N-Aminofluorescein

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.