Xylenol orange is an organic reagent, most commonly used as a tetrasodium salt as an indicator for metal titrations. When used for metal titrations, it will appear red in the titrand and become yellow once it reaches its endpoint. Historically, commercial preparations of it have been notoriously impure,[2] sometimes consisting of as little as 20% xylenol orange, and containing large amounts of semi-xylenol orange and iminodiacetic acid. Purities as high as 90% are now available.
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Preferred IUPAC name
2,2′,2′′,2′′′-{(1,1-Dioxo-2,1λ6-benzoxathiole-3,3(1H)-diyl)bis[(6-hydroxy-5-methyl-3,1-phenylene)methylenenitrilo]}tetraacetic acid | |
Other names
XO[1]
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.015.049 |
EC Number |
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PubChem CID
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UNII |
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CompTox Dashboard (EPA)
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Properties | |
C31H32N2O13S | |
Molar mass | 672.66 g·mol−1 |
Melting point | 195 °C (383 °F; 468 K) |
200 mg/mL | |
Hazards | |
GHS labelling: | |
Warning | |
H315, H319, H335 | |
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
NFPA 704 (fire diamond) | |
Flash point | > 93 °C (199 °F; 366 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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It is fluorescent, and has excitation maximums of 440 & 570 nm and an emission maximum of 610 nm.[3]
References
edit- ^ Li, Zhong-Guang (2019-01-01), Khan, M. Iqbal R.; Reddy, Palakolanu Sudhakar; Ferrante, Antonio; Khan, Nafees A. (eds.), "Chapter 5 - Measurement of Signaling Molecules Calcium Ion, Reactive Sulfur Species, Reactive Carbonyl Species, Reactive Nitrogen Species, and Reactive Oxygen Species in Plants", Plant Signaling Molecules, Woodhead Publishing, pp. 83–103, ISBN 978-0-12-816451-8, archived from the original on 2023-11-11, retrieved 2023-11-11
- ^ Gay, Craig; Collins, James; Gebicki, Janusz M. (1999), "Determination of Iron in Solutions with the Ferric–Xylenol Orange Complex", Analytical Biochemistry, 273 (2): 143–148, doi:10.1006/abio.1999.4207, PMID 10469483
- ^ "Fluorescence - Fluorochrome Data Tables". Molecular Expressions Microscopy Primer: Specialized Microscopy Techniques. 2018-09-11. Retrieved 2020-01-30.