Purity Of Dyes Research Articles

The Synthesis and Application of Reactive Dyes Based on 4,4'-methylene bis-m-nitro aniline on Various Fibres

Hot brand bisazo reactive dyes (D1 to D10) have been synthesized by coupling tetrazotised 4,4’-methylene bis-m-nitro aniline with various cyanurated coupling components. They were applied on silk, wool and cotton fibres. Their dyeing performance on silk, wool and cotton has been assessed. The purity of dyes was checked by thin layer chromatography. The IR spectra showed all characteristic band and PMR spectra of representative dye showed all the signals. The percentage dye bath exhaustion on different fibres was reasonably good and acceptable. The dyed fibres showed moderate to very good fastness to light, washing and rubbing.

Azo reactive dyes: ultrafiltration and application to cotton by exhaustion and digital ink-jet printing

Three reactive dyes have been synthesized by coupling 1-amino-phenyl-4-beta hydroxyethyl sulfone sulfate ester with 1-amino-8-hydroxynaphalene-3,6-disoulphonic acid (H-acid). The dyes synthesized were then purified using ultrafiltration and water-based reactive ink jet inks were prepared for digital printing applications. The dyes were characterized by their spectrophotometrical data ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy, optical emission spectroscopy, X-ray diffraction and elemental analysis. The purity of dyes was checked by thin layer chromatography and their dyeing performance was assessed on cotton fibers by exhaustion (dyeing) and ink-jet printing. Ink-jet inks with the dyes synthesized were prepared and their physical properties were measured in order to evaluate their suitability for ink-jet printing. Color measurements and fastness properties were performed for the dyed and digitally printed samples. Coloristic values of the dyed/ printed samples were as expected, that is, K/ S values of the dyed samples were much higher than those of the printed ones, K/ S values of the samples dyed with the ultrafiltrated dyes were higher than those with the initial dyes and the rest of the coloristic co-ordinates L, a, b, C, H, were in line with strength changes of the dyes before and after ultrafiltration. The dyed samples had excellent wash fastness and medium light fastness. Ultrafiltration slightly improves the fastness properties of the dyed samples.

Optimization of Photoelectrode for Flexible Dye-sensitized Solar Cell and Preliminary Study of Tandem Cell

Based on the preparation of flexible dye-sensitized solar cells (DSC) by cold isostatic pressing method, optimization of the paste and tandem DSC were investigated. The results presented that hydrothermal treatment of P25 paste could improve the stability of the paste and the efficiency of DSC obviously. Proper amount of 200 nm TiO2 particles was added to the P25 paste to enhance light scattering of photoelectrode. The highest conversion efficiency of 3.11% was obtained at the 4:1 ratio of P25 to 200 nm TiO2. Subsequently, N719 and N749 double-layer tandem DSC were studied. The results show that the efficiency of the double-layer tandem DSC is higher than that of N749 totally sensitized DSC but lower than that of N719 totally sensitized DSC. This may be caused by that thicker photoelectrode hampers the electronic transmission and dyes contact impacts the purity of dyes. The thickness of photoelectrode and cell structure need to be optimized.

Contact allergy from disperse dyes in textiles–a review

Several disperse dyes (DDs) are still considered to be the most important allergens in textile dermatitis, but there are sparse data about their current use in textiles. The aim of this review was to evaluate published studies and reports on contact allergy to DDs published in PubMed during the last 22 years (1990-2012). Prevalence data are provided by study and by dye, as well as by the described clinical peculiarities of DD dermatitis. We reviewed 54 studies. In total, 26 DDs were tested. The average prevalence in screening studies was >1% for Disperse Blue 106, Disperse Blue 124, and Disperse Orange 3. There is a lack of data on patch testing with Disperse Blue 26, Disperse Blue 102, Disperse Orange 37, Disperse Orange 149, Disperse Yellow 23 and Disperse Yellow 49, which are listed as allergens by the EU Commission. It is necessary to check the purity and identity of dyes used for patch testing, confirm the clinical relevance of positive reactions by patch testing with suspected textiles, and, if the results are positive, determine the culprit dye.

