CN109738400B - Method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing - Google Patents
Method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing Download PDFInfo
- Publication number
- CN109738400B CN109738400B CN201811515590.6A CN201811515590A CN109738400B CN 109738400 B CN109738400 B CN 109738400B CN 201811515590 A CN201811515590 A CN 201811515590A CN 109738400 B CN109738400 B CN 109738400B
- Authority
- CN
- China
- Prior art keywords
- caffeine
- pyridyl
- tetra
- cdte quantum
- porphyrin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Abstract
A method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing belongs to the technical field of analysis and detection. The method comprises the following steps: synthesizing CdTe quantum dots; synthesizing a tetra- (4-pyridyl) zinc porphyrin self-assembly; dropwise adding CdTe quantum dots on a filter paper wafer paper device, and absorbing and fixing the CdTe quantum dots by a filter paper wafer on the paper device to obtain a CdTe quantum dot paper sensing device substrate; preparing a mixed solution of caffeine and tetra- (4-pyridyl) zinc porphyrin self-assemblies with different concentrations, dropwise adding the mixed solution on a CdTe quantum dot paper sensing device substrate, observing in an ultraviolet dark box, photographing each CdTe quantum dot paper sensing substrate, and finishing to obtain a caffeine standard colorimetric card; and detecting the concentration of the caffeine in the sample to be detected, preparing a mixed solution of the caffeine to be detected and the self-assembly body, dripping the mixed solution on the quantum dot paper sensing substrate, and comparing with a standard colorimetric card to obtain the concentration of the caffeine. The method is simple and accurate.
Description
Technical Field
The invention belongs to the technical field of nano material preparation and paper sensing analysis and detection, and particularly relates to controllable preparation of nano porphyrin and a method for detecting caffeine based on CdTe quantum dot paper sensing.
Background
Caffeine is an alkaloid mainly found in tea, coffee, cocoa, kola nut and other plants and is widely used as an additive in the fields of food, beverage and medicine. Proper caffeine intake can improve attention and work efficiency, but excessive intake can cause many adverse effects. One of the main active ingredients of tea leaves has been found to be caffeine, which plays an important role in various physiological actions such as bronchial muscle relaxation, central nervous system stimulation, gastric acid secretion and diet. This is why there have been many studies to develop reliable caffeine determination methods. In recent years, many modern techniques have been applied to the analysis of caffeine, such as ultraviolet-visible spectrophotometry, ultrasonic extraction techniques, high performance liquid chromatography, near infrared spectroscopy, and the like. However, these techniques are often expensive, complex and time consuming. Here, a simple, fast, sensitive and low-cost analysis technique for analyzing caffeine is very necessary. Colorimetric analysis shows great promise for solving the problems involved, with theoretical and technical simplicity. Therefore, an efficient, simple and reliable means for detecting caffeine is needed.
Disclosure of Invention
One of the purposes of the invention is to provide a preparation method of nano porphyrin, which has simple preparation and mild reaction conditions; the second purpose is to provide a method for detecting caffeine based on a CdTe quantum dot fluorescent color visual paper sensing substrate, which not only can detect caffeine rapidly and with high sensitivity, but also can realize instrument-free on-site instant detection.
In order to achieve the purpose, the invention discloses a method for detecting caffeine by visual paper sensing, which is characterized by comprising the following specific steps:
(1) synthesis of CdTe quantum dot
Dissolving cadmium dichloride and N-acetyl-L-cysteine in pure water, uniformly mixing, then sequentially adding a sodium tellurite solution and a sodium borohydride solution, and finally reacting in an oven to obtain fluorescent CdTe quantum dots;
(2) synthesis of tetra- (4-pyridyl) zinc porphyrin self-assembly
Dissolving tetra- (4-pyridyl) zinc porphyrin, namely porphyrin, in an N, N-dimethylformamide solution to obtain a tetra- (4-pyridyl) zinc porphyrin N, N-dimethylformamide solution, adding the tetra- (4-pyridyl) zinc porphyrin N, N-dimethylformamide solution into a dodecyl trimethyl ammonium bromide aqueous solution, and performing ultrasonic and water bath ageing to obtain a tetra- (4-pyridyl) zinc porphyrin self-assembly, namely nano porphyrin;
(3) preparation of CdTe quantum dot paper sensing device substrate
Dropwise adding CdTe quantum dots on a filter paper wafer paper device, and absorbing and fixing the CdTe quantum dots by a filter paper wafer on the paper device to obtain a CdTe quantum dot paper sensing device substrate;
(4) standard colorimetric card for making caffeine
Respectively preparing mixed solutions of caffeine and tetra- (4-pyridyl) zinc porphyrin self-assemblies with different concentrations, sequentially dripping the mixed solutions on a CdTe quantum dot paper sensing device substrate, observing in an ultraviolet dark box, reacting the caffeine with different concentrations in the mixed solutions with the CdTe quantum dot paper sensing substrate to generate different colors, photographing each CdTe quantum dot paper sensing substrate, and finishing to obtain a caffeine standard colorimetric card;
(5) detecting caffeine concentration in a test sample
And (3) preparing a caffeine sample to be detected and a tetra- (4-pyridyl) zinc porphyrin self-assembly into a mixed solution, dropwise adding the mixed solution on the CdTe quantum dot paper sensing substrate, wherein the CdTe quantum dot paper sensing substrate has a color response to the sample, and contrasting the standard caffeine colorimetric card obtained in the step (4) to obtain the concentration of caffeine in the sample.
