Crystal Violet dyes

The decolorization of crystal violet dye by reaction with sodium hydroxide is a convenient means for studying mixing effects in continuous-flow reactors. The reaction is... 

Going, R. E., Massler, M. Dute, H. L. (1960). Marginal penetration of dental restorations as studied by crystal violet dye and Journal of the American Dental Association, 61, 285-300. 

Hexa(hydroxyethyl)pararosaniline nitrile has been used in a chemical radiochromic dosimeter.130 Ferricyanide oxidation of leuco Crystal Violet to Crystal Violet dye finds use in detection of various heavy metals131 at trace quantities. Oxidation of leuco triphenylmethanes by chloramine-T is catalyzed by iodide and therefore is used for detection of iodide.132 On the other hand, the inhibition of the catalytic effect of iodide by some ions can be used for determining traces of Ag(I), Hg(II), Pd(II). In addition, the triphenylmethane leuco dyes, phenolphthalein or phenol red are used extensively as indicators in calorimetric and titrimetric determinations. 

In principle, the same photoexcited reactant, if it is liable both to oxidation and reduction, can inject both electrons (into an -type semiconductor) and holes (into a p-type semiconductor). Such a material is, for example, the crystal-violet dye. Figure 25 shows the spectra of cathodic photocurrent iph at p-type gallium phosphide and anodic photocurrent at n-type zinc oxide both in a solution, which does not absorb light (dashed lines), and in the presence of crystal violet the absorption spectrum of the latter is also shown for comparison. 

Fig. 25. Absorption spectrum of the crystal-violet dye (a) and the spectra of anodic photocurrent at an electrode of n-type ZnO (b) and of cathodic photocurrent at an electrode of p-type GaP (c) in the presence of crystal violet (in pA/cm2). The dashed line is the photocurrent in the absence of the dye. [From Gerischer (1977b).]...

Such anionic surfactants that form ion pairs with methylene blue and that are extractable with chloroform are known as Methylene Blue Active Substances (MBAS). Other cationic dyes, such as crystal violet dye, may be used instead of methylene blue. Extraction of such an ion-pair complex into benzene has been reported (Hach, 1989). Detection Limit = 10 pg/L. 

Interestingly a crystal violet dye was used as a IPR for indirect photometric detection. Common inorganic anions were separated and detected at the absorption maximum of the dye with classical reversed phase columns. The affinity of the analytes decreased in the order of 8203 > 804 > I" > N03" > Br > N02 > CL, which is the same as that observed with classical anion exchange chromatography [136]. 

Crystal violet dye elution (CVDE) (Kueng et al, 1989 Scragg Ferreira, 1991)... 

Like COClj (Section 10.2.1.4), COBr reacts with N,N-dimethylaniline in the presence of either zinc bromide or aluminium(III) bromide to give a "crystal violet" dye ... 

Crystal violet, a trigonal conjugated cationic dye with electronic CT from peripheral dimethylamino donor groups to an electron deficient sp hybridized central carbon atom. A resonantly enhanced (3 value of 580 x 10 ° esu has been reported at 1.064 nm, in acetone solution = 590 nm) by Zyss et al. [16] The 1st hyperpolarizability, p, of crystal violet dye was measured at 1450 and 1500 nm by Rao et al. [91]. The resonance-free P value, p(°) for this octupole is comparable with that of the dipolar dye Disperse Red 1 but with the nonlinearity-transparency trade-off worse for the octupole. Symmetric cyanine dyes of the kind Me2N+ CH-(CH CH)n-NMe2 normally exhibit no first hyperpolarizabilities but have relatively long absorption... 

Effect of additives on the pho ostability of Crystal Violet dye and fluoran dye on silica gell ... 

Iodine in water may be analyzed by amperometric titration or by a colorimetric procedure using leucocrystal violet. In the latter method, mercuric chloride is added to the potable water sample, hydrolyzing iodine to hypoiodous acid. The latter reacts instantaneously with leucocrystal violet, forming a crystal violet dye. The absorbance is measured at a wavelength of 592 nm. 

Kesari et al. (Kesari et al., 1998) developed a simple and sensitive spectrophotometric method for the determination of iodine in tap water, sea water, soil, iodized salt and pharmaceuticals samples. The said method was based on oxidation of F to lOs" with bromine water and liberation of free I2 from IQ3" by addition of K1 in acidic medium. I2 is then reacted with leuco crystal violet and the crystal violet dye liberated shows maximum absorbance at 591 nm. Beer s law is obeyed over the concentration range from 0.04 to 0.36 mg/1 of iodine in a final solution volume of 25 ml. The method is free of interference of other major toxicants. 

The crystal violet dye (CV) is a dark green pxjwder soluble in water, chloroform, isopropyl alcohol, but not in in ether and ethyhc alcohol The crystal violet dye can be used as antiseptic and a pH indicator for some substances. Its chemical composition is C25 H30 CIN3 and molecular weigh 407.98. In Fig 4 we show its absorphon spectra showing a peak in the spectral hne at 591 nm, making a displacement of the absorption curve towards the yellow and orange color... 

Norland Optical Adhesive 65 as Holographic Material presents a photosensitive material comprising Norland Optical Adhesive 65 mixed with crystal violet dye with a high potential for recording holographic elements in real time. The results from recording of Fourier holograms of binary objects are presented. 

Compared to activated carbon, the graphite adsorbent used by the group in Manchester has a very low specific surface area of around 3 m g [25]. Consequently, the adsorption capacity of this adsorbent is relatively low. For example, a Nyex adsorbent was reported to have a loading capacity for atrazine of only around 0.7 mg g [25] and for a crystal violet dye only 2 mg g [26]. However, 1(X) % regeneration efficiencies were achieved after only... 

Brown NW, Rohtats EPL, Garforth AA, Dryfe RAW (2004) Elecbochcanical regeneration of a carbon based adsorbent loaded with crystal violet dye. Electrochim Acta 49 3269—3281... 

Figure 8.1 Color change as evidence of a chemical reaction. When a solution containing hydroxide ion is added to crystal violet dye, the intensity of the color decreases with time until it disappears. The product of the reaction is colorless in water solution. 

A method was devised to determine extinction coefficients of radicals. A flash photolysis unit with filters to confine irradiation to a spectral region where only biimidazoles absorbed was utilized to generate radicals whose initial absorbance was recorded photographically from an oscilloscope. In the same cell another solution was then photolyzed as above. This second solution contained an identical concentration of biimidazole to the first plus leuco Crystal Violet dye, tris-(4-dimethylamino-phenyl) methane, and toluenesulfonic acid. The absorbance of dye produced by oxidation of leuco dye by was observed at an unobstructed wavelength. The extinction of the dye at this wavelength in this medium was determined experimentally. The stoichiometry of radical attack on dye was and the quantum yield of this reaction under... 

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