Synthesis, characterization and application of novel bisazo reactive dyes on various fibers

Ten hot brand bisazo reactive dyes (D1 to D10) have been synthesized by coupling bis(diazotised), 4,4'-methylene bis(2,6-dichloroaniline) (A) with various 5-sulfo anthranilo cyanurated coupling components (R) and their dyeing performance as reactive dyes has been assessed on silk, wool and cotton fibres. The purity of dyes was checked by TLC. The IR spectra and 1H-NMR spectra prove the structure of newly reactive dyes. The percentage dye bath exhaustion on different fibres was reasonable good and acceptable. The dyes exhibited high levels of light, washing and rubbing fastness.

Disperse dyes based on 2-aminothiazole derivatives for cellulose triacetate fabric

A range of azo disperse dyes was prepared by coupling diazotized 2-amino-4-(p-nitrophenyl)-5-nitrothiazole with various substituted arylamines. Spectral properties in the infrared and visible range of the dyes obtained were investigated. All the dyes, when applied on cellulose triacetate fabric as 2% shade, showed fairly good to very good light fastness and very good to excellent fastness to washing, perspiration, rubbing and sublimation. All the dyes gave a wide range of reddish brown to indigo shades with very good depth and levelness on fabric. The purity of dyes was checked by thin layer chromatography. The percentage dyebath exhaustion and fixation on fabric was reasonably good and acceptable.

Synthesis, characterization and application of quinazolinone based reactive dyes for various fibers

Seven hot brand heterocyclic mono azo reactive dyes (7a–g) have been synthesized by coupling diazotized 2-phenyl-3{4′-[(4″-aminophenyl)sulphonyl]phenyl}-quinazoline-4(3H)-one-6-sulphonic acid (4) with various 2-chloro-4-nitro anilino cyanurated coupling components (6a–g) and their dyeing performance on silk, wool, and cotton has been assessed. The purity of dyes was checked by thin layer chromatography. These dyes were identified by recording IR and 1H-NMR spectra. The λ max, R f value, %exhaustion, %fixation, light fastness, wash fastness, rubbing fastness, reflectance (%R) value, and K/S value have also been studied.

Analysis of dimeric cyanine–nucleic acid dyes by capillary zone electrophoresis in N, N-dimethylacetamide as non-aqueous organic solvent

A method based on capillary zone electrophoresis is presented for the determination of the purity of commercial dimeric cyanine dyes (TOTO, YOYO, BOBO, all -1 and -3 species, LOLO-1, POPO-1) that are common as fluorescent probes for nucleic acid staining. These dyes are tetracharged cations, and have a strong tendency to interact with negatively charged centres, where they are rapidly adsorbed, especially from aqueous solutions. Thus anionic sites at the capillary wall must be avoided, and aqueous buffers are not suitable. The method introduced here avoids both complications, using non-aqueous N, N-dimethylacetamide as solvent, and suppressing the dissociation of silanol groups at the capillary surface due to selection of acidic separation conditions (20 mmol/l perchloric acid as background electrolyte). The present method enables the determination of the purity of all 10 dyes in less than 15 min. The selectivity of the method allows separation of at least five main and differentiating a number of unresolved minor contaminants as demonstrated in detail for TOTO-3 as an example. Quantitation (with 100% normalisation of the peak areas) of nine lots of this dye results in a purity between 33 and 87%.

Synthesis and Characterization of Monomeric and Polymeric Disperse Dyes for Hydrophobic Fibres

Some monomeric disperse dyes based on 2-amino-5-mercapto-1,3,4-thiadiazole have been synthesized by coupling with derivatives of N-phenylacrylamide. Polymeric dyes have been prepared by free radical polymerization of monomeric dyes and were characterized by IR spectra, Intrinsic viscosity, molecular weight by Vapour Pressure Osmometry, thermogravimetry analysis, bleeding test and elemental analysis. The monomeric dves have been also characterized by IR spectral studies and elemental analysis. The purity of dyes was checked by thin layer chromatography. All the dyes were applied as disperse dyes on nylon and polyester fibres. These dyes have been found to give a wide range of colour shades with very good depth and levelness on each fibre. The percentage dye bath exhaustion on different fibres have been found to be good to very good. The dyed fibres showed good to excellent fastness to light on nylon and polyester fibres. The washing, rubbing, perspiration and sublimation fastness properties of the dyed fibres has been found to be very good to excellent.