Preferably, in the step (1), the pH value of the mixed solution of cadmium dichloride and N-acetyl-L-cysteine is adjusted to 8.0-8.5, the temperature of an oven is controlled to be 200-220 ℃, and the red fluorescence-emitting CdTe quantum dots with the emission wavelength of 640-660 nm are obtained.
Preferably, in the step (1), the ratio of the amounts of the N-acetyl-L-cysteine, the cadmium dichloride and the sodium tellurite is as follows: 1.2-1.5: 1:0.2 as a preferable scheme, in the step (2), the amount ratio of the tetra- (4-pyridyl) zinc porphyrin to the dodecyl trimethyl ammonium bromide is 1: 290-305.
Preferably, in the step (3), the concentration of the CdTe quantum dots is 3-4 μmol/L.
Preferably, in the step (3), the CdTe quantum drop is added in an amount of 8-10 uL in the step (2), the filter paper wafer paper device is a circular filter paper with the diameter of 4-6 mm, and the paper sensing substrate dropwise added with the CdTe quantum dots is placed in a 36-39 ℃ oven and baked for 5-7 minutes.
Preferably, the tetra- (4-pyridyl) zinc porphyrin self-assembly is nanospheres with the particle size of nano porphyrin being 70-100 nm.
Preferably, the concentration of the tetra- (4-pyridyl) zinc porphyrin self-assembly in the step (4) and the step (5) is the same and is 30-33 μ M.
Preferably, the concentration of caffeine in the mixed solution in the step (4) is a gradient concentration in the range of 1nM to 1000nM, respectively. The concentration of the porphyrazine, which is a self-assembly of tetra- (4-pyridyl) zinc porphyrin, in the mixed solution is 31.2. mu.M, and more preferably, the concentration of caffeine is 1000nM self-assembly, 500nM self-assembly, 100nM self-assembly, 50nM self-assembly, 10nM self-assembly, and 1nM self-assembly, respectively, in this order.
Preferably, in the step (4), the photos with different colors generated by the reaction of the caffeine with the CdTe quantum dot paper sensing substrate with different concentrations are imported into the image processing software to extract color values in the pictures, and the standard colorimetric result of the caffeine is simulated by using the color values.
The method or the CdTe quantum dot paper chip substrate can detect the concentration of caffeine in pure samples and complex matrixes of tea water, cell culture fluid, human plasma and newborn bovine serum of Longjing tea in West lake.
The invention has the advantages that: compared with the existing caffeine detection method, the method for detecting caffeine based on the CdTe quantum dot paper sensing substrate has the characteristics of simple preparation, rapid field detection, low cost, high response speed, high sensitivity and high selectivity, and the CdTe quantum dot paper sensing substrate has a specific reaction on caffeine and can be used for detecting caffeine in a complex matrix water sample.
Drawings
FIG. 1 is a schematic diagram of the mechanism of detecting caffeine based on a CdTe quantum dot paper sensing substrate of the invention;
FIG. 2 is an ultraviolet-visible spectrum of a tetra- (4-pyridyl) zinc porphyrin self-assembly in the visualized paper sensing nano porphyrin fluorescence sensor of the invention, with the abscissa as wavelength and the ordinate as absorbance;
FIG. 3 is a transmission electron microscope picture of the tetra- (4-pyridyl) zinc porphyrin self-assembly in the visualized paper-sensing nano porphyrin fluorescence sensor of the present invention, which is a nanosphere;
FIG. 4 is a feasibility test chart of detecting caffeine with the CdTe quantum dot paper sensing substrate of the invention; FIG. 4A shows that the color of the paper sensing substrate fixed with CdTe quantum dots is purple red; FIG. 4B is a dark blue color reaction diagram after tetra- (4-pyridyl) zinc nano-porphyrin is added to the CdTe quantum dot paper sensing substrate; FIG. 4C is a color reaction diagram of a mixed solution of caffeine and tetra- (4-pyridyl) zinc nano-porphyrin after being added to a CdTe quantum dot paper sensing substrate, which is light purple red, and 4A-4C are colorimetric results obtained by extracting color values of the images 4A-4C;
FIG. 5 is a graph showing the results of standard colorimetry of caffeine prepared according to the present invention, FIGS. 5A to 5F are graphs corresponding to colors produced by caffeine of 1nM, 10nM, 50nM, 100nM, 500nM, and 1000nM in this order, and FIG. 5G is a blank control (color of paper sensor substrate); FIGS. 5A-5G are standard colorimetric results of caffeine obtained by extracting color values of FIGS. 5A-5G; the color of fig. 5a is dark blue, the color of fig. 5b is blue, the color of fig. 5c is bluish purple, the color of fig. 5d is light purple, the color of fig. 5e is dark purple, the color of fig. 5f is light purplish red, and the color of fig. 5g is purplish red.
