Spectrophotometric Investigations

Type I gives the same absorption spectrum as free hematin c in acid solution, with a strong band at 635 m/i and less pronounced bands at 542 and 505 m.fi. The position of the Soret band was not determined for type I. Type II shows a spectram intermediate between I and III the band in red is less intense than in I, and is displaced to 622 m/t. Other absorption maxima are found at 525, 497, 395 (Soret band), and 275 m/i. Type III shows the previously well-known bands of ferricytochrome c in about neutral solutions 695 and 655 m/ (visible only in strong solutions), 565, 530,408,365, and 280 m/u. Tj je IV gives bright red solutions because it has no bands in red and the general light absorption in red is lower than in any of the other types. Spectroscopic absorption maxima were found at 565, 537, 408, 355, and 280 m/t. Tyn e V shows bands at 565, 536, 412, 350, and 290 m/x. 

Type II gives a fluoride compound with a strong band at 601 mp. It can exist only in a very narrow pH range around pH 3. The reason is that at lower pH values the hydrofluoric acid becomes more and more undissociated, whereas at higher pH values type II merges into III, which gives 

Ferroq/tochrome c shows the same bands in the spectroscope over the entire pH scale. Precise spectrophotometric measurements of the light absorption at different acidities seem not to have been carried out. Unpublished experiments by K. G. Paul show that the absorption coefficient at 550 mp, on top of the main visible band, changes its value somewhat between pH 9 and 10, indicating a heme-linked group with pK in this region. 

There are, however, also other reasons in support of the assumption that heme-linked groups in ferrocytochrome are affected by changes in pH. Below pH 4 and above pH 13 ferrocytochrome c is autoxidizable. Between pH 3 and pH 12 no carbon monoxide compounds are formed but at pH 2 

From pH 5.5 to pH 8.5, the normal region of titration of the histidine imidazole, a total of about two equivalents was titrated in both ferric and ferrous cytochrome. Not even the whole of these two equivalents, however, can be attributed to imidazole according to the determination of the apparent heat of dissociation with the aid of titrations at 0° and 20°C. On the strength of these data it was suspected that two of the three imidazole nuclei present in the cytochrome c molecule were linked to the iron in a way that displaced their pK values out of the normal range. 

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For a review of spectrophotometric investigations of this type of carbanion, see Buncel, E. Menon, B. in Buncel Durst, Ref. 84, p. 97. 

Tc(III), Tc(IV) and Tc(V) P-diketonate complexes are stable in acid solution. In fact, when a chloroform solution of TcCl2(acac)2 was shaken with 1 M hydrochloric acid solution, no detectable change in the distribution ratio of the complex - defined as the ratio of the concentration of technetium in the organic phase to that in the aqueous phase - was observed over a 24 h period [26]. However, when the technetium complexes were backextracted into aqueous alkaline solution, decomposition occurred [26-29]. In all the cases studied, spectrophotometric investigation revealed that pertechnetate was formed quantitatively as a final product. 

Benesi HA, Hildebrand JH (1949) A Spectrophotometric investigation of the interaction of iodine with aromatic hydrocarbons. J Am Chem Soc 71 2703-2707... 

Bacci M., Baldini F., Scheggi A.M., Spectrophotometric investigations on immobilized acid-base indicators. Anal. Chim. Acta 1988 207 343. 

In the standard equation for multiwavelength spectrophotometric investigations, based on Beer-Lambert s law, the matrix Y is written as the product of the matrices C and A. According to the Singular Value Decomposition (SVD), Y can also be decomposed into the product of three matrices... 

This interpretation is in agreement with the results of a recent Raman spectroscopic study 93) supporting the absence of [MX4 ]" — ions and also with the results of other spectrophotometric investigations 9X In the system AsI3-HMPA the final spectrum is obtained at a molar ratio D Asl3 = 2 1, whereas with the weaker donor DMA a considerable excess of donor is required in order to attain the final spectrum. 

Fig. 2 Cyclic voltammogram of Np(VI) in 3.1 M LiOH on a Pt electrode (area 0.5 cm ), first scan, 20 mV s (reprinted from Radiochimica Acta, Vol. 89, A. V. Gelis, P. Vanysek, M. P. Jensen, K. L. Nash, Electrochemical and Spectrophotometric Investigations of Neptunium in Alkaline Media, Pages 565-571,2001, with permission from Oldenbourg Wissenschaftsverlag GmbH).

Apparatus. The course of reaction was followed by periodically measuring the volume of oygen absorbed at constant pressure, and by analysis. The apparatus and techniques for measuring oxygen uptakes have already been described (3). Spectrophotometric investigation of complexes in solution was carried out using a Unicam SP800 spectrophotometer. 

In the course of polarographic and spectrophotometric investigations of isomeric phthalaldehydes, it has been observed that substituted benzaldehydes... 

