Preparation method and application of an acidic medium identifying iron ion indicator

Abstract

This invention relates to a method for preparing and applying an acidic medium-based iron ion recognition indicator. The indicator contains an aminoquinoline structure and a sulfosalicylic acid structure. It exhibits excellent dual colorimetric and fluorescence responses to ferric ions. When the sample contains Fe... 3+ At that time, Fe 3+ It can undergo complexation reactions with the -NH-CO-, -OH, and quinoline-N groups in the indicator, changing the solution from colorless to brown. This allows for qualitative analysis of iron ions by naked-eye observation. Simultaneously, the fluorescence weakens, and the fluorescence intensity is similar to that of Fe. 3+ The content exhibits a good linear relationship, reaching the nanomolar level, enabling quantitative detection of iron ions and Fe. 3+ It has extremely excellent selectivity, and can identify and detect iron ions not only in normal environments, but also accurately identify iron ions under extreme conditions of strong acidity. It is stable, can be used in acidic media, and has strong anti-interference ability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorescence detection, and particularly relates to a preparation method and application of an acidic medium recognition iron ion indicator. BACKGROUND

[0002] Iron is an element widely existing in nature, which can be divided into iron single substance, Fe 2+ (ferric ion) and Fe 3+ (ferrous ion). The iron single substance is a metal material, which is widely used in various steel products such as power grid supports and metal products. However, the iron single substance is unstable under the conditions of atmosphere, water, acid and alkali, and is easy to be oxidized to form Fe 2+ and Fe 3+ compounds. The iron ion is a +3 valence ion obtained by losing 3 outer electrons of the iron element, and is the most stable ion of iron, which has strong oxidizing property. The iron ion is a transition metal ion, and the content of the iron ion is too high, which can also cause certain pollution to the environment, and has certain influence on soil, atmosphere, lake and the like. Therefore, the quantitative detection of the iron ion is particularly important.

[0003] At present, there are many indicators for Fe 3+ . The commonly used indicators reported include o-phenanthroline, potassium ferricyanide, sulfosalicylic acid and potassium thiocyanate. However, the commonly used indicators are interfered under strong acidic conditions, and are interfered by other metal ions to different degrees. Therefore, it is urgent to provide a technical scheme to improve the above technical problems. SUMMARY

[0004] In view of the deficiencies and problems in the prior art, the application aims to provide a preparation method and application of an acidic medium recognition iron ion indicator.

[0005] The application is implemented by the following technical scheme:

[0006] The application provides an acidic medium recognition iron ion indicator, which is an acidic medium iron ion fluorescence probe. The acidic medium recognition iron ion indicator has the structure of formula (1).

[0007] The acidic medium recognition iron ion indicator has an amino quinoline structure and a sulfosalicylic acid structure in the structure, and the acidic medium recognition iron ion indicator has good color development and fluorescence double response to trivalent iron ions. When the sample to be detected contains Fe 3+ , the Fe 3+ can react with the -NH-CO- group, -OH group and quinoline-N group in the indicator to form a complex, the solution changes from colorless to brown, naked eye recognition can be realized, and fluorescence is weakened, so that the colorimetric fluorescence double response of the iron ion is realized. Please refer to Figure 1 ,Figure 1 The acid medium iron ion indicator detects Fe 3+ in a color development process.

[0008] The application also provides a preparation method of the acid medium iron ion indicator, characterized by comprising the following steps:

[0009] 8-aminoquinoline, sulfosalicylic acid, a polar organic solvent, a dehydrating agent, and a catalyst are mixed to perform a condensation reaction to obtain the acid medium iron ion indicator.

[0010] Preferably, the molar ratio of the 8-aminoquinoline to the sulfosalicylic acid is 1:1-1:2, more preferably 1:1.2-1:1.8, and most preferably 1:1.5; the polar organic solvent is DMF (N,N-dimethylformamide); the dehydrating agent is DCC (N,N'-dicyclohexyl carbodiimide); the catalyst is DMAP (4-dimethylaminopyridine); the condensation reaction temperature is 110-130°C, more preferably 120°C, and the condensation reaction time is 12-18h, more preferably 14-16h. Please refer to Figure 2 , Figure 2 for a synthesis route of the acid medium iron ion indicator.

[0011] The application monitors the condensation reaction by TCL (thin layer chromatography) until the raw materials are completely reacted.

