Fast atom bombardment mass spectra of involatile monophosphonated and mixed sulphonated/monophosphonated azo dyestuffs

Fast atom bombardment mass spectra of a range of involatile monophosphonated and mixed sulphonated/monophosphonated azo dyestuffs are presented. Good spectra are obtained and the fragmentations are discussed with special reference to the ions formed by cleavage of the azo linkage. The negative ion spectra are shown to be superior in terms of signal to background and structural information to those obtained in the positive ion mode. The results are compared with those obtained from sulphonated azo dyestuffs.     

Tricyclische CuII- und NiII-Chelate aus 2,2-Bis-(2-hydroxyarylazo)-biphenyl bzw. -diphenylsulfid

Tricyclic Cu^II and Ni^II chelates are produced from some 2,2′-bis-(2-hydroxyaryl-azo)-biphenyls and -diphenyl sulphides. From their electron spectra it is concluded that in the Ni complexes of the azo-biphenyl dyestuffs the central atom is coordinated in a different way (probably planar) from that in the corresponding Cu complexes. On the other hand, the valences of both metals in the azo-diphenyl sulphide complexes seem to have the same steric arrangement. This arrangement is probably the same as that of the Cu^II ion in the azobiphenyl dyestuffs, which could be tetrahedral.     

Steric hindrance effects in the use of heterocyclic azodyestuffs as spectrophotometric reagents

The heterocyclic azo dyestuffs 4-(n-methyl-2 -pyridylazo)-resorcinol (where n = 3', 4', 5', 6') have been prepared, and their possible use as spectrophotometric reagents investigated. The dyestuffs are shown to function analogously to the parent ligand 4-(2'-pyridylazo) resorcinol (PAR) in giving red complexes with the ions Co(2+), Ni(2+), Cu(2+), Zn(2+) and UO(2)(2+). Steric effects resulting from the position of the methyl group in the heterocyclic ring are shown to occur in relation both to the spectra of the dyestuffs themselves and to the sensitivity of their reactions with the metal ions.     

Tetrachlorogallate(III) complexes with basic triphenylmethane and diphenylnaphthylmethane dyestuffs

A general survey is given of the properties of tetrachlorogallate(III) complexes with basic dyestuffs of the triphenylmethane and diphenylnaphthylmethane class; solvents for extraction, the absorption spectra and molar absorptivities, the optimum concentrations of the dyestuffs and of hydrochloric acid, the stability of the compounds and their composition are also described. Analytical methods for the determination of traces of gallium by means of many of these complexes are suggested.     

The modern mass spectrometer—a complete chemical laboratory

Using nitrobenzene as an example, various ways in which a contemporary mass spectrometer can be utilized to yield a wealth of information about the compound studied are reviewed. Applying a variety of different techniques and procedures, in addition to the conventional low resolution mass spectrum, the following nitrobenzene spectra have been obtained: collision induced dissociation mass spectrum, mass analysed ion kinetic energy spectra, collision induced dissociation mass analysed ion kinetic energy spectra, spectra obtained at constant B/E, spectra obtained at constant B²/E, high voltage scans of metastable ion fragmentation processes, consecutive fragmentations in different field free regions, charge exchange mass spectra, charge stripping mass spectra, doubly charged ion mass spectra, chemical ionization mass spectra, negative ion mass spectra, negative ion mass analysed ion kinetic energy spectra, negative ion mass analysed ion kinetic energy collision induced dissociation spectra, charge inversion spectra, etc. The complementary types of information available from the above studies are discussed to show the unique versatility of mass spectrometry as a technique for the examination of organic compounds.     

The factors affecting the reflectance spectra of some dyes adsorbed on alumina

Various factors affecting the diffuse reflectance spectra of eosin B, rhodamine B, fuchsin, and o-nitrophenol adsorbed on Chromatographic alumina under various conditions were studied to explore the potential analytical application of reflectance spectroscopy to dyestuffs separated by thin-layer chromatography. Regeneration temperature, pH and grade of adsorbent, and humidity were found to influence the spectra but the technique may be utilized for the photometric analysis of food dyes adsorbed on alumina ; straight lines passing through the origin were obtained when the Kubelka-Munk function was plotted against a suitable concentration range of dye. For reproducible results, it is essential to employ the same grade of adsorbent and to prepare samples under uniform conditions of humidity.     

Use of fast atom bombardment mass spectrometry for the characterization of nitroaromatic isomers

Positive and negative ion fast atom bombardment (FAB) mass spectra of some monosubstituted nitroaromatic isomers are reported. Generally ions carresponding to [M + H]⁺ and M⁺ are observed in the positive ion FAB spectra; ions such as [M ? H] ^? and M^?˙ are observed in the negative ion FAB spectra. The use of FAB mass spectra to distinguish the isomers is discussed. Comparisons of FAB, chemical ionization and electron impact mass spectra of the same isomers (wherever possible) are reported. The structural information obtained in the negative ion FAB spectra complement those obtained in the positive ion FAB spectra.     

