The red impurity in trypan blue

Lloyd, John; Field, Frederick E.

doi:10.1007/bf02114229

Cited by 6 publications

(2 citation statements)

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“…A possible pathway for A ’s formation during the synthesis of the dye is the reaction of H acid with a minor amount of diazotized 3-aminobiphenyl instead of with diazotized aniline. While A is a newly identified compound, its 3-biphenyl-4-ylazo positional isomer has been previously identified as an impurity in Niagara blue 2B [44], a biological stain chemically related to D&C Red No. 33.…”

Section: Resultsmentioning

confidence: 99%

Preparative separation and identification of novel subsidiary colors of the color additive D&C Red No. 33 (Acid Red 33) using spiral high-speed counter-current chromatography

Weisz

Ridge

Mazzola

et al. 2015

Journal of Chromatography A

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Three low-level subsidiary color impurities (A, B, and C) often present in batches of the color additive D&C Red No. 33 (R33, Acid Red 33, Colour Index No. 17200) were separated from a portion of R33 by spiral high-speed counter-current chromatography (HSCCC). The separation involved use of a very polar solvent system, 1-BuOH/5 mM aq. (NH4)2SO4. Addition of ammonium sulfate to the lower phase forced partition of the components into the upper phase, thereby eliminating the need to add a hydrophobic counterion as was previously required for separations of components from sulfonated dyes. The very polar solvent system used would not have been retained in a conventional multi-layer coil HSCCC instrument, but the spiral configuration enabled retention of the stationary phase, and thus, the separation was possible. A 1 g portion of R33 enriched in A, B, and C was separated using the upper phase of the solvent system as the mobile phase. The retention of the stationary phase was 38.1%, and the separation resulted in 4.8 mg of A of >90% purity, 18.3 mg of B of >85% purity, and 91 mg of C of 65–72% purity. A second separation of a portion of the C mixture resulted in 7 mg of C of >94% purity. The separated impurities were identified by high-resolution mass spectrometry and NMR spectroscopic techniques as follows: 5-amino-3-biphenyl-3-ylazo-4-hydroxy-naphthalene-2,7-disulfonic acid, A; 5-amino-4-hydroxy-6-phenyl-3-phenylazo-naphthalene-2,7-disulfonic acid, B; and 5-amino-4-hydroxy-3,6-bis-phenylazo-naphthalene-2,7-disulfonic acid, C. The isomers A and B are compounds reported for the first time. Application of the spiral HSCCC method resulted in the additional benefit of yielding 930 mg of the main component of R33, 5-amino-4-hydroxy-3-phenylazo-naphthalene-2,7-disulfonic acid, of >97% purity.

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Section: Resultsmentioning

confidence: 99%

Preparative separation and identification of novel subsidiary colors of the color additive D&C Red No. 33 (Acid Red 33) using spiral high-speed counter-current chromatography

Weisz

Ridge

Mazzola

et al. 2015

Journal of Chromatography A

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“…The staining ofislet cell nuclei was associated with a red-shift of the absorbance spectrum of Trypan Blue. Commercially available Trypan Blue is known to contain small impurities of azo dyes (Lloyd & Field, 1970;Dijkstra, 1972). The spectral shift in islet-cell nuclei cannot be due to a selective uptake of these Vol.…”

Section: Discussionmentioning

confidence: 99%

Alloxan cytotoxicity in vitro. Microscope photometric analyses of Trypan Blue uptake by pancreatic islet cells in suspension

Grankvist

Lernmark

Täljedal

1977

Biochemical Journal

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Suspensions of islet cells were prepared by shaking pancreatic islets from non-inbred ob/ob mice in a Ca2+-free buffer. The cells were incubated with or without 20 mM-alloxan, and subsequently with Trypan Blue. The uptake of Trypan Blue by cell nuclei was analysed by microscope photometry and by counting the frequency of cells appearing stained on visual inspection. Cells classified as stained or unstained by inspection showed no overlap in nuclear absorbance. Suspensions not exposed to alloxan contained 70-80% of unstained cells. Alloxan markedly decreased the frequency of unstained cells, an effect counteracted by 5 or 20 mM-D-glucose. The spectrum of Trypan Blue in islet-cell nuclei was red-shifted by about 20 nm. A similar red-shift was observed on adding the dye to solutions of albumin or histones, but not on mixing the dye with DNA. Binding to basic proteins may explain the concentrative uptake of Trypan Blue in dead cells and contribute to the oncogenic transformation of phagocytotically active cells. Beta-Cells in vitro are killed by alloxan and hence represent a valid model for studying the diabetogenic action of the drug.

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He(I) photoelectron spectra of d-metal compounds

Furlani¹,

Cauletti²

1978

New Theoretical Aspects

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The red impurity in trypan blue

Cited by 6 publications

References 0 publications

Preparative separation and identification of novel subsidiary colors of the color additive D&C Red No. 33 (Acid Red 33) using spiral high-speed counter-current chromatography

Preparative separation and identification of novel subsidiary colors of the color additive D&C Red No. 33 (Acid Red 33) using spiral high-speed counter-current chromatography

Alloxan cytotoxicity in vitro. Microscope photometric analyses of Trypan Blue uptake by pancreatic islet cells in suspension

He(I) photoelectron spectra of d-metal compounds

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