Dye Purity Research Articles

Exploring the Word of Thin-Layer Chromatography: A Review

A common analytical method in chemistry for separating and identifying mixture ingredients is called thin-layer chromatography (TLC). A thin coating of stationary phase, often silica gel or alumina, is put into a sample, which is then placed on a flat substrate like a glass plate. The sample is then exposed to a mobile phase, often a solvent, that follows capillary action through the stationary phase. Thin-layer chromatography may be used to determine the chemicals that are present in a particular sample and track the development of a reaction. Additionally, similar substances in a mixture may be separated using TLC. Thin-layer chromatography is the favoured technique in many standard procedures in environmental chemistry, industrial chemistry, dye purity, plant material, and herbal analysis. Without having to read the whole report, it aids readers in rapidly grasping the size and importance of the study.

Desalination of Dye by Charged Mosaic Membrane

Desalination and purification of dye can improve its quality and value. Membrane separation technology is one of the main technologies of dye desalination and purification. The charged mosaic membrane (CMM) is prepared by interfacial polymerization (IP) in this paper. And then it is applied in desalination and purification of crude dye. The results shows Rejection of the CMM for NaCl and Reactive Light Yellow (PF-6GS) is 13.2% and 99.2%, respectively. Its flux increases from 6.22 L·m-2·h-1 to 18.5 L·m-2·h-1 when the operating pressure increases from 0.2MPa to 0.5Mpa. Its flux reduces from 13.32 L·m-2·h-1 to 11.11 L· m-2·h-1 and its rejection for NaCl gradually improves from12.5% to 13.7% when NaCl concentration increases from 500 mg·L-1 to 2000mg·L-1. Its flux gradually reduces from 10.17 L·m-2·h-1 to 8.21 L·m-2·h-1 and the rejection for the dye all exceeds 99.00% when the PF-6GS concentration increases from 500mg·L-1 to 2000mg·L-1. After the crude dye is desalinated via five times the NaCl concentration in dye solution reduces from 8775mg·L-1 to 658mg·L-1, the conductivity of dye solution reduces from 28.6 ms/m to 8.92 ms/m, dye purity increases from 72.6% to 97.0%.

Synthesis of Direct dyes based on non-carcinogenic amines for leather and textile industry

ABSTRACT: A series of direct dyes based on 4,4'-diaminodiphenylamine-2'-sulphonic acid (1-5) have been synthesized to be used as potential alternative to benzidine ( human carcinogenic) and they are eco-friendly. Benzidine derivatives containing alkoxy groups ortho to an amino group of meta-phenyl diamine removed carcinogenicity. The Benzidine analogue was diazotized and coupled with widely used dye intermediate dye like FC acid to generate a group of direct dyes giving yellow, mustard, blue, purple and greenish black shades on cotton, leather and wool. Dye structures were confirmed by visible absorption spectra, IR spectra, and fastness property. Dye purity was confirmed by TLC using BuOH: EtOH: NH4OH:H2O (3:1:0:5:1) as the fluent. The dyed fabrics showed very good to excellent wash fastness and moderate to good light and perspiration fastness properties.

Analysis of dye degradation products and assessment of the dye purity in dye-sensitized solar cells

For commercialization of dye-sensitized solar cells (DSSCs), improvement of their long-term stability and efficiency is important. A key component in solar cells is the dye, its high purity and high stability. Here, methods for dye extraction and purification, and for determination of dye purity and dye degradation in DSSCs, were developed. A method was developed for extraction of the dye Z907 from intact solar cells using a water/ethanol mixture containing tetrabutylammonium hydroxide. The N719 dye synthesized in our laboratory was purified by gel filtration on Sephadex LH20. These dyes, along with the dyes N3 and RuL2 (NC)2, were analyzed using nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography coupled to an electrospray ionization quadrupole-time-of-flight mass analyzer (LC/MS) operating in negative ionization mode. Purification of the synthesized N719 removed several impurities, including its undesired isomer with the thiocyanate ligand attached to ruthenium through sulfur instead of nitrogen. The dyes N719 and Z907 were successfully extracted from solar cells and together with N3 and RuL2 (NC)2 analyzed by LC/MS, although N719 isomerized almost immediately in basic aqueous solution. The [M-H](-1) ions were observed and the measured mass was within a ±6 ppm range from the exact mass. LC/MS in combination with NMR spectroscopy was shown to provide useful information on dye structure, purity, and on the efficiency of the purification methods. These methods allow for further studies of solar cell dyes, which may provide the detailed information needed for the improvement and eventual commercialization of the solar cell technology.