Synthesis and Characterization of Novel Monoazo N‐Ester‐1,8‐Naphthalimide Disperse Dyestuffs

Five novel monoazo disperse dyestuffs based on N‐ester‐1,8‐naphthalimide were synthesized. Acenaphthene was nitrated, then oxidized to 4‐nitro‐1,8‐naphthalic anhydride. 4‐Nitro‐1,8‐naphthalic anhydride was reacted with methyl and ethyl glycinate in alcoholic media, followed with reduction. 4‐Amino‐N‐methyl and ethyl glycinate‐1,8‐naphthalimide were obtained. These products were diazotized and coupled with appropriate aromatic amines to give bluish‐red or violet dyestuffs. All intermediates and dyestuffs were purified and characterized by ¹H‐NMR, FTIR, DSC, UV‐VIS and Elemental Analysis. Dispersion of dyestuffs was prepared in water and applied to polyester fabrics. The dyed fabrics showed that four of the synthesized dyestuffs were suitable for coloring polyester fibers, producing deep bluish red with very good build up properties.     

Ion mobility detection after supercritical fluid chromatography

Using a unidirectional flow ion mobility detector, non-selective detection, tunable selective detection, and complete Fourier transformed ion mobility spectra were successfully obtained after supercritical fluid chromatography on compounds with higher molecular weights than have been previously investigated. In the most selective mode, single oligomers from polymeric material could be independently detected. Using the Fourier transform capabilities of this instrument, complete ion mobility spectra for each oligomer could be obtained in a single chromatographic separation. The collection of individual ion mobility spectra of the components of polymeric material has not been possible prior to the technique described in this paper. Only complex ion mobility spectra of polymeric mixtures are available in the literature. The spectra obtained in this study are all simple, uncomplicated spectra consisting of only one or two product ion peaks. K_o values reported in this work range from 0.633 to 1.61, which are some of the lowest values ever reported in ion mobility spectrometry. With the unidirectional flow design of the detector, the supercritical fluid mobile phase, carbon dioxide, was efficiently eliminated from the detector so that the ion mobility spectrometer could be operated in its normal manner. The fact that CO₂ did not interfere with normal ion mobility operation indicates that other supercritical fluids may also be compatible with this sensitive and versatile detection method.     

Charge exchange using a double quadrupole mass spectrometer

Charge exchange mass spectra obtained on a double quadrupole (QQ) mass spectrometer are compared with those obtained by other methods. The effects of reagent ion recombination energies and of axial ion translational energy on these spectra are followed.     

Nichtchelatierende Farbstoffe als Basis empfindlicher spektrophotometrischer Methoden zur Bestimmung von Elementen

Zusammenfassung Zu den empfindlichsten, zur Spurenanalyse besonders geeigneten spektrophotometrischen Methoden gehören extraktions- und flotationsspektrophotometrische Methoden auf der Basis von lonenassoziaten unter Mitwirkung nichtchelatierender Farbstoffe. Eine Systematisierung der angewandten Gruppen basischer und saurer Farbstoffe wurde vorgenommen. Die Möglichkeiten der Bestimmung einzelner Elemente mit entsprechenden, nichtchelatierenden Farbstoffen wurden in erschöpfender Weise gezeigt. Anorganische und organische Liganden wurden angeführt, die die zu bestimmenden Elemente in die zur Assoziation mit Farbstoffen geeigneten Komplexanionen bzw.-kationen überführen. Probleme der Extraktion sowie der Extraktionsmittel wurden erörtert. Die Rolle sehr empfindlicher, zur Bestimmung kleiner Spurenmengen vieler Elemente geeigneter flotationsspektrophotometrischer Methoden wurde hervorgehoben.

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Non-chelating dyestuffs as basis for sensitive spectrophotometric methods for determining elements

Summary Extraction and flotation Spectrophotometric methods based on ion associates with participation of non-chelating dyestuffs are among the most sensitive Spectrophotometric methods and especially suitable for trace analysis. A systematization of the groups of basic and acid dyestuffs employed was undertaken. The possibilities of determining individual elements with appropriate non-chelating dyes were shown exhaustively. Inorganic and organic ligands were cited which convert the elements to be determined into complex anions or cations suitable for association with dyestuffs. Problems of extraction and the extractants were discussed. The role of very sensitive flotation Spectrophotometric methods suitable for determining small trace amounts of many elements was emphasized.

     

Analysis of dyestuff degradation products by capillary electrophoresis.

Capillary electrophoresis (CE) with two different detection methods, mass spectrometry (MS) and UV absorption spectroscopy with photodiode array detection (UV/DAD), was used for the analysis of the degradation products of dyestuffs. We have studied wet oxidation with solid catalyst as the treatment method of wastewaters containing dyestuffs. When the Orange II (C.I. Acid Orange 7) solution was used as the model wastewater, treated solution contained unknown highly polar degradation products. We were able to determine the molecular masses of some products by CE-MS. From this clue, we tried to identify these products by CE-UV/DAD. By means of the comparison of the migration time and UV spectra of standard samples, three degradation products were identified. The separation of degradation products was successful within 15 min.     

