Rapid quantitative detection method of bisphenol A

Abstract

The invention relates to a rapid quantitative detection method of bisphenol A. The rapid quantitative detection method comprises the following steps: preparation of a detection solution: mixing nanogold and a bisphenol A nucleic acid aptamer, adding a solution to be detected, stirring for 60 minutes, adding a metal salt solution, and stirring for 3 minutes to obtain the detection solution; infrared irradiation: irradiating the detection liquid with infrared laser, recording the temperatures T1 and T2 of the detection liquid after the infrared irradiation is carried out for 0 min and 5 min, and calculating T = T2-T1; and analysis and calculation: carrying out analysis and calculation through a linear regression equation T = 1.1234 CBPA + 3.8923 to obtain the concentration CBPA of bisphenol A in the liquid to be detected. Different from the prior art, the technical scheme establishes a method for detecting bisphenol A by adopting system temperature change. The method is simple and rapid to operate and accurate in qualitative and quantitative detection, and trace bisphenol A can be detected.

Description

Technical Field

[0001] The present application relates to the field of chemical detection, and in particular to a method for rapid quantitative detection of bisphenol A. Background Art

[0002] BPA is a widely used industrial raw material, usually used to make polycarbonate plastics, epoxy resins and thermal paper. Due to its stable chemical properties and difficulty in degradation, it can enter the environment through various pathways and accumulate in environmental media. BPA has been found in rivers, soil, sediments and fish, and is ubiquitous in the environment. Bisphenol A (BPA) is a typical endocrine disruptor that can interfere with the synthesis, secretion, transport and binding of an organism's own hormones, produce effects similar to the organism's own hormones, interfere with human endocrine and metabolic activities, cause metabolic disorders in the human body, and lead to metabolic syndromes such as diabetes, hyperlipidemia and hypertension. In addition, BPA has an impact on the function of the human reproductive system, embryonic and nervous system development, and childhood obesity.

[0003] Traditional methods for BPA mainly include gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). These analytical methods have good separation efficiency and resolution and can efficiently realize trace analysis of multiple components. However, they require the collection of a large number of environmental samples, and the use of chromatography / mass spectrometry instruments for analysis after complex pretreatment such as enrichment and concentration and interference removal. This is not only time-consuming, but also requires expensive equipment and high analysis costs, which limits their further application.

[0004] Point-of-care testing technology is an instant, on-site testing method that uses a portable small analytical instrument. Compared with traditional testing methods, point-of-care testing technology can not only achieve rapid and instant testing, but also is simple to operate and has no stringent requirements on test personnel and test environment. It has shown great advantages in the fields of real-time disease diagnosis, health management and environmental monitoring. The light-responsive temperature change sensor based on photothermal conversion provides a reliable way to achieve real-time monitoring of BPA because of its low price and easy operation and portability. Summary of the invention

[0005] In view of the above problems, the present application provides a rapid quantitative detection method for bisphenol A by using system temperature changes, which is simple and convenient, has a short detection time, high sensitivity and a low detection limit.

[0006] The present application discloses a rapid quantitative detection method for bisphenol A, comprising the following steps:

[0007] Preparation of the test solution: Mix the nano-gold and bisphenol A nucleic acid aptamer and add the test solution, stir for 60 minutes, then add the metal salt solution and stir for more than 3 minutes to obtain the test solution;

[0008] Infrared irradiation: irradiate the test liquid with an infrared laser, record the temperatures T1 and T2 of the test liquid at 0 min and 5 min of infrared irradiation, and calculate ΔT=T2-T1;

[0009] Analysis and calculation: Through the linear regression equation △T=1.1234C BPA +3.8923 for analysis and calculation, and the concentration of bisphenol A in the test solution C is obtained. BPA .

[0010] Different from the existing technology, the above technical solution establishes a method for detecting BPA by using a nano-gold particle precipitation system and using the temperature change of the system to detect the content of bisphenol A. The method is simple to operate, rapid, accurate in qualitative and quantitative analysis, and can detect trace amounts of bisphenol A.

