Resazurin

Resazurin
Names
IUPAC name
7-hydroxy-10-oxidophenoxazin-10-ium-3-one
Other names
Alamar Blue, Vybrant, UptiBlue, diazo-resorcinol, azoresorcin, resazoin, resazurine
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.008.171 Edit this at Wikidata
UNII
  • InChI=1S/C12H7NO4/c14-7-1-3-9-11(5-7)17-12-6-8(15)2-4-10(12)13(9)16/h1-6,14H ☒N
    Key: PLXBWHJQWKZRKG-UHFFFAOYSA-N ☒N
  • InChI=1/C12H7NO4/c14-7-1-3-9-11(5-7)17-12-6-8(15)2-4-10(12)13(9)16/h1-6,14H
    Key: PLXBWHJQWKZRKG-UHFFFAOYAB
  • [1]: C1=CC2=C(C=C1O)OC3=CC(=O)C=CC3=[N+]2[O-]
Properties
C12H7NO4
Molar mass 229.191 g·mol−1
soluble
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P261, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Resazurin (7-Hydroxy-3H-phenoxazin-3-one 10-oxide) is a phenoxazine dye that is weakly fluorescent, nontoxic, cell-permeable, and redox‐sensitive.[2][3] Resazurin has a blue to purple color above pH 6.5 and an orange color below pH 3.8.[4] It is used in microbiological, cellular, and enzymatic assays because it can be irreversibly reduced to the pink-colored and highly fluorescent resorufin (7-Hydroxy-3H-phenoxazin-3-one). At circum-neutral pH, resorufin can be detected by visual observation of its pink color or by fluorimetry, with an excitation maximum at 530-570 nm and an emission maximum at 580-590 nm.[5]

When a solution containing resorufin is submitted to reducing conditions (Eh < -110 mV), almost all resorufin is reversibly reduced to the translucid non-fluorescent dihydroresorufin (also known as hydroresorufin) and the solution becomes translucid (the redox potential of the resorufin/dihydroresorufin pair is -51 mV vs. standard hydrogen electrode at pH 7.0). When the Eh of this same solution is increased, dihydroresorufin is oxidized back to resorufin, and this reversible reaction can be used to monitor if the redox potential of a culture medium remains at a sufficiently low level for anaerobic organisms.

Resazurin (pH indicator)
below pH 3.8 above pH 6.5
3.8 ⇌ 6.5

Resazurin solution has one of the highest values known of Kreft's dichromaticity index.[6] This means that it has a large change in perceived color hue when the thickness or concentration of observed sample increases or decreases.

Usually, resazurin is available commercially as the sodium salt.

  1. ^ "Resazurin | C12H7NO4 | ChemSpider".
  2. ^ Bueno, C.; Villegas, M. L.; Bertolotti, S. G.; Previtali, C. M.; Neumann, M. G.; Encinas, M. V. (2002). "The Excited-State Interaction of Resazurin and Resorufin with Aminesin Aqueous Solutions. Photophysics and Photochemical Reaction". Photochemistry and Photobiology. 76 (4): 385–90. doi:10.1562/0031-8655(2002)0760385TESIOR2.0.CO2. PMID 12405144. S2CID 222102027.
  3. ^ Haggerty, Roy; Martí, Eugènia; Argerich, Alba; Schiller, Daniel von; Grimm, Nancy B. (2009). "Resazurin as a "smart" tracer for quantifying metabolically active transient storage in stream ecosystems". Journal of Geophysical Research: Biogeosciences. 114 (G3). Bibcode:2009JGRG..114.3014H. doi:10.1029/2008JG000942. hdl:10261/38263. ISSN 2156-2202.
  4. ^ "Resazurin, sodium salt". www.thomassci.com. Retrieved 2023-12-10.
  5. ^ Chen, J. L., Steele, T. W., & Stuckey, D. C. (2015). Modeling and application of a rapid fluorescence-based assay for biotoxicity in anaerobic digestion. Environmental science & technology, 49(22), 13463-13471.http://pubs.acs.org/doi/10.1021/acs.est.5b03050
  6. ^ Kreft, Samo; Kreft, Marko (2009). "Quantification of dichromatism: A characteristic of color in transparent materials". Journal of the Optical Society of America A. 26 (7): 1576–81. Bibcode:2009JOSAA..26.1576K. doi:10.1364/JOSAA.26.001576. PMID 19568292.