[0012] After the condensation reaction, the application performs post-treatment on the condensation reaction solution, comprising the following steps:

[0013] The condensation reaction solution is washed with water to remove the polar organic solvent, the dehydrating agent, and the condensing agent of the condensation reaction solution, and the aqueous solution is extracted with a polar solvent to remove the polar solvent, and the remaining liquid is separated by column chromatography to obtain the acid medium iron ion indicator pure product. The polar solvent for extracting the aqueous solution is preferably CH2Cl2; the way to remove the polar organic solvent is preferably reduced pressure distillation; the stationary phase for column chromatography separation is preferably silica gel; the eluent is preferably CH2Cl2 and C6H 14 ; and the volume ratio of the CH2Cl2 and C6H 14 is preferably 1:5.

[0014] The application also provides application of the acid medium iron ion indicator in trivalent iron ion detection.

[0015] Preferably, the trivalent iron ion detection comprises the following steps:

[0016] The sample to be tested is mixed with the acid medium iron ion indicator solution in an acid medium, and if the sample to be tested shows brown color, the sample to be tested contains trivalent iron ion;

[0017] The mixture of the sample to be tested and the fluorescent probe is subjected to ultraviolet absorption spectrum test, and the ultraviolet absorption intensity of the sample to be tested at 300 nm is obtained, and the concentration of iron ions in the sample to be tested is obtained according to the ultraviolet absorption intensity and the first standard curve; the first standard curve is a linear relationship curve of the molar ratio of iron ions, the indicator and the ultraviolet absorption intensity; the drawing method of the first standard curve preferably comprises the following steps: preparing a solution with a probe molar concentration of 1×10 -5 mol / L, dividing it into 10 groups, the volume of each group of solution is 2mL, and the molar ratio of iron ions to probe in each group is 0:1, 0.1:1, 0.2:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1 and 5:1; each group of solution is subjected to ultraviolet absorption spectrum test, and the ultraviolet absorption intensity of each group of solution at 300 nm is obtained, and the first standard curve is drawn with the concentration of iron ions as the abscissa and the ultraviolet absorption intensity as the ordinate;

[0018] Alternatively, under the excitation wavelength of 300 nm laser irradiation, the mixture of the sample to be tested and the indicator is subjected to fluorescence emission spectrum test, and the fluorescence intensity of the sample to be tested at 408 nm is obtained, and the concentration of iron ions in the sample to be tested is obtained according to the fluorescence intensity and the second standard curve; the second standard curve is a linear relationship curve of the molar ratio of iron ions, the fluorescent probe and the fluorescence intensity;

[0019] Preferably, the sample to be tested is an aqueous solution; the solvent of the acidic medium iron ion indicator solution is preferably water; the concentration of the acidic medium iron ion indicator solution is preferably 10mM; the molar ratio of iron ions in the sample to be tested to the acidic medium iron ion indicator is preferably 0-5:1 (i.e. equivalents), more preferably 0.3:1-0.7:1 (i.e. equivalents).

[0020] Preferably, in the ultraviolet absorption spectrum test and the fluorescence emission spectrum test, the linear detection range of iron ions in the sample to be tested is independently 0.003-0.009mmol.

[0021] Compared with the prior art, the beneficial effects are:

[0022] The application provides a preparation method of an acidic medium iron ion indicator having a structure shown in formula 1. The acidic medium iron ion indicator has an amino quinoline structure and a sulfosalicylic acid structure in the structure, and the acidic medium iron ion indicator has good color development and fluorescence double response to trivalent iron ions. When the sample to be tested contains Fe 3+ , the Fe 3+The complexation reaction with -NH-CO- group, -OH group and quinoline-N group in the indicator agent can change the solution from colorless to brown, that is, the color development process of Fe 3+ Naked eye recognition, while fluorescence is weakened, and the fluorescence intensity has a good linear relationship with the content of Fe 3+ , which reaches the nanomolar level, so that the quantitative detection of iron ions can be realized. 3+ The indicator agent has extremely excellent selectivity, and can not only recognize and detect iron ions in a conventional environment, but also can accurately recognize iron ions in a strong acidic extreme condition. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Color development process of the acid medium iron ion recognition indicator agent for detecting Fe 3+ .

[0024] Figure 2 Synthetic route of the acid medium iron ion recognition indicator agent.

[0025] Figure 3 NMR hydrogen spectrum of the acid medium iron ion recognition indicator agent.

[0026] Figure 4 UV absorption spectrum of 1×10 -5 mol / L indicator agent and 0-5 equivalent iron ions.

[0027] Figure 5 Fluorescence emission spectrum of 1×10 -5 mol / L indicator agent and 0-5 equivalent iron ions.