Oxymercuration of alkenes is an electrophilic reaction involving the addition of mercuric salt and of a protic solvent (alcohols) according to reaction 9. UV/VIS spectrophotometric investigation of the olefin/mercuric salt reaction mixtures in methylene chloride provides evidence of the presence of an electron donor-acceptor complex between olefin and mercuric salt110 which is considered to be on the reaction pathway of the oxymercuration. 

A spectrophotometric investigation of the ground-state absorption of benzophenone in pure SC CO2 and in the presence of 2-propanol was performed in order to determine both benzophenone solubility and the potential for solute/solute or co-solvent/solute aggregations. Linear Beer s law plots of absorbance versus concentration of benzophenone over a concentration range of 1-15 mM in SC OO2 insured that the ketone was fully disolved and in a non-associated form under the conditions of the laser experiments (- 10 mM). Analysis of the absorption spectrum of benzophenone in SC CO2 ranging from high to low pressure, resulted in absorption bands nearly... 

V02+, forming the vanadyl (V02+) species (Scheme 4). The results of Secco s spectrophotometric investigation were largely confirmed by 51V NMR followed under similar catalytic conditions [83],... 

These results were not quite in agreement with those of spectrophotometric investigations reported by Brand and his co-workers [104], Brand suggested that the difference was due to insufficient knowledge of the true form of nitro compounds in the solutions under consideration. He assumed that nitro compounds... 

Figure 4 Spectrophotometric investigation of the photolysis of ketoconazole in a methanolic solution (3.6mg/100mL Suntest CPS with UV-filter). (A) Absorption change at the spectral maximum of 242nm, (B) UV absorption spectrum of the solution (1) before irradiation (2) after an irradiation period of 100 minutes.

MePhie, P. (1972). A spectrophotometric investigation of the pepsinogen-pepsin conversion. J. Bjof. Otem. 247, 4277-4281-... 

Homsher R, Zak B. Spectrophotometric investigation of sensitive complexing agents for the determination of zinc in serum. Clin Chem 1985 31 1310-3. 

Spectrophotometric Analysis. Florescamine (Fluram, Roche Diagnostics) is a nonfluorescent compound that reacts with primary and secondary amines to form fluorescent compounds. It has been used chiefly in the spectrophotometric investigation and assays of biological compounds. This investigation utilized the compound to determine concentrations of primary and secondary amines. 

Kuntic V, Kosanic M, Malesev D, Radovic Z. Spectrophotometric investigation of Pd(II)-rutin complexes and its application to rutin determination in tablets. Pharmazie 1998 53 724-6. 

Kuntic V, Malesev D, Radovic Z, Kosanic M, Mioc U, Vukojevic V. Spectrophotometric investigation of uranil(II)-rutin complex in 70% ethanol. J Agric Food Chem 1998 46 5139-42. 

In an infrared spectrophotometric investigation, Vasilyev and Emanuel [13] attribute the 847 cm 1 band to the O—O bond of a hydroperoxidic structure and favor structure II for the X peroxide. The authors base their argument on the fact that, in peracetic acid, this band is 856 cm 1 and, generally speaking, it is 835—855 cm"1 in hydroperoxides, Nevertheless, the band corresponding to the 0—0 bond is 840—842 cm"1 in acyl peroxides [14], whereas, in diacyl peroxides [15], it is 890—904 cm 1 and hence the argument put forward is not decisive. 

Disubstituted barbituric acids when subjected to UV-spectrophotometric investigations reveal the following facts, namely ... 

Ref. 11 Zommer S and Szuszkiewicz J. Spectrophotometric investigations of acid-base properties of hydrazides of isonicotinic and cyanoacetic acids. Chemia Analityczna (Warsaw, Poland), 14(5), 1075-1083 (1969) CA 72 89616n. 

Ref. 65 Rekker RF and Nauta WT. Spectrophotometric investigation of isonicotinoyl hydrazide (INH). A contribution to the knowledge of the yellow isonicotinoyl hydrazide-p-aminosalicylic acid combination (INH-PAS), Pharm. Weekblad, 99(42), 1157-1165 (1964) CA 63 435c. 

Zommer-Urbanska S, Bojarowicz H, Spectrophotometric investigations of protolytic equilibria of mefenamic acid and determination by means of Fe(III) in methanol-aqueous media,... 

Knight, R. J. and R. N. Sylva. 1975. Spectrophotometric investigation of iron(III) hydrolysis in light and heavy water at 25°C. J. Inorg. Nucl. Chem. 37, 779-783. 

Spectrophotometric investigation of the UV, visible, and near-infrared regions made possible the determination of the electronic spectra of each individual species and, thus, provided information about the solvation of the copper(II)-chloro complexes in DMF. The matrix rank treatment of more than 1000 spectrophotometric data demonstrates the presence of a minimum of four absorbing species the free copper ion and three chloro complexes. 

Basavaiah K and Swamy JM (2001) Application of potassium dichromate and iron-thiocyanate in the spectrophotometric investigations of phenothiazines. II Farmaco 56(8) 579-585. 

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