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Tartrazine came into being in the late 19th century. Swiss dye chemist Johann Heinrich Ziegler at Bindschedler'sche Fabrik f眉r Chemische Industrie (Basel) developed the yellow azo dye in 1884 and in 1887. By the 1890s, the process was being used for fabric dye and food coloring. Today, tartrazine is known by several names throughout the world (e.g., FD&C Yellow 5, E102, Acid Yellow 23); it is used in foods, cosmetics, and paints.
Tartrazine鈥檚 chemical properties, however, make it much more significant than a safe, readily available dye. It has sharp absorption resonances in the near-UV spectrum (300鈥�400 nm) and the blue region of the visible spectrum (400鈥�500 nm).
Biology researchers want to develop deep-tissue optical imaging methods that can penetrate opaque tissue and are suitable for living animals. Last year, in a counterintuitive hypothesis, Mark L. Brongersma, Guosong Hong, and a large team of co-workers at Stanford University (CA) suggested that strongly absorbing molecules, such as those in dyes, in live biological tissues. After testing 21 dyes, they found that .
The team first applied tartrazine to slices of chicken breast and 鈥溾�. They then moved on to tests on mice. By massaging the dye into a mouse鈥檚 scalp, they were able to see the cerebral blood vessels; an application on a mouse鈥檚 abdomen allowed them to watch it digest its latest meal. The transparent effect lasted 10鈥�20 minutes; the dye is easily washed off.
The medical possibilities for noninvasive in vivo testing are far-ranging. The path to use on humans, however, will not be easy; human skin presents myriad variations to challenge researchers.
For more information about tartrazine, see the .
Tartrazine聽hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Acute toxicity, oral, category 4 | H302鈥擧armful if swallowed |  |
| Skin corrosion/irritation, category 3 | H316鈥擟auses mild skin irritation | |
| Skin sensitization, category 1 | H317鈥擬ay cause an allergic skin reaction | |
| Serious eye damage/eye irritation, category 2B | H320鈥擟auses eye irritation | |
| Acute toxicity, inhalation, category 5 | H333鈥擬ay be harmful if inhaled | |
| Respiratory sensitization, category 1 | H334鈥擬ay cause allergy or asthma symptoms or breathing difficulties if inhaled |  |
*Compilation of multiple safety data sheets, in which hazard statements vary considerably. Others state, 鈥渘ot a hazardous substance or mixture鈥�.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. .
Molecules from the Journals
Thiophene sulfone1 (aka thiophene S,S-dioxide) is formally an oxidation product of thiophene2, but the direct oxidation of thiophene leads mostly to other products. In 1953, William J. Bailey and Earl W. Cummins at聽Wayne University and the University of Maryland (both in College Park, MD) were the in a complex six-step procedure beginning from butadiene sulfone3 (better known as sulfolene).
In recent decades, thiophene sulfone and its derivatives have been studied for their applications in electronics and optics. In 1998, for example, Giovanna Barbarella at Area Ricerca C.N.R. (Bologna Italy), Olga Pudova at the Latvian Institute of Organic Synthesis (Riga), and collaborators at other institutions reported that oligothiophene S,S-dioxides had compared with their non-oxide counterparts.
Last month, Pan膷e Naumov, Jialiang Xu, and colleagues, principally at New York University Abu Dhabi and Nankai University (Tianjin, China), described single-crystal thiophene sulfone as a 鈥溾�. They stated that the crystal is 鈥渁 favorable choice for prototypical low-power precision applications such as microactuators, soft robotics, and wearable devices鈥�.
Gypsum4 (calcium sulfate dihydrate, CaSO4鈥�2贬2O) is a common mineral and a major byproduct of phosphoric acid manufacture. It is widely used in agriculture as a calcium and sulfur nutrient and for improving soil structure. It is also used in construction, especially for manufacturing drywall. It was in 1903 by German chemist Paul Rohland in an article about the conversions among gypsum, its half-hydrate (CaSO4鈥⒙紿2O, plaster of Paris), and anhydrite (CaSO4).
Last month, Merve Ye艧ilba艧 and colleagues at the SETI Institute (Mountain View, CA), Ume氓 University (Sweden), Caltech (Pasadena, CA), and Universit茅 Grenoble Alpes (France) reported that geochemical transformations of gypsum in various environments on Earth may have implications for . Their experiments demonstrated two ways that gypsum could dehydrate under Martian conditions: loss of water from gypsum at 鈮�110 潞C (below the Martian surface) and the interaction of gypsum and chloride salts to displace water.
1. CAS Reg. No. 27092-46-2.
2. CAS Reg. No. 110-02-1.
3. CAS Reg. No. 77-79-2.
4. CAS Reg. No. 10101-41-4.
Molecules from the Journals
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Tartrazine聽fast facts
| CAS Reg. No. | 1934-21-0 |
| SciFindern name | 1H-Pyrazole-3- carboxylic acid, 4,5- dihydro-5-oxo-1-(4- sulfophenyl)-4-[2-(4- sulfophenyl)diazenyl]-, sodium salt (1:3) |
| Empirical formula | C16H9N4Na3O9S2 |
| Molar mass | 534.36 g/mol |
| Appearance | Bright orange-yellow powder |
| Melting point | >300 潞C (dec.) |
| Water solubility | 200 g/L (25 潞C) |
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