Ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor as well as preparation method and application thereof

Abstract

The invention relates to the technical field of colorimetric method visual detection, in particular to an ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor as well as a preparation method and application thereof. The ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor is formed by taking negatively charged sodium citrate modified gold nanoparticles as a raw material, modifying the gold nanoparticles in an aqueous solution by adopting ammonium thioglycolate, and fixing ammonium thioglycolate molecules on the surfaces of the gold nanoparticles through Au-S bonds. The sensor disclosed by the invention not only has the characteristics of simplicity in preparation, convenience in operation, low cost, high response speed and high sensitivity, but also can be used for simultaneously identifying and detecting moxifloxacin, ciprofloxacin and chromium ions (III). The sensor has been successfully applied to detection of actual samples, and is expected to be applied to the fields of environmental sewage detection and the like on a large scale.

Description

Technical Field

[0001] The invention relates to the technical field of colorimetric visualization detection, in particular to an ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor and a preparation method and application thereof. Background Art

[0002] Moxifloxacin (MOX) and ciprofloxacin (CIP) are both quinolone antibiotics with high activity against a broad spectrum of Gram-negative and Gram-positive bacteria. Therefore, they have been widely used in human and veterinary medicine to treat diseases such as acute bacterial sinusitis, acute bacterial chronic bronchitis, mild to moderate community-acquired pneumonia, and skin and soft tissue infections caused by sensitive microorganisms; they are also used to treat bacterial infections resistant to other antibiotics (including aminoglycosides and β-lactam antibiotics). Although MOX and CIP have significant therapeutic effects in medicine, uncontrolled use will inevitably lead to their residues being discharged into the environment and food, accumulating in large quantities in the human body through biological cycles, and ultimately causing serious side effects on human health and ecological environmental issues. Another chemical substance of concern to human health is trivalent chromium ion (Cr(III)). Chromium ion (III) is an important micronutrient that can effectively maintain physiological processes such as carbohydrates, fat cells and proteins in the human body. However, excessive intake of chromium ions (III) will strongly bind to DNA in human cells and cause DNA damage, which will adversely affect the structure and composition of cells and ultimately cause the risk of cancer. In recent years, chromium ions (III) have been widely used in industrial production processes, such as chrome plating, dye and pigment manufacturing, leather tanning and wood preservation. Therefore, it is also one of the most common heavy metal ions in industrial wastewater.

[0003] At present, the traditional methods for detecting antibiotics and heavy metal ions mainly include gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectroscopy (AAS) and fluorescence detection. However, the complex detection process, high cost, expensive large instruments and professional operation have greatly limited their application in rapid, on-site and real-time detection. In recent years, a series of colorimetric detection methods for antibiotics and heavy metal ions have been developed, represented by gold nanoparticles. They are not only low-cost, but also can be used for simple, on-site and real-time detection without the help of complex instruments. However, the sensors reported so far for detecting antibiotics and heavy metal ions are usually single-parameter sensors. Although these sensors have the advantages of high sensitivity and high accuracy, they inevitably have the disadvantages of complex operation, low work efficiency, high cost and incomplete information.

[0004] Therefore, considering the complexity of the sample detection environment, it is particularly important to develop a new method that is low-cost, simple to operate, fast, provides comprehensive information, has high sensitivity, and can simultaneously identify and detect the three targets of MOX, CIP and chromium (III). Summary of the invention

[0005] The present invention aims to solve the defects in the prior art and provides a colorimetric sensor of ammonium thioglycolate functionalized gold nanoparticles. The sensor is simple and fast to operate, has high sensitivity, can quantitatively detect moxifloxacin, ciprofloxacin and chromium (III) ions in real time, and realizes simultaneous detection of multiple targets.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing an ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor, comprising the following steps:

[0008] Step 1: preparing gold nanoparticle solution by reducing chloroauric acid with sodium citrate;

[0009] Step 2: Add ammonium thioglycolate and ultrapure water to the gold nanoparticle solution prepared in step 1, mix well, and obtain an ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor.

[0010] In the above preparation method, negatively charged sodium citrate-modified gold nanoparticles AuNPs are used as raw materials, and ammonium thioglycolate is used to modify AuNPs in an aqueous solution. The ammonium thioglycolate molecules are fixed on the surface of the gold nanoparticles through Au-S bonds to form a functionalized colorimetric sensor ATG-AuNPs. Here, ammonium thioglycolate serves as a protective agent to prevent the aggregation of gold nanoparticles.

