Product ID: M2786

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Availability: In stock


4’,5’-Dimethylfluorescein is a pH indicator for use in live cell analysis or for in vitro applications.

This derivative of the standard dye fluorescein is useful for measuring pH values in many applications. Adding the two methyl groups to fluorescein decreases the acidity of the dye, giving it a pKa of about 7.0. Ratiometric measurements using an excitation ration of 490/450 nm make it possible to precisely measure pH in varied environmental conditions. Its membrane permeant diacetate has been used for intracellular pH measurements.

Technical Data
SKU M2786
CAS Number 118797-71-0
Unit Size 5mg
Emission Wavelength 520
Extinction 480
Detection Method Fluorescence
Molecular Formula C₂₂H₁₆O₅
Molecular Weight 360.36
Soluble In DMSO, MeOH
Storage Conditions RT

References and Citations


  • Rajasekar, Mani; Khan, Sulaiman Mahaboob; Devaraj, Sivasithamparam Niranjali; Das, Thangamuthu Mohan (2011) "Design, synthesis, and biological evaluation of a novel class of fluorescein-based N-glycosylamines." Carbohydrate Research 346(13): 1776-1785.
  • Pietrancosta, Nicolas; Kessler, Albane; Favre-Besse, Franck-Cyril; Triballeau, Nicolas; Quentin, Thomas; Giros, Bruno; El Mestikawy, Salah; Acher, Francine C. (2010) "Rose Bengal analogs and vesicular glutamate transporters (VGLUTs). Bioorganic & Medicinal Chemistry 18(18): 6922-6933.
  • Hauser, Christina T.; Tsien, Roger Y. (2007) "A hexahistidine-Zn2+-dye label reveals STIM1 surface exposure." Proceedings of the National Academy of Sciences of the United States of America 104(10): 3693-3697.
  • Cassel D; Rothenberg P (1987) "Measurement of growth factor-induced changes in intracellular pH." Methods in Enzymology 147415-147427.
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