CN104122222B - Absorption spectrum analytical method for detecting ultraviolet ratio of micro-amount Zn＜2+＞or F＜-＞ - Google Patents

Abstract

The invention relates to an ultraviolet ratio absorption spectroscopic analysis method for detecting a trace amount of Zn2 ⁺ or F- ^, which belongs to the field of analytical chemistry. 1,5-bis(7-hydroxy-8-coumarin methylene)-diaminocarbamide, abbreviated as s3, is a reagent for detecting trace amounts ^of Zn ²⁺ or F-. In DMF (N,N-dimethylformamide)/H ₂ O (2/3, v/v) solution, when measuring Zn ²⁺ , it forms ratio absorption at 360nm and 310nm, and has isoabsorption at 338nm point; when measuring F ^‑ , a ratio absorption is formed at 400nm and 310nm, and there is an isoabsorptive point at 354nm. The concentration linear range for detecting Zn ²⁺ or F ^‑ is two orders of magnitude, and the detection limit is as low as 10 ^‑7 mol·L ^‑1 . The preparation method of reagent s3 is obtained by using 7-hydroxycoumarin and carbohydrazide as raw materials, and connecting 8-formyl-7-hydroxycoumarin to both ends of the carbohydrazide. The structural formula is:

Description

An Ultraviolet Ratio Absorption Spectroscopic Method for Detecting Trace Zn2+ or F-

technical field

The invention belongs to the field of analytical chemistry, in particular ^to an ultraviolet ratio absorption spectroscopic analysis method for detecting trace Zn2 ⁺ or F-.

Background technology: Ratio absorption measurement technology is an important method in ultraviolet absorption spectroscopic analysis. The ratio of the absorbance at the absorption wavelength is used as a detection signal to detect a substance. Since the ratio absorption probe reagent uses the ratio of the absorbance at the two maximum absorption wavelengths measured under the same environment as the signal parameter, if there is an influence, the absorbance at the two places will have the same change, the errors cancel each other out, and the ratio is basically not affected. The result is Therefore, the application of ratiometric absorption probe reagents can reduce the data distortion caused by factors such as probe concentration, samples and equipment, and obtain more accurate results. It is also very meaningful to improve the selectivity, sensitivity, dynamic response range, etc. Compared with the variation of absorption intensity at a single wavelength, the ratio variation of absorption at different wavelengths has higher stability and accuracy. For probes with a single wavelength, in practical applications, they will be affected by factors such as the concentration of the probe itself, test conditions, fluctuations in light source intensity, and instrument sensitivity, which will reduce the accuracy of the measurement. However, reports on the ratiometric absorptiometry technique are extremely rare.

Zinc is the second most abundant metal after iron in the life system, and the adult human body contains 2-3g of zinc. It has been recognized that zinc plays a very important role in the life process, for example, it is closely related to the existence of zinc in the synthesis of enzymes, neurotransmission, protein structure and function, etc. Zinc also affects human immune function and learning and memory ability Wait. in many physiological processes

plays an important role. At the same time, the impact of zinc ions on the environment has also attracted widespread attention. Therefore, the development of an effective zinc ion detection method is of great significance for related research in the fields of life sciences, medicine, and the environment. At present, although there are many reports on the detection of zinc ions, there are still some problems, such as low sensitivity, low selectivity and other defects. The use of ultraviolet ratio absorption method to detect zinc ions has the advantages of high sensitivity and high selectivity.

Fluoride ion is one of the important trace elements in the human body, which is very important to the health of the human body. It can effectively prevent dental caries, increase bone density, and is widely used in the treatment of osteoporosis; at the same time, clinical medical research shows that a large High dose intake or long-term intake of a small amount of fluoride ions will cause damage to human stomach and kidney function and cause bone fluorosis. The content of fluoride ions will have an important impact on the environment, such as the freshwater environment on which human beings depend. The detection of fluoride ions is of great significance no matter from the perspective of human health or environmental protection. Compared with traditional fluoride ion detection methods such as ion chromatography, the UV ratio absorption method has the advantages of convenient detection, high sensitivity, and wide dynamic response range.

SUMMARY OF THE INVENTION: The purpose of this invention is to research a new method for detecting trace Zn ²⁺ or F ^- with high sensitivity, high selectivity and high stability. The object of the present invention is to detect Zn ²⁺ or F ^- by ratio absorptiometry through the new color developing reagent developed and synthesized by the inventor.