FIG. 6 is a colorimetric result chart for detecting caffeine in a complex matrix aqueous solution of tea leaves of Longjing West lake based on a CdTe quantum dot paper sensing substrate; the color of fig. 6A is bluish purple, the color of fig. 6B is bluish purple, the color of fig. 6C is purple, the color of fig. 6D is purplish red, and the color of fig. 6E is purplish red.
FIG. 7 is a colorimetric result chart for detecting caffeine in a complex matrix aqueous solution of a cell culture solution based on a CdTe quantum dot paper sensing substrate; the color of fig. 7A is blue, the color of fig. 7B is bluish purple, the color of fig. 7C is purple, the color of fig. 7D is light purple red, and the color of fig. 7E is purple red.
FIG. 8 is a colorimetric result graph for detecting caffeine in a human plasma complex matrix aqueous solution based on a CdTe quantum dot paper sensing substrate. The color of fig. 8A is dark blue, the color of fig. 8B is blue, the color of fig. 8C is purple, the color of fig. 8D is light purplish red, and the color of fig. 8E is purplish red.
FIG. 9 is a colorimetric result chart of caffeine detection in a complex matrix aqueous solution of newborn bovine serum based on a CdTe quantum dot paper sensing substrate. The color of fig. 9A is dark blue, the color of fig. 9B is blue, the color of fig. 9C is purple, the color of fig. 9D is light purplish red, and the color of fig. 9E is purplish red.
FIG. 10 is a specificity diagram for detecting caffeine based on CdTe quantum dot paper sensing substrate of the present invention; FIGS. 10A-10G are color reaction diagrams of theophylline, theobromine, adenine, hypoxanthine, purine, caffeine, and tetrakis- (4-pyridyl) zinc porphyrinones mixed and then dropped on a paper sensing substrate in sequence. The color of fig. 10A is bluish purple, the color of fig. 10B is blue, the color of fig. 10C is blue, the color of fig. 10D is dark blue, the color of fig. 10E is dark blue, the color of fig. 10F is light purplish red, and the color of fig. 10G is dark blue.
Detailed Description
For a better understanding of the present invention, reference will now be made in detail to the present invention, examples of which are illustrated in the accompanying drawings.
In order to solve the problems of complex instrument operation and long analysis time in the existing caffeine detection technology, the invention provides a method for detecting caffeine based on a CdTe quantum dot paper sensing substrate, and particularly relates to a method for preparing standard colorimetric results of caffeine with different concentrations by utilizing the principle that the fluorescence color of CdTe quantum dots can be changed by a mixed solution of caffeine and tetra- (4-pyridyl) zinc porphyrin self-assemblies, and the concentration of the caffeine to be detected is judged by contrasting the color with the standard colorimetric results. Hereinafter, preferred embodiments of the method for detecting caffeine using self-assembled porphyrin according to the present invention will be described in detail with reference to specific examples.
Example 1
A method for detecting pure caffeine solution based on a CdTe quantum dot paper sensing substrate comprises the following steps:
(1) synthesizing CdTe quantum dots;
(1) synthesis of CdTe quantum dot
Dissolving cadmium dichloride (0.1142g) and N-acetyl-L-cysteine (0.098g) in 40mL of ultrapure water, stirring at normal temperature and normal pressure for 15 minutes, adjusting the pH of the solution to 8.2 by using a sodium hydroxide solution, then filling nitrogen, carrying out ice bath stirring for 20 minutes, adding sodium tellurite (0.0216g), and stirring for 15 minutes; adding sodium borohydride (0.0113g), stirring for 15min, putting the solution into a reaction kettle, reacting for 55 min in an oven at 200 ℃, cooling to room temperature to obtain a red light-emitting solution with the emission wavelength of 645nm and the concentration of 7.138 multiplied by 10-6mol·L-1CdTe quantum dots.