Textile dye allergic contact dermatitis prevalence

This article summarizes textile dye prevalence studies and makes recommendations for advancing knowledge about textile-dye sensitization. Prevalence data is provided by study and by dye. Dermatology teams are encouraged to conduct textile-dye prevalence studies in countries other than Italy, include dyes for which the least prevalence data has been collected, to standardize method of application and reading, and to verify purity and identity of dyes used for patch testing. Testing with pure dyes and other chemicals in dye formulations should provide insights in choosing dye systems that will decrease sensitization.

The Purity of Fluorescent Dyes: a Report Delivered to the Scientific Session of the Annual Meeting of the Biological Stain Commission

The Biological Stain Commission occasionally has been requested to certify fluorochromes as biological stains. Although formal certification is unlikely in the near future, the Commission is nevertheless concerned with the quality of these reagents. Commercial samples of fourteen fluorochromes were investigated for the presence of fluorescent organic impurities using reverse phase thin layer chromatography. Our findings suggest that some fluorochrome dyes are pure, but most are impure. Most fluorochromes vary in purity among vendors and among batches sold by single vendors. Impurities may be present at such high concentration that little of the presumed compound is present. Some impurities behave quite differently from the nominal dye. This may either create confusion or it might be useful. In the latter case, however, the impurity may occur only in a single batch. Impurities result from problems related to organic syntheses, separations, and economics. Solving those problems is often expensive, and what is expensive may not be performed. Fortunately, knowledge of synthetic chemistry often permits identification of fluorochromes likely to be impure. Moreover, predictions of likely staining effects of particular impurities can be made if appropriate structure-activity models are available. Possible actions by the Commission aimed at limiting the problems resulting from impurities of fluorescent dyes are noted.

Optimization of capillary zone electrophoresis-electrospray mass spectrometry for cationic and anionic laser dye analysis employing opposite polarities at the injector and interface

On-line capillary zone electrophoresis-electrospray mass spectrometry (CZE-ES-MS) has been used to investigate the purity of laser dyes. A CZE-ES-MS interface linking a Dionex CE System I and a Vestec 201 clectrospray mass spectrometer was constructed and employed for this purpose. Interface optimization studies revealed that maximum sensitivity conditions are significantly different from maximum stability conditions. Use of a cationic surfactant, cetyltrimethylammonium chloride, proved effective at reducing the interaction between the cationic laser dye, Rhodamine 6G, and the wall of the silica capillary, a problem which can otherwise persist even at low pH. To direct electroosmotic flow towards the detector, negative voltages were applied to the CZE source vial. This enabled efficient separation of Rhodamine 6G from low level isomeric and analogue impurities which were detected using positive voltages at the mass spectrometer ion source. Despite intrinsic difficulties associated with negative-ion ES-MS, negative-ion detection was used in combination with positive CZE potentials to separate and characterize analogue impurities found in the anionic laser dye Eosin Y. Impurities present in such laser dyes can have profound effects on the operating efficiencies of dye lasers and the usable lifetime of the dye.

Analysis of xanthene dyes by reversed-phase high-performance liquid chromatography on a polymeric column followed by characterization with a diode array detector

A high-performance liquid chromatographic method on a polymeric column was developed for the analysis of xanthene dyes. The rigid polystyrene-divinylbenzene column was connected to a photodiode array detector to verify the identity and the purity of the dyes. For eosin Y a within-day precision of 1–2% was obtained, and on a day-to-day basis the coefficient of variation was 4.2%. The purity of commercial xanthene dyes was investigated, and the results show the divergence between the actual dye contents and the dye contents indicated on the label.

Chemical structure and purity of dyes used in lymphograms

Because of confusion in the literature, studies were performed on several samples of patent blue violet and Alphazurine 2G to determine their chemical structure and purity. Nuclear magnetic resonance studies revealed that three distinct compounds and one mixture had all been labeled as the same compound. The purity of the dyes varied from batch to batch, as shown by thin-layer chromatography. Caution should be exercised in the use of these dyes for lymphograms.

Letter: Chemical structure and purity of dyes used in lymphangiograms.

Letter: Chemical structure and purity of dyes used in lymphangiograms.