A detection method for trivalent antimony ions / hexavalent chromium ions in the environment based on chromogenic reagents

Abstract

The present invention discloses a detection method for trivalent antimony ions / hexavalent chromium ions in the environment based on a chromogenic reagent, belonging to the detection of heavy metal ions, which comprises the following steps: taking a sample to be tested, adding an acid solution to adjust the pH value of the sample to be tested; adding a chromogenic reagent and a surfactant to the test solution, mixing and then standing; after sufficient reaction, measuring the absorbance by spectrophotometry, and corresponding the measured absorbance value of trivalent antimony ions / hexavalent chromium ions to the standard curve to obtain the concentration of trivalent antimony ions or hexavalent chromium ions in the sample to be tested. In the present invention, Sb<supgt;3+< / supgt; / Cr<supgt;6+< / supgt; reacts with the chromogenic reagent to form a stable orange-red complex, which has the characteristics of low detection limit and high sensitivity for trivalent antimony ions and hexavalent chromium ions. In addition, this method does not need to rely on large-scale instrument equipment, and is simple, efficient and convenient to operate.

Description

Technical Field

[0001] The present invention belongs to the field of heavy metal detection, and particularly relates to a method for detecting trivalent antimony ions / hexavalent chromium ions in the environment based on a color reagent. Background Art

[0002] Antimony and chromium are toxic metals. They can accumulate in organisms. Long-term exposure to an environment containing antimony / chromium may cause health problems such as heart diseases, respiratory problems, liver and kidney damage, and skin lesions. Antimony / chromium can also pollute the soil and affect crop growth. Therefore, monitoring and controlling the trace content of antimony / chromium in the environment is of great significance for protecting the environment and human health. Effective, rapid, and sensitive detection and analysis methods are essential for studying the current distribution status of antimony and chromium in the environment and research on the prevention and control of heavy metal pollution. Currently, the detection methods for heavy metals include atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence spectrometry (XRF), ultraviolet-visible spectrophotometry, flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), etc. These methods have their own advantages and applicable scenarios, and appropriate detection techniques can be selected according to specific detection requirements and conditions. However, some methods involve large-scale instruments, with high costs, complex operations, and are difficult to popularize.

[0003] Spectrophotometry has been widely used due to its advantages such as simplicity, rapidity, high sensitivity, low cost, and easy popularization. The original spectrophotometric method for detecting antimony is to detect by preparing stibine and using 5-Br-PADAP for color development. The process of preparing stibine in this method is complex, with large errors and potential safety hazards. There are also literature reports on using phenylfluorone to detect heavy metal antimony, but the sensitivity can only reach 0.1 mg / L, which cannot meet the maximum emission limit standard of 0.05 mg / L required by industries such as textiles. Summary of the Invention

[0004] Object of the Invention: To solve the above technical problems, the present invention aims to provide a method for detecting trivalent antimony ions / hexavalent chromium ions in the environment based on a color reagent. The color reagent used in the detection method of the present invention contains coordination sites with high affinity for Sb 3+ and Cr 6+ It has high sensitivity, high selectivity, high stability, simple operation, and can effectively detect Sb in water such as industrial wastewater 3+ and Cr 6+ contents simultaneously. Its detection method is simple and highly sensitive, fully meeting the existing maximum limit requirements. It is a new method for detecting heavy metal antimony and chromium in water that is easy to promote and use. It has strong innovative significance and practical value.

[0005] Technical solution: To achieve the above object, a detection method for trivalent antimony ions / hexavalent chromium ions in the environment based on a chromogenic agent according to the present invention includes the following steps:

[0006] (1) Take a sample to be tested, and add an acid solution to adjust the pH value of the sample to be tested;

[0007] (2) Add a chromogenic agent and a surfactant to the test solution, mix and then let stand;

[0008] (3) After sufficient reaction, measure the absorbance by spectrophotometry, and correspond the measured absorbance value of trivalent antimony ions / hexavalent chromium ions to the standard curve to obtain the concentration of trivalent antimony ions or hexavalent chromium ions in the sample to be tested;

[0009] The structural formula of the chromogenic agent is as follows:

[0010] ;

[0011] Among them, R is selected from , , , or .

[0012] Among them, the environment includes a water environment or a soil environment.

[0013] Among them, the acid solution in step (1) is hydrochloric acid or sulfuric acid, and the pH is adjusted to 2-7.

[0014] Further, the acid solution in step (1) is a 20% hydrochloric acid solution, and the pH value of the reaction system is adjusted to 3.