(2) Synthesis of tetra- (4-pyridyl) zinc porphyrin self-assembly
0.0032g of solid powder of tetrakis- (4-pyridyl) zinc porphyrin was weighed out and dissolved in 5mLN, N-dimethylformamide to give a concentration of 9.356X 10-4mol·L-1Tetra- (4-pyridyl) zinc porphyrin N, N-dimethylformamide solution. Dodecyl trimethyl Bromide (0.0003g,0.02 mol. L)-1) Dissolving in 14mL of water solution, adding 1mL of tetra- (4-pyridyl) zinc porphyrin N, N-dimethylformamide solution, performing ultrasonic treatment for 5-10min, and heating and aging in 70 ℃ water bath for 10-15min to obtain a very stable green transparent colloidal solution. 6.237X 10 are obtained-5mol·L-1The tetra- (4-pyridyl) zinc porphyrin self-assembly is represented as nanospheres with the particle size of 70-100 nm by a transmission electron microscope as shown in figure 2.
(3) Preparation of CdTe quantum dot paper sensing substrate
10 mu L of CdTe quantum dots (3.569 mu M) are sucked by a liquid transfer gun and respectively dripped on 3 round filter papers with the diameter of 6mm to prepare 3 CdTe quantum dot paper sensing substrates, the 3 CdTe quantum dot paper sensing substrates are placed in a 37 ℃ oven to be dried slightly for about 5 minutes, the paper sensing substrates are observed to be rose red in a 365nm ultraviolet dark box, and a picture is taken.
(4) Standard colorimetric card for preparing pure caffeine solution
Preparing a solution 1: a mixed solution of 1nM caffeine and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 2: a mixed solution of 10nM caffeine and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 3: a mixed solution of 50nM caffeine and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 4: a mixed solution of 100nM caffeine and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 5: a mixed solution of 500nM caffeine and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 6: a mixed solution of 1000nM caffeine and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
sucking 10 mu L of the above solutions 1 to 6 by using a liquid-transferring gun, respectively dripping the solutions on a CdTe quantum dot paper sensing substrate, observing different color changes in an ultraviolet dark box, taking a picture in a 365nm ultraviolet dark box, storing the picture, guiding the picture into Photoshop software, extracting a color value RGB value on the picture, and simulating a color round point by using the value to obtain the caffeine standard colorimetric card.
In conjunction with the caffeine standard colorimetric card shown in FIG. 5, FIGS. 5A to 5F correspond to colors produced by 1nM, 10nM, 50nM, 100nM, 500nM, 1000nM caffeine in this order, and FIG. 5G is a blank control (color of paper sensor substrate).
Referring to fig. 1 and 4, it can be seen from fig. 1 that the tetra- (4-pyridyl) zinc porphyrin can quench the fluorescence of the CdTe quantum dots, and the mixed solution of caffeine and tetra- (4-pyridyl) zinc nano porphyrin can change the fluorescence color of the CdTe quantum dots. FIG. 4A shows the color of the paper sensing substrate with CdTe quantum dots fixed; as shown in fig. 4B, the fluorescence quenching of CdTe quantum dots changed from rosy to blue after the tetra- (4-pyridyl) zinc nano porphyrin was added to the paper sensing substrate, as shown in fig. 4C, the blue color changed to light red by adding the mixed solution of caffeine and tetra- (4-pyridyl) zinc nano porphyrin to the paper sensing substrate, and the color of the paper sensing substrate also changed with the concentration of caffeine in the mixed solution, as shown in fig. 5, the concentration of caffeine in the mixed solution was increased from 1nM to 1000nM, the color of the paper sensing substrate changed from blue to purple, then to light rosy, and finally to reddish, thereby achieving the effect of visually detecting caffeine on paper.
Example 2
A method for detecting caffeine in a west lake Longjing tea water sample based on a CdTe quantum dot paper sensing substrate comprises the following steps:
(1) synthesizing CdTe quantum dots;
CdTe quantum dot synthesized by adopting the method of the step (1) in the example 1
(2) Synthesis of tetra- (4-pyridyl) zinc self-assembled porphyrin
The tetra- (4-pyridyl) zinc nano-porphyrin solution was synthesized by the method of the step (2) in example 1.
(3) Preparation of CdTe quantum dot paper sensing substrate
The CdTe paper sensor substrate was prepared using the method of step (3) in example 1.
(4) Preparation of caffeine west lake Longjing tea water sample solution
Soaking the hair tips at 80 deg.C for 10min, diluting the filtrate by 100 times, and preparing caffeine with different concentrations
(5) Standard colorimetric card for making caffeine in tea water
Preparing a solution 1: a mixed solution of a 1nM aqueous sample of caffeine West lake Longjing tea and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 2: a mixed solution of 10nM aqueous sample of caffeine West lake Longjing tea and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 3: a mixed solution of a 50nM aqueous sample of caffeine West lake Longjing tea and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 4: a mixed solution of a 100nM aqueous sample of caffeine West lake Longjing tea and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 5: a mixed solution of a 500nM aqueous sample of caffeine West lake Longjing tea and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 6: a mixed solution of a 1000nM aqueous sample of caffeine West lake Longjing tea and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
sucking 10 mu L of the above solutions 1 to 6 by using a liquid-transferring gun, respectively dripping the solutions on a CdTe quantum dot paper sensing substrate, observing different color changes in an ultraviolet dark box, taking a picture in a 365nm ultraviolet dark box, storing the picture, guiding the picture into Photoshop software, extracting a color value RGB value on the picture, and simulating a color round point by using the value to obtain the caffeine standard colorimetric card.