[0028] Figure 6 Linear relationship curve of fluorescence intensity of 1×10 -5 mol / L indicator agent and 0.3-0.9 equivalent iron ions.

[0029] Figure 7 Selectivity test results of the acid medium iron ion recognition indicator agent for iron ions.

[0030] Figure 8 Test results of the acid medium iron ion recognition indicator agent in an acidic medium. DETAILED DESCRIPTION

[0031] The purpose of the present application is to provide a preparation method and application of an acid medium iron ion recognition indicator agent.

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] The present application will be further described in conjunction with the embodiments without departing from the spirit or essential characteristics of the present application.

[0034] The present application provides an acidic medium recognizing iron ion indicator, which is an acidic medium iron ion fluorescent probe.

[0035] The acidic medium recognizing iron ion indicator contains an aminoquinoline structure and a sulfosalicylic acid structure in the structure, and the acidic medium recognizing iron ion indicator has good color development and fluorescence double response to trivalent iron ions. 3+ When the sample to be measured contains Fe 3+ , the Fe 3+ can react with the -NH-CO- group, -OH group and quinoline-N group in the indicator to change the solution from colorless to brown, so that naked eye recognition can be realized, and fluorescence is weakened, so that colorimetric fluorescence double response of iron ions is realized. Figure 1 , Figure 1 The acidic medium iron ion indicator detects the color development process of Fe 3+ .

[0036] The present application further provides a preparation method of the acidic medium recognizing iron ion indicator, which comprises the following steps.

[0037] 8-aminoquinoline, sulfosalicylic acid, a polar organic solvent, a dehydrating agent and a catalyst are mixed to perform condensation reaction, so that the acidic medium recognizing iron ion indicator is obtained.

[0038] Further, the molar ratio of the 8-aminoquinoline to the sulfosalicylic acid is 1:1-1:2, more preferably 1:1.2-1:1.8, and most preferably 1:1.5; the polar organic solvent is DMF (N,N-dimethylformamide); the dehydrating agent is DCC (N,N'-dicyclohexyl carbodiimide); the catalyst is DMAP (4-dimethylamino pyridine); the temperature of the condensation reaction is 110-130 DEG C, more preferably 120 DEG C, and the time of the condensation reaction is 12-18 h, more preferably 14-16 h. Figure 2 , Figure 2 The present application further provides a synthesis route of the acidic medium iron ion indicator.

[0039] The present application monitors the condensation reaction by TCL (thin layer chromatography) until the raw materials are completely reacted.

[0040] After the condensation reaction, the present application carries out post-treatment on the condensation reaction solution, including the following steps:

[0041] The condensation reaction solution is washed with water to remove the polar organic solvent, dehydrating agent and condensing agent of the condensation reaction solution, and the aqueous solution is extracted with a polar solvent to remove the polar solvent, and the remaining liquid is separated by column chromatography to obtain the pure product of the acidic medium iron ion indicator. The polar solvent for extracting the aqueous solution is preferably CH2Cl2; the method for removing the polar organic solvent is preferably reduced pressure distillation; the stationary phase for column chromatography separation is preferably silica gel; the eluent is preferably CH2Cl2 and C6H 14 ; and the volume ratio of CH2Cl2 and C6H 14 is preferably 1:5.

[0042] The present application also provides the use of the acidic medium iron ion indicator in the detection of ferric ions.

[0043] Further, the detection of ferric ions includes the following steps:

[0044] The sample to be tested is mixed with the acidic medium iron ion indicator solution in an acidic medium, and if the sample to be tested shows brown color, it contains ferric ions;

[0045] The mixture of the sample to be tested and the fluorescent probe is tested by ultraviolet absorption spectrum to obtain the ultraviolet absorption intensity of the sample to be tested at 300 nm, and the concentration of iron ions in the sample to be tested is obtained according to the ultraviolet absorption intensity and the first standard curve; the first standard curve is a linear relationship curve of the molar ratio of iron ions and the indicator and the ultraviolet absorption intensity; the drawing method of the first standard curve preferably includes the following steps: preparing a solution with a probe molar concentration of 1×10 -5 mol / L, dividing it into 10 groups, the volume of each group of solution is 2mL, and the ratio of the molar concentration of iron ions and the probe in each group is 0:1, 0.1:1, 0.2:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1 and 5:1; each group of solution is tested by ultraviolet absorption spectrum to obtain the ultraviolet absorption intensity of each group of solution at 300 nm, and the first standard curve is drawn with the concentration of iron ions as the abscissa and the ultraviolet absorption intensity as the ordinate;