The present invention detects a trace amount of Zn ²⁺ or F ^- Ultraviolet ratio absorption spectroscopic analysis method, is to use chemical name to be the compound of 1,5-bis(7-hydroxyl-8-coumarin methylene)-dicarbazide , abbreviated as s3, is used as a reagent for detecting trace Zn ²⁺ or F ^- by the ratiometric absorption method of ultraviolet spectroscopy; (1) Reagent s3 is prepared in DMF (N,N-dimethylformamide)/H ₂ O (2/3 , v/v) in the solution as a reagent for the ultraviolet spectrum ratio absorption detection of trace Zn ²⁺ , when measuring Zn ²⁺ , a ratio absorption is formed at 360nm and 310nm, and there is an isoabsorbance point at 338nm, in a certain concentration range of Zn ²⁺ Inside, the absorbance ratio at 360nm and 310nm has a linear relationship with the Zn ²⁺ concentration, and the Zn ²⁺ is determined by the ratio absorbance method; (2) Reagent s3 is used as a reagent for detecting trace F ^- by the ratio absorption method of ultraviolet spectroscopy in DMF solvent, and the determination of F When ^- , a ratio absorption is formed at 400nm and 310nm, and there is an isoabsorbance point at 354nm. Within a certain concentration range of F- ^{, the ratio of absorbance at 400nm and 310nm has a linear relationship with the F- concentration} , ^and the F- is determined by the ratio absorbance method.

The above-mentioned ultraviolet ratio absorption spectrometry method for detecting trace amounts of Zn ²⁺ or F ^- is (1) other coexisting metal ions when measuring Zn ²⁺ : Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , One of Ba ²⁺ , Sr ²⁺ , Hg ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Cd ²⁺ , Pb ²⁺ , Ag ⁺ , Al ³⁺ , Fe ³⁺ , Cr ³⁺ , in When the concentration is equivalent to the concentration of Zn ²⁺ , it will not interfere with the determination of Zn ²⁺ ; (2) When measuring F-, other coexisting anions: Cl ^- , Br ^- , I ^- , HSO ₄ ^- , AcO ^- , NO ₃ ^- , ClO ₄ ^- , PF ₆ ^- , H ₂ PO ₄ ^- , PF ₆ ^- , when the concentration is equivalent to that of F ^- , do not interfere with the determination of F ^- .

The above-mentioned ultraviolet ratio absorption spectrometry method for detecting trace amounts of Zn ²⁺ or F ^- is (1) reagent s3 is used as an ultraviolet spectrum ratio absorption method to detect trace amounts of Zn ²⁺ , and the concentration linear range of detection is 2.0×10 ^-7 ~2.2 ×10 ^-5 mol·L ^-1 , the detection limit is as low as 10 ^-7 mol·L ^-1 ; (2) Reagent s3 is used as the ratiometric absorption method of ultraviolet spectrum to detect trace F ^- , and the concentration linear range of detection is 4.0×10 ^-7 ~1.0×10 ^-5 mol·L ^-1 , the detection limit is as low as 10 ^-7 mol·L ^-1 .

The above-mentioned a kind of detection trace Zn ²⁺ or F ^- Ultraviolet ratio absorption spectroscopic analysis method is that the chemical structural formula of the reagent s3 is:

Molecular formula: C ₂₁ H ₁₄ N ₄ O ₇

Molecular weight: 434.09

Melting point: greater than 300°C

Solubility: Slightly soluble in chloroform, dimethyl sulfoxide, N,N-dimethylformamide, etc., insoluble in ethanol.

Spectral properties: In the mixed solvent (v/v, 2/3) of N,N-dimethylformamide (DMF) solution and water, the fluorescence excitation wavelength is 310nm, the emission wavelength is 454nm, and the ultraviolet absorption wavelength is 310nm.

