Dye erythrosin

Quinophthalon dyes Quinoline yellow Xanthene dyes Erythrosine (see below)... 

It appears that Charlton et al.94,95 have discovered the first methods for reversible and continuous optical measurement of the clinically highly important alkali and earth alkali ions. In one approach94 they use plasticized poly(vinyl chloride) along with valinomycin as the ion carrier, and a detection scheme that was later refered to as co-extraction. In their system, potassium ion is extracted into plasticized PVC, and the same quantity of the anionic red dye erythrosine is co-extracted into it. The extracted erythrosine is quantified via absorbance or reflectance. 

The macrocycle, tetramethyltetra-azacyclotetradecane (4-Me-cyclam-14), gives selectively with Cd a cationic complex that can be extracted with the acid dye Erythrosin as counter-ion into CHCI3 (e = 1.1-10 at 550 nm) [65]. The cationic complex of cadmium with cryptand(2.2.1), associated with Erythrosin, has been also applied for determining Cd (nitrobenzene-toluene, e = 1.05-10 ) [66]. 

Manganese has been determined in the form of ion-associates the anionic chloro-oxine complex of manganese with Rhodamine 6G, extractable into benzene (e = 7.0-10 ) [46], and the cationic complex of Mn(II) with phen, associated with the acid dye Erythrosin, and extractable into ethyl acetate (e = 1.5-10 ) [47]. 

The structure of the polymer produced from titanocene dichloride and the xanthene dye Erythrosine B is given as 2. 

Dye-Sensitized Photoisomerization. One technological appHcation of photoisomerization is in the synthesis of vitamin A. In a mixture of vitamin A acetate (all-trans stmcture) and the 11-cis isomer (23), sensitized photoisomerization of the 11-cis to the all-trans molecule occurs using zinc tetraphenylporphyrin, chlorophyU, hematoporphyrin, rose bengal, or erythrosin as sensitizers (73). Another photoisomerization is reported to be responsible for dye laser mode-locking (74). In this example, one metastable isomer of an oxadicarbocyanine dye was formed during flashlamp excitation, and it was the isomer that exhibited mode-locking characteristics. 

Erythrosine (E 127, FD C Red No. 3, Cl Food Red 14) is a xanthene dye named disodium salt of 2-(2,4,5,7-tetraiodo-3-oxido-6-oxoxanthen-9-yl)benzoate monohydrate (or disodium salt of 9-(o-carboxyphenyl)-6-hydroxy-2,4,5,7-tetraiodo-... 

In the food industry, synthetic dyes can be used also in the form of lakes obtained by precipitation of a soluble colorant onto an insoluble base. There are several insoluble bases, but only alumina is permitted for food application by FDA and EU regulation. All the synthetic food dyes can be obtained and used in food in the form of aluminium lakes, except erythrosine due to concerns about inorganic iodine content. 

Narayanan V.A., Stokes D.L., Vo-Dihn T., Vibrational spectral-analysis of eosin-y and erythrosin-b - intensity studies for quantitative detection of the dyes, J. Raman Spectrosc. 1994 25 415-422. 

A thin film dissolved oxygen sensor was fabricated by entrapping erythrosin B in a sol-gel matrix95. The silica sol-gel doped with the dye was deposited onto the cleaned glass slides by the spin-coating method. The sensor was linear in the most useful range of dissolved oxygen concentrations, up to 9.1 mg l 1 concentration obtained in air saturated water at 20 °C. 

Dual-Spectrum Also called Workman. A thermographic copying process. A transparent film base, coated with 4-methoxy-l-naphthol and a photo-reducible dye such as erythrosine, receives the image, which is then transferred to a paper sensitized with sodium behenate. Invented in 1961 by W. R. Workman at the Minnesota Mining and Manufacturing Company, MN, and commercialized for office copying, but later superseded by various electrophotographic processes. 

Baugh and co-workers exposed solutions of phenylbutazone to the light of a projector lamp in the presence of typical dyes used to colour sugar-coated tablets. Erythrosine sodium photosensitized decomposition of the drug via, it was suggested, singlet oxygen [134]. 

The second family ofxanthene dyes is fluorescein and its derivatives. Fluorescein itself is only slightly fluorescent in alcohol solution. In contrast, the alkali salt obtained by addition of alkali exhibits the well-known yellow-green fluorescence characteristic of the fluorescein dianion (uranin). Fluorescein and its derivatives, e.g. eosin Yand erythrosin Y, are known to be very sensitive to pH and can thus be used as pH fluorescent probes (see Chapter 10). 