Histotechnologists, the Color Index and dye purity

Histotechnologists skillfully use histochemical stains to demonstrate various components in tissue sections with different colors, and most histology laboratories have available a wide range of biological dyes to stain histological tissue sections. Histotechnologists can improve their skills by paying attention to the Color Index number for each dye they use, i.e. a special five digit number assigned to each dye to separate it from any other dye used in the histology laboratory. This short article reviews briefly the use of the Color Index, dye generic names and dye purity.

An overview of the methylene blue ISO test for assessing the activities of photocatalytic films

The main features are described of the ISO published standard: 10678:2010, namely the ‘Determination of photocatalytic activity of surfaces in an aqueous medium by degradation of methylene blue’. The main underlying assumptions of the standard are considered, namely: (i) dye purity, (ii) adsorption and pH, (iii) light source, (iv) stirring and diffusion, (v) reaction mechanism and (vi) kinetics. Possible sources of errors arising form these assumptions are identified and changes to the standard's protocol suggested. The major suggested changes are: (i) a source of MB+ of known and proven on site high purity (>90%) should be used to make up the standard test solution, which should have a referenced absorbance, 0.74, at 665nm; (ii) the conditioning solution should be the same concentration as the standard test solution, (iii) the initial pH of the reaction solution should lie in the range: 5.5–6.0; (iv) a BLB UVA light with a europium-doped strontium fluoroborate or borate phosphor should be used; (v) the reaction solution should be vigorously and continuously stirred if possible; (vi) the solution height should be the minimum recommended value of 2cm, and the photoreactor cylinder i.d., 4.7cm; (vii) after the 3h irradiation the reaction solution should be left stirring overnight to check that no dye photoreductive bleaching has occurred. Application of most of these suggestions should improve considerably the standard's reported current poor percentage errors for repeatability within a lab (9.2%) and reproducibility between labs (30.6%).

Influence of source and quality on the color characteristics of annatto dyes and formulations

Annatto dyes containing different strengths of bixin, norbixin and their formulations such as water-soluble liquid, and oil soluble liquid were measured for L*, a* and b* in a Hunter color meter and the Yellow (Y) and red (R) units in a Lovibond tintometer. Seed source and dye purity had a significant effect ( P < 0.05) on the color characteristics L*, a*, b* and Y and R units of bixin/norbixin dyes and their formulations. These characteristics behaved independently when different dyes diluted to a common concentration of 50 mg bixin or norbixin/L. However, when individual bixin/norbixin dyes serially diluted L*, b* decreased and a* values increased with increase in concentration of bixin/norbixin. Similarly the increase in concentration of bixin/norbixin have shown decreasing trend on Y/R values due to increase in R-values in the tintometer. It has been observed that a* and R units generally increased with increase in concentration, and L* and b* values decreased and Y values are almost constant in both the bixin and norbixin dyes. However the b*/a* values showed lower values in bixin dyes and higher in norbixin dyes. Similarly R-values were higher in bixin dyes when compared to norbixin dyes.

Bias in the absorption coefficient determination of a fluorescent dye, standard reference material 1932 fluorescein solution

The absorption coefficient of standard reference material ® (SRM ®) 1932, fluorescein in a borate buffer solution (pH=9.5) has been determined at λ=488.0, 490.0, 490.5 and 491.0 nm using the US national reference UV/visible spectrophotometer. The purity of the fluorescein was determined to be 97.6% as part of the certification of SRM 1932. The solution measured was prepared gravimetrically by diluting SRM 1932 with additional borate buffer. The value of the absorption coefficient was corrected for bias due to fluorescence that reaches the detector and for dye purity. Bias due to fluorescence was found to be on the order of −1% for both monochromatic and polychromatic (e.g., diode-array based) spectrophotometers.