[0011] In an optional embodiment, the specific process of preparing the gold nanoparticle solution by the sodium citrate reduction chloroauric acid method in step 1 is: stirring and heating the chloroauric acid solution to boiling, and then quickly adding the freshly prepared sodium citrate solution. When the solution changes from light yellow to wine red, continue heating for 30 minutes, then stop heating, continue stirring, and naturally cool to room temperature to obtain the gold nanoparticle solution.

[0012] In an optional embodiment, the concentration of the chloroauric acid solution is 1 mmol / L and the volume is 100 mL; the volume of the sodium citrate solution is 10 mL and the concentration is 38.8 mmol / L.

[0013] In an optional embodiment, the concentration of the gold nanoparticle solution in step 2 is 2.4-8 nmol / L.

[0014] In an optional embodiment, the concentration of ammonium thioglycolate in step 2 is 0.5-4 mmol / L.

[0015] In an optional embodiment, in step 2, the volume ratio of the gold nanoparticle solution, ammonium thioglycolate and ultrapure water is 160:4:26.

[0016] In an optional embodiment, the mixing temperature in step 2 is 25-33° C. and the mixing time is 60 minutes.

[0017] In a second aspect, the present invention provides an ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor prepared by the preparation method described in the first aspect.

[0018] In a third aspect, the present invention provides an application of the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor described in the second aspect for simultaneously identifying and detecting moxifloxacin, ciprofloxacin and chromium (III) ions.

[0019] In the process of detecting moxifloxacin and ciprofloxacin, the carboxyl oxygen on the functionalized gold nanoparticles and the fluorine on moxifloxacin and ciprofloxacin form OF bonds, which shortens the distance between the functionalized gold nanoparticles, thereby losing the protection of the ammonium thioglycolate on the gold nanoparticles, and causing the functionalized gold nanoparticles to aggregate together; in addition, in the process of detecting chromium (III) ions, the carboxyl groups on the functionalized gold nanoparticles will form coordination bonds with the chromium (III) ions and approach them, thereby losing the protection of the ammonium thioglycolate on the gold nanoparticles, and finally causing the functionalized gold nanoparticles to aggregate together; all of the above utilize the properties of the surface plasmon resonance of gold nanoparticles to indicate the presence of moxifloxacin, ciprofloxacin and chromium (III) ions in aqueous solution by the change of the solution from red to blue-gray.

[0020] In a fourth aspect, the present invention provides a method for simultaneously detecting the contents of moxifloxacin, ciprofloxacin and chromium (III) ion, comprising the following steps:

[0021] The ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor described in the second aspect is added to the sample to be tested, and the absorbance is measured by using a UV-visible spectrophotometer. The absorbance is calculated based on the spectral ratio A at 600 nm, 640 nm, 650 nm and 520 nm. 600 / A 520 , A 640 / A 520 , A 650 / A 520 Moxifloxacin, ciprofloxacin and chromium ion (III) were quantitatively detected respectively.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention utilizes AuNPs modified with ammonium thioglycolate, and the synthesis steps are simple and the reaction conditions are mild;

[0024] (2) The present invention does not require large instruments, and the test results can be identified by naked eye observation or ultraviolet-visible spectrometry;

[0025] (3) The reagents and operation procedures used in the present invention have no toxic or side effects;

[0026] (4) The method of the present invention is simple, rapid, and easy to operate, and can be used for rapid on-site in-situ detection.

[0027] (5) Compared with the single-parameter sensor, the multi-parameter sensor of the present invention can realize the simultaneous identification and rapid detection of three substances: moxifloxacin, ciprofloxacin and chromium (III) ion.

[0028] (6) Compared with a single-parameter sensor, the multi-parameter sensor of the present invention has the characteristics of high working efficiency, low cost and comprehensive information provision. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Transmission electron micrographs of 13 nm gold nanoparticles (a), ammonium thioglycolate functionalized gold nanoparticles (b), aggregation of ammonium thioglycolate functionalized gold nanoparticles induced by moxifloxacin (c), aggregation of ammonium thioglycolate functionalized gold nanoparticles induced by ciprofloxacin (d), and aggregation of ammonium thioglycolate functionalized gold nanoparticles induced by chromium ions (III) (e), as well as photographs of the corresponding solution colors.

