N-Aminofluorescein

• CAT Number: I043066
• CAS Number: 98907-26-7
• Molecular Formula: C20H14N2O4
• Molecular Weight: 346.34
• Purity: ≥95%
• Synonyms: 2-amino-3′,6′-dihydroxyspiro[isoindole-3,9′-xanthene]-1-one
• InChI: InChI=1S/C20H14N2O4/c21-22-19(25)13-3-1-2-4-14(13)20(22)15-7-5-11(23)9-17(15)26-18-10-12(24)6-8-16(18)20/h1-10,23-24H,21H2
• InChIKey: CHYVTSCIBXXQJT-UHFFFAOYSA-N
• SMILES: C1=CC=C2C(=C1)C(=O)N(C23C4=C(C=C(C=C4)O)OC5=C3C=CC(=C5)O)N

N-Aminofluorescein is a fluorescein hydrazide with spiro form, a highly selective and sensitive fluorescence probe for Cu2+. N-Aminofluorescein has no selective fluorescence response to other common metal ions, can be used for direct detection of Cu2+ in biological systems with λex/em=495/516 nm[1][2].
Guidelines (Following is our recommended protocol. This protocol only provides a guideline, and should be modified according to your specific needs).
N-Aminofluorescein consists of a fluorescein moiety and a hydrazide group to recognize and bind Cu2+, can promote the hydrolysis of amide[1].
N-Aminofluorescein (FG) shows selectivity on Cu2+ and shows the absorption and emission bands at 632 nm and 515 nm in 70% aqueous HEPES buffered solution (pH 7.4) containing Cu2+[2].
Guidelines (Following is our recommended protocol. This protocol only provides a guideline, and should be modified according to your specific needs).
General procedure for Cu2+ determination[1]:
1.Prepare the 1.0 mM stock solution of spiro form fluorescein hydrazide in ethanol;
2.Conduct the fluorescence-on reaction in 0.01 M Tris-HCl buffer (pH 7.2), with 10 μM N-Aminofluorescein;
3.Add an appropriate volume of sample solution with a final Cu2+ concentration of not more than 10 μM, and adjust the final volume 10 mL with 0.01 M Tris-HCl buffer (pH 7.2);
4.After 2 h, transfer a 3-mL portion of the solution to a 1-cm quartz cell, and measure the fluorescence intensity/spectrum at room temperature with λex/em = 495/516 nm and both excitation and emission slit widths of 5 nm;?
5.In the meantime, prepare a blank solution containing no Cu2+ and measure with the same conditions for comparison.

Reference

[1]. Chen X, et al. A selective fluorescence-on reaction of spiro form fluorescein hydrazide with Cu(II). Anal Chim Acta. 2006 Aug 11;575(2):217-22.
 [Content Brief]

[2]. Uzra Diwan, et al. A water compatible turn ‘on’ optical probe for Cu2+ based on a fluorescein-sugar conjugate. Sensors and Actuators B: Chemical. 2014;196:345-351.