[0011] Furthermore, the correlation coefficient of the linear regression equation is R 2 =0.9884, minimum detection limit 0.16nmol / L.

[0012] Furthermore, the concentration of bisphenol A is BPA ≦10nmol / L.

[0013] Furthermore, the nucleic acid aptamer is the nucleotide sequence shown in SEQ ID NO.1.

[0014] Furthermore, the metal salt solution is a NaCl solution.

[0015] Furthermore, in the detection solution, the concentration of the metal salt is ≧30mmol / L, the concentration of the bisphenol A nucleic acid aptamer is ≧100nmol / L, and the concentration of the nanogold is 2mmol / L.

[0016] Furthermore, in the detection solution, the concentration of the metal salt is 30 mmol / L, and the concentration of the bisphenol A nucleic acid aptamer is 100 nmol / L.

[0017] Furthermore, the infrared laser irradiation uses a point laser with an operating wavelength of 808nm and a power of 1W.

[0018] The above-mentioned records related to the invention content are only an overview of the technical solution of the present application. In order to enable ordinary technicians in the field to more clearly understand the technical solution of the present application, and then implement it according to the text of the specification and the contents recorded in the drawings, and to make the above-mentioned purpose and other purposes, features and advantages of the present application easier to understand, the following is an explanation in combination with the specific implementation mode and drawings of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings are only used to illustrate the principles, implementation methods, applications, characteristics and effects of the specific embodiments of the present application and other related contents, and shall not be considered as limitations of the present application.

[0020] In the drawings of the specification:

[0021] Figure 1 is the reaction principle diagram;

[0022] Figure 2 The color diagram of the solution before illumination for 4 groups of experiments.

[0023] Figure 3 Temperature diagram for 4 groups of experiments with different light exposure times.

[0024] Figure 4 This is the temperature difference △T diagram between the experimental group and the blank group at different NaCl concentrations.

[0025] Figure 5 This is the temperature difference △T diagram between the experimental group and the blank group at different BPA reaction times.

[0026] Figure 6 This is the temperature difference △T diagram between the experimental group and the blank group at different NaCl reaction times.

[0027] Figure 7 Temperature difference △T diagram between the experimental group at different aptamer concentrations and the blank group.

[0028] Figure 8 This is the temperature difference △T change diagram for different concentrations of BPA.

[0029] Fig. 9 It is the linear relationship diagram of 1nmol / L-10nmol / L PA concentration. DETAILED DESCRIPTION

[0030] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0031] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0032] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0033] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0034] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0035] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0036] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0037] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0038] The present application discloses a rapid quantitative detection method for bisphenol A, comprising the following steps:

[0039] Preparation of the test solution: Mix the nano-gold and bisphenol A nucleic acid aptamer and add the test solution, stir for 60 minutes, then add the metal salt solution and stir for more than 3 minutes to obtain the test solution;

[0040] Infrared irradiation: irradiate the test liquid with an infrared laser, record the temperatures T1 and T2 of the test liquid at 0 min and 5 min of infrared irradiation, and calculate ΔT=T2-T1;

[0041] Analysis and calculation: Through the linear regression equation △T=1.1234C BPA +3.8923 for analysis and calculation, and the concentration of bisphenol A in the test solution C is obtained. BPA .

[0042] Principle of this application: Under the action of metal salt ions, the gold nanoparticles will change from a dispersed state to an aggregated state, and the color will also change from the dispersed red state to the aggregated blue state. After adding the aptamer, the aptamer will be tightly adsorbed on the surface of the gold nanoparticles, so that they will not aggregate under the action of metal salt ions, so that the gold nanoparticles will always be in a dispersed state, and the color of the solution will not change. However, if the target molecule BPA is added to the solution, the aptamer will combine with BPA and then fall off the surface of the gold nanoparticles. The gold nanoparticles will continue to aggregate under the action of metal salt ions, and the color of the solution will also change from red to blue.