[0030] Figure 2 These are UV-visible spectra of 13nm gold nanoparticles, ammonium thioglycolate functionalized gold nanoparticles, moxifloxacin-induced aggregation of ammonium thioglycolate functionalized gold nanoparticles, ciprofloxacin-induced aggregation of ammonium thioglycolate functionalized gold nanoparticles, and chromium ion (III)-induced aggregation of ammonium thioglycolate functionalized gold nanoparticles, and photographs of the corresponding solution colors.

[0031] Figure 3 The comparison chart of the aggregation degree of ammonium thioglycolate functionalized gold nanoparticles induced by each antibiotic and each metal ion and the corresponding solution color photograph, the horizontal axis is the type of antibiotic and metal ion, the vertical axis is the UV-visible spectrum absorbance A when the final concentration of antibiotics in ammonium thioglycolate functionalized gold nanoparticles is 200μmol / L and the final concentration of metal ions is 10μmol / L 600 / A 520 ratio.

[0032] Figure 4These are photographs of the corresponding solution colors, UV-visible absorption spectra and standard curves when moxifloxacin is present at different concentrations in the mixed solution (the final concentration of moxifloxacin is 10μmol / L, 20μmol / L, 30μmol / L, 40μmol / L, 50μmol / L, 60μmol / L, 70μmol / L, 80μmol / L, 90μmol / L, 100μmol / L, 110μmol / L, 120μmol / L, 130μmol / L, 140μmol / L, 150μmol / L, 160μmol / L, 170μmol / L, 180μmol / L, 190μmol / L and 200μmol / L).

[0033] Figure 5 These are photographs of the corresponding solution colors, UV-visible absorption spectra and standard curves when ciprofloxacin is present at different concentrations in the mixed solution (final ciprofloxacin concentrations are 10μmol / L, 20μmol / L, 30μmol / L, 40μmol / L, 50μmol / L, 60μmol / L, 70μmol / L, 80μmol / L, 90μmol / L and 100μmol / L).

[0034] Figure 6 Photographs of the corresponding solution colors, UV-visible absorption spectra and standard curves when chromium (III) ions are present at different concentrations (final concentrations of chromium (III) ions are 1μmol / L, 2μmol / L, 2.3μmol / L, 2.7μmol / L, 3μmol / L, 3.3μmol / L, 3.7μmol / L, 4μmol / L, 4.3μmol / L, 4.7μmol / L and 5μmol / L) in the mixed solution. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] Example 1 Preparation of Ammonium Thioglycolate Functionalized Gold Nanoparticle Colorimetric Sensor

[0037] (1) Preparation of AuNPs:

[0038] Gold nanoparticles were prepared by sodium citrate reduction of chloroauric acid (the transmission electron microscopy image is shown in Figure 1(a)). First, all glassware and magnets used are soaked in aqua regia, then cleaned with ultrapure water, placed in an oven, dried and set aside. 100 mL of 1 mmol / L chloroauric acid solution is added to a three-necked flask equipped with a reflux device, stirred and heated to boiling in a magnetic stirrer at a speed of 12 rpm, and then 10 mL of freshly prepared 38.8 mmol / L sodium citrate solution is quickly added. When the solution changes from light yellow to wine red, continue heating for 30 minutes, then stop heating, continue stirring, and cool naturally to room temperature to obtain gold nanoparticles AuNPs, which are stored in a refrigerator at 2 to 8 ° C for later use;

[0039] (2) Preparation of ATG-AuNPs

[0040] 160 μL of 3 nmol / L AuNPs, 4 μL of 4 mmol / L ammonium thioglycolate and 26 μL of ultrapure water were added to an EP tube and mixed evenly. After reacting for 60 min on a constant temperature mixer at 400 rpm at room temperature of 25 °C, a visualized ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor (ATG-AuNPs) was obtained. The results of transmission electron microscopy and UV-visible spectrophotometry showed that the ammonium thioglycolate molecules were fixed on the surface of the gold nanoparticles through Au-S bonds (e.g. Figure 1 (b) Figure 2 shown).

