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Chromoionophore I


9-(Diethylamino)-5-(octadecanoylimino)-5H-benzo[a]phenoxazine, N-Octadecanoyl-Nile blue, 3-Octadecanoylimino-7-(diethylamino)-1,2-benzophenoxazine, ETH 5294
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
MDL number:
PubChem Substance ID:

Quality Level

product line



91-93 °C (lit.)


λex 614 nm; λem 663 nm (protonated)

SMILES string




InChI key


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General description

Visit our Sensor Applications portal to learn more.
Chromoionophore I (ETH 5294, 3-octadecanoylimino-7-diethylamino-l,2-benzophenoxazine) is a H+-selective neutral chromoionophore, which is lipophilic in nature and is a highly basic dye molecule.


Chromoionophore I may be used for the test zone preparation in the multianalyte sensor, during environmental monitoring, using photographic digital camera.
Selected application examples
Assay of K+ and of Ca2+ activity with solvent polymeric optode membrane based on ETH 5294 and potassium ionophore I (valinomycin)


Bottomless glass bottle. Contents are inside inserted fused cone.

Legal Information

Selectophore is a trademark of Sigma-Aldrich Chemie GmbH

Storage Class Code

13 - Non Combustible Solids

WGK Germany


Flash Point F

Not applicable

Flash Point C

Not applicable

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves

Certificate of Analysis

Certificate of Origin

Anna Baranowska-Korczyc et al.
The Analyst, 145(16), 5594-5602 (2020-08-11)
Core-shell modified nanofiber mats were used as ion-selective membranes for the first time. Keeping the overall macroscopic size of the sensing element the same as for classical plasticized poly(vinyl chloride) membranes, herein the proposed nanofiber based systems resulted in ultrathin...
Design and characterization of a novel ammonium ion selective optical sensor based on neutral ionophores.
Seiler K
Analytical Sciences, 5 (5), 557-561 (1989)
Fatehy M Abdel-Haleem et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 201, 98-104 (2018-05-08)
Preparation of novel salicylate-selective optical sensors (bulk optodes) was performed and applied successfully for salicylate determination in pharmaceutical formulations, Aspirin® and Aspocid®. t-butyl calix[4]arene ionophore was incorporated in a plasticized poly (vinyl-chloride) membrane containing the chromoionophore ETH5294 (O1) or ETH7075...
Environmental monitoring using a conventional photographic digital camera for multianalyte disposable optical sensors.
Lapresta FA and Vallvey C.
Analytica Chimica Acta, 706 (2), 328-337 (2011)
L Lvova et al.
Analytica chimica acta, 988, 96-103 (2017-09-17)
A systematic study of a series of diaza-18-crown-6 8-hydroxyquinoline (DCHQ) chemosensors, devoted to Mg(II) ion detection, was performed. Functionalization of DCHQ by peripheral substituents allowed the development of novel all-solid-state optodes via inclusion inside PVC-based polymeric films. The influence on...

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