[0043] When irradiated by infrared laser, gold nanoparticles will strongly absorb the emitted infrared light through the surface plasmon resonance effect (SPR), and quickly convert the absorbed light energy into heat energy, causing the gold nanoparticles to heat up rapidly and transfer heat energy to the surrounding area of ​​the particles, causing the overall temperature of the solution to continue to rise. Therefore, the present application is designed to construct a gold nanoparticle flocculation system using gold nanoparticles, nucleic acid aptamers, and metal salt ions. The BPA added to the system will react with the nucleic acid aptamer, affecting the aggregation effect of the gold nanoparticles, and further affecting the temperature of the system. Within the effective detection range, the higher the BPA content in the system, the more the gold nanoparticles aggregate, and the higher the temperature of the solution, and the two are positively correlated. The present application detects the concentration of the target molecule BPA by the temperature change of the solution after irradiation with an infrared laser. The experimental principle diagram is shown in the figure. Figure 1 shown.

[0044] Different from the existing technology, the above technical scheme establishes a method for detecting BPA by using a nano-gold particle coagulation system and using the temperature change of the system to detect the content of bisphenol A. The method is simple to operate, rapid, accurate in qualitative and quantitative analysis, and can detect trace amounts of bisphenol A.

[0045] Furthermore, the correlation coefficient of the linear regression equation is R 2 =0.9884, minimum detection limit 0.16nmol / L.

[0046] Furthermore, the concentration of bisphenol A is BPA ≦10nmol / L.

[0047] Furthermore, the nucleic acid aptamer is the nucleotide sequence shown in SEQ ID NO.1.

[0048] Furthermore, the metal salt solution is a NaCl solution.

[0049] Furthermore, in the detection solution, the concentration of the metal salt is ≧30mmol / L, the concentration of the bisphenol A nucleic acid aptamer is ≧100nmol / L, and the concentration of the nanogold is 2mmol / L.

[0050] Furthermore, in the detection solution, the concentration of the metal salt is 30 mmol / L, and the concentration of the bisphenol A nucleic acid aptamer is 100 nmol / L.

[0051] The configuration of the solution in this embodiment

[0052] ① 100 μmol / L bisphenol A nucleic acid aptamer: first place the centrifuge tube containing bisphenol A aptamer powder into a centrifuge, centrifuge at 3000 rpm for 20 seconds and slowly open the centrifuge tube cover, then add the required volume of ultrapure water to the centrifuge tube wall, cover the centrifuge tube cover after adding, and fully shake and mix for 3 minutes, then put the centrifuge tube into a 95°C drying oven and let it stand for 2 minutes, and then divide and store it. In this experiment, the concentration of the mother solution of bisphenol A nucleic acid aptamer prepared after the above pretreatment is 100 μmol / L. The prepared bisphenol A nucleic acid aptamer stock solution is stored in the freezer layer of a refrigerator at -20°C.

[0053] ②2mmol / L BPA solution: First, weigh 0.0091g ​​of BPA powder using an electronic balance, add anhydrous ethanol to make the volume to 20mL, and you can get a BPA solution with a concentration of 2mmol / L.

[0054] ③1 mol / L NaCl solution: First, weigh 5.844 g of NaCl crystal powder using an electronic balance, add distilled water to make up to 100 mL, and you can get a NaCl solution with a concentration of 1 mol / L.

[0055] Example 1: Feasibility test of gold nanoparticle coagulation system for detecting BPA

[0056] Before the experiment, the feasibility of the experiment is verified.

[0057] Four different groups of experiments A, B, C, and D were set up respectively.

[0058] Group A: 150 μL of gold nanoparticles and 60 μL of distilled water were mixed and shaken evenly, and then directly exposed to infrared light for 5 minutes. The solution was photographed and recorded before illumination, and the data was measured and recorded with a sensitive thermometer after illumination.

[0059] Group B: 150 μL of gold nanoparticles and 50 μL of distilled water were mixed and shaken at room temperature for 30 minutes, then 10 μL of NaCl salt solution (1 mol / L) was added and shaken for 3 minutes, and infrared light was irradiated for 5 minutes; the solution was photographed and recorded before illumination, and the data was measured and recorded with a sensitive thermometer after the illumination.

[0060] Group C: 150 μL of gold nanoparticles, 25 μL of nucleic acid aptamer (2 μmol / L) and 25 μL of distilled water were mixed and shaken at room temperature for 30 minutes, then 10 μL of NaCl salt solution (1 mol / L) was added and shaken for 3 minutes, and infrared light was irradiated for 5 minutes; the solution was photographed and recorded before illumination, and the data was measured and recorded with a sensitive thermometer after the illumination.

[0061] Group D: 150 μL of gold nanoparticles, 25 μL of nucleic acid aptamer (2 μmol / L), 25 μL of bisphenol A solution (2 μmol / L), after oscillating and mixing at room temperature for 30 minutes, 10 μL of NaCl salt solution (1 mol / L) was added and oscillated for 3 minutes, and infrared light was irradiated for 5 minutes; the solution was photographed and recorded before illumination, and the data was measured and recorded with a sensitive thermometer after the illumination.

[0062] Figure 2 The color photos of the four test sample solutions before illumination are shown in Figure 1. The temperature values ​​after illumination are A32.5℃, B52.8℃, C58.1℃, and D62.1℃. Figure 2 Three conclusions can be drawn:

[0063] ① From the comparison between A and B, it can be seen that the temperature measured in B after illumination is much higher than that in A, and AuNPs are completely precipitated to the bottom, indicating that AuNPs rapidly precipitate under the induction of metal salt ions, and the color of the solution changes rapidly, showing good color development and contrast effects.

[0064] ② From the comparison between B and C, it can be seen that the color of C is dark red, and the temperature after illumination is slightly higher than that of B, indicating that AuNPs are not completely aggregated. The addition of aptamer has a good protective effect on AuNPs, showing a good color and contrast effect. However, the temperature of C after illumination is slightly higher than that of B, which may be because the AuNPs of B are completely aggregated to the bottom.

[0065] ③From the comparison between C and D, it can be seen that the color of D turns gray-blue, and the temperature after illumination is also higher than that of C, which indicates that the added BPA will react with the aptamer, causing the aptamer to fall off the surface of AuNPs. After AuNPs lose the protection of the aptamer, they rapidly undergo a coagulation reaction under the induction of metal salt ions, thereby changing the color and temperature of the solution.

[0066] From the above three conclusions, it can be seen that it is feasible to detect BPA using the gold nanoparticle precipitation system, and the conditions can be optimized on this basis.

[0067] Example 2 Optimization of experimental conditions for detecting BPA using AuNPs coagulation system

[0068] In order to make the heating effect most obvious, we need to optimize the different conditions of the experiment. We use the single variable control test method to optimize the BPA detection conditions of the AuNPs coagulation system. This experiment mainly examines five factors during the detection process: infrared laser irradiation time, NaCl concentration, reaction time of AuNPs with aptamer and BPA, reaction time of NaCl and AuNPs, and aptamer concentration.

[0069] 1. Optimization of irradiation time

[0070] AuNPs will undergo surface plasmon resonance (SPR) when irradiated by infrared lasers, absorbing the light energy of the infrared laser and converting it into heat energy, thereby increasing the temperature of the solution. Therefore, the duration of illumination will have a direct impact on the AuNPs system. Therefore, it is necessary to investigate the influence of different irradiation times of infrared lasers on the heating effect of the AuNPs system.

[0071] Four groups of experiments similar to Example 1 were set up, and the steps and conditions of each group of experiments were the same except for the irradiation time of the infrared laser, so as to realize the control of the single variable of the irradiation time of the infrared laser. The irradiation time was from 0 to 7 minutes, and the temperature data was recorded every 0.5 minutes until the irradiation of 7 minutes was completed.

[0072] Depend on Figure 3 It can be seen that before 5 minutes, the temperature of the four groups of experiments after illumination increased with the increase of illumination time. This is because after the illumination time increases, the AuNPs precipitation system also absorbs more light energy and converts it into heat energy, so the temperature is also increasing accordingly. After 5 minutes of illumination, the temperature change of the system gradually tends to be gentle.

[0073] In order to conduct rapid detection and improve efficiency, 5 min was selected as the infrared irradiation time.

[0074] 2. Optimization of NaCl concentration

[0075] The metal salt ions in the NaCl solution are an important factor affecting whether AuNPs aggregate. The concentration of metal salt ions when reacting with AuNPs directly determines the degree of AuNPs coagulation, so it is necessary to investigate the concentration of the NaCl solution.

[0076] Optimization of NaCl concentration Two blank tests were set up: blank group and test group. The blank group did not add the target molecule BPA, and the test group needed to add 25 μL of bisphenol A solution (2 μmol / L). First, the blank group used a pipette to transfer 150 μL of gold nanoparticles, 25 μL of nucleic acid aptamers (2 μmol / L), and 25 μL of distilled water to the well plate. The test group used a pipette to transfer 150 μL of gold nanoparticles, 25 μL of nucleic acid aptamers (2 μmol / L), and 25 μL of bisphenol A solution (2 μmol / L) to the well plate. After the two groups were mixed evenly, they reacted at room temperature for 30 minutes. Then, 10 μL of different concentrations of NaCl (0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 mol / L) were added to change the concentration of the NaCl solution. After adding, the temperature of each group was measured under infrared light for 5 minutes, and the value was recorded, and the temperature difference △T between the two groups of experiments was calculated.

[0077] Depend on Figure 4 It can be seen that when the NaCl concentration is between 10-30mmol / L, the temperature difference △T between the two groups of tests continues to increase, and when the NaCl concentration is greater than 30mmol / L, the growth trend of the temperature difference △T between the two groups of tests gradually decreases. In order to save detection time and improve efficiency, a 30mmol / L NaCl solution was selected.

[0078] 3. Optimization of reaction time of AuNPs / aptamer and BPA

[0079] Aptamer can be adsorbed on the surface of AuNPs to form an AuNPs / aptamer complex, which prevents AuNPs from coagulation reaction and plays a good protective role. However, the subsequently added BPA reacts with Aptamer and peels Aptamer off the surface of AuNPs. Therefore, the reaction time of the AuNPs / aptamer complex and BPA directly determines the degree of protection of the AuNPs surface by aptamer, and has a significant effect on the heating effect of the AuNPs coagulation system. Therefore, it is very necessary to investigate the different reaction times of the AuNPs / aptamer complex and BPA.

[0080] When the infrared laser irradiation time was 5 min and the NaCl concentration was 30 mmol / L, the reaction times of AuNPs / aptamer and BPA in the control test group and the blank group were 40, 50, 60, 70, 80, and 90 min, respectively. That is, the reaction time of AuNPs / aptamer and BPA was changed, the temperature of each group was measured and recorded, and the temperature difference △T between the two groups of experiments was calculated.

[0081] from Figure 5 It can be seen that in the reaction time of 40-90 min between the AuNPs / aptamer complex and BPA, the difference △T between the test group and the blank group reached the maximum peak when the reaction time was 60 min, so 60 min was selected as the optimal reaction time of AuNPs-aptamer and BPA.

[0082] 4. Optimization of reaction time of NaCl and AuNPs

[0083] In addition to the concentration of NaCl, the reaction time of NaCl and AuNPs also plays a key role in the effect of NaCl on the AuNPs coagulation system. Therefore, it is quite necessary to study and investigate the reaction time of NaCl.