Example 3
The method for detecting caffeine in a cell culture solution sample based on the CdTe quantum dot paper sensing substrate comprises the following steps:
(1) synthesizing CdTe quantum dots;
CdTe quantum dot synthesized by adopting the method of the step (1) in the example 1
(2) Synthesis of tetra- (4-pyridyl) zinc self-assembled porphyrin
The tetra- (4-pyridyl) zinc nano-porphyrin solution was synthesized by the method of the step (2) in example 1.
(3) Preparation of CdTe quantum dot paper sensing substrate
The CdTe paper sensor substrate was prepared using the method of step (3) in example 1.
(4) Preparation of cell culture solution sample solution
Centrifuging cell culture solution, taking supernatant, diluting 100 times, and preparing caffeine with different concentrations
(5) Standard colorimetric card for caffeine in cell culture liquid sample
Preparing a solution 1: a mixed solution of a 1nM sample of caffeine cell culture fluid and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 2: a mixed solution of 10nM caffeine cell culture sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 3: a mixed solution of a 50nM sample of caffeine cell culture fluid and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 4: a mixed solution of a 100nM sample of caffeine cell culture fluid and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 5: a mixed solution of a 500nM sample of caffeine cell culture solution and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 6: a mixed solution of a 1000nM sample of caffeine cell culture fluid and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
sucking 10 mu L of the above solutions 1 to 6 by using a liquid-transferring gun, respectively dripping the solutions on a CdTe quantum dot paper sensing substrate, observing different color changes in an ultraviolet dark box, taking a picture in a 365nm ultraviolet dark box, storing the picture, guiding the picture into Photoshop software, extracting a color value RGB value on the picture, and simulating a color round point by using the value to obtain the caffeine standard colorimetric card.
Example 4
The method for detecting caffeine in a human plasma sample based on the CdTe quantum dot paper sensing substrate comprises the following steps:
(1) synthesizing CdTe quantum dots;
CdTe quantum dot synthesized by adopting the method of the step (1) in the example 1
(2) Synthesis of tetra- (4-pyridyl) zinc self-assembled porphyrin
The tetra- (4-pyridyl) zinc nano-porphyrin solution was synthesized by the method of the step (2) in example 1.
(3) Preparation of CdTe quantum dot paper sensing substrate
The CdTe paper sensor substrate was prepared using the method of step (3) in example 1.
(4) Preparation of human plasma sample solution
Human plasma is centrifuged, supernatant is diluted by 100 times and used as solvent to prepare caffeine with different concentrations
(5) Standard colorimetric card for caffeine in human plasma sample
Preparing a solution 1: a mixed solution of 1nM caffeine human plasma sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 2: a mixed solution of 10nM caffeine human plasma sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 3: a mixed solution of a 50nM caffeine human plasma sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 4: a mixed solution of 100nM caffeine human plasma sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 5: a mixed solution of 500nM caffeine human plasma sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 6: a mixed solution of 1000nM caffeine human plasma sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
sucking 10 mu L of the above solutions 1 to 6 by using a liquid-transferring gun, respectively dripping the solutions on a CdTe quantum dot paper sensing substrate, observing different color changes in an ultraviolet dark box, taking a picture in a 365nm ultraviolet dark box, storing the picture, guiding the picture into Photoshop software, extracting a color value RGB value on the picture, and simulating a color round point by using the value to obtain the caffeine standard colorimetric card.
Example 5
The method for detecting caffeine in a newborn bovine serum sample based on the CdTe quantum dot paper sensing substrate comprises the following steps:
(1) synthesizing CdTe quantum dots;
CdTe quantum dot synthesized by adopting the method of the step (1) in the example 1
(2) Synthesis of tetra- (4-pyridyl) zinc self-assembled porphyrin
The tetra- (4-pyridyl) zinc nano-porphyrin solution was synthesized by the method of the step (2) in example 1.
(3) Preparation of CdTe quantum dot paper sensing substrate
The CdTe paper sensor substrate was prepared using the method of step (3) in example 1.
