A method for detecting a complex

Abstract

The present invention provides a complex detection method, which relates to the technical field of boron trifluoride detection, comprising the following steps: measuring I 1 / I 01 ……I n / I 0n ; With the concentration of A1…An as the horizontal axis, I 1 / I 01 ……I n / I 0n Draw a standard curve as the ordinate; take the dilution of the boron trifluoride-ether complex to be tested, Ax; take Bx, measure the fluorescence intensity of Bx, record it as I 0x , mix Ax and Bx to get Cx, measure I x ; Calculation I x / I 0x The value M is taken, and M is brought into the standard curve to determine the concentration value X; the concentration of boron trifluoride in the boron trifluoride-ether complex to be tested is kX. The present invention realizes the concentration detection of BF3 by different enhancement capabilities of different concentrations of BF3 on the fluorescence intensity of 7-diethylaminocoumarin derivatives, and the detection accuracy is high, the sensitivity is high, and the detection limit of BF3 is low.

Description

Technical Field

[0001] The invention relates to the technical field of boron trifluoride detection, and in particular to a method for detecting a complex. Background Art

[0002] Boric acid, also known as boron-10 isotope, has the chemical formula 10B. It is a white powdery crystal or scaly shiny crystal with a natural purity of 19.4% in nature. It has strong neutron absorption and radiation protection functions. Boric acid usually exists in the form of boron trifluoride ether complex or in the form of solid 10B, H310BO3. Benefiting from the powerful radiation protection and thermal neutron absorption functions of boric acid-10 and the continuous breakthrough of boric acid-10 process technology, boric acid-10 has been widely used in nuclear radiation shielding in the field of nuclear power generation, energy supply and neutron protection in the field of national defense industry.

[0003] In the field of nuclear power generation, boric acid-10 can not only be used directly in nuclear power plants as the preferred chemical compensation control agent to ensure that the neutron shielding function of the nuclear reactor cooling system is efficient and safe, thereby effectively improving the safety, flexibility and service life of nuclear power plants, but also be used as the core raw material for nuclear reactor control rods to improve the level of nuclear reactor reaction intensity control. In addition, as a neutron shielding material, boric acid-10 can also be used in nuclear waste storage and transportation, effectively preventing nuclear proliferation and making nuclear waste treatment more efficient, safe and reliable.

[0004] Boric acid products are the core materials of boron-10 series neutron absorbers and are the decisive materials for the miniaturization of nuclear reactors and the lightweighting of equipment. Boric acid is usually stored in the form of boron trifluoride ether complex. The anhydrous ether added to the boron trifluoride ether complex is often excessive. The molar concentration of boron trifluoride in the boron trifluoride ether complex can be detected by nuclear magnetic resonance. The boron trifluoride ether complex is quantitatively analyzed by nuclear magnetic resonance (NMR) technology. The molar concentration of the sample to be tested is calculated by comparing the peak intensity of quantitative NMR with a reference substance of known molar concentration. However, this detection method has low accuracy and high detection limit, and cannot accurately measure the molar concentration of BF3 in the boron trifluoride ether complex. Summary of the invention

[0005] The invention provides a complex detection method, which solves the technical problems of low accuracy and high detection limit in the prior art method for measuring the molar concentration of BF3 in a boron trifluoride ether complex.

[0006] In order to achieve the above-mentioned invention object, the technical solution provided by the present invention is as follows:

[0007] A method for detecting a complex comprises the following steps:

[0008] S1. Dilute pure boron trifluoride-ether complex with anhydrous ether to different concentrations to obtain solutions A1, A2, A3, ..., An;

[0009] S2, dissolving 7-diethylaminocoumarin derivatives in a dichloromethane solution to obtain a 7-diethylaminocoumarin derivative dilution, taking n equal portions of the 7-diethylaminocoumarin derivative dilution to obtain solutions B1, B2, B3, ..., Bn;

[0010] S3, measure the fluorescence intensity of B1, B2, B3...Bn solution, record it as I 01 ,I 01 ,I 03 ,……I 0n ;

[0011] S4, adding the A1 to B1 to obtain solution C1, adding the A2 to B2 to obtain solution C2, adding the A3 to B3 to obtain solution C3, ... adding the An to Bn to obtain solution Cn;

