Rare earth ion liquid as well as preparation method and application thereof in detection of ferric ions

[0036] The synthesis of embodiment 1 rare earth ionic liquid

[0037] 1) Synthesis of intermediate 1-butyl-3-methylimidazolium bromide

[0038] N-methylimidazole and butane bromide were distilled under reduced pressure separately for use.

[0039] Heating with a silicone oil bath to raise the temperature of N-methylimidazole to 50°C, and then adding bromobutane dropwise into the three-necked flask containing N-methylimidazole with a constant pressure dropping funnel, the molar ratio of the two is 1:1.1, after the dropwise addition, react at 50°C-60°C under reflux for about 48h. Filter and recrystallize with a mixture of acetonitrile and ethyl acetate (the volume ratio of acetonitrile and ethyl acetate is 1:2) with a total volume of 30 mL to obtain the intermediate 1-butyl-3-methylimidazolium bromide, the reaction formula is as follows :

[0040]

[0041] Intermediate 1-Butyl-3-methylimidazolium Bromide

[0042] 2) Synthesis of intermediate 1-butyl-3-methylimidazole nitrate

[0049] Example 2 Application of Rare Earth Ionic Liquids as Fluorescent Probes in Detection of Ferric Ions

[0050] Accurately add 2.5mL standard detection solution (aqueous solution of 1mol / L rare earth ionic liquid) to several cuvettes, and then add 10μL aqueous solution of 1mol / L metal cation (Zn 2+ , Pb 2+ 、Cd 2+ , Hg 2+ 、Co 2+ 、Ni 3+ 、Cr 3+ , Ca 2+ , Fe 2+ , Fe 3+ 、Cu 2+ ), so that the final concentration of metal cations is 4×10 -3 mol / L, respectively measure its fluorescence spectrum at 325nm excitation wavelength, the results are as follows figure 1 shown. Draw a histogram of the fluorescence intensity of different metal cations at 480nm, such as figure 2 shown.

[0051] From figure 1 and figure 2 It can be seen from the figure that at the excitation wavelength of 325nm, the addition of other heavy metal cations does not cause a significant change in the fluorescence intensity, only the addition of Fe 3+ After that, the fluorescence intensity of th

[0052] Example 3 Rare earth ionic liquid is used as a fluorescent probe to determine the detection limit of ferric ions

[0053] Accurately add 2.5mL of standard detection solution (aqueous solution of 1mol / L rare earth ionic liquid) to several cuvettes, and then add 10μL of different concentrations of Fe with a pipette gun 3+ Aqueous solutions (concentrations from low to high are 4×10 -4 , 4.5×10 -4 , 5×10 - 4 , 5.5×10 -4 , 6×10 -4 , 6.5×10 -4 , 7×10 -4 , 7.5×10 -4 , 8×10 -4 , 8.5×10 -4 , 9×10 -4 、10 -3 , 2×10 -3 , 3×10 -3 , 4×10 -3 mol / L), respectively measure its fluorescence spectrum at 325nm excitation wavelength, such as image 3 shown. Draw a histogram of the fluorescence intensity at 480nm of different concentrations of ferric ions, such as Figure 4 shown.

[0054] From image 3 and Figure 4 It can be seen that as the concentration of iron ions increases, the fluorescence intensity of the fluorescent probe decreases gradually until it is quenched