(4) Preparation of newborn bovine serum sample solution
Centrifuging newborn calf serum, taking supernatant, diluting 100 times, and preparing caffeine with different concentrations by using the supernatant as solvent
(5) Standard colorimetric card for caffeine in new-born bovine serum matrix
Preparing a solution 1: a mixed solution of a sample of 1nM caffeine-newborn bovine serum and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 2: a mixed solution of 10nM caffeine newborn bovine serum sample and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 3: a mixed solution of a 50nM sample of caffeine newborn bovine serum and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 4: a mixed solution of 100nM caffeine-newborn bovine serum sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 5: a mixed solution of 500nM caffeine newborn bovine serum sample and 31.2. mu.M tetra- (4-pyridyl) zinc porphyrin self-assembly;
solution 6: a mixed solution of 1000nM caffeine-newborn bovine serum sample and 31.2. mu.M of tetra- (4-pyridyl) zinc porphyrin self-assembly;
and (3) sucking 10 mu L of the above solutions 1 to 6 by using a liquid-transfering gun, respectively dripping the solutions on a CdTe quantum dot paper sensing substrate, observing different color changes in an ultraviolet dark box, taking a picture in a 365nm ultraviolet dark box, storing the picture, guiding the picture into Photoshop software, extracting a color value RGB value on the picture, and simulating a color round point by using the value to obtain a caffeine standard colorimetric result.
Compared with the traditional method for measuring caffeine by a chromatography method, the method provided by the invention has the advantages of simple preparation, mild reaction conditions, high sensitivity to caffeine detection, strong anti-interference capability and good response, and the visual paper sensing nano porphyrin fluorescence sensor has practical application value in the fields of biochemistry, food, medicine and the like.
Examples 1-5 exemplify methods for detecting caffeine pure samples and caffeine in complex matrices of tea water, cell culture fluid, human plasma and newborn bovine serum of Longjing tea in West lake based on CdTe quantum dot paper sensing substrates.
The above examples only show 5 embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A method for detecting caffeine based on nano porphyrin fluorescent paper sensing visualization is characterized by comprising the following steps:
(1) synthesis of CdTe quantum dot
Dissolving cadmium dichloride and N-acetyl-L-cysteine in pure water, uniformly mixing, then sequentially adding sodium tellurite and sodium borohydride, and finally reacting in an oven to obtain fluorescent CdTe quantum dots;
(2) synthesis of tetra- (4-pyridyl) zinc porphyrin self-assembly
Dissolving tetra- (4-pyridyl) zinc porphyrin, namely porphyrin, in an N, N-dimethylformamide solution to obtain a tetra- (4-pyridyl) zinc porphyrin N, N-dimethylformamide solution, adding the tetra- (4-pyridyl) zinc porphyrin N, N-dimethylformamide solution into a dodecyl trimethyl ammonium bromide aqueous solution, and performing ultrasonic and 70 ℃ water bath aging to obtain a tetra- (4-pyridyl) zinc porphyrin self-assembly, namely nano porphyrin;
(3) preparation of CdTe quantum dot paper sensing device substrate
Dripping CdTe quantum dots on a filter paper wafer of the paper device, and absorbing and fixing the CdTe quantum dots by the filter paper wafer on the paper device to obtain a CdTe quantum dot paper sensing device substrate;
(4) standard colorimetric card for making caffeine
Preparing a mixed solution of caffeine and tetra- (4-pyridyl) zinc porphyrin self-assembly solutions with different concentrations, sequentially dropwise adding the mixed solution onto a CdTe quantum dot paper sensing substrate, observing in an ultraviolet dark box, reacting the caffeine with different concentrations with the CdTe quantum dot paper sensing substrate to generate different colors, photographing each CdTe quantum dot paper sensing substrate, and finishing to obtain a caffeine standard colorimetric card;
(5) detecting caffeine concentration in a test sample
And (3) preparing a sample and the tetra- (4-pyridyl) zinc porphyrin self-assembly solution into a mixed solution, dropwise adding the mixed solution on a paper sensing substrate, wherein the paper sensing substrate has color response to the sample, and contrasting the standard caffeine colorimetric card obtained in the step (4) to obtain the concentration of caffeine in the sample.
2. The method for detecting caffeine visually based on nano-porphyrin fluorescent paper sensing, according to claim 1, characterized in that in step (1), the pH of the mixed solution of cadmium dichloride and N-acetyl-L-cysteine is adjusted to 8.0-8.5, the temperature of the oven is controlled to 200-220 ℃, and CdTe quantum dots which emit red fluorescence with the wavelength of 640-660 nm are obtained.
3. The method for detecting caffeine based on nano-porphyrin fluorescence paper sensing visualization, according to claim 1, wherein the concentration of the tetra- (4-pyridyl) zinc porphyrin self-assembly solution in step (4) and step (5) is the same, and is 30-33 μ M; the concentrations of caffeine in the mixed solution in the step (4) are gradient concentrations in the range of 1nM to 1000nM, respectively.