[0041] Example 2 Application of Ammonium Thioglycolate Functionalized Gold Nanoparticle Colorimetric Sensor

[0042] (1) Selective detection

[0043] To 190 μL ATG-AuNPs, 10 μL of 4 mmol / L moxifloxacin (MOX), tetracycline (TC), ciprofloxacin (CIP), pefloxacin (PEF), lomefloxacin hydrochloride (LXN) and 10 μL of 200 μmol / L interfering ion solutions of Cr(III), Al(III), Mn(II), Pb(II), Cu(II), Hg(II), Ni(II), Fe(II), Ag(I), Fe(III), Zn(II), Ca(II), Ba(II), and Mg(II) were added respectively to control the final concentrations of interfering antibiotics and interfering heavy metal ions in ATG-AuNPs to be 200 μmol / L and 10 μmol / L, respectively. The mixture was mixed and allowed to stand at room temperature (25 °C) for 1 min. Then, the UV-visible spectra of the reaction systems were measured. The A 600 / A 520 The ratio of different antibiotics and different metal ions to the aggregation degree of functionalized gold nanoparticles (such as Figure 3Among all antibiotics and metal ions, moxifloxacin, ciprofloxacin and chromium ions (III) have significant ability to induce aggregation of gold nanoparticles stabilized by ammonium thioglycolate. The transmission electron microscopy images of the aggregation of gold nanoparticles functionalized with ammonium thioglycolate induced by moxifloxacin, ciprofloxacin and chromium ions (III) (as shown in Figure 2) show that moxifloxacin, ciprofloxacin and chromium ions (III) have significant ability to induce aggregation of gold nanoparticles functionalized with ammonium thioglycolate Figure 1 (c) Figure 1 (d) and Figure 1 (e)); UV-visible spectra of aggregation of ammonium thioglycolate functionalized gold nanoparticles induced by moxifloxacin, ciprofloxacin and chromium (III) ions (as shown in Figure 2 shown).

[0044] (2) Detection of moxifloxacin

[0045] A certain amount of moxifloxacin solution was added to ATG-AuNPs to control the final concentration of moxifloxacin to be 10 μmol / L, 20 μmol / L, 30 μmol / L, 40 μmol / L, 50 μmol / L, 60 μmol / L, 70 μmol / L, 80 μmol / L, 90 μmol / L, 100 μmol / L, 110 μmol / L, 120 μmol / L, 130 μmol / L, 140 μmol / L, 150 μmol / L, 160 μmol / L, 170 μmol / L, 180 μmol / L, 190 μmol / L and 200 μmol / L, and the mixture was mixed and allowed to stand at room temperature of 25 °C for 1 min. The UV-visible spectra of each reaction system were then measured, and three parallel tests were designed for each concentration (such as Figure 4 (a)). The MOX concentration is taken as the horizontal axis and A is taken as the horizontal axis. 600 / A 520 The value of is used as the vertical coordinate to draw a standard curve, establish the linear regression equation of moxifloxacin, and calculate the regression equation and correlation coefficient. Figure 4 (b) and Figure 4 As shown in (c), this method showed good linear relationship when the concentration of MOX was in the range of 0-100 μmol / L and 100-200 μmol / L. 600 / A 520 The linear relationship between the ratio and MOX concentration is y = 0.0014x + 0.3203, R 2 = 0.9982 and y = 0.0076x-0.3083, R 2 =0.9971, and the detection limit is as low as 1.57 μmol / L, indicating that this method has high sensitivity to MOX. It can be seen that with the increase of MOX concentration, A 600 / A 520 The value of is getting bigger and bigger, which indicates that the aggregation degree of functionalized gold nanoparticles is getting bigger and bigger.600 / A 520 The ratio of MOX was used for quantitative detection.

