CN106568773B - A kind of manganese ion colorimetric detection kit and detection method thereof - Google Patents

Abstract

The invention relates to the technical field of environmental and biological analysis, in particular to a manganese ion colorimetric detection kit and a detection method thereof. The kit comprises an acetic acid-sodium acetate buffer solution, a potassium periodate solution, an aminotriacetic acid solution, a gold nanorod solution containing Cetyl Trimethyl Ammonium Bromide (CTAB), a standard colorimetric card C and a colorimetric tube; in the gold nanorod solution containing Cetyl Trimethyl Ammonium Bromide (CTAB), the concentration of the nanorods is 0.5-10nM, and the concentration of the CTAB is 0.01-100 mM. The method for detecting the manganese ions has the advantages of high sensitivity, good selectivity, simplicity in operation, easiness in observation by naked eyes and the like, and can realize the detection of the manganese ions in the environmental sample under the debugging of the experimental conditions of the system.

Description

A kind of manganese ion colorimetric detection kit and detection method thereof

technical field

The invention relates to the technical field of environmental and biological analysis, in particular to a manganese ion colorimetric detection kit and a detection method thereof.

Background technique

Manganese is one of the essential trace elements in the human body, plays an important role in the composition of many enzymes, and is also an essential component of normal bone structure. Manganese deficiency can cause neurasthenia syndrome, and even lead to the reduction of insulin and synthesis and secretion; while excessive manganese may cause poisoning. Occupational manganese poisoning is caused by long-term inhalation of manganese fume and manganese dust with high manganese content. Especially for workers in ferromanganese smelting, electrode manufacturing and welding, manganese ore mining, crushing or dry battery production, long-term exposure to manganese can cause neurological symptoms such as Parkinson's syndrome or Wilson's disease. Therefore, the detection of manganese ions in environmental and biological samples is very important.

In the water environment, because manganese ions cannot be decomposed, they have bioconcentration and biomagnification effects in organisms, so that the higher the food chain, the higher the manganese ion content in the body. also bigger. As humans at the top of the food chain, when they eat these water organisms with high concentrations of heavy metal ions, they are also the most harmed. Therefore, the detection of manganese ions in environmental and water samples is very necessary.

At present, the detection methods of manganese ions mainly include atomic absorption method, catalytic photometry, fluorescence spectrophotometry, chemiluminescence method, inductively coupled plasma mass spectrometry and other methods. However, these technologies require expensive large-scale instruments, or the detection methods are too complicated to realize on-site detection and technology promotion. Compared with the above detection techniques, the advantage of colorimetric analysis is that it is easy to observe with the naked eye, which is very suitable for on-site real-time detection, simple operation and low price. Gold nanoparticles have a very large molar extinction coefficient due to their surface plasmon resonance absorption, so they have obvious advantages in colorimetric analysis.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a manganese ion colorimetric detection kit and a detection method thereof.

To achieve the above object, the technical scheme adopted in the present invention is:

A manganese ion colorimetric detection kit, the kit is an acetic acid-sodium acetate buffer solution, a potassium periodate solution, a nitrilotriacetic acid solution, and a gold nanorod containing cetyltrimethylammonium bromide (CTAB). Solution, standard colorimetric card C and colorimetric tube;

In the gold nanorod solution containing cetyltrimethylammonium bromide (CTAB), the concentration of nanorods is 0.5-10 nM, and the concentration of CTAB is 0.01-100 mM.

The acetic acid-sodium acetate buffer solution has a pH of 3.6-5.8 and a solution concentration of 0.01-1M;

The concentration of the potassium periodate solution is 0.01-1M;

The concentration of the nitrilotriacetic acid solution is 0.01-1M.

Preferably, the pH of the acetic acid-sodium acetate buffer in the kit is 5.4, and the concentration is 50 mM; in the gold nanorod solution containing cetyl ammonium bromide (CTAB), the gold nanorod concentration is 2.3 nM, and the aspect ratio is 2.3 nM. The concentration of CTAB is 0.1M; the concentration of potassium periodate solution is 0.02M; the concentration of nitrilotriacetic acid solution is 0.01M.