[0015] Among them, the surfactant in step (2) is any one or a combination of several of Tween-80, CTMAB, OP-100, and OP-CTMAB, the concentration is not more than 5%, and the addition amount is 0.2-1.0 mL.

[0016] Among them, the surfactant is a Tween-80 microemulsion.

[0017] Preferably, the surfactant is a 4% Tween-80 microemulsion, and the dosage is 0.5 mL

[0018] Among them, the concentration of the chromogenic agent in step (2) is 1-5 g / L, and the addition amount is 0.1-1 mL.

[0019] Preferably, the concentration of the chromogenic agent is 1 g / L, and the addition amount is 0.1 mL.

[0020] Among them, the standing time after mixing in step (2) is 1 - 20 min.

[0021] Among them, the structural formula of the color developer described in step (2) is as follows:

[0022] 。

[0023] Among them, the preparation method of the color developer is: adding an organic solvent and concentrated sulfuric acid to 1,2,4-triacetoxybenzene, stirring and heating under reflux until a clear solution is obtained, adding 4-aminobenzaldehyde, 4-formylbenzoic acid, 4-nitrobenzaldehyde, 2-hydroxybenzaldehyde or 4-formylbenzenesulfonic acid to the mixture, keeping the stirred mixture under reflux, and then adding K 2 S 2 O 8 , the mixture changes from a brown solution to a viscous dark suspension, continues to reflux, and then is poured into ice water, stirred, filtered to obtain the product, and dried under vacuum to obtain the color developer.

[0024] Preferably, the preparation method of the color developer is: adding 1,2,4-triacetoxybenzene to a round-bottomed flask equipped with a heater and a mechanical stirrer, adding 50% EtOH as a solution and a small amount of concentrated sulfuric acid, heating under reflux until a clear solution is obtained. Dropwise add p-aminobenzylamine in an amount half of the amount of substance of 1,2,4-triacetoxybenzene to the boiling mixture within 2 minutes. Keep the stirred mixture under reflux and stir for 1.5 h. Subsequently, under the reflux condition at 80 °C, add K in an amount half of the amount of substance of 1,2,4-triacetoxybenzene within 50 minutes 2 S 2 O 8 , the mixture changes from a brown solution to a viscous dark suspension, and the content is refluxed for another 20 minutes. Then it is poured into ice water with a volume twice that of the solution, stirred for 30 minutes, filtered to obtain the product, and dried in a vacuum oven at 60 °C to obtain 9-(4-aminophenyl)-2,6,7-trihydroxyxanthene-3-one, which is the color developer.

[0025] Among them, the maximum absorption wavelength of trivalent antimony ions in step (3) is 560 nm, and the maximum absorption wavelength of hexavalent chromium ions is 500 nm.

[0026] The detection method provided by the present invention shows specific recognition and color development for trivalent antimony ions / hexavalent chromium ions in the detection of the recognition of twelve metal ions by a specific color developer.

[0027] The detection method and color developer determination analysis of the present invention mainly include the following steps:

[0028] Optimization of measurement conditions: By finely adjusting the pH value, selecting the appropriate type and concentration of acid solution, optimizing the type and dosage of microemulsion, determining the optimal maximum absorption wavelength, and reasonably setting measurement parameters, the sensitivity, stability, and specific selectivity are maximized.

[0029] Investigation of anti-interference ability: When detecting antimony / chromium by this invention, study the interference of other heavy metal ions on the detection results, and establish detection conditions with specific selectivity to improve the detection accuracy of antimony / chromium.

[0030] Repeatability study: Detect the same sample multiple times, and investigate the repeatability of the detection results under the same conditions to evaluate the stability of the detection method and reagents.

[0031] Investigation of method reliability: Compare the detection results of this invention with standard solutions to verify its accuracy and precision, and ensure the reliability of the detection method.

[0032] Using spectrophotometry, taking the absorbance values obtained from the antimony / chromium concentrations of each antimony / chromium standard solution and the corresponding standard solution to be detected as the ordinate, and the concentration of trivalent antimony ions / hexavalent chromium ions as the abscissa, draw a standard curve;

[0033] Obtain the solution to be detected, and after pretreatment, add acid solution to adjust the pH value of the standard solution to be detected;

[0034] Add a color reagent and a homogeneous agent to the solution to be detected, mix and then let it stand;

[0035] Detect the Sb 3+ / Cr 6+ in the solution to be detected by spectrophotometry. The determination wavelength of Sb 3+ is 560 nm, and the determination wavelength of Cr 6+ is 500 nm;

[0036] After sufficient reaction, measure the absorbance by spectrophotometry, and correspond the measured absorbance value to the standard curve to obtain the concentration of trivalent antimony ions / hexavalent chromium ions in the sample to be detected.