A kind of above-mentioned detection trace Zn ²⁺ or F ^- Ultraviolet ratio absorption spectroscopic analysis method is that the preparation method of described reagent s3 is to take 7-hydroxycoumarin as raw material, take dichloromethane as solvent, use acetic anhydride to After the 7-hydroxyl group in 7-hydroxycoumarin is protected to obtain 7-acetoxycoumarin, trifluoroacetic acid is used as a catalyst and solvent to react with hexamethylenetetramine to synthesize the intermediate 8-methanol Acyl-7-hydroxycoumarin; and then synthesized by the reaction of intermediate 8-formyl-7-hydroxycoumarin and carbohydrazide in ethanol solution to obtain the symmetrical configuration of coumarin fluorescent reagent s3: 1,5- Two (7-hydroxy-8-coumarin methylene)-diaminocarbamide, the synthetic route is as follows:

The above-mentioned a kind of detection trace Zn ²⁺ or F ^- Ultraviolet ratio absorption spectroscopic analysis method is that the probe reagent s3 synthesis process conditions are:

(1) Synthesis of 7-acetoxycoumarin

N Under protection, add ₇ -hydroxycoumarin, dichloromethane, acetic anhydride, pyridine in the three-necked flask, the molar ratio is by 7-hydroxycoumarin:acetic anhydride=1:2～2.5, stirring reaction at room temperature, filtrate reduces The solvent was distilled off under pressure, dissolved in water, extracted with ethyl acetate, washed with saturated brine, dried over sodium sulfate, filtered, and purified by column chromatography to obtain 7-acetoxycoumarin:

Reaction temperature: room temperature

Response time: 12h

Reaction solvent: dichloromethane

Eluent: Chloroform

(2) Synthesis of intermediate 8-formyl-7-hydroxycoumarin

Under the ice bath protected by _N2 , add 7-acetoxycoumarin and trifluoroacetic acid into the three-necked flask, stir, and when the temperature drops to 0°C, add hexamethylenetetramine, the molar ratio is 7-acetoxy Base coumarin: hexamethylenetetramine=1:1.5~1.8, reflux, distill off the solvent under reduced pressure, add water and heat up to 60°C, stir, filter, extract the filtrate with chloroform, wash with saturated brine, dry, filter, The solvent was distilled off under reduced pressure, and all precipitated fractions were purified by column chromatography to obtain intermediate 8-formyl-7-hydroxycoumarin:

Reaction temperature: reflux

Reaction time: 8 hours

Reaction solvent: trifluoroacetic acid

Eluent: chloroform/methanol (v/v =100/1)

(3) 1,5-bis(7-hydroxy-8-coumarin methylene)-diaminocarbamide

Under the protection of N ₂ , add 8-formyl-7-hydroxycoumarin, absolute ethanol, and carbohydrazide to the three-necked flask, and the molar ratio is 8-formyl-7-hydroxycoumarin: carbohydrazide=1: 0.4~0.6, reflux, filter, and recrystallize with chloroform and methanol to obtain milky white solid 1,5-bis(7-hydroxy-8-coumarin methylene)-diaminocarbazide:

Reaction temperature: reflux

Reaction time: 5 hours

Reaction solvent: ethanol

The reagent s3 synthesized by the present invention can produce double absorption peaks and isoabsorptive points when interacting with Zn ²⁺ or F- ^, and the ratio change of the double absorption peaks is in a linear relationship with the corresponding ion concentration, and the change of the ratio of the double absorption peaks is not affected by the reagent. Self-concentration, test conditions, changes in light source intensity and instrument stability and other factors, thus making the determination more stable and accurate.

The invention has a detection limit as low as 10 ^-7 mol·L ^-1 for the determination of Zn ²⁺ or F ^- , and many metal ions or anions do not interfere with the determination, thereby achieving the purpose of good selectivity and high sensitivity. Due to the good selectivity and low interference of the method, many separation steps are omitted during the detection, so that the operation is simple and the analysis accuracy is high.

The invention can be used for the detection of metal ion Zn ^{2+ and} the detection of anion F-; it can be detected in water-soluble medium, and it can also be detected under the condition of non-aqueous medium DMF.

The structure of the reagent s3 synthesized in the present invention is characterized by nuclear magnetic resonance spectrum, mass spectrum and infrared spectrum. The structural characterization data are listed in Table 1.

Description of drawings:

Figure 1 Absorption spectra of reagent s3 in DMF/H ₂ O solution in the presence of different metal ions.

DMF/H ₂ O (2/3, v/v) solution with a concentration of 1.00×10 ^-5 mol·L ^-1 reagent s3, without adding metal ions or adding 2.00×10 ^-4 mol·L ^-1 metal ions Zn ²⁺ , Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Sr ²⁺ , Hg ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Cd ²⁺ , Pb ²⁺ , Ag ⁺ , Al ³⁺ , Fe ³⁺ , Cr ³⁺ UV absorption spectrum. The DMF/H ₂ O mixed solution of reagent s3 has absorption at 310nm, the addition of Zn ²⁺ makes the absorption peak of reagent s3 at 310nm red-shifted to 360nm and the absorbance decreases, and an isosbestic point appears at 338nm at the same time, other The addition of experimental metal ions hardly changed the absorption spectrum of reagent s3.

Fig. 2 The effect of coexisting metal ions on the ratiometric absorption detection of Zn ²⁺ by reagent s3 ultraviolet spectroscopy.

In the DMF/H ₂ O (2/3, v/v) solution of reagent s3 with a concentration of 1.00×10 ^-5 mol·L ^-1 , after adding 2.00×10 ^-4 mol·L ^-1 of Zn ²⁺ Absorbance at wavelengths of 310 nm and 360 nm were measured. Then add the same amount of other metal ions: Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , ^{Ca 2+} , Ba ²⁺ , Sr ²⁺ , Hg ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Cd ²⁺ , Pb ²⁺ , Ag ⁺ , Al ³⁺ , ^{Fe 3+} , Cr ³⁺ , measure the change of absorbance ratio at wavelengths 310 and 360nm respectively . The black bars represent the absorbance ratios of different metal ions added to the reagent s3 solution. The red bar indicates the change of the absorbance ratio after adding the above-mentioned other metal ions to the mixed solution of reagent s3-Zn ²⁺ respectively. It shows that the ratio absorption of reagent s3 to detect Zn ²⁺ is not affected by the coexistence of other metal ions mentioned above. The ratio absorption wavelengths are 310 and 360nm.

Fig. 3 The ratiometric absorption titration spectra of different concentrations of Zn ²⁺ on reagent s3 by UV spectroscopy.

In the DMF/H ₂ O (2/3, v/v) solution of reagent s3 with a concentration of 1.00×10 ^-5 mol·L ^-1 , add different concentrations of Zn ²⁺ to the reagent s3 solution, with the Zn ²⁺ The addition of , respectively measured the absorption spectrum curve. The absorption peak of reagent s3 at 310nm gradually red-shifted to 360nm, and an isosbestic point appeared at 338nm at the same time. Ratio absorption is formed at 310nm and 360nm wavelengths.

Fig. 4 Calibration curve of reagent s3 for ratiometric absorption detection of Zn ²⁺ by UV absorption spectroscopy. The ordinate is the absorbance ratio at the absorption wavelengths of 360nm and 310nm respectively, and the abscissa is the concentration of Zn ²⁺ . The concentration linear range of Zn ²⁺ response is 2.0×10 ^-7 ~2.2×10 ^-5 mol·L ^-1 .

Fig. 5 Absorption spectra of the DMF solution of reagent s3 in the presence of different anions.

DMF solution with a concentration of 1.00×10 ^-5 mol·L ^-1 reagent s3, without adding anion or adding 5.00×10 ^-5 mol·L ^-1 anion F ^- , Cl ^- , Br ^- , I ^- , HSO ₄ ^- , AcO ^- , NO ₃ ^- , ClO ₄ ^- , PF ₆ ^- , H ₂ PO ₄ ^- UV absorption spectrum. The addition of F ^- made the absorption peak of reagent s3 at 310nm gradually red-shifted to 400nm, and at the same time an isosbestic point appeared at 354nm. The addition of anions in the other above experiments hardly changed the absorption spectrum of reagent s3.

Figure 6 The influence of coexisting anions on the detection of F ^- by reagent s3 ultraviolet absorption spectrometry.