Dye purity and dye standardization for biological staining

This review starts with a short discussion of what is meant by a pure dye and a brief description of how dyes are produced. A listing of the types of impurities encountered in dyes is made, followed by technical investigations and assessments of dyes and their impurities including methods for separating, identifying and assaying dye components. In the second part of the review, descriptions are given of the standardized staining method approach using standard staining methods for assessing stains, and practical responses to stain impurity including commercial quality control, third-party quality control and standardization of reagents, protocols and documentation. Finally, reference is made to the current state of affairs in the dye field.

Dye purity and dye standardization for biological staining

This review starts with a short discussion of what is meant by a pure dye and a brief description of how dyes are produced. A listing of the types of impurities encountered in dyes is made, followed by technical investigations and assessments of dyes and their impurities including methods for separating, identifying and assaying dye components. In the second part of the review, descriptions are given of the standardized staining method approach using standard staining methods for assessing stains, and practical responses to stain impurity including commercial quality control, third-party quality control and standardization of reagents, protocols and documentation. Finally, reference is made to the current state of affairs in the dye field.

Submarine Gel Electrophoresis Purification of a Small Molecule: 99.9998 Fluorescently Pure IMI2

HPLC and related techniques failed to raise the fluorescence purity of a BODIPY−imidazole dye (IMI2) above 99.5%, based on assessment of dye purity by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). This difficulty was overcome by employing submarine gel electrophoresis, which raised the fluorescence purity level to about 99.9998%. This estimate of final dye purity was made by using immobilized metal affinity chromatography to selectively remove the dye from a sample that was then analyzed by CE-LIF as a 5000× more concentrated sample than the original. The amount of dye purified on a 87- × 67- × 10-mm (l × w × h) gel in a 40-min run was at the 0.5-mg level. The dye was recovered by soaking the sliced-out electrophoretic band in methanol. We are now in a position to employ this dye for labeling of trace phosphomonoester analytes without being hampered by dye impurities, by further developing methodology that we reported previously (Wang, P.; Giese, R. W. Anal. Chem. 1993, 65,...

GLYCERIN/DYE SOLUTION UPTAKE IN PRESERVED DECORATIVE FOLIAGE

The commercial production of preserved plant materials for decorative purposes is expanding. The industry, once dominated by a relatively small number of large wholesale firms, marketing through traditional retail florists, is undergoing change. A large retail craft supply industry, country accent retail stores and home-based businesses selling at craft fairs have greatly expanded the market for preserved plant materials. Glycerin has often been used to maintain flexibility and reduce breakage of preserved foliages. Dyes are added to the glycerin to add color to the tissue as the chlorophyll fades. Competition in the marketplace places constant pressure on controlling costs. Technical grade dyes of lower dye purity and higher salt concentrations have a lower cost per gram of material than food grade dyes. The effect of the two grades of dye on uptake of glycerin/dye solutions into Eucalyptus cinerea were measured. Under both growth chamber and laboratory room environments glycerin solution alone was systemically absorbed at a greater rate and in larger quantity than either grade of dye. A variation in systemic absorption between grades of dye was also indicated.

Colorimetric determination of atmospheric sulfur dioxide using 1,3,5-trinitrobenzene

The pararosaniline method has been widely used for colorimetric determination of sulfur dioxide in the atmosphere because of its simplicity, sensitivity, and specificity. However, analyses must be carried out carefully with close attention to temperature, pH, and dye purity. 1,3,5-trinitrobenzene (TNB) forms an addition complex (I) with sulfite in a dimethyl sulfoxide (Me/sub 2/SO)-water mixture to give a highly colored solution. The equilibrium constant for the formation of I is at least one hundred times greater in an aqueous solution containing 70% (v/v) Me/sub 2/SO than in water. Since this reaction gives rapid and stable color development with high absorbance and the blank, attributable to TNB, is not observed, sulfur dioxide in the atmosphere is analyzed with a Me/sub 2/SO-water system containing TNB.

The Use of Solvent-Nonsolvent Mixtures for the Purification of Anionic Dyes

The use of Dimethylformamide-Trichloroethylene (DMF-TCE) as a solvent-nonsolvent mixture is suggested for the purification of acid and direct dyes of varying degrees of sulphonation. The dye purity was varied from 93% to 100% as indicated by the sodium analysis of the purified dyes. In addition to TCE the feasibility of various other solvents as precipitating agents was also qualitatively tested.