[0037] Preferably, the preparation method of various reagents in the detection of trivalent antimony ions / hexavalent chromium ions is as follows:

[0038] (1) Preparation method of color reagent solution: Weigh 0.1 - 0.5 g of color reagent such as 9-(4-aminophenyl)-2,6,7-trihydroxyxanthene-3-one, dissolve it with DMF, and prepare it into a 100 mL solution with a concentration of 1 - 5 g / L.

[0039] (2) Preparation of 20% hydrochloric acid solution: Take 100 grams of concentrated hydrochloric acid (mass fraction is 36.5%), add 82.5 grams of water, and 20% hydrochloric acid solution can be prepared.

[0040] (3) Preparation of 20% sulfuric acid solution: First, add 70 mL of water to a beaker, measure 12.3 mL of 98% concentrated sulfuric acid, slowly pour it along the wall of the beaker into the water, and stir with a glass rod while pouring to ensure uniform mixing and prevent splashing. After the solution cools to room temperature, add water to make up to 100 mL and make the volume constant.

[0041] (4) Preparation of Tween-80 microemulsion: The mass ratio of Tween-80 microemulsion is configured as Tween-80: n-heptane: n-butanol: deionized water = 1 - 10 : 1 - 10 : 1 - 5 : 10 - 100.

[0042] Among them, other coexisting ions when measuring trivalent antimony ions / hexavalent chromium ions include: Ag + 、Al 3+ 、Ba 2+ 、Cd 2+ 、Co 2 + 、Cu 2+ 、Fe 3+ 、K + 、Mg 2+ 、Ni 2+ , when the concentration is comparable to that of Sb 3+ / Cr 6+ , they do not interfere with the determination.

[0043] Furthermore, the detection of trivalent antimony ions / hexavalent chromium ions; the concentration is 0.05 - 1 mg / L.

[0044] Among them, the linear equation of the standard curve of Sb 3+ is y = 0.52323x + 0.13275 (R 2 = 0.99673), the detection range of trivalent antimony ion concentration is 0.05 - 1 mg / L, and the detection limit of trivalent antimony ion concentration is 0.005 mg / L. The linear equation of the standard curve of Cr 6+ is y = 0.347x + 0.0146 (R 2 = 0.99506), the detection limit of hexavalent chromium ion is 5×10 -2 mg / L, and the detection range is 0.08 - 1 mg / L.

[0045] The present invention uses a solution with pH = 2 - 7 as the acidic solution, such as 9-(4-aminophenyl)-2,6,7-trihydroxyxanthene-3-one solution as the chromogenic reagent, and Tween-80 microemulsion as the surfactant. By using spectrophotometry, it can detect trivalent antimony ions / hexavalent chromium ions in the aqueous phase. Among them, the detection range of trivalent antimony ions is 0.05 - 1 mg / L, the apparent molar absorptivity is 1.368×10 4 L / (mol·cm), and the detection limit is about 5×10 -3 mg / L. The detection range of hexavalent chromium ions is 0.08 - 1 mg / L, the apparent molar absorptivity is 6.136×10 3 L / (mol·cm), and the detection limit is about 5×10 -2 mg / L.

[0046] Under the optimal experimental conditions, the chromogenic reagent provided by the present invention has a detection limit of 0.005 mg / L for antimony, a detection range of 0.05 - 1 mg / L, an apparent molar absorptivity of 1.368×10 4 L / (mol·cm), a detection limit of 0.05 mg / L for chromium, a detection range of 0.08 - 1 mg / L, and an apparent molar absorptivity of 6.136×10 3 L / (mol·cm). It has a low detection limit and high sensitivity, does not cause environmental pollution during the detection process, does not rely on large-scale instrument equipment, and is simple, efficient and convenient to operate.

[0047] The chromogenic reagent used in the detection method of the present invention contains application functional groups composed of multiple hydroxyl groups in its structure, and reacts with Sb 3+ / Cr 6+ to form a stable complex. Through the carefully designed molecular structure, the chromogenic reagent has good chemical stability and photostability, which ensures that the chromogenic reagent can maintain stable chromogenic characteristics under different environmental conditions (such as different temperatures and light conditions), avoids the influence of environmental factors on the detection results, and improves the accuracy and repeatability of the detection results.

