Calcein Blue


Application: Metal indicator, fluorometric

ChemicalName: 8-[N,N-Bis(carboxymethyl)aminomethyl]-4-methylunbelliferone
CAS: 54375-47-2

Appearance: White or pale yellow powder
Sensitivity: To pass test
MW: 321.28, C15H15NO7

Storage Condition: ambient temperature, protect from light
Shipping Condition: ambient temperature


Product Description
Calcein Blue is a fluorescent metal indicator in EDTA titration. It is highly soluble in alkaline solutions, but slightly soluble in water. Its proton dissociation constants are reported to be pKa1=2.45, pKa2=7.24 and pKa3=11.3. Calcein Blue solution emits bright blue fluorescence (λem=445 nm) at pH 4-11, but no fluorescence at pH 12 or higher. The blue fluorescence of the Calcein Blue solution at pH 4-11 is quenched by metal ions such as Co, Cu, Mn, Ni, and Pb. However, Calcein Blue forms a highly fluorescent complex with alkaline earth metals at pH 12 or higher. Since the endpoint of the chelate titration is clear by UV irradiation at 200-370 nm in a dark room, highly stained samples can be used. Calcein Blue is also suitable to determine Fe and Zr ions. Calcein Blue-Zn chelate can detect 10 ppb of F-. Calcein Blue aqueous solution emits laser at 449-490 nm.

Chemical Structure

1. D. H. Willkins, Calcein Blue – A New Metalfluorechromic Indicator for Chelatometric Titrations. Talanta. 1960;4:182-184.
2. J. H. Eggers, Umbellikomplexon Und Xanthokomplexonein Beitrag zur Kenntnnis Komplexometrischer Fluoreszensindikatoren. Talanta. 1960;4:38-43.
3. H. N. Elsheimer, Complexometric Determination of Gallium with Calcein Blue as Indicator. Talanta. 1967;14:97-102.
4. M. A. Salam Khan, et al., A Structural Study of the Methyleneiminodiacetic Acid Derivatives of Some 7-Hydroxycoumarins. Anal Chim Acta. 1968;43:153-156.
5. R. V. Hems, et al., Spectrofluorimetric Determination of Submicrogram Amounts of Zirconium with Calcein Blue. Anal Chem. 1970;42:784-787.
6. T. L. Har, et al., Spectrofluorimetric Determination of Traces of Fluoride Ion by Ternary Complex Formation with Zirconium and Calcein Blue. Anal Chem. 1971;43:136-139.
7. T. Imasaka, et al., Characteristics of Coordination Compounds of Calcein Blue for a Tunable Oraganic Liquid Laser. Bull Chem Soc Jpn. 1976;49:2687-2695.
8. K. A. Matsoukas, et al., Spectrofluorimetric Determination of Magnesium in Blood Serum with Calcein Blue. Anal Chim Acta. 1989;227:211-218.

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