N-Aminofluorescein 

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 Cu^2+[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.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

346.34

C₂₀H₁₄N₂O₄

98907-26-7

Solid

Off-white to light yellow

516

495

O=C1N(N)C2(C3=C(OC4=C2C=CC(O)=C4)C=C(O)C=C3)C5=C1C=CC=C5

Room temperature in continental US; may vary elsewhere.

-20°C, protect from light

*In solvent : -80°C, 6 months; -20°C, 1 month (protect from light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (protect from light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [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.