The final absorption spectra of the reaction mixture exhibited absorption maxima at 271,325 and 387 nm. The first order rate constant k for decomposition was found to be k = (8.86 + 0.08) x 10 4s 1at [H+] = 2.0 M at 30°C. 

FIGURE 8.5 Absorption spectra of zeaxanthin dissolved in pure ethanol (solid line), in ethanol/water mixture with 1 4 ratio (dotted line), and in 3 2 ethanol/water mixture. Minor bands of the H-aggregate are denoted by. ... 

FIGURE 14.3 (See color insert following page 336.) Ground state absorption spectra of lxlO-5 M zeaxanthin in various MeOD/D20 mixtures. 

Galego and Arroyo [14] described a simultaneous spectrophotometric determination of OTC, hydrocortisone, and nystatin in the pharmaceutical preparations by using ratio spectrum-zero crossing derivate method. The calculation was performed by using multivariate methods such as partial least squares (PLS)-l, PLS-2, and principal component regression (PCR). This method can be used to resolve accurately overlapped absorption spectra of those mixtures. 

Figure 5. UV absorption spectra of a thin film of an equimolar mixture of TTDBM/SEGDVE as a function of exposure time to a Pyrex-filtered medium pressure mercury lamp (I 19 mW cm"2).

The dependence of steady photocurrents on excitation wavelength corresponded well with the absorption spectra of AMP in LB films as shown in Figure 7 independent of the molar ratio or the surface pressure of deposition. Much higher photocurrents were observed at the same bias voltage in LB films deposited at 50 mN nr1 (film A) than those at 20 mN m1 (film B). Figure 21 shows a bias voltage dependence of the ratio of photocurrents at 560 nm for film A and film B, I50/I2O/ deposited from 1 5 and 1 10 mixtures. The ratio was... 

Fig.8. Absorption spectra of monolayers of C180AZON02 and CI8OAZOCOOH and their mixture 1 C180AZ0N02,...

The infrared, NMR, and electronic absorption spectra of the two complexes H2FeRu2Os(CO)i3 and H2FeRuOs2(CO)13 have been taken to indicate a structure for these compounds similar to H2FeRu3(CO)13. However, the infrared and low-temperature proton NMR spectra of both compounds indicate that they exist as a mixture of isomers the two projected isomers for H2FeRu2Os(CO)13 are shown in Fig. 58 (247). The mixed manganese and rhenium-osmium complexes, H3MOs3(CO)13, have been prepared by acidification of the reaction mix-... 

Fig. 2 (a) Schematic of the formation of silver clusters using DNA oligonucleotide as scaffold. After complexation of DNA with silver cations, the mixture is reduced with NaBtL, and the fluorescent cluster is formed, (b) Absorption spectra of silver clusters acquired every 30 min using [5 -AGGTCGCCGCCC-3 ] = 10 uM. [Ag+] = 60 uM. and [BfLj-] = 60 pM. The foremost spectrum was acquired 9 min after adding the BH4, and it has at 426 nm. The inset spectrum shows the last spectmm in the series (692 min), with peaks at 424 and 520 nm. (c) Induced circular dichroism spectra. The cell path length was 5 cm. The spectra were collected 2 min (A, dashed-dotted line), 20 min (B, dotted line), 40 min (C,fine dashed line), 60 min (D, coarse dotted line), and 150 min (E, solid line) after adding the BH [32]... 

Fig. 2.162. Absorption spectra of Amphiopl expressed in HEK293s cells (a) and the HPLC patterns of retinal oximes (b). Absorption spectra and the HPLC patterns were measured before (a, curve 1, and b, top trace) and after irradiation at 520 nm for 2 min (a, curve 2, and b, middle trace). The HPLC pattern of retinal oximes extracted from a mixture of irradiated and non-irradiated bovine rhodopsin in equal amounts is indicated as a reference (b, bottom trace). The absorption maxima of the original pigment and its phoroproduct are shown in panel (a). Reprinted with permission from M. Koyanagi et al. [334].

Abstract Aspartame (Apt), Acesulfame-K (Ace-K) low-calorie, high-potency artificial sweeteners ate cnnently nsed in beverages and dietary food and drinks. Their increased application in food and drink prodncts has given a new impetus to develop fast and accurate methods for their determination. Absorption spectra of Asp, Caf, Ace-K and BA strongly overlap. Therefore a direct determination of these analytes in quaternary mixture is impossible without a separation step. In order to overcome this difficulty partial least squares (PLS) method has been proposed. 

The fact that the boron trifluoride t-butyl fluoride (and chloride) system and the boron trifluoride isopropyl fluoride systems on thermal decomposition yielded polymer mixtures may indicate the equilibrium in equation (1). On measuring absorption spectra of boron trifluoride—... 

Figure 1. Absorption spectra of lignin peoxidase oxycomplex and compound II. Also shown is the calculated spectra of the mixtures of oxycomplex and compound II. In descending order of the Soret peak extinction coefficient, 100% oxycomplex (416 nm) is shown in solid line the mixture of 75% oxycomplex and 25% compound II (417 nm) in long dashed line the mixture of 50% oxycomplex and 50% compound II (417 nm) in dotted line the mixture of 25% oxycomplex and 75% compound II (419 nm) in dashed-dot line and 100% compound II (420 nm) in me um dashed line.

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