Ponceau 4R, E-124 and Erythrosine, E-127) using a buffered mobile phase. Separation of dyes was performed in an ODS column (150 X 3.9 mm i.d. particle size 3 pm). Components of the mobile phase were methanol (eluent A) and 0.1 M NaH2P04/Na2HP04 buffer (pH = 7). The gradient elution started with 20 per cent A and reached 100 per cent in 2 min, final hold 4 min. The flow rate was 2 ml/min and dyes were detected at 520 nm. The baseline separation of dyes in 6 min is illustrated in Fig. 3.34. Commercial samples were diluted and injected into the analytical column without any pretreatment. The amounts of dyes found in the samples are compiled in Table 3.20. It was concluded from the good validation parameters that the technique is specific, sensitive, accurate and rapid. Consequently, its application for the determination of these synthetic dyes in drinks was proposed [112],... 

CZE using cyclodextrins (CD) as buffer additives has also been employed for the determination of synthetic dyes in various food products. The synthetic dyes New coccine, Erythrosine, Allura red AC, Tartrazine, Sunset yellow FCF, Brilliant blue FCF, Indigo carmine and Fast green FCF were included in the experiments. Measurements were carried out in a used-silica capillary (47 cm length, 40 cm to the detector, 50 pm i.d.). Capillary temperature was 25°C and separation voltage was 20 kV. Pressure injection was performed... 

Another CE method was developed and employed for the separation of the components of FD C Red No. 3 (erythrosine). The separations were also carried out by RP-HPLC and the efficacy of the methods was compared. The chemical structures of the main components of the dye are shown in Fig. 3.167. The components of erythrosine were separated in a fused-silica capillary (43 cm effective length X 75 /xm i.d.). The running buffer was 50 mM sodium tetraborate, 25 mM SDS (pH 9.3). Analytes were detected at 516 nm. HPLC measurements were realized in an octylsilica column (150 X 4.6 mm i.d. particle size 5 /xm) at 35°C. Solvent A was 0.1 M aqueous ammonium acetate and solvent B consisted of methanol. The gradient programme was 0 min, 55 per cent A 20 min 35 per cent A 21 min, 100 per cent B, final hold, 4 min. The flow rate was 1 ml/min. The separations of the components of the standard mixture (left) and those of a real sample (right) by CE are shown in Fig. 3.168. The electropherograms clearly illustrate that the method allows the baseline separation of the dye components even in real commercial samples. The main... 

Toxicological studies on direct food additives have revealed toxic and harmful actions. Food dyes and preservatives have been used since ancient Roman times to improve the color of wine or to disinfect wine containers. The development of chemistry led to many unwise experiments, such as the dying of food with copper, chrome, lead, mercury, arsenic, and cadmium salts. In the U.S. in 1906, over 300 food dyes were officially tested, of which only seven passed and were allowed to be used in food. Only two of them - erythrosine and idigotine - are permitted now. The lists of preservatives are also constantly modified in different countries. Quite recently, formic acid, which is used to preserve semi-products, was banned in Poland due to its deleterious effects. 

Nonchelating dyes include basic triphenylmethane dyes (e.g., Brilliant Green, Malachite Green, Crystal Violet), xanthene dyes (e.g., Rhodamine B, Rhodamine 6G), azine dyes (e.g., Methylene Blue), and acid dyes (e.g., Eosin, Erythrosin). These are intensely colored and when paired with an oppositely charged analyte ion lead to high sensitivities. 

Eosin is a dye that is obtained by reaction of fluorescein with bromine (Eq. 9). This reaction has been carried out in batch and flow reactors, and both eosin and erythrosine (the tetraiodine derivative) have been obtained. The mechanism and... 

With rose bengal and erythrosin as xanthene dye sensitizers, the... 

Similarly, using our standard method for column chromatography, quantitative separation was obtained, for Erythrosine, but also for the other food dyes in contemporary use It is also notable that there was no significant matrix effect observed for DI, tap or well water. 

A more conventional mechanism appears to be operative in the photopolymerization of ethyl acrylate [178] and methyl methacrylate [179] in aqueous solution, sensitized by fluorescein and Erythrosin, respectively. Ascorbic acid is the reducing agent in both cases and it is observed that the reaction does not proceed in the absence of buffer, usually phosphate buffer pH 6. Polymer formation starts after an induction period but its dependence on light intensity and ascorbic acid concentration has not been determined. The rate of photopolymerization is proportional to the monomer concentration and to the square root of the light intensity, dye, and ascorbic acid concentration. The authors report the order with respect to the monomer as 3/2. However, from our analysis of the data for fluorescein, which are more... 

Erythrosin (Gr spi/fif/ocr-red), tetraiodofluorescein, was synthesized first by Gnehm [220] and named by him. It has been used as a food coloring for many years and is the red dye of maraschino cherries, Tylenol capsules, and bright red luncheon meats. It is known as FD C Food Dyers and Colorists 3 and has received substantial attention from the FDA over the last 10 years since it causes bladder cancer when ingested in huge amounts by rats. It has recently been banned as a food dye in the United States, but is a source of dietary iodine for the Japanese [221], It is also used as a stain. 

---