4. The method for detecting caffeine based on nanoporphyrin fluorescent paper sensing visualization as described in claim 1, wherein the mixed solution in step (4) is 1nM caffeine and 31.2 μ M tetra- (4-pyridyl) zinc porphyrin self-assembly solution, 10nM caffeine and 31.2 μ M tetra- (4-pyridyl) zinc porphyrin self-assembly solution, 50nM caffeine and 31.2 μ M tetra- (4-pyridyl) zinc porphyrin self-assembly solution, 100nM caffeine and 31.2 μ M tetra- (4-pyridyl) zinc porphyrin self-assembly solution, 500nM caffeine and 31.2 μ M tetra- (4-pyridyl) zinc porphyrin self-assembly solution, 1000nM caffeine and 31.2 μ M tetra- (4-pyridyl) zinc porphyrin self-assembly solution, respectively.
5. The method for visually detecting caffeine based on nanoporphyrin fluorescent paper sensing as claimed in claim 1, wherein in step (4), photographs with different colors generated by reaction of caffeine with paper sensing substrates at different concentrations are imported into graphic processing software to extract color values in the pictures, and the color values are used to simulate a standard colorimetric card for caffeine.
6. The method for detecting caffeine visually based on nano-porphyrin fluorescence paper sensing according to claim 2, wherein in the step (1), the ratio of the amounts of N-acetyl-L-cysteine, cadmium dichloride and sodium tellurite is 1.2-1.5: 1.0:0.2.
7. The method for detecting caffeine visually based on nano-porphyrin fluorescence paper sensing according to claim 1, wherein in the step (2), the ratio of the amount of tetra- (4-pyridyl) zinc porphyrin to the amount of dodecyl trimethyl ammonium bromide is 1: 290-305.
8. The method for detecting caffeine based on nano-porphyrin fluorescence paper sensing visualization, as claimed in claim 1, wherein in step (3), the concentration of CdTe quantum dots is 3-4 μmol/L.
9. The method for visually detecting caffeine based on nano-porphyrin fluorescence paper sensing according to claim 1, wherein in the step (3), the CdTe quantum dot dropping amount is 8-10 uL, the filter paper wafer paper device is a circular filter paper with a diameter of 4-6 mm, and the paper sensing substrate to which the CdTe quantum dots are dropped is placed in an oven at 36-39 ℃ and dried for 5-7 minutes.
10. The method for detecting caffeine based on nano-porphyrin fluorescence paper sensing visualization as claimed in claim 1, wherein nano-spheres with particle size of 70-100 nm are contained in the tetra- (4-pyridyl) zinc porphyrin self-assembly solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811515590.6A CN109738400B (en) | 2018-12-12 | 2018-12-12 | Method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811515590.6A CN109738400B (en) | 2018-12-12 | 2018-12-12 | Method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109738400A CN109738400A (en) | 2019-05-10 |
| CN109738400B true CN109738400B (en) | 2021-08-06 |
Family
ID=66358799
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811515590.6A Active CN109738400B (en) | 2018-12-12 | 2018-12-12 | Method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109738400B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112833959A (en) * | 2021-01-27 | 2021-05-25 | 中南民族大学 | O-shaped catalyst2-CO2-T three-parameter real-time monitoring system |
| CN116183535B (en) * | 2023-04-23 | 2023-08-29 | 中国科学技术大学 | Method, system, equipment and medium for analyzing spectrum of macromolecular solution aging process |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102924532A (en) * | 2011-08-09 | 2013-02-13 | 中国科学院理化技术研究所 | Iron hydrogenase mimic compound, preparation method thereof, photocatalytic hydrogen production system containing iron hydrogenase mimic compound and method for preparing hydrogen |
| CN106674238A (en) * | 2016-12-30 | 2017-05-17 | 中南民族大学 | Tetra-(4-pyridyl) zinc porphyrin self-assembly nanocrystallization method |
| CN106706591A (en) * | 2017-02-27 | 2017-05-24 | 中南民族大学 | Method for recognizing quantitative chiral amino acid by using reversible nano porphyrin fluorescence sensor |
| CN107557000A (en) * | 2017-11-14 | 2018-01-09 | 浙江工业大学 | Class A3B-type asymmetric metal platinum porphyrin organic luminescent material and application thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9696298B2 (en) * | 2003-04-03 | 2017-07-04 | Enzo Life Sciences, Inc. | Multisignal reagents for labeling analytes |
| US20080108147A1 (en) * | 2006-11-03 | 2008-05-08 | Tie Wei | Reduction of non-specific binding in immunoassays |
| US10529003B2 (en) * | 2008-04-07 | 2020-01-07 | Mohammad A. Mazed | Optical biomodule for detection of diseases at an early onset |
-
2018
- 2018-12-12 CN CN201811515590.6A patent/CN109738400B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102924532A (en) * | 2011-08-09 | 2013-02-13 | 中国科学院理化技术研究所 | Iron hydrogenase mimic compound, preparation method thereof, photocatalytic hydrogen production system containing iron hydrogenase mimic compound and method for preparing hydrogen |