Saffron yellow: characterization of carotenoids by high performance liquid chromatography with electrospray mass spectrometric detection

Saffron is one of the oldest natural dyestuffs and is obtained from the dried stigmata of Crocus sativus L. Nowadays, saffron is considered as an invaluable spice of golden‐yellow hue, a precious ingredient in the Eastern and Mediterranean cuisines. It is characterized by a bitter taste that is caused by the chemical properties of its constituents. The yellowness of saffron results from the presence of crocins (glycosyl esters of crocetin), its main color compounds, which are examined in the present study in the crude methanol extracts by high performance liquid chromatography (HPLC) coupled with spectrophotometric and electrospray mass spectrometric detection (HPLC–UV‐Vis–ESI MS). This technique allowed the separation and identification of trans‐ and cis‐isomers of crocins. Their mass spectra registered in the negative ion mode comprised the quasi‐molecular and fragment ions, as well as a range of other ions. Doubly charged ions were found for trans‐isomers only, due to the high symmetry of their molecules. Modification of the eluent allowed the identification of several signals corresponding to adduct ions of crocins with the used additives. Copyright © 2009 John Wiley & Sons, Ltd.     

Fast atom bombardment mass spectra of involatile naphthalene sulphonic acids and sulphonate salts

Fast Atom Bombardment mass spectra of a range of involatile naphthalene sulphonic acids and sulphonates are presented. Excellent spectra are obtained for the mono-, di- and the previously unexamined trisulphonated compounds. The relative value of positive and negative ion spectra for the study of these species is discussed. The results are shown to be superior to those obtained by other mass spectrometric methods.     

Thin-layer chromatographic separation and detection of synthetic dye stuffs in alcoholic drinks and beverages

Summary A TLC technique for the detection and separation of dyestuffs in alcoholic drinks has been described. The migration distance and the colours of the separated coloured spots of 27 internationally recognised dye-stuffs obtained from alcoholic beverages are recorded.     

Removal of acidic dyestuffs in aqueous solution by nanofiltration

Separation of acidic dyestuffs, including Acid red 4, Acid orange 10, and Acid red 27, from aqueous solution by nanofiltration (NF) was shown to be a feasible process to accomplish an effective removal over a broad operational range. For most experiments conducted in this study, dyestuff rejections of greater than 98% were achieved. The permeate flux for experiments conducted with various dyestuffs was increased with increasing operating pressure and solution temperature. The permeability was increased and the rejection of dyestuffs was slightly decreased with increasing cross-flow velocity of solution. The effect of solution pH on the rejection of dyestuff was elucidated by the electrostatic characteristics between the species of dyestuff and the membrane surface. Maximum permeability was obtained for experiments operated in aqueous solution of pH 5, which was close to the isoelectric point of the membrane.     

Field ionization mass spectrometry—I. Nucleosides

The field ionization mass spectra of a series of nucleosides are reported, and compared with spectra obtained by conventional electron-impact ionization. The latter are complex, with structurally significant molecular ion and sugar cleavage peaks often of low intensity or completely absent. In contrast, the field ion spectra are extremely simple, with all except guanosine (highest mass peak [M — 18]) showing intense molecular ion peaks, and the characteristic sugar (S) and base (B + H) cleavage products as the only other important fragments.     

Studies of dyestuffs in fibres by Fourier Transform Raman spectroscopy

FT Raman spectroscopy is shown to be a powerful tool for the direct observation of low levels of dyestuffs in acrylic fibres. In the systems studied here, it is also found to yield more specific information than the complementary infrared technique. In contrast to conventional Raman spectroscopy with visible excitation, the near infrared laser used here does not induce fluorescence in the dye. Acrylic polymer bands can be efficiently subtracted to yield superbly detailed spectra of the dye in its physiochemical state in the fibre. The subtraction spectra provide valuable information on the nature of the dye and can be compared with spectra of pure dyes. Caution should be taken when subtracting spectra since small shifts in the frequency of the excitation laser line passing through the interferometer can generate artefacts in the final subtraction spectrum.     

Cyclization of peptide b9 ions

The product ion mass spectra obtained by CID of the b₉ ions derived by loss of neutral alanine from the MH⁺ ion of the peptides Tyr(Ala)₉, (Ala)₄Tyr(Ala)₅, and (Ala)₈TyrAla are essentially identical, indicative of full cyclization reaction to a common intermediate before fragmentation. This leads to abundant nondirect sequence ions in the product ion mass spectra of the b₉ ions. The product ion mass spectra of the b₈ ions from the first two peptides also are essentially identical. The fragmentation of the MH⁺ ions also leads to low intensity nondirect sequence ions in the product ion mass spectra. N-terminal acetylation blocks the cyclization and eliminates nondirect sequence fragment ions in the product ion mass spectra.     

谈禁用偶氮染料

本文就欧盟针对部分对于人体有害的偶氮染料的禁用背景及其还原或分解产物和中间体的化学名称、毒性原理和毒性类型作了简要介绍。