The standard colorimetric card C is a manganese standard color scale solution with different concentrations, and the different concentrations are 0nM, 5nM, 10nM, 15nM, 20nM, 25nM, 30nM, 40nM, 50nM, and 100nM respectively.

A method for detecting manganese ions by a manganese ion colorimetric detection kit comprises adding an acetic acid-sodium acetate buffer solution into a colorimetric tube, then adding a sample to be tested, shaking and mixing, and then adding a gold nanorod containing CTAB after mixing. solution, shake well; then add potassium periodate solution and nitrilotriacetic acid solution in turn, shake and mix well; then incubate at 20-40 ℃ for 10-30 minutes, carry out color reaction, observe the color by naked eye or UV-visible spectrometer, Determine the manganese ion content by comparing with the standard color chart C.

In the gold nanorod solution containing cetyltrimethylammonium bromide (CTAB), the concentration of nanorods is 0.5-10 nM, and the concentration of CTAB is 0.01-100 mM.

The acetic acid-sodium acetate buffer solution has a pH of 3.6-5.8 and a solution concentration of 0.01-1M;

The concentration of the potassium periodate solution is 0.01-1M;

The concentration of the nitrilotriacetic acid solution is 0.01-1M.

The pH of the acetic acid-sodium acetate buffer in the kit is 5.4, and the concentration is 50 mM; in the gold nanorod solution containing cetyl ammonium bromide (CTAB), the gold nanorod concentration is 2.3 nM, and the aspect ratio is 2.3 nM. 2:1, the concentration of CTAB is 0.1M; the concentration of potassium periodate solution is 0.02M; the concentration of nitrilotriacetic acid solution is 0.01M.

The standard colorimetric card C is a manganese standard color scale solution with different concentrations, and the different concentrations are 0nM, 5nM, 10nM, 15nM, 20nM, 25nM, 30nM, 40nM, 50nM, and 100nM respectively.

The preparation of the standard colorimetric card C is to take 0-100nM manganese standard color scale solutions of different concentrations and place them in colorimetric tubes respectively, add acetic acid-sodium acetate buffer solution, shake and mix, and then add CTAB-containing gold after mixing. Nanorod solution, shake well; then add potassium periodate solution and nitrilotriacetic acid solution in turn, shake and mix well; then incubate at 20-40°C for 10-30 minutes, carry out color reaction, and use professional camera to record color development results , after collecting the pictures, use the pictures with color gradients to form the manganese ion standard colorimetric card C.

The principle of the present invention (see Fig. 1) is that in an acidic solution, ammonia triacetic acid is used as an activator, and manganese ions catalyze potassium periodate to oxidize gold nanorods to generate trivalent manganese ions, which can be reduced to manganese again. ions, resulting in the formation of cyclically catalytically etched gold nanorods with a simultaneous change in their absorption spectrum (see Figure 3) accompanied by significant morphological changes (Figure 2) and color changes (Figure 4), which are correlated with manganese ion concentration There is a linear relationship (see Figure 5).

The advantages of the present invention:

The invention utilizes the manganese ion catalyzed etching gold nanorod colorimetric method to detect manganese ions, and has the advantages of high sensitivity (detection limit is 10 nM), good selectivity, simple operation, high speed, easy observation with naked eyes, and is suitable for on-site real-time detection.

Description of drawings

Fig. 1 is the principle of manganese ion catalyzed etching gold nanorod provided by the present invention.

Fig. 2 is the transmission electron microscope image before and after manganese ion catalytic etching of gold nanorods provided in the embodiment of the present invention; wherein, the gold nanorods are before (left) and after (the middle is low concentration, the right is high concentration) before manganese ion catalytic etching ).

FIG. 3 is an absorption spectrum diagram of manganese ions (concentration from low to high) after catalytic etching of gold nanorods provided in an embodiment of the present invention.

FIG. 4 is a manganese ion standard colorimetric card C provided in an embodiment of the present invention.