In the DMF solution of reagent s3 with a concentration of 1.00×10 ^-5 mol·L ^-1 , the absorption peak at 310 nm gradually red-shifted to 400 nm after adding 5.00×10 ^-5 mol·L ^-1 F ^- solution. Then add the same amount of other anions Cl ^- , Br ^- , I ^- , HSO ₄ ^- , AcO ^- , NO ₃ ^- , ClO ₄ ^- , PF ₆ ^- , H ₂ PO ₄ ^- to the mixed solution of reagent s3-F ^- , after PF ₆ ^-one , measure the change in absorbance. The black bar represents the absorbance ratio at 400nm and 310nm after adding different anions to the data s3 solution. The red bars represent the absorbance ratios after adding the above-mentioned other anions to the mixed solution of the data S3-F ^- mixture respectively. It is shown that the data S3 detects the ratiometric uptake of F ^- is not affected by the coexistence of other anions mentioned above. The ordinate is the ratio of absorbance at 400nm to 310nm.

Fig. 7 The ratiometric absorption titration spectra of different concentrations ^of F- versus data s3 UV spectrometry.

Add different concentrations of F ^- to the DMF solution of data s3 with a concentration of 1.00×10 ^-5 mol·L ^-1 . With the addition of F ^- , the measured absorption spectrum curves. The absorption peak of data s3 at 310nm gradually red shifted to 400nm, and an isoabsorptive point appeared at 354nm at the same time. Absorption at 400nm and 310nm wavelengths forms a ratiometric absorption.

Fig. 8 Calibration curve ^of reagent s3 ultraviolet absorption spectrometry ratio absorption detection F-. The ordinate is the absorbance ratio at the absorption wavelengths of 400nm and 310nm respectively, and the abscissa is the concentration ^of F-. The concentration linear range of F ^- response is 4.0×10 ^-7 ~1.0×10 ^-5 mol·L ^-1 .

detailed description

Embodiment one:

The preparation method of each reagent in the analytical method of the present invention is:

(1) Preparation of reagent s3 solution: weigh 44mg of reagent s3, dissolve it in DMF, and prepare 100mL solution with a concentration of 1.00×10 ^-3 mol·L ^-1 ;

(2) Zn ²⁺ standard solution: Weigh 59.5 mg of analytically pure Zn(NO ₃ ) ₂ , dissolve it in double distilled water, and prepare a 100 mL solution. The concentration of Zn ²⁺ is 2.00×10 ^-3 mol·L ^-1 ; Dilute step by step with twice-distilled water to an appropriate concentration as required; the preparation of other coexisting metal ion solutions is the same.

(3) F ^- stock solution (2.00×10 ^-3 mol×L ^-1 ): Weigh 52.2 mg tetrabutylammonium fluoride and dissolve it in DMSO to prepare a 100 mL solution. The preparation of other anions is the same.

The UV-visible spectrophotometer model used in the present invention is UV-1800, produced by Japan Shimadzu Corporation.

The reagent s3 in the method of the present invention can be used as a ratio absorption reagent for detection of trace Zn ²⁺ or F ^- ions. It has the advantages of superior detection performance, good detection stability, low background interference, high selectivity, low detection limit, no need for separation, and can be tested in water-soluble or non-aqueous media. The operation and control method is simple and the performance is unique.

Embodiment two:

(1) Detection of metal ions

Add the DMF stock solution of reagent s3 (1.00×10 ^-4 mol·L ^-1 , 1 mL) and metal ion Zn ²⁺ (2.00×10 ^-3 mol·L ^-1 , 1 mL) into a 10.0 mL volumetric flask, and use DMF/H ₂ O (2/3, v/v) solution was diluted to the mark, and shaken to measure the ultraviolet absorption spectrum.

Add about 3ml of reagent s3 (1.00×10 ^-5 mol·L ^-1 ) in DMF/H ₂ O (2/3, v/v) solution to a 1 cm cuvette for UV absorption spectrum test, reagent s3 After adding Zn ²⁺ (2.00×10 ^-4 mol·L ^-1 ), the absorption peak of reagent s3 at 310nm was red-shifted to 360nm and the absorbance decreased by 0.042, and an isoabsorbing point appeared at 338nm. Under the same conditions, add Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Sr ²⁺ , Hg ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ² into the reagent s3 solution respectively ⁺ , Ag ⁺ , Pb ²⁺ , Cd ²⁺ , Al ³⁺ , Cr ³⁺ , Fe ³⁺ metal ions hardly change the absorption spectrum and intensity of reagent s3, reagent s3 is only selective for Zn ²⁺ The ratio of absorbance at 360nm to 310nm wavelength is selected for quantitative determination (figure 1).

Under the above-mentioned ultraviolet spectrum test conditions, the ratio absorption value of Zn ²⁺ detected by reagent s3 at 360nm and 310nm is when the above-mentioned metal ions exist as coexisting ions in the mixed solution of reagent s3-Zn ²⁺ respectively, when the concentration of coexisting metal ions and the test When the Zn ²⁺ ions are equivalent, the relative deviation of the influence of the ratio absorbance on the detection of Zn ²⁺ is within 5%, and does not interfere with the determination (figure 2).

Under the above-mentioned ultraviolet spectrum test conditions, the concentration change of Zn ²⁺ and the ultraviolet absorption spectrum change of reagent s3 and the absorbance ratio at 360nm and 310nm were respectively measured to obtain the absorption spectrum titration curve (accompanying drawing 3) and the ratio absorption method calibration curve ( Figure 4). From the slope of the calibration curve and the standard deviation of the blank value measured 10 times, the concentration linear range and detection limit of the reagent s3 ultraviolet absorption method ratio absorption detection Zn ²⁺ were measured and calculated and listed in Table 2.

Table 2 Analytical parameters for detection of Zn ²⁺ ions by reagent s3

(2) Detection of anions

Add the DMF stock solution of reagent s3 (1.00×10 ^-4 mol·L ^-1 , 1 mL) and anion F ^- (5.00×10 ^-4 mol·L ^-1 , 1 mL) into a 10.0 mL volumetric flask. Dilute to the mark with DMF solution, shake well, and transfer to a 1cm quartz cuvette for ultraviolet absorption spectrum measurement.

Scan the ultraviolet absorption spectrum of the DMF solution of reagent s3 (1.00×10 ^-5 mol L ^-1 ), add F ^- (concentration of 5.00×10 ^-5 mol L ^-1 ) to make the concentration of reagent s3 at 310nm The absorption peak gradually red-shifted to 400nm, and an isoabsorptive point appeared at 354nm. In addition to the addition of F ^- , the reagent s3 has obvious absorption signals, other experimental anions Cl ^- , Br ^- , I ^- , HSO ₄ ^- , NO ₃ ^- , AcO ^- , ClO ₄ ^- , PF ₆ ^- , H ₂ PO ₄ ^- There is no obvious ultraviolet absorption response signal for reagent s3 (figure 5). It shows that the reagent s3 has the performance ^of ultraviolet absorption recognition and detection for F-.

Under the test conditions of the above ^{-mentioned ultraviolet absorption method,} the absorbance of the reagent s3 detecting F- is present in the mixed solution of the reagent s3 ^- F- as coexisting ions respectively ^{. -} The relative deviation of the influence of absorbance is within 3%, without interfering with the determination (Figure 6)

In the DMF solution, with 310nm as the maximum absorption wavelength, measure the ratio absorption change of the corresponding reagent s3 solution when the F ^- concentration changes, and obtain the calibration curve (Fig. 8). According to the slope of the calibration curve and the standard deviation of the blank value determined 10 times, the concentration linear range and detection limit of reagent s3 for detecting specific ions were determined and calculated, and listed in Table 3.

Table 3 Analytical parameters of reagent s3 for detecting F ^- ions

Embodiment three: the synthetic preparation of reagent s3 among the present invention

(1) Synthesis of 7-acetic anhydride coumarin

Under the protection of N ₂ , in a 250 mL round bottom flask, add 7-hydroxycoumarin (9.3 g, 57.3 mmol), dichloromethane 120 mL, stir, then add acetic anhydride (11.7 g, 114.6 mmol), pyridine 7 -8 drops, reacted at room temperature for 12 hours, after the reaction was completed, the solvent was distilled off under reduced pressure, dissolved in water, extracted with ethyl acetate, washed with saturated brine, dried over sodium sulfate, filtered, the solvent was distilled off under reduced pressure, and the crude product was subjected to column chromatography Separation (eluent: chloroform) yielded 11.16 g of a white product, 7-acetic anhydride coumarin, with a yield of 95.4%.

(2) Synthesis of intermediate raw material 7-hydroxy-8-formyl coumarin

Under the protection of _N2 , under ice cooling, in a 250mL round bottom flask, add 7-acetic anhydride coumarin (15g, 73.51mmol), 100mL of trifluoroacetic acid, stir, and when the temperature drops to 0°C, add Hexamethylenetetramine (15g, 106.26mmol) was reacted under ice bath for 1h, the reaction temperature was gradually raised to room temperature, and then refluxed and stirred for 8h, the solvent was distilled off under reduced pressure, 150mL of water was added to the remaining solution, and the mixture was liter Stir at 60°C for 30 min, filter, extract the filtrate with chloroform, wash with saturated brine, dry over sodium sulfate, filter, distill off the solvent under reduced pressure, combine the precipitated parts, and separate by column chromatography (eluent: chloroform/methanol, v/v , 100/1) to obtain milky white product 7-hydroxy-8-formyl coumarin 2.61g, yield 18.6%.

(3) Synthesis of fluorescent reagent s3, namely 1,5-bis(7-hydroxy-8-coumarin methylene)-diaminocarbamide

Under the protection of N ₂ , in a 250ml three-neck flask, add 7-hydroxy-8-formylcoumarin (600mg, 3.16mmol) and 70mL of absolute ethanol, stir, raise the temperature until it dissolves, and then cool down to room temperature. Carbohydrazide (142mg, 1.58mmol) was dissolved in 20mL of absolute ethanol and added dropwise, heated to reflux for 5h. After the reaction was completed, it was filtered and recrystallized with chloroform methanol to obtain 470 mg of the milky white target product with a yield of 68.7%. mp ＞300 ℃C; ¹ H NMR (CDCl ₃ , 400MHz), δ(ppm): 4.349(s, 1H), 6.282(d, 1H, J=9.6Hz), 6.881(d, 1H, J=8.8Hz ), 7.559(d, 1H, J=8.8Hz), 7.969(d, 1H, J=9.2Hz), 8.822(s, 1H), 11.391(s, 1H); ESI-MS: m/z 457.0 [M +Na] ⁺ .

Claims (6)

1. a kind of detection trace Zn²⁺Or F^-Ultraviolet ratio absorption spectroanalysis method, it is characterized in that with chemical name be 1,5- bis- The compound of (7- hydroxyl -8- cumarin methylene)-diaminourea, is abbreviated as s3, is used for as ultraviolet spectra ratio absorption process Detection trace Zn²⁺Or F^-Reagent；（1）Reagent s3 is in DMF（N,N-dimethylformamide）And H₂The volume ratio of O is 2:3 solution Middle as ultraviolet spectra ratio absorption detecting trace Zn²⁺Reagent, measure Zn²⁺When, form ratio at 360nm and 310nm and inhale Receive, have isobestic point at 338nm, in Zn²⁺In the range of finite concentration, absorbance ratio and Zn at 360nm and 310nm²⁺Concentration Linear, measure Zn with ratio absorbance method²⁺；（2）Reagent s3 absorbs inspection as ultraviolet spectroscopy ratio in DMF solvent Micrometer amount F^-Reagent, measure F^-When, form ratio at 400nm and 310nm and absorb, have isobestic point at 354nm, in F^- In the range of finite concentration, absorbance ratio and F at 400nm and 310nm^-Concentration is linear, is measured with ratio absorbance method F^-.

2. a kind of detection trace Zn according to claim 1²⁺Or F^-Ultraviolet ratio absorption spectroanalysis method, it is characterized in that （1）Measure Zn²⁺When other coexistent metallic ions：Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ba²⁺,Sr²⁺, Hg²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd^{2 +}, Pb²⁺, Ag⁺, Al³⁺, Fe³⁺, Cr³⁺One of, in concentration and Zn²⁺When concentration is suitable, do not disturb Zn²⁺Mensure；（2）When measuring F-, Other counter anions：Cl^-, Br^-, I^-, HSO₄ ^-, AcO^-, NO₃ ^-, ClO₄ ^-, PF₆ ^-, H₂PO₄ ^-, PF₆ ^-, in concentration and F^-Concentration is suitable When, do not disturb F^-Mensure.

3. a kind of detection trace Zn according to claim 1²⁺Or F^-Ultraviolet ratio absorption spectroanalysis method, it is characterized in that （1）Reagent s3 detects trace Zn as ultraviolet spectra ratio absorption process²⁺, the concentration range of linearity of detection is 2.0 × 10^-7~2.2 ×10^-5mol·L^-1, test limit as little as 10^-7mol·L^-1；（2）Reagent s3 detects micro as ultraviolet spectra ratio absorption process F^-, the concentration range of linearity of detection is 4.0 × 10^-7～1.0 × 10^-5mol·L^-1, test limit as little as 10^-7mol·L^-1.

4. a kind of detection trace Zn according to claim 1²⁺Or F^-Ultraviolet ratio absorption spectroanalysis method, it is characterized in that Described reagent s3 chemical structural formula is：

Molecular formula：C₂₁H₁₄N₄O₇

Molecular weight：434.09

Fusing point：More than 300 DEG C of dissolubilities：It is slightly soluble in chloroform, dimethyl sulfoxide, DMF, insoluble in ethanol, spectrum Property：In N,N-dimethylformamide（DMF）Solution is 2 with the mixed solvent volume ratio of water:3（V/v, 2/3）In fluorescence swash Sending out wavelength is 310nm, and launch wavelength is 454nm, and UV absorption wavelength is 310nm.

5. a kind of detection trace Zn according to claim 4²⁺Or F^-Ultraviolet ratio absorption spectroanalysis method, it is characterized in that The preparation method of described reagent s3 is with umbelliferone as raw material, with dichloromethane as solvent, with acetic anhydride to 7- hydroxyl In cumarin, the hydroxyl of 7- position carries out after protection obtains AP20am15, with trifluoroacetic acid as catalysts and solvents, with Hexamethylenetetramine reacts, and synthesis obtains intermediate 8- formoxyl-umbelliferone；Again by intermediate 8- formoxyl -7- hydroxyl Butylcoumariii and carbohydrazide are synthesized the coumarin fluorescent reagent s3 obtaining symmetrical configurations in ethanol solution：1,5- bis- (7- Hydroxyl -8- cumarin methylene)-diaminourea, synthetic route is as follows：

.

6. according to a kind of detection trace Zn described in claim 5²⁺Or F^-Ultraviolet ratio absorption spectroanalysis method, it is characterized in that Probe reagent s3 synthetic technological condition is：

（1）The synthesis of AP20am15

N₂Under protection, add umbelliferone, dichloromethane, acetic anhydride, pyridine in there-necked flask, it is fragrant that mol ratio presses 7- hydroxyl Legumin:Acetic anhydride=1:2 ~ 2.5, reaction is stirred at room temperature, filtrate decompression is distilled off solvent, with being extracted with ethyl acetate after water dissolves Take, saturated common salt water washing, sodium sulphate is dried, filter, column chromatography purifies and AP20am15 is obtained：

Reaction temperature：Room temperature

Reaction time：12h

Reaction dissolvent：Dichloromethane

Eluant, eluent：Chloroform

（2）The synthesis of intermediate 8- formoxyl-umbelliferone

N₂Under the ice bath of protection, add AP20am15, trifluoroacetic acid, stirring in there-necked flask, treat that temperature is down to 0 DEG C When, add hexamethylenetetramine, mol ratio presses AP20am15:Hexamethylenetetramine=1:1.5 ~ 1.8, backflow, subtract Pressure is distilled off solvent, adds water to be warming up to 60 DEG C of stirrings, filters, filtrate chloroform extraction, saturated common salt water washing, is dried, Filter, vacuum distillation removes solvent, all sediment fraction column chromatographies are purified and obtains intermediate 8- formyl-umbelliferone：

Reaction temperature：Backflow

Reaction time：8 h

Reaction dissolvent：Trifluoroacetic acid

Eluant, eluent：Chloroform/methanol（v/v =100/1）

（3）1,5- bis- (7- hydroxyl -8- cumarin methylene)-diaminourea

N₂Under protection, in there-necked flask add 8- formyl-umbelliferone, absolute ethyl alcohol, carbohydrazide, mol ratio press 8- formyl- Umbelliferone:Carbohydrazide=1:0.4 ~ 0.6, backflow, filter, obtain Off-white solid 1,5- with chloroform and recrystallizing methanol Two (7- hydroxyl -8- cumarin methylene)-diaminourea：

Reaction temperature：Backflow

Reaction time：5 h

Reaction dissolvent：Ethanol.