[0046] (3) Detection of Ciprofloxacin

[0047] A certain amount of ciprofloxacin solution was added to ATG-AuNPs to control the final concentration of ciprofloxacin to be 10 μmol / L, 20 μmol / L, 30 μmol / L, 40 μmol / L, 50 μmol / L, 60 μmol / L, 70 μmol / L, 80 μmol / L, 90 μmol / L and 100 μmol / L, respectively. The mixture was allowed to stand at room temperature of 25 °C for 1 min, and then the UV-visible spectra of each reaction system were measured respectively. Three parallel tests were designed for each concentration (such as Figure 5 (a)). With CIP concentration as the horizontal axis and A as the horizontal axis 640 / A 520 The value of is used as the vertical coordinate to draw a standard curve, establish the linear regression equation of CIP, and calculate the regression equation and correlation coefficient. Figure 5 As shown in (b), this method shows a good linear relationship in the range of CIP concentration from 0 to 100 μmol / L. 640 / A 520 The linear relationship between the ratio and CIP concentration is y = 0.0101x-0.8364, R 2 =0.9925, and the detection limit is as low as 1.30 μmol / L, indicating that this method has high sensitivity to CIP. It can be seen that with the increase of CIP concentration, A 640 / A 520 The value of is getting bigger and bigger, which indicates that the aggregation degree of functionalized gold nanoparticles is getting bigger and bigger. 640 / A 520 The ratio of CIP was used to quantitatively detect CIP.

[0048] (4) Detection of chromium ion (III)

[0049] A certain amount of chromium ion (III) solution was added to ATG-AuNPs to control the final concentration of chromium ion (III) to be 1 μmol / L, 2 μmol / L, 2.3 μmol / L, 2.7 μmol / L, 3 μmol / L, 3.3 μmol / L, 3.7 μmol / L, 4 μmol / L, 4.3 μmol / L, 4.7 μmol / L and 5 μmol / L, respectively. The mixture was allowed to stand at room temperature of 25°C for 1 min, and then the UV-visible spectra of each reaction system were measured respectively. Three parallel experiments were designed for each concentration (such as Figure 6 (a)). The concentration of chromium ion (III) is taken as the horizontal axis and A is taken as the horizontal axis. 650 / A 520 The value of is used as the vertical coordinate to draw a standard curve, establish the linear regression equation of chromium ion (III), and calculate the regression equation and correlation coefficient. Figure 6 As shown in (b), the method showed a good linear relationship when the concentration of chromium ion (III) was in the range of 0 to 5 μmol / L. 650 / A 520 The linear relationship between the ratio and the concentration of chromium ion (III) is y = 0.2310x-1.1176, R 2 =0.9984, and the detection limit is as low as 56.9 nmol / L, indicating that this method has high sensitivity to chromium ions (III). It can be seen that with the increase of chromium ion (III) concentration, A 650 / A 520 The value of is getting bigger and bigger, which indicates that the aggregation degree of functionalized gold nanoparticles is getting bigger and bigger. 650 / A 520 The ratio of chromium ion (III) was used for quantitative detection.

[0050] (5) Recovery rate experiment in actual water samples

[0051] Moxifloxacin solutions with a concentration of 0.4mmol / L were prepared in ultrapure water, tap water, and lake water, and three groups of experiments were repeated. 10μL of different water containing 0.4mmol / L MOX (final concentration of 20μmol / L) was added to 190μL ATG-AuNPs, and the reaction was allowed to stand for 1min at room temperature of 25℃. The UV-visible spectrophotometer was then used to measure the UV-visible spectrophotometer to detect the UV-visible absorption curves of ATG-AuNPs for different water types.

[0052] As shown in Table 1, in the MOX spike experiment of tap water and lake water, the recovery rate of MOX compared with ultrapure water was distributed around 90-110%. The specific recovery rates of MOX in different water samples were: 100.32% for laboratory tap water and 102.00% for Wenying Lake in Datong City. The results show that the detection method is accurate and reliable in detecting MOX in actual water samples.

[0053] Table 1 Recovery of MOX in different water samples

[0054] Water sample type Tap water Lake source laboratory Wenying Lake Recovery rate 100.32 102.00

[0055] A 0.4mmol / L ciprofloxacin solution was prepared in ultrapure water, tap water, and lake water, and three sets of experiments were repeated. 10μL of different water containing 0.4mmol / L CIP (final concentration of 20μmol / L) was added to 190μL ATG-AuNPs, and the reaction was allowed to stand for 1min at room temperature of 25℃. The UV-visible spectrophotometer was then used to measure the UV-visible spectrophotometer to detect the UV-visible absorption curves of ATG-AuNPs for different water types.

[0056] As shown in Table 2, in the CIP spike experiment of tap water and lake water, the recovery rate of CIP compared with ultrapure water was distributed around 90-110%. The specific recovery rates of CIP in different water samples were: 102.52% for laboratory tap water and 100.82% for Wenying Lake in Datong City. The results show that the detection method is accurate and reliable in detecting CIP in actual water samples.

[0057] Table 2 Recovery of CIP in different water samples

[0058] Water sample type Tap water Lake source laboratory Wenying Lake Recovery rate 102.52 100.82

[0059] A 0.04mmol / L chromium ion (III) solution was prepared in ultrapure water, tap water, and lake water, and three sets of experiments were repeated. 10μL of different water containing 0.04mmol / L chromium ion (III) (final concentration of 2μmol / L) was added to 190μL ATG-AuNPs, and the reaction was allowed to stand for 1min at room temperature of 25℃. Then, the UV-visible spectrophotometer was used to measure the UV-visible spectrophotometer to detect the UV-visible spectroscopic absorption curves of different water types for ATG-AuNPs.

[0060] As shown in Table 3, in the chromium ion (III) spike experiment of tap water and lake water, the recovery rate of chromium ion (III) compared with ultrapure water was distributed around 90-110%. The specific recovery rates of chromium ion (III) in different water samples were: 100.33% for laboratory tap water and 103.00% for Wenying Lake in Datong City. The results show that the detection method is accurate and reliable in detecting chromium ion (III) in actual water samples.

[0061] Table 3 Recovery of chromium ion (III) in different water samples

[0062] Water sample type Tap water Lake source laboratory Wenying Lake Recovery rate 100.33 103.00

[0063] The above description is only for better explaining the embodiments of the present invention, and is not intended to limit the present invention. Any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims

1. A method for preparing a colorimetric sensor of ammonium thioglycolate functionalized gold nanoparticles, characterized in that: The steps include: Step 1: preparing gold nanoparticle solution by reducing chloroauric acid with sodium citrate; Step 2: Add ammonium thioglycolate and ultrapure water to the gold nanoparticle solution prepared in step 1, mix well, and obtain an ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor.

2. The method for preparing the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 1, characterized in that: The specific process of preparing the gold nanoparticle solution by the sodium citrate reduction chloroauric acid method in step 1 is: stirring and heating the chloroauric acid solution to boiling, then quickly adding the freshly prepared sodium citrate solution, and when the solution changes from light yellow to wine red, continuing to heat for 30 minutes, then stopping heating, continuing to stir, and naturally cooling to room temperature to obtain the gold nanoparticle solution.

3. The method for preparing the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 2, characterized in that: The concentration of the chloroauric acid solution is 1 mmol / L, and the volume is 100 mL; the volume of the sodium citrate solution is 10 mL, and the concentration is 38.8 mmol / L.

4. The method for preparing the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 1, characterized in that: The concentration of the gold nanoparticle solution in step 2 is 2.4-8 nmol / L.

5. The method for preparing the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 1, characterized in that: The concentration of ammonium thioglycolate in step 2 is 0.5-4 mmol / L.

6. The method for preparing the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 1, characterized in that: In step 2, the volume ratio of the gold nanoparticle solution, ammonium thioglycolate and ultrapure water is 160:4:

26.

7. The method for preparing the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 1, characterized in that: The mixing temperature in step 2 is 25-33° C. and the mixing time is 60 min.

8. The ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor prepared by the preparation method according to any one of claims 1 to 7.

9. The use of the ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 8, characterized in that: For simultaneous recognition and detection of moxifloxacin, ciprofloxacin and chromium (III) ion.

10. A method for simultaneously detecting the contents of moxifloxacin, ciprofloxacin and chromium (III) ion, characterized in that: The steps include: The ammonium thioglycolate functionalized gold nanoparticle colorimetric sensor according to claim 8 is added to the sample to be tested, and the absorbance is measured by using a UV-visible spectrophotometer. The absorbance is calculated based on the spectral ratio A at 600 nm, 640 nm, 650 nm and 520 nm. 600 / A 520 , A 640 / A 520 , A 650 / A 520 Moxifloxacin, ciprofloxacin and chromium (III) ion were quantitatively detected respectively.

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