Fig. 5 is the standard curve of manganese ion detection of the present invention.

FIG. 6 is a result of a selectivity experiment for detecting manganese ions ( FIG. 6A ) and a corresponding photo ( FIG. 6B ) according to an embodiment of the present invention.

FIG. 7 is a flow chart of detecting manganese ions according to an embodiment of the present invention.

Detailed ways

The present invention is further described in detail through the following examples. But the present invention is by no means limited to this.

The kit of the invention adopts weak acid acetic acid with pH=3.6-5.8 and concentration of 0.01-1M, so that the oxidation reaction of potassium periodate catalyzed by manganese is under weak acid conditions, and CTAB-modified gold nanorods, wherein CTAB is used as a surface The active agent has a sensitizing effect and promotes the catalytic effect of nitrilotriacetic acid. During the reaction process, the gold nanorods are blue in normal state. From blue to red, this change has a certain linear relationship with the concentration change of manganese ions added as catalysts, and the detection of manganese ions is carried out according to this linear relationship.

Example Manganese ion (spike) detection in drinking water

The kit includes acetic acid-sodium acetate buffer solution, potassium periodate solution, nitrilotriacetic acid solution, gold nanorod solution containing cetyltrimethylammonium bromide (CTAB), standard colorimetric card C and colorimetric tube ;

The acetic acid-sodium acetate buffer solution is prepared by using analytically pure sodium acetate and glacial acetic acid with secondary deionized water. The pH of the prepared buffer solution is 5.4 and the concentration is 50 mM.

The described potassium periodate solution concentration is 0.02M, obtained by dissolving analytically pure potassium periodate in secondary deionized water;

The concentration of described nitrilotriacetic acid solution is 0.01M, obtained by dissolving analytically pure nitrilotriacetic acid in secondary deionized water;

The gold nanorod solution containing cetyltrimethylammonium bromide (CTAB) was prepared as follows:

1) Synthesis of gold seed solution: add 50 μL of chloroauric acid solution (50 mM) to 7.7 mL of 0.1 M cetyltrimethylammonium bromide (CTAB) solution, stir and shake, and then add 600 μL of ice-cold borohydride Sodium (0.01M) solution, shake at an accelerated rate for a few minutes, stop when the color of the mixed solution changes from bright yellow to purple-gray, and stand at 26°C for 2 hours before use.

2) Nanorod synthesis: Add 1200 μL of chloroauric acid (50 mM) solution to 100 mL of 0.1 M cetyltrimethylammonium bromide (CTAB) solution, stir and mix, and then add 300 μL of silver nitrate (0.01 M ) solution, add 960 μL of ascorbic acid (0.1M) solution after mixing, when the solution changes from yellow-brown to colorless, add 200 μL of the above-synthesized gold seed solution to the solution while stirring, and continue to stir until the color of the solution gradually changes from colorless It is blue-green, stop stirring, and stand for 20 hours to obtain gold nanorods. From the transmission electron microscope, the aspect ratio of gold nanorods is about 2:1 (see Figure 2 (left)), and the radial absorption peak of the UV-Vis absorption spectrum is at 660nm-670nm (see the absorption spectrum of Figure 3), according to Lambertian Beer's Law, the concentration of nanorods was estimated to be 2.3 nM.

The preparation of standard colorimetric card C is to prepare 10 μL of manganese standard color scale solution with concentrations of 0nM, 5nM, 10nM, 15nM, 20nM, 25nM, 30nM, 40nM, 50nM and 100nM.

i.e. the kit:

Acetic acid-sodium acetate buffer solution, pH 5.4, concentration 50mM;

Potassium periodate solution, the concentration is 0.02M;

nitrilotriacetic acid solution, the concentration is 0.01M;

Colorimetric tube, 2mL;

glass graduated straw;

Manganese standard color scale solution;

Manganese standard color chart.

