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]. N-Aminofluorescein can be used to measure the concentration of copper ions in cells^[3].

Guide (The following is our recommended protocol. This protocol is for reference only and should be modified according to your specific needs).
N-Aminofluorescein consists of a fluorescein moiety and a hydrazide group, which can recognize and bind Cu²⁺ and promote amide hydrolysis^[1].
N-Aminofluorescein is selective for Cu²⁺, showing absorption and emission bands at 632 nm and 515 nm, respectively, in 70% HEPES buffered aqueous solution (pH 7.4) containing Cu^2+[2].
Guide (The following is our recommended protocol. This protocol is provided as a guideline and should be modified according to your specific needs).
General procedure for Cu²⁺ determination^[1]:
1. Prepare a 1 mM stock solution of spirolactam fluorescein hydrazide in ethanol;
2. Perform the fluorescence turn-on reaction in 0.01 M Tris-HCl buffer (pH 7.2) by adding 10 μM N-Aminofluorescein;
3. Add an appropriate amount of sample solution so that the final concentration of Cu²⁺ does not exceed 10 μM, and adjust the final volume to 10 mL with 0.01 M Tris-HCl buffer (pH 7.2);
4. After 2 h, transfer 3 mL of the solution into a 1 cm quartz cuvette, and measure at room temperature with λex/em = 495/516 nm and excitation and emission slit widths of 5 nm;
5. Prepare a blank solution without Cu²⁺ and measure under 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.

  [3]. Zhi HT, et al. Anticancer efficacy triggered by synergistically modulating the homeostasis of anions and iron: Design, synthesis and biological evaluation of dual-functional squaramide-hydroxamic acid conjugates. Bioorg Chem. 2024 Jun;147:107421.  [Content Brief]