[0048] The chromogenic reagent used in the detection method of the present invention has coordination sites with high affinity for trivalent antimony ions / hexavalent chromium ions, and can form stable complexes with trivalent antimony ions / hexavalent chromium ions. This specific structural design significantly improves the sensitivity of the chromogenic reagent to trivalent antimony ions / hexavalent chromium ions. When the concentration of trivalent antimony ions / hexavalent chromium ions changes, the change range of absorbance is large, so as to realize the high-sensitivity detection of low-concentration trivalent antimony ions / hexavalent chromium ions. It not only has high sensitivity and high selectivity, but also is simple to operate and has good stability, and can effectively detect the content of trivalent antimony ions / hexavalent chromium ions in water, providing a new solution for environmental monitoring.

[0049] Among the existing methods, flame atomic absorption spectrophotometry and graphite furnace atomic absorption spectrophotometry have low detection limits, and involve large instruments, and are costly, complicated to operate, and difficult to popularize. Currently, many industries require the maximum emission limit of antimony to be less than 0.05 mg / L. Therefore, researching and developing new non-toxic, highly sensitive spectrophotometric detection methods for antimony / chromium is a task of great significance. The method of the present invention can achieve high-sensitivity detection of low-concentration trivalent antimony ions / hexavalent chromium ions. In addition, the method is simple to operate, has strong stability, can effectively determine the content of trivalent antimony ions / hexavalent chromium ions in water, and is significantly better than the detection limit of existing methods. The color developer is an environmentally friendly material and will not cause environmental pollution during the detection process.

[0050] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0051] 1. The detection limit of the detection method of the present invention is low, because the color developer and Sb 3+ / Cr 6+ It can form a stable complex and cause obvious absorbance changes even at extremely low concentrations. The detection method of the present invention realizes the detection of Sb 3+ As low as 5 × 10 -3 mg / L and Cr 6+ As low as 5 × 10 -2 The detection limit of mg / L is used to simultaneously detect trace amounts of Sb in environmental and industrial wastewater 3 + / Cr 6+ , which is of great significance for environmental protection and human health monitoring.

[0052] 2. The color developer in the detection method of the present invention has high sensitivity, and the new color developer has the same 3+ / Cr 6+ High affinity coordination site, able to bind Sb 3+ / Cr 6+ The specific structural design significantly improves the color development agent to form a stable complex. 3 + / Cr 6+ sensitivity.

[0053] 3. The selectivity of the color developer in the detection method of the present invention is enhanced. By introducing a functional group with specific recognition ability, it can specifically bind to Sb 3+ / Cr 6+ The reaction combination has good selectivity and is less interfered by other metal ions, such as copper, iron, cadmium, nickel and other metal ions. When this method is used to detect trivalent antimony ions / hexavalent chromium ions, the interference of other metal ions in the sample can be eliminated, and the results are more reliable.

[0054] 4. The specific detection method of the present invention based on a specific chromogenic agent has simple detection operations, does not require reliance on large-scale equipment and instruments, is simple to operate, takes a short time, is highly efficient and convenient, and has no strict requirements on the detection environment and time, thus ensuring rapid determination. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is the ultraviolet absorption spectrum diagram of the complex of the chromogenic agent of the present invention and trivalent antimony ions;

[0056] Figure 2 It is the ultraviolet absorption spectrum diagram of the chromogenic agent of the present invention;

[0057] Figure 3 It is the ultraviolet absorption spectrum diagram of the complex of the chromogenic agent of the present invention and hexavalent chromium ions;

[0058] Figure 4 It is the diagram of the influence of the microemulsion surfactant and its dosage on the absorbance of the BWT-Sb 3+ / Cr 6+ complex;

[0059] Figure 5 It is the diagram of the influence of different pH values on the absorbance of the BWT-Sb 3+ / Cr 6+ complex. The chromogenic agent does not complex with metal ions under alkaline conditions, where pH = 2, 3, 4, 5, 6, 7;

[0060] Figure 6 It is the diagram of the influence of the Tween-80 surfactant and its dosage on the absorbance of the BWT-Sb 3+ / Cr 6+ complex;

[0061] Figure 7 It is the diagram of the influence of the dosage of the chromogenic agent on the absorbance;

[0062] Figure 8 It is the fitting diagram of the absorbance standard curve of the Sb 3+ concentration (0.05 - 1 mg / L) of the present invention;

