Metacresol purple

Last updated
Metacresol purple
M-cresol purple.svg
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.017.237 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • CC1=C(C=CC(=C1)O)C2(C3=CC=CC=C3S(=O)(=O)O2)C4=C(C=C(C=C4)O)C
Properties
C21H18O5S
Molar mass 382.43 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Metacresol purple or m-cresol purple, also called m-cresolsulfonphthalein, is a triarylmethane dye and a pH indicator. It is used as a capnographic indicator for detecting detect end-tidal carbon dioxide to ensure successful tracheal intubation in an emergency. [1] [2] It can be used to measure the pH in subzero temperatures of saline or hypersaline media. [3]

In colorimetric capnography, the indicator is incorporated in an aqueous matrix that provides a pH just above the indicator's colour change. [4] When exposed to carbon dioxide (CO2), it undergoes a colour change from purple to yellow, because when CO2 dissolves in the matrix, it forms carbonic acid. [5]

In chemistry, it has two useful indicator ranges: [2]

See also

Related Research Articles

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2
) in the respiratory gases. Its main development has been as a monitoring tool for use during anesthesia and intensive care. It is usually presented as a graph of CO
2
(measured in kilopascals, "kPa" or millimeters of mercury, "mmHg") plotted against time, or, less commonly, but more usefully, expired volume (known as volumetric capnography). The plot may also show the inspired CO
2
, which is of interest when rebreathing systems are being used. When the measurement is taken at the end of a breath (exhaling), it is called "end tidal" CO
2
(PETCO2).

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3
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4
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<i>o</i>-Cresolphthalein Chemical compound

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References

  1. "Capnography". LITFL • Life in the Fast Lane Medical Blog. Retrieved 2017-07-30.
  2. 1 2 "m-Cresol Purple 857890". Sigma-Aldrich. Retrieved 2017-07-30.
  3. Loucaides, Socratis; Rèrolle, Victoire M. C; Papadimitriou, Stathys; Kennedy, Hilary; Mowlem, Matthew C; Dickson, Andrew G; Gledhill, Martha; Achterberg, Eric P (2017). "Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures". Scientific Reports. 7 (1): 2481. Bibcode:2017NatSR...7.2481L. doi:10.1038/s41598-017-02624-0. PMC   5449408 . PMID   28559544.
  4. Gedeon, A.; Krill, P.; Mebius, C. (1994-09-01). "A new colorimetric breath indicator (Colibri)". Anaesthesia. 49 (9): 798–803. doi: 10.1111/j.1365-2044.1994.tb04457.x . ISSN   1365-2044. PMID   7978140. S2CID   44501202.
  5. Hagberg, Carin A. (2007-02-23). Benumof's Airway Management. Elsevier Health Sciences. ISBN   978-0323070171.
Metacresol purple(pH indicator)
below pH 7.4above pH 9.0
7.49.0
Metacresol purple(pH indicator)
below pH 1.2above pH 2.8
1.22.8