| CN106674238A (en) * | 2016-12-30 | 2017-05-17 | 中南民族大学 | Tetra-(4-pyridyl) zinc porphyrin self-assembly nanocrystallization method |
| CN106706591A (en) * | 2017-02-27 | 2017-05-24 | 中南民族大学 | Method for recognizing quantitative chiral amino acid by using reversible nano porphyrin fluorescence sensor |
| CN107557000A (en) * | 2017-11-14 | 2018-01-09 | 浙江工业大学 | Class A3B-type asymmetric metal platinum porphyrin organic luminescent material and application thereof |
Non-Patent Citations (6)
| Title |
|---|
| "Turn-off" fluorescent sensor based on double quantum dots coupled with chemometrics for highly sensitive and specific recognition of 53 famous green teas;Ou Hu et al.,;《Analytica Chimica Acta》;20171227;第1-29页 * |
| Comparative Study on the Efficiency of the PhotodynamicInactivation of Candida albicans Using CdTe Quantum Dots,Zn(II) Porphyrin and Their Conjugates as Photosensitizers;Osnir S. Viana et al.;《Molecules》;20150518(第20期);第8893-8912页 * |
| Photophysical studies of CdTe quantum dots in the presence of a zinc cationicporphyrin;Páraic M. Keane et al.;《Dalton Trans》;20121231(第41期);第13159–13166页 * |
| Photosensitization of the luminescence of CdTe nanocrystals by noncovalently bound Zn tetraphenylporphyrin;Matteo Amelia et al.;《Inorganica Chimica Acta》;20110907(第381期);第247-250页 * |
| Recognition of Caffeine in Aqueous Solutions;Roberto Fiammengo et al.;《Chem. Eur. J.》;20031231;第9卷(第3期);第784-792页 * |
| 应用于环境光催化的几种含硫四氮杂卟啉的合成、表征和性能初探;高兰昌;《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》;20140515(第5期);第B014-237页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109738400A (en) | 2019-05-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104927867B (en) | A kind of ratio fluorescent probe of bivalent cupric ion and its preparation method and application | |
| CN108680572B (en) | Method for visually and rapidly detecting nitrite by using color/fluorescence dual signals and application | |
| CN109738400B (en) | Method for visually detecting caffeine based on nano porphyrin fluorescent paper sensing | |
| CN106957644B (en) | A kind of fingerprint detection probe based on long-persistence nano material and preparation method thereof and the application in latent fingerprint detection | |
| CN106916159A (en) | One kind switch nanometer porphyrin fluorescence sensor controllable method for preparing | |
| US11567009B1 (en) | Method for identifying origin of chrysanthemi flos | |
| CN112033943A (en) | Arginine detection method based on quantum dot-copper ion fluorescent substrate sensor | |
| CN110044894B (en) | Colorimetric detection method of triadimenol | |
| CN109738399B (en) | Method for detecting dopamine by visual paper sensing | |
| CN105115963B (en) | The detection method of heavy metal Hg | |
| Zhou et al. | Carbon dots-based modularization fluorescent probe for simultaneous detection of Hg2+ and Cu2+ in water, cells and zebrafish | |
| CN116515489B (en) | Bicolor ratio fluorescent probe for visual rapid detection of trace water color identification in alcohol and application thereof | |
| CN109852389B (en) | Preparation method and application of fluorescence sensor for detecting ochratoxin A | |
| CN109825298A (en) | The method of paper chip the detection silver ion and serine of CdTe quantum based on dimercaptosuccinic acid modification | |
| Liu et al. | Use of a smartphone for intelligent detection of cyromazine based on Tween 20 modified gold nanoparticles | |
| CN115015207A (en) | Dual-mode colorimetric detection fluorescent test paper for food pigment and preparation method and application thereof | |
| CN115521786A (en) | Red light carbon dot, preparation method thereof and application thereof in brilliant blue detection | |
| CN115260509A (en) | Boric acid functionalization based multi-emission metal organic framework compound Eu-MOF and application thereof in gallic acid detection | |
| CN102661950A (en) | Test card for quickly detecting melamine | |
| CN111504969B (en) | Preparation method and application of fluorescent sensor based on carbon dot-quantum dot ratio | |
| CN109520980B (en) | Method for detecting vitamin C in food by fluorescent/nuclear magnetic dual-function probe | |
| CN109813689B (en) | Method for detecting carbamate pesticide based on CdTe quantum dot paper chip substrate | |
| CN111024689B (en) | White spirit alcoholic strength detection method based on color-changing nano material | |
| CN113861962A (en) | Ratiometric fluorescent probe, preparation method thereof and application thereof in detection of hydrogen peroxide | |
| CN111679350B (en) | Plasma metal-semiconductor composite film, preparation method thereof and application thereof in non-edible pigment detection |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |