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Sigma-Aldrich

Cresol red

indicator grade, Dye content 95 %

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Synonym(s):
o-Cresolsulfonphthalein
Empirical Formula (Hill Notation):
C21H18O5S
CAS Number:
1733-12-6
Molecular Weight:
382.43
Beilstein:
343399
EC Number:
217-064-2
MDL number:
MFCD00005878
PubChem Substance ID:
24847173

grade

indicator grade

Quality Level

200

form

powder or crystals

composition

Dye content, 95%

technique(s)

titration: suitable

color

red-brown

pH

7.2-8.8, yellow to red

useful pH range

1.8-2.0, orange to yellow(acid)
7.0-8.8, yellow to violet(alkaline)

mp

290 °C

density

0.998 g/cm3

λmax

367 nm (2nd)
570 nm

application(s)

diagnostic assay manufacturing
hematology
histology

storage temp.

room temp

SMILES string

Cc1cc(ccc1O)C2(OS(=O)(=O)c3ccccc23)c4ccc(O)c(C)c4

InChI

1S/C21H18O5S/c1-13-11-15(7-9-18(13)22)21(16-8-10-19(23)14(2)12-16)17-5-3-4-6-20(17)27(24,25)26-21/h3-12,22-23H,1-2H3

InChI key

OBRMNDMBJQTZHV-UHFFFAOYSA-N

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General description

Cresol Red, also known as o-cresol red, belongs to the phthalein and sulphonphthalein group of dyes. Cresol red changes color from orange to yellow at pH between 0.2-1.8 and yellow to violet at pH between 7.0-8.8. In alkaline solutions, cresol red is present as a hydrophilic dianion. The dianion is small and is violet in color, possessing a larger conjugated system than the yellow hydroxyquinone.

Application

Cresol Red is a widely used pH indicator for routine pH assessments like microbial culture media preparations. In addition, Cresol red is a suitable constituent of PCR reagent systems. Cresol Red is used as a tracking dye in DNA, RNA (agarose), and protein (polyacrylamide) electrophoresis.

Storage Class Code

11 - Combustible Solids

WGK

WGK 3

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Atsushi Seki et al.
Analytica chimica acta, 582(1), 154-157 (2007-03-28)
Novel spectroscopic sensor based on a hetero-core structured fiber optic is described in this paper. The hetero-core structured fiber optic consists of multi mode fibers and a short piece of single mode fiber which was inserted in the multi mode
Paula C A Jerónimo et al.
The Analyst, 130(8), 1190-1197 (2005-07-16)
An optical biosensor based on immobilised carbonic anhydrase and its application to the determination of the anti-glaucoma agent acetazolamide by enzyme inhibition measurements, is described. The enzyme and a pH indicator dye, cresol red, were physically immobilised in overlapped sol-gel
K Elamrani et al.
Biochimica et biophysica acta, 727(1), 22-30 (1983-01-05)
The kinetics of H+/OH- diffusion across dimyristoyl phosphatidic acid bilayer membranes was measured by following the absorbance of the pH-sensitive indicator Cresol red (o-cresolsulfonphthalein) entrapped in single lamellar vesicles after rapidly changing the external pH in a stopped-flow apparatus. The
K Schilling et al.
Clinical chemistry, 39(2), 251-256 (1993-02-01)
If buffer/indicator systems are used as optical thermometers in multicuvettes, the temperature resolution is limited by errors of optical measurements produced mainly by variations of pathlength and blank transmittance of the wells. Theoretical and practical approaches show that, in multicuvettes
H N Nigg et al.
Journal of economic entomology, 97(6), 1850-1860 (2005-01-26)
We needed a technique to compare the consumption of baits by individual Carribbean fruit fly, Anastrepha suspensa (Loew). By improving consumption and determining individual dose, we could lower pesticide concentration while retaining bait/pesticide efficacy and potentially reduce the environmental impact
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