[0046] Alternatively, under laser irradiation at an excitation wavelength of 300 nm, the mixture of the sample to be tested and the indicator is subjected to fluorescence emission spectrum test, and the fluorescence intensity of the sample to be tested at 408 nm is obtained, and the concentration of iron ions in the sample to be tested is obtained according to the fluorescence intensity and a second standard curve; the second standard curve is a linear relationship curve of the molar ratio of iron ions and the fluorescence probe and the fluorescence intensity;

[0047] Preferably, the sample to be tested is an aqueous solution; the solvent of the acidic medium iron ion indicator solution is preferably water; the concentration of the acidic medium iron ion indicator solution is preferably 10 mM; the molar ratio of iron ions in the sample to be tested to the acidic medium iron ion indicator is preferably 0-5:1 (i.e. equivalents), and more preferably 0.3:1-0.7:1 (i.e. equivalents).

[0048] Further, in the ultraviolet absorption spectrum test and the fluorescence emission spectrum test, the linear detection range of iron ions in the sample to be tested is independently 0.003-0.009 mmol.

[0049] Example 1: Synthesis of acidic medium iron ion indicator (QL-SA)

[0050] Synthesis of compound QL-SA: 8-aminoquinoline (0.32 g, 1.00 mmol) and sulfosalicylic acid (0.44 g, 1.00 mmol) were dissolved in a flask with anhydrous DMF (25 mL), mixed and stirred for 15 min. Then, DCC (0.25 g, 1.20 mmol) and DMAP (0.10 g, 0.80 mmol) were slowly added to the solution and reacted at room temperature under nitrogen atmosphere for 16 h. After the reaction was completed, the reaction was quenched with water, extracted with 3x50 mL of dichloromethane, and dried with anhydrous sodium sulfate, and the solvent was removed under reduced pressure, and then the mixture was purified by silica gel column chromatography using CH2Cl l2 / C6H 14 (1:5, v / v) as eluent to obtain light yellow QL-SA solid (0.55 g, 90% yield).

[0051] Its nuclear magnetic hydrogen spectrum was tested in deuterated chloroform, please refer to Figure 3 .

[0052] NMR (400 MHz, CDC13) δ: 10.99 (s, 1H), 8.87 (t, J = 5.2 Hz, 2H), 8.79 (q, J = 4.6 Hz, 1H), 8.51 (d, J = 2.0 Hz, 1H), 8.20 (dd, J = 20.4, 8.2 Hz, 2H), 8.02 (d, J = 8.6 Hz, 1H), 7.57 (d, J = 4.3 Hz, 2H), 7.53 (dd, J = 8.1, 3.8 Hz, 2H).

[0053] Example 2: Response of acidic medium recognition iron ion indicator (QL-SA) to iron ion

[0054] The fluorescence emission spectrum and UV absorption spectrum of the indicator QL-SA after adding Fe 3+ in solution (solvent is pure water) were measured to study its response to Fe 3+ . The specific steps are as follows:

[0055] Prepare a solution of the probe with a molar concentration of 1 x 10 -5 mol / L, divide it into 10 groups, and the volume of each group of solution is 2 mL. The ratio of iron ion to probe molar concentration in each group is 0:1, 0.1:1, 0.2:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1 and 5:1. The UV absorption spectrum and fluorescence emission spectrum under excitation wavelength of 300 nm laser irradiation were tested.

[0056] The UV absorption spectrum of 1 x 10 -5 mol / L probe and 0-5 equivalents of iron ion is shown in Figure 4 .

[0057] The fluorescence emission spectrum of 1 x 10 -5 mol / L probe and 0-5 equivalents of iron ion is shown in Figure 5 .

[0058] As can be seen from Figure 4 , after adding Fe 3+ , the absorption peak at 300 nm increases with the increase of Fe 3+ content and reaches saturation when the Fe 3 + content is 5 equivalents. At the same time, the probe solution is colorless at the beginning, and after adding iron ion, the solution becomes obviously brown, that is, the naked eye can be used to qualitatively analyze the iron ion.

[0059] As can be seen from Figure 5 , the fluorescence intensity of QL-SA is 8400 at the beginning, and when Fe -5 is gradually added to QL-SA (1 x 10 mol / L), the fluorescence intensity of QL-SA gradually decreases.3+ At that time, the emission peak at 408 nm increased with Fe 3+ With increasing equivalent, the peak gradually decreases, reaching saturation at 5 equivalents, which can lead to a 70-fold fluorescence shutdown reaction.

[0060] In fluorescence emission spectroscopy testing, 1×10 -5 Please refer to the linear relationship curves between mol / L probe and 0.3–0.9 equivalent iron ions and fluorescence intensity. Figure 6 As shown.