[0012] S5. Measure the fluorescence intensity of C1, C2, C3, ... Cn, and record them as I1, I2, I3, ... I n ;

[0013] S6, make I1 / I 01 、I2 / I 02 、I3 / I 03 ,……I n / I 0n ;

[0014] S7, with the concentration of A1, A2, A3...An as the horizontal axis, and the corresponding value I1 / I 01 、I2 / I 02 、I3 / I 03 ,……I n / I 0n Plot a standard curve for the ordinate;

[0015] S8, taking the boron trifluoride-ether complex analyte, diluting it k times with anhydrous ether to obtain a dilution of the boron trifluoride-ether complex analyte, Ax;

[0016] S9, taking an equal amount of the 7-diethylaminocoumarin derivative dilution as B1 to obtain Bx, and measuring the fluorescence intensity of Bx, which is recorded as I 0x , the Ax and Bx are mixed to obtain Cx, and the fluorescence intensity of Cx is measured and recorded as I x ;

[0017] S10. Calculation I x / I 0x The value M of the standard curve is substituted into the ordinate of the standard curve to determine the concentration value X corresponding to the value M;

[0018] S11. The concentration of boron trifluoride in the boron trifluoride-ether complex analyte is kX.

[0019] Preferably, the molar concentrations of boron trifluoride in A1, A2, A3, ..., An in S1 increase successively.

[0020] Preferably, the molar concentrations of boron trifluoride in A1, A2, A3, ... An in S1 increase arithmetically.

[0021] Preferably, n is a multiple of 10.

[0022] Preferably, n is 20, and the molar concentrations of boron trifluoride in A1, A2, A3, ..., An in S1 are 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, ..., 0.2 mol / L, respectively.

[0023] Preferably, the concentration of the 7-diethylaminocoumarin derivative dilution in S2 is 0.1-0.2 mol / L.

[0024] Preferably, the 7-diethylaminocoumarin derivative in S2 is 3-(2'-thiophene)-7-diethylaminocoumarin or 3-(2'-thiophene)-7-diethylamino-4-methoxycoumarin.

[0025] Preferably, the 7-diethylaminocoumarin derivative is 3-(2'-thiophene)-7-diethylamino-4-methoxycoumarin.

[0026] Preferably, the volumes of An and Bn in S4 are equal.

[0027] Preferably, the k in S8 is 10-50.

[0028] It should be explained here that the molecular weight of pure boron trifluoride-ether complex is 141.93, the density is 1.120-1.140 g / mL at 20°C, and the BF3 content is 47.0-47.7%, so the molar concentration of BF3 in pure boron trifluoride-ether complex is about 7.7 mol / L, that is, this molar concentration is the maximum molar concentration of BF3 in boron trifluoride-ether complex. When k is 50, the molar concentrations of boron trifluoride in A1, A2, A3...An described in S1 are 0.01 mol / L, 0.02 mol / L, 0.03 mol / L,...0.2 mol / L, respectively, the theoretically detectable maximum concentration of boron trifluoride in the boron trifluoride-ether complex analyte is 0.2*50=10 mol / L, which is greater than the theoretical maximum molar concentration of BF3 in boron trifluoride-ether complex, so full range coverage can be achieved during the detection process.

[0029] In the present invention, a boron trifluoride-ether complex of known purity is firstly prepared into a boron trifluoride-ether complex ether mixture of different concentrations, and then the mixture is added into a 7-diethylaminocoumarin derivative, the fluorescence intensity in the 7-diethylaminocoumarin derivative before and after the addition of the boron trifluoride-ether complex ether mixture is measured, the ratio of the two is calculated, and a standard curve is prepared; then, a boron trifluoride-ether complex to be tested is taken, diluted by a certain multiple, and then added into the 7-diethylaminocoumarin derivative, the ratio of the fluorescence intensity before and after the addition is measured, and the corresponding BF3 concentration value is found on the standard curve according to the ratio, and then multiplied by the dilution multiple to obtain the BF3 concentration value in the boron trifluoride-ether complex to be tested.