Detection method: respectively add it to a colorimetric tube containing 1 mL of acetic acid-sodium acetate buffer solution, shake and mix well, add gold nanorods containing CTAB, and shake well; then add potassium periodate solution and nitrilotriacetic acid solution and shake Mix well; after mixing, add the gold nanorod solution containing CTAB, and shake well; then incubate at 20-40°C for 10-30 minutes to carry out color reaction, use a professional camera to record the color results, collect pictures, use The pictures with color gradients form the manganese standard colorimetric card C (see Figure 4). At the same time, the corresponding UV-Vis absorption spectrum can be collected, and a standard curve can be made according to the peak shift (see Figure 5).

Specifically, the detection of manganese ions (spiked) in drinking water:

(1) Take a 2.0 mL colorimetric tube, add 1 mL of acetic acid-sodium acetate buffer solution to each colorimetric tube, add 10 μL of spiked samples containing three different concentrations of manganese ions, shake and mix well, mark 1, 2, No. 3, respectively add gold nanorods containing CTAB, shake well;

(2) Add potassium periodate solution and nitrilotriacetic acid solution in turn, shake and mix;

(3) Incubate at 20-40°C for 10-30 minutes,

(3) Observe the color change, and compare the colorimetric tube with the standard colorimetric card C to determine the concentration range of manganese ions in the drinking water spiked sample. It can be seen that it corresponds to the colorimetric card concentration. The peak shift was obtained from the spectrogram, and the definite content of manganese ions was determined according to the standard curve. The standard addition recovery rate of the detection results of this method was 85-103% (see Table 1), indicating the reliability of the practical application of this method.

Table 1 Manganese ion spike test results

Claims (4)

1. A manganese ion colorimetric detection kit is characterized in that: the kit comprises an acetic acid-sodium acetate buffer solution, a potassium periodate solution, an aminotriacetic acid solution, a gold nanorod solution containing Cetyl Trimethyl Ammonium Bromide (CTAB), a standard colorimetric card C and a colorimetric tube;

in the gold nanorod solution containing Cetyl Trimethyl Ammonium Bromide (CTAB), the concentration of the nanorods is 2.3nM, the length-diameter ratio is 2:1, and the CTAB concentration is 0.1M;

the pH of the acetic acid-sodium acetate buffer solution is 5.4, and the solution concentration is 50 mM;

the concentration of the potassium periodate solution is 0.02M;

the concentration of the amino-triethyl acid solution is 0.01M;

the standard colorimetric card C is manganese standard color-scale solution with different concentrations of 0nM,5nM,10nM,15nM,20nM,25nM,30nM,40nM,50nM and 100nM respectively.

2. The method for detecting manganese ions by using the manganese ion colorimetric detection kit according to claim 1, which is characterized in that: adding acetic acid-sodium acetate buffer solution into a colorimetric tube, adding a sample to be detected, uniformly mixing, adding a gold nanorod solution containing CTAB, and uniformly mixing; sequentially adding a potassium periodate solution and an ammonia-troacetic acid solution, shaking and uniformly mixing; and then incubating for 10-30 minutes at the temperature of 20-40 ℃, carrying out color reaction, observing the color by naked eyes or an ultraviolet visible spectrometer, and comparing with a standard color comparison card C to determine the content of manganese ions.

3. The method for detecting manganese ions by using the manganese ion colorimetric detection kit according to claim 2, wherein the method comprises the following steps: the pH value of the acetic acid-sodium acetate buffer solution in the kit is 5.4, and the concentration is 50 mM; in gold nanorod solution containing cetyl ammonium bromide (CTAB), the concentration of the gold nanorods is 2.3nM, the length-diameter ratio is 2:1, and the concentration containing CTAB is 0.1M; the concentration of the potassium periodate solution is 0.02M; the concentration of the solution of the amino-triethyl acid was 0.01M.

4. The method for detecting manganese ions by using the manganese ion colorimetric detection kit according to claim 3, wherein the method comprises the following steps: the standard colorimetric card C is manganese standard color-scale solution with different concentrations of 0nM,5nM,10nM,15nM,20nM,25nM,30nM,40nM,50nM and 100nM respectively.

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