[0061] Depend on Figure 6 It can be seen that the fluorescence intensity is related to Fe 3+ The content showed a good linear relationship. Based on the 3σ / K rule, the effect of probe QL-SA on Fe was calculated. 3+ The detection limit is 3.21 × 10⁻⁶. -9 M(σ=0.12,K=4.68×10 8 This technology has reached the nanomolar level, enabling quantitative detection of iron ions.

[0062] Example 3: Selectivity test of iron ions by an acidic medium-mediated iron ion identification indicator (QL-SA)

[0063] In containing QL-SA (1×10) -5 Add 10 equivalents of interfering ions to a solution of (mol / L) (solvent: water), and refer to the results. Figure 7 As shown, the effect of QL-SA on Na was tested. + K + Ag + Ba 2+ Co 2+ Hg 2+ Ca 2+ Cu 2 +,Ni 2+ Zn 2+ Mg 2 + Cd 2+ The fluorescence response of probe QL-SA was observed, and the results showed that the probe QL-SA exhibited a fluorescence response upon the addition of Fe. 3+ The fluorescence intensity decreased by approximately 45-fold, while other analytes showed little change, indicating that the indicator QL-SA has a significant effect on Fe. 3+ It has extremely high selectivity.

[0064] Example 4: Testing of QL-SA (acidic medium for iron ion identification) under different acidic conditions

[0065] In containing QL-SA (1×10) -5The results are shown in Table 1. Table 1: The fluorescence intensity of QL-SA in the presence of Fe3+in different pH solutions (water as solvent) with 5 equivalents of Fe3+added, respectively Figure 8 As shown in Figure 2, the fluorescence response of QL-SA to Fe3+was tested at pH from 2 to 8, and it was found that the fluorescence intensity did not change greatly at pH 2 to 7, indicating that the indicator can not only recognize and detect Fe3+in a normal environment, but also can accurately recognize Fe3+in an extremely acidic condition.

[0066] The above description only expresses the preferred embodiments of the present application, which is described in more detail and in more detail, but cannot be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications, improvements and substitutions can be made, which are within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. An acidic medium recognizing iron ion indicator, which is an acidic medium iron ion fluorescent probe, characterized by, The acid medium iron ion indicator has the structure of formula (1). Formula (1).

2. The method for preparing an acidic medium recognizing iron ion indicator according to claim 1, characterized in that, The method comprises the following steps: The 8-aminoquinoline, sulfosalicylic acid, polar organic solvent, dehydrating agent and catalyst are mixed to perform a condensation reaction to obtain the acid medium iron ion indicator.

3. The method for preparing an acid medium recognizing iron ion indicator according to claim 2, characterized in that: The molar ratio of the 8-aminoquinoline to the sulfosalicylic acid is 1:1-1:2; the polar organic solvent is DMF; the dehydrating agent is DCC; the catalyst is DMAP; the condensation reaction is performed at a temperature of 110-130°C for 12-18 hours.

4. The acid medium iron ion indicator of claim 1 or the acid medium iron ion indicator prepared by the preparation method of any one of claims 2-3 is applied in ferric ion detection, and the application is non-disease diagnosis or treatment.

5. Use according to claim 4, characterized in that, The ferric ion detection comprises the following steps: The sample to be tested is mixed with the acid medium iron ion indicator solution in an acid medium, and if the sample to be tested shows brown color, the sample to be tested contains ferric ion; The mixture of the sample to be tested and the indicator is subjected to ultraviolet absorption spectrum test to obtain the ultraviolet absorption intensity of the sample to be tested at 300 nm, and the concentration of the ferric ion in the sample to be tested is obtained according to the ultraviolet absorption intensity and a first standard curve; the first standard curve is a linear relationship curve of the molar ratio of the ferric ion to the indicator and the ultraviolet absorption intensity; Alternatively, the mixture of the sample to be tested and the indicator is subjected to fluorescence emission spectrum test under excitation wavelength of 300 nm laser irradiation to obtain the fluorescence intensity of the sample to be tested at 408 nm, and the concentration of the ferric ion in the sample to be tested is obtained according to the fluorescence intensity and a second standard curve; the second standard curve is a linear relationship curve of the molar ratio of the ferric ion to the indicator and the fluorescence intensity.

6. Use according to claim 5, characterized in that: In the ultraviolet absorption spectrum test and the fluorescence emission spectrum test, the linear detection range of the ferric ion in the sample to be tested is independently 0.003-0.009 mmol.

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