[0030] The coumarin skeleton of the 7-diethylaminocoumarin derivatives of the present invention is an electron acceptor, and the electron-rich groups introduced at the 7-position and the 3-position of the coumarin are electron-donating groups. When the BF3-ether complex is added to the 7-diethylaminocoumarin derivatives, the N-diethyl group can be complexed with BF3, and the electron-donating group diethylamino therein acts as a Lewis base and reacts with the Lewis acid BF3 to form a new borate complex. When 3-(2'-thiophene)-7-diethylaminocoumarin is used, BF3 and 3-(2'-thiophene)-7-diethylaminocoumarin are complexed to form a stable compound, and BF3 can also have a strong coordination effect with the sulfur atom in the 3-(2'-thiophene)-7-diethylaminocoumarin, thereby enhancing the fluorescence properties of the 3-(2'-thiophene)-7-diethylaminocoumarin. This complexation can destroy the charge transfer mechanism inside the 3-(2'-thiophene)-7-diethylaminocoumarin molecule, thereby improving the fluorescence emission efficiency. When 3-(2'-thiophene)-7-diethylaminocoumarin reacts with BF3, the formation of the complex leads to the obstruction of charge transfer, so that the excited state energy cannot be dissipated through internal charge transfer, but is emitted in the form of fluorescence. This increases the fluorescence quantum yield of 3-(2'-thiophene)-7-diethylaminocoumarin, thereby enhancing its fluorescence intensity. 3-(2'-thiophene)-7-diethylaminocoumarin is highly sensitive to BF3, which can ensure that it has a close detection limit.

[0031] In addition, a strong electron donor group methoxy (-OCH3) is introduced into 3-(2'-thiophene)-7-diethylaminocoumarin, that is, when the 7-diethylaminocoumarin derivative is 3-(2'-thiophene)-7-diethylamino-4-methoxycoumarin, the methoxy group is a strong electron donor group, which can provide electrons together with the sulfur atom, and react with the electron acceptor BF3 as an electron donor to form a stable adduct. The introduction of the strong electron donor group methoxy can effectively improve the sensitivity of 7-diethylaminocoumarin derivatives to BF3 and reduce the detection limit of BF3. In addition, the introduction of the methoxy group can provide additional electron density to the aromatic ring to enhance the resonance structure, thereby improving the fluorescence performance.

[0032] Compared with the prior art, the above technical scheme has at least the following beneficial effects: the present invention realizes the concentration detection of BF3 by different enhancement capabilities of different concentrations of BF3 on the fluorescence intensity of 7-diethylaminocoumarin derivatives, and the detection accuracy is high; the 7-diethylaminocoumarin derivatives used have high reaction sensitivity with BF3, and the detection limit of BF3 is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a standard curve diagram of a complex detection method provided in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] A method for detecting a complex comprises the following steps:

[0037] S1. Diluting pure boron trifluoride-ether complex with anhydrous ether to different concentrations to obtain solutions A1, A2, A3, ..., A20, wherein the molar concentrations of boron trifluoride in A1, A2, A3, ..., An in S1 are 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, ..., 0.2 mol / L, respectively;

[0038] S2, dissolving 3-(2'-thiophene)-7-diethylaminocoumarin in a dichloromethane solution to obtain a 7-diethylaminocoumarin derivative dilution solution with a concentration of 0.2 mol / L, taking n equal portions of the 7-diethylaminocoumarin derivative dilution solution to obtain solutions B1, B2, B3, ... B20;

[0039] S3, measure the fluorescence intensity of B1, B2, B3...B20 solution, record it as I 01 ,I 01 ,I 03 ,……I 020 ;

[0040] S4, adding the A1 to B1 to obtain solution C1, adding the A2 to B2 to obtain solution C2, adding the A3 to B3 to obtain solution C3, ... adding the A20 to B20 to obtain solution C20, the volumes of An and Bn are equal;

[0041] S5. Measure the fluorescence intensity of C1, C2, C3, ... C20, and record them as I1, I2, I3, ... I 20 ;

[0042] S6, make I1 / I 01 、I2 / I 02 、I3 / I 03 ,……I 20 / I 020 ;

[0043] S7, with the concentration of A1, A2, A3 ... A20 as the horizontal axis, and the corresponding value I1 / I 01 , I2 / I 02 、I3 / I 03 ,……I 20 / I 020 Draw a standard curve for the ordinate, such as Figure 1 ;

[0044] S8, taking pure boron trifluoride-ether complex and diluting it with anhydrous ether to a molar concentration of boron trifluoride of 2.6 mol / L as the boron trifluoride-ether complex analyte, diluting it 50 times with anhydrous ether to obtain a boron trifluoride-ether complex analyte dilution, Ax;

[0045] S9, taking an equal amount of the 7-diethylaminocoumarin derivative dilution as B1 to obtain Bx, and measuring the fluorescence intensity of Bx, which is recorded as I 0x , the Ax and Bx are mixed to obtain Cx, and the fluorescence intensity of Cx is measured and recorded as I x ;

[0046] S20, Calculation I x / I 0x The value of is 2.2, and 2.2 is substituted into the ordinate of the standard curve to determine that the concentration value corresponding to the value of 2.2 is approximately 0.0522 mol / L;

[0047] S11. The concentration of boron trifluoride in the boron trifluoride-ether complex analyte is 50*0.0522=2.61 mol / L, and the error rate is = (2.61-2.6) / 2.6*%=0.384%.

[0048] The molar concentration of boron trifluoride in the boron trifluoride-ether complex analyte in this embodiment detected by nuclear magnetic resonance is 2.62 mol / L, and the error rate is = (2.62-2.6) / 2.6*% = 0.77%.

[0049] It is obvious that the error rate of the molar concentration of boron trifluoride in the boron trifluoride-ether complex analyte measured by the method in this embodiment is lower.

[0050] Example 2

[0051] A method for detecting a complex comprises the following steps:

[0052] S1. Diluting pure boron trifluoride-ether complex with anhydrous ether to different concentrations to obtain solutions A1, A2, A3, ..., A10, wherein the molar concentrations of boron trifluoride in A1, A2, A3, ..., An in S1 are 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, ..., 0.1 mol / L, respectively;

[0053] S2, dissolving 3-(2'-thiophene)-7-diethylaminocoumarin and 3-(2'-thiophene)-7-diethylamino-4-methoxycoumarin in a dichloromethane solution to obtain a 7-diethylaminocoumarin derivative dilution with a concentration of 0.01 mol / L, taking n equal portions of the 7-diethylaminocoumarin derivative dilution to obtain solutions B1, B2, B3, ... B10;

[0054] S3, measure the fluorescence intensity of B1, B2, B3...B10 solution, record it as I 01 ,I 01 ,I 03 ,……I 010 ;

[0055] S4, adding the A1 to B1 to obtain solution C1, adding the A2 to B2 to obtain solution C2, adding the A3 to B3 to obtain solution C3, ... adding the A20 to B20 to obtain solution C10, and the volumes of An and Bn are equal;

[0056] S5. Measure the fluorescence intensity of C1, C2, C3, ... C10, and record them as I1, I2, I3, ... I 20 ;

[0057] S6, make I1 / I 01 、I2 / I 02 、I3 / I 03 ,……I 10 / I 010 ;

[0058] S7, with the concentration of A1, A2, A3 ... A10 as the horizontal axis, and the corresponding value I1 / I 01 , I2 / I 02 、I3 / I 03 ,……I 10 / I 010 Plot a standard curve for the ordinate;

[0059] S8, taking pure boron trifluoride-ether complex and diluting it with anhydrous ether to a molar concentration of boron trifluoride of 0.4 mol / L as the boron trifluoride-ether complex analyte, diluting it 10 times with anhydrous ether to obtain a boron trifluoride-ether complex analyte dilution, Ax;

[0060] S9, taking an equal amount of the 7-diethylaminocoumarin derivative dilution as B1 to obtain Bx, and measuring the fluorescence intensity of Bx, which is recorded as I 0x , the Ax and Bx are mixed to obtain Cx, and the fluorescence intensity of Cx is measured and recorded as I x ;

[0061] S10. Calculation I x / I 0x The value M of the standard curve is substituted into the ordinate of the standard curve to determine the concentration value X corresponding to the value M;

[0062] S11. The concentration of boron trifluoride in the boron trifluoride-ether complex analyte is 10X.

[0063] The measurement error in this embodiment is similar to that in Embodiment 1.

[0064] Example 3

[0065] This example is similar to Example 2, except that the concentration of the 7-diethylaminocoumarin derivative dilution in S2 of this example is 0.012 mol / L; and the dilution factor in S8 is 11 times.

[0066] The measurement error in this embodiment is similar to that in Embodiment 1.

[0067] The detection limit of the 7-diethylaminocoumarin derivative dilution in Examples 1, 2, and 3 was tested; the specific method was to add a relatively low concentration of a boron trifluoride-ether complex ether mixture to the 7-diethylaminocoumarin derivative dilution, and observe when the fluorescence intensity was significantly enhanced. The corresponding boron trifluoride concentration in the boron trifluoride-ether complex ether mixture was recorded as the detection limit of the solution. The test results are as follows;

[0068]

[0069] It can be seen from the above data that the detection method of the present invention is sensitive and highly accurate.

[0070] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for detecting a complex, characterized in that: The following steps are involved: S1. Dilute pure boron trifluoride-ether complex with anhydrous ether to different concentrations to obtain solutions A1, A2, A3, ..., An; S2, dissolving 7-diethylaminocoumarin derivatives in a dichloromethane solution to obtain a 7-diethylaminocoumarin derivative dilution, taking n equal portions of the 7-diethylaminocoumarin derivative dilution to obtain solutions B1, B2, B3, ..., Bn; S3, measure the fluorescence intensity of B1, B2, B3...Bn solution, record it as I 01 ,I 01 ,I 03 ,……I 0n ; S4, adding the A1 to B1 to obtain solution C1, adding the A2 to B2 to obtain solution C2, adding the A3 to B3 to obtain solution C3, ... adding the An to Bn to obtain solution Cn; S5. Measure the fluorescence intensity of C1, C2, C3, ... Cn, and record them as I1, I2, I3, ... I n ; S6. Make I1 / I 01 , I2 / I 02 , I3 / I 03 , …… I n / I 0n ; S7, with the concentration of A1, A2, A3...An as the horizontal axis, and the corresponding value I1 / I 01 、I2 / I 02 、I3 / I 03 ,……I n / I 0n Plot a standard curve for the ordinate; S8, taking the boron trifluoride-ether complex analyte, diluting it k times with anhydrous ether to obtain a dilution of the boron trifluoride-ether complex analyte, Ax; S9, taking an equal amount of the 7-diethylaminocoumarin derivative dilution as B1 to obtain Bx, and measuring the fluorescence intensity of Bx, which is recorded as I 0x , the Ax and Bx are mixed to obtain Cx, and the fluorescence intensity of Cx is measured and recorded as I x ; S10. Calculation I x / I 0x The value M is substituted into the ordinate of the standard curve to determine the concentration value X corresponding to the M value; S11, the concentration of boron trifluoride in the boron trifluoride-ether complex analyte is kX; The 7-diethylaminocoumarin derivatives described in S2 are 3-(2'-thiophene)-7-diethylaminocoumarin and 3-(2'-thiophene)-7-diethylamino-4-methoxycoumarin.

2. The method for detecting a complex according to claim 1, characterized in that: The molar concentrations of boron trifluoride in A1, A2, A3, ..., An described in S1 increase successively.

3. The method for detecting a complex according to claim 2, characterized in that: The molar concentrations of boron trifluoride in A1, A2, A3...An described in S1 increase arithmetically.

4. The method for detecting a complex according to claim 2, characterized in that: The n is a multiple of 10.

5. The method for detecting a complex according to claim 4, characterized in that: The n is 20, and the molar concentrations of boron trifluoride in A1, A2, A3, ..., An in S1 are 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, ..., 0.2 mol / L, respectively.

6. The method for detecting a complex according to claim 1, characterized in that: The concentration of the 7-diethylaminocoumarin derivative dilution solution in S2 is 0.1-0.2 mol / L.

7. The method for detecting a complex according to claim 1, characterized in that: The volumes of An and Bn in S4 are equal.

8. The method for detecting a complex according to claim 1, characterized in that: The k in S8 is 10-50.

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