[0063] Figure 9 It is the fitting diagram of the absorbance standard curve of the Cr 6+ concentration (0.1 - 1 mg / L) of the present invention;

[0064] Figure 10 It is the ultraviolet absorption spectrum diagram of the selectivity of the chromogenic agent for metal ions in the presence of different metal ions. DETAILED DESCRIPTION OF THE INVENTION

[0065] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0066] The materials, reagents, etc. used in the following examples can be obtained from commercial sources without special instructions. For the experimental methods without specific conditions noted in the examples, they are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0067] Specific preparation of each reagent in the examples:

[0068] Preparation method of the chromogenic reagent solution: Weigh 0.1 g of chromogenic reagent 9-(4-aminophenyl)-2,6,7-trihydroxyxanthen-3-one, dissolve it with DMF, and prepare it into a 100 mL solution with a concentration of 1 g / L.

[0069] Preparation of 20% hydrochloric acid solution: Take 100 g of concentrated hydrochloric acid (mass fraction 36.5%), add 82.5 g of water, and 20% hydrochloric acid solution can be prepared.

[0070] Preparation of 20% sulfuric acid solution: First add 70 mL of water to a beaker, measure 12.3 mL of 98% concentrated sulfuric acid, slowly pour it along the wall of the beaker into the water, and stir with a glass rod while pouring to ensure uniform mixing and prevent splashing. After the solution cools to room temperature, make up the water to 100 mL and make the volume constant.

[0071] Preparation of 4% Tween-80 microemulsion: Weigh 4 g of Tween-80, 3 g of n-heptane, 0.8 g of n-butanol, and 92.2 g of deionized water, mix them and stir at room temperature for 30 min.

[0072] Preparation of CTMAB microemulsion: Weigh 2 g of CTMAB, 1 g of n-heptane, 0.5 g of n-butanol, and 96.5 g of deionized water, mix them and stir at room temperature for 30 min.

[0073] Preparation of OP-100 microemulsion: Weigh 4.5 g of OP-100, 3 g of n-heptane, 1 g of n-butanol, and 91.5 g of deionized water, mix them and stir at room temperature for 30 min.

[0074] Preparation of CTMAB-OP microemulsion: Weigh 2.5 g of OP-100, 2 g of CTMAB, 0.5 g of n-heptane, 2 g of n-butanol, and 93 g of deionized water, mix them and stir at room temperature for 30 min.

[0075] Antimony / chromium standard solution: Weigh 1.0000 g of metallic antimony / chromium (99.99%), make the volume constant in a 1 L volumetric flask, and the concentration of the resulting solution is 1 mg / mL. Dilute it to a solution with a concentration of 1 - 5 mg / L when in use.

[0076] Preparation of other coexisting ion solutions: Take nitrate or hydrochloride of various metals of analytical grade, dissolve them with acid, and prepare an aqueous solution with a concentration of 10 mg / L.

[0077] Chromium metal: Analytical grade, Nanjing Wanqing Chemical Glass Instrument Co., Ltd., C915977-100G;

[0078] Antimony metal: Analytical grade, Shanghai Macklin Biochemical Co., Ltd., A875370-5G;

[0079] Tween-80: Chemical pure, Shanghai Bide Pharmaceutical Technology Co., Ltd., BD148605;

[0080] CTMAB: Chemical pure, Shanghai Bide Pharmaceutical Technology Co., Ltd., BD21539;

[0081] OP-100: Chemical pure, Shanghai Bide Pharmaceutical Technology Co., Ltd., BD146108.

[0082] Example 1

[0083] Add 1 g of 1,2,4-triacetoxybenzene to a round-bottom flask equipped with a heater and a mechanical stirrer, add 25 ml of 50% EtOH as a solution and 1 ml of concentrated sulfuric acid, and heat under reflux until a clear solution is obtained. Dropwise add 4-aminobenzaldehyde, which is half the amount of substance of 1,2,4-triacetoxybenzene, to the boiling mixture within 2 minutes, and keep the stirred mixture under reflux for another 1.5 h. Subsequently, add K, which is half the amount of substance of 1,2,4-triacetoxybenzene, within 50 minutes under reflux at 80 °C 2 S 2 O 8 , the mixture changes from a brown solution to a viscous dark suspension. After the addition is completed, continue the reflux reaction for 20 minutes. Then pour it into ice water with twice the volume of the solution, stir for 30 minutes, filter to obtain the product, and dry it in a vacuum oven at 60 °C to obtain 9-(4-aminophenyl)-2,6,7-trihydroxyxanthen-3-one, which is the color reagent. 9-(4-aminophenyl)-2,6,7-trihydroxyxanthen-3-one solid (BWT), purity 90%, yield 66%. The NMR report is 1 H NMR (400 MHz, DMSO- d 6 ) δ 7.32(d, J = 8.5 Hz, 2H), 7.16 (s, 2H), 7.04 (s, 2H), 6.98 (d, J = 8.2 Hz, 2H).ESI-ESI (m / z) Anal. Calcd for C19 H 13 NO 5 (335.08), found: 336.05 [M + H] + .

[0084] The structure is as follows:

[0085] .

[0086] Example 2

[0087] The synthesis steps were the same as those in Example 1, except that 4-aminobenzaldehyde was replaced with 4-formylbenzoic acid to obtain 4-(2,3,7-trihydroxy-6-oxoxanthen-9-yl)benzoic acid with a purity of 85% and a yield of 50%. The NMR report is 1 H NMR (400 MHz, DMSO- d 6 ) δ 7.84 (d, J = 8.0 Hz, 2H), 7.23 (d, J = 8.1 Hz, 2H), 6.47 (s, 2H), 6.33 (s, 2H). ESI-ESI (m / z) Anal. Calcd for C 20 H 12 O 7 (364.06), found: 365.00 [M + H] + .

[0088] The structure is as follows:

[0089] .

[0090] Example 3

[0091] The synthesis steps were the same as those in Example 1, except that 4-aminobenzaldehyde was replaced with 4-nitrobenzaldehyde to obtain 2,6,7-trihydroxy-9-(4-nitrophenyl)xanthen-3-one with a purity of 87% and a yield of 58%. The NMR report is 1 H NMR (400 MHz, DMSO- d 6 ) δ 8.48 (d, J = 8.2 Hz, 2H), 7.76 (d, J = 8.2 Hz, 2H), 6.70 (s, 2H), 6.25 (s, 2H). ESI-ESI (m / z) Anal. Calcd for C 19 H 11NO 7 (365.05), found: 366.00 [M + H] +

[0092] The structure is as follows:

[0093] .

[0094] Example 4

[0095] The synthesis steps are the same as those in Example 1, except that 4-aminobenzaldehyde is replaced with 2-hydroxybenzaldehyde to obtain 2,6,7-trihydroxy-9-(2-hydroxyphenyl)xanthen-3-one with a purity of 90% and a yield of 64%. The NMR report is 1 H NMR (400 MHz, DMSO- d 6 ) δ 9.78 (s, 1H), 9.01 (s, 1H), 7.73 – 7.58 (m, 1H), 7.54 – 7.37 (m, 1H),7.25 (s, 1H), 7.26 – 7.06 (m, 2H), 6.75 (s, 1H), 6.65 – 6.46 (m, 1H), 6.49 –6.35 (m, 1H).ESI-ESI (m / z) Anal. Calcd for C19H 12 O6 (336.06), found: 337.05 [M+ H] + .

[0096] The structure is as follows:

[0097] .

[0098] Example 5

[0099] The synthesis steps are the same as those in Example 1, except that 4-aminobenzaldehyde is replaced with 4-formylbenzenesulfonic acid to obtain the structure as follows:

[0100] .

[0101] Example 6

[0102] Application of the chromogenic agent prepared in Example 1 in detecting trivalent antimony ions, including the following steps:

[0103] (1) 9-(4-Aminophenyl)-2,6,7-trihydroxyxanthen-3-one prepared in Example 1 is a yellow liquid itself, as Figure 2 shown to have an absorption peak at 473 nm under an ultraviolet-visible spectrophotometer. When adding Sb3+ / Cr 6+ There is an orange-red complex BWT-Sb 3+ / Cr 6+ formed (i.e., there is an orange-red complex BWT-Sb when 1 ml of 1 g / L chromogenic reagent solution is added to 5 ml of 5 mg / L antimony / chromium standard solution), 3+ / Cr 6+ formed), BWT-Sb 3+ has an absorption peak at 560 nm, as Figure 1 shown. BWT-Cr 6+ has an absorption peak at 500 nm, as Figure 3 shown.

[0104] (2) Determination of surfactant: Four different types of microemulsions (surfactants), namely Tween-80, CTMAB, OP-100, and CTMAB-OP, were prepared respectively. 0.5 ml of different types of surfactants were taken, and 5 ml of 1 mg / L antimony or chromium standard solution and 100 ul of 1 g / L chromogenic reagent solution were added to each of them. 20% hydrochloric acid was added to adjust the pH of the system to 3 and the volume was made up to 10 mL. After standing at room temperature for 15 min, the determination was carried out with a UV spectrophotometer. Taking the BWT-Sb 3+ / Cr 6+ complex solution without surfactant as the control, as Figure 4 shown, for the BWT-Sb 3+ / Cr 6+ complex containing CTMAB, OP-100, and CTMAB-OP surfactants, its absorbance increased slightly compared with the absorbance value of the control BWT-Sb 3+ / Cr 6+ complex, while the absorbance in 4% Tween-80 increased by 2 times compared with the control. Finally, 4% Tween-80 was selected as the surfactant.

[0105] (3) Determination of acid solution: Reaction systems with different pH values were prepared. 5 ml of 1 mg / L antimony or chromium standard solution and 1 ml of 1 g / L chromogenic reagent solution were added to each of them. 20% hydrochloric acid was added to adjust the pH of the system to 2 - 7. After standing at room temperature for 15 min, the determination was carried out with a UV spectrophotometer. As Figure 5 shown, in the acid solution system with pH = 3, the absorbance value of the BWT-Sb 3+ / Cr 6+ complex is the highest. Finally, the acid solution with pH = 3 was selected.

[0106] (4) Respectively take 0.1 mL, 0.2 mL, 0.3 mL, 0.4 mL, 0.5 mL, 0.6 mL, 0.7 mL of 4% Tween-80, add 5 mL of 1 mg / L antimony or chromium standard solution and 1 mL of 1 g / L color reagent solution to each of them, adjust the pH of the system to 3 with 20% hydrochloric acid and make the volume up to 10 mL. After standing for 15 min at room temperature, measure with a UV spectrophotometer. The results show that: as Figure 6 shown, when the dosage of 4% Tween-80 is 0.5 mL, the absorbance is the largest and stable. Therefore, the optimal dosage of 4% Tween-80 is 0.5 mL.

[0107] (5) Determination of the optimal dosage of the color reagent: Prepare 0.5 mL of 4% Tween-80, 5 mL of 1 mg / L antimony / chromium standard solution, and add 1 g / L color reagent to 20 μL, 40 μL, 60 μL, 80 μL, 100 μL, 120 μL, 140 μL. Add 20% hydrochloric acid to adjust the pH of the system to 3 and make the volume up to 10 mL. After standing for 15 min at room temperature, measure with a UV spectrophotometer. As the dosage of the color reagent increases, the absorbance of the complex gradually increases. When the dosage of the color reagent increases to 100 - 140 μL, the absorbance of the complex reaches the maximum and remains basically unchanged. When the dosage of the color reagent continues to increase, the absorbance of the complex decreases instead. As Figure 7 shown, therefore, when measuring, select the dosage of 1 g / L color reagent as 100 μL.

[0108] Example 7

[0109] Prepare the BWT color reagent solution (concentration is 1 g / L) prepared in Example 1, 20% hydrochloric acid solution, 4% Tween-80 solution. At the same time, prepare different concentrations of trivalent antimony ion solutions for use. Detect each substance according to the optimal addition amount and detection method in Example 6.

[0110] Using the spectrophotometric method, measure the absorbance of the mixed solution of different concentrations of trivalent antimony ions and BWT color reagent, and measure the BWT solution with the same concentration as the blank control. Take the difference in absorbance between the measured system solution containing different concentrations of trivalent antimony ions and the blank control system solution as the ordinate, and the concentration of trivalent antimony ions as the abscissa to draw a standard curve; as Figure 8 shown, take the absorbance of the system solution containing different concentrations of trivalent antimony ions obtained as the ordinate, and the concentration of trivalent antimony ions as the abscissa to draw a standard curve; as Figure 8 shown, in the concentration range of 0.01 - 0.1 mg / L of trivalent antimony ions, the standard curve equation is y = 0.52323x + 0.13275 (R 2= 0.99673); The apparent molar absorption coefficient ε = 1.368*10 4 L / (mol·cm), The detection limit of trivalent antimony ions is 5×10 -3 mg / L, and the detection range is 0.05 - 1 mg / L.

[0111] Example 8

[0112] Prepare BWT chromogenic reagent solution (concentration 1 g / L), 20% hydrochloric acid solution, 4% Tween-80 solution. At the same time, prepare different concentrations of hexavalent chromium ion solutions for use, with the addition amounts of each substance being the optimal ones in Example 5.

[0113] Using spectrophotometry, measure the absorbance of the mixed solution of hexavalent ions and BWT chromogenic reagent with different concentrations, and measure the BWT solution with the same concentration as the blank control. Take the difference in absorbance between the measured system solution containing different hexavalent chromium ion concentrations and the blank control system solution as the ordinate, and the concentration of hexavalent chromium ions as the abscissa to plot the standard curve; as Figure 9 shown, take the absorbance of the system solution containing different hexavalent chromium ion concentrations as the ordinate, and the concentration of hexavalent chromium ions as the abscissa to plot the standard curve; as Figure 9 shown, in the concentration range of 0.01 - 0.1 mg / L for hexavalent chromium ions, the standard curve equation is y = 0.347x + 0.0146 (R 2 = 0.99506); The apparent molar absorption coefficient ε = 6.136*10 3 L / (mol·cm), The detection limit of hexavalent chromium ions is 5×10 -2 mg / L, and the detection range is 0.08 - 1 mg / L.

[0114] Furthermore, compare the experiments of Examples 6 and 7 using the chromogenic reagents prepared in Examples 1 - 4 of the present invention. The results are shown in Table 1.

[0115] Table 1 Detection results of different chromogenic reagents

[0116]

[0117] Example 9

[0118] Prepare 12 groups of test solutions. Each of the 12 groups of test solutions only contains 5 ml of Ag + , Al 3+ , Ba 2+ , Cd 2+ , Co 2+ , Cr 6+ , Cu 2+ , Fe 3+ , K + , Mg2+ , Ni 2+ , Sb 3+ , and the concentration of each metal ion is 5 mg / L. 100 μl of the chromogenic reagent solution prepared in Example 1 at 1 g / L and 0.5 ml of 4% Tween-80 solution were respectively added thereto. 20% hydrochloric acid was added to adjust the pH of the system to 3, and deionized water was used to make up the volume to 10 ml. The chromogenic reagent solution with the same concentration and containing no metal ions was used as the blank solution. After standing at room temperature for 15 min, measurement was carried out using an ultraviolet spectrophotometer. The results showed that, as Figure 10 shown, the chromogenic reagent showed specific detection for Sb 3+ / Cr 6+ in the detection of the recognition of twelve metal ions.

[0119] In summary, the detection method of the present invention has higher sensitivity than the existing methods and meets the requirements of the industry's maximum limit. The method of the present invention is simple, fast, and easy to promote and use.

Claims

1. A method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer, characterized in that: The steps include: (1) Take the sample to be tested and add acid to adjust the pH value of the sample to be tested; (2) Add a color developer and a surfactant to the test solution, mix and let stand; (3) After sufficient reaction, the absorbance is measured by spectrophotometry, and the measured absorbance value of trivalent antimony ions is matched to the standard curve to obtain the concentration of trivalent antimony ions in the sample to be tested; The developer structural formula is as follows: ; Among them, R is selected from .

2. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The environment includes a water environment or a soil environment.

3. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The acid solution in step (1) is hydrochloric acid or sulfuric acid, and the pH is adjusted to 2-7.

4. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The surfactant in step (2) is any one or a combination of Tween-80, CTMAB, OP-100, and OP-CTMAB, with a concentration of no more than 5% and an addition amount of 0.2-1.0 mL.

5. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The surfactant is Tween-80 microemulsion.

6. The method for detecting heavy metal trivalent antimony ions in an environment based on a color developer according to claim 1, characterized in that: The concentration of the color developer in step (2) is 1-5 g / L, and the amount added is 0.1-1 mL.

7. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The standing time after mixing in step (2) is 1-20 min.

8. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The preparation method of the color developer is as follows: adding an organic solvent and concentrated sulfuric acid to 1,2,4-triacetoxybenzene, stirring, heating and reflux until a clear solution is obtained, adding 4-aminobenzaldehyde to the mixture, keeping the stirred mixture under reflux, and then adding K2S2O8, the mixture changes from a brown solution to a viscous dark suspension, continuing to reflux, and then pouring into ice water, stirring, filtering to obtain a product, and vacuum drying to obtain a color developer.

9. The method for detecting trivalent antimony ions of heavy metals in an environment based on a color developer according to claim 1, characterized in that: The maximum absorption wavelength of the trivalent antimony ion in step (3) is 560 nm.

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