[0084] Under the conditions of infrared laser irradiation time of 5 min, NaCl concentration of 30 mmol / L, and reaction time of AuNPs / aptamer and BPA of 60 min, the reaction times of the control test group and the blank group after adding NaCl were 1, 2, 3, 4, and 5 min, respectively. That is, the reaction time of NaCl and AuNPs was changed, and the other steps remained unchanged. After measuring the temperature of each group, the value was recorded, and the temperature difference △T between the two groups of experiments was calculated.

[0085] like Figure 6 As shown in the figure, the temperature difference △T between the blank group and the test group increases with the increase of NaCl reaction time, because more and more AuNPs react and precipitate with metal salt ions. However, this growth trend gradually decreases after 3 minutes. In order to achieve the effect of rapid detection, we set 3 minutes as the optimal reaction time of NaCl.

[0086] 5. Optimization of aptamer concentration

[0087] In addition to the reaction time, the concentration of aptamer also plays a crucial role in the effect of aptamer on the AuNPs coagulation system. The two conditions together determine the extent of the influence of aptamer on the AuNPs coagulation system, so we need to explore the concentration of aptamer.

[0088] Under the conditions of infrared laser irradiation time of 5 min, NaCl solution concentration of 30 mmol / L, reaction time of AuNPs / aptamer and BPA of 60 min, and reaction time of AuNPs and NaCl of 3 min, 10, 15, 20, and 25 μL of 1 μmol / L aptamer solution and 25 μL of 1.2 μmol / L aptamer solution were added to the blank group and the test group, respectively. That is, the aptamer concentration was changed, and other steps remained unchanged. The temperature of each group was measured and the values ​​were recorded, and the temperature difference △T between the two groups of experiments was calculated.

[0089] from Figure 7 We can see that as the concentration of aptamer increases, the temperature difference △T between the blank group and the test group also increases. When the concentration of aptamer increases from 50nmol / L to 100nmol / L, the increase in △T is the largest. After that, although △T increases with the increase in aptamer concentration, the amplitude changes very little and tends to be more stable. Therefore, 100nmol / L is selected as the optimal concentration of aptamer.

[0090] 6. BPA working curve

[0091] After the above optimization experiments, we can derive the best experimental conditions: infrared laser irradiation time is 5 min, NaCl concentration is 30 mmol / L, reaction time of AuNPs with aptamer and BPA is 60 min, reaction time of NaCl is 3 min, and aptamer concentration is 100 nmol / L.

[0092] Under the above optimal conditions, 0, 0.5, 0.8, 1, 2, 5, 8, 10, 20, 50, and 100 nmol / L BPA solutions were added respectively. Three parallel samples were made for each concentration. The temperature of each sample was measured and the value was recorded. The temperature difference △T is as follows: Figure 8 shown.

[0093] The temperature difference △T increases with the increase of BPA concentration, and shows a good linear relationship in the range of 1-10nmol / L. Fig. 9 As shown, the linear equation is the temperature difference △T = 1.1234C BPA +3.8923, correlation coefficient R 2 =0.9884.

[0094] 7. Stability test

[0095] Stability is one of the key factors for accurate quantification, so we randomly selected BPA with a concentration of 20nmol / L for stability testing and conducted 5 groups of identical parallel tests. The results are shown in Table 1:

[0096] Table 1: Stability test of 20 nmol / L BPA

[0097] 8. Determination of minimum limit

[0098] The detection limit is a parameter commonly used to evaluate the detection ability of an analytical method in a low concentration range. The specific definition is the minimum concentration or content of a substance required to produce an analytical signal that can be reliably detected. It is an important indicator for evaluating the detection ability of a detection method. In order to determine the minimum concentration of BPA in the sample that the method proposed in this article can detect within a given confidence level, the minimum concentration of BPA is accurately quantitatively determined under the premise that the measurement error can meet the predetermined requirements. According to the minimum limit formula L = KSb / S

[0099] Where:

[0100] L——lower limit of determination of the method;

[0101] Sb——Standard deviation (temperature) of multiple measurements of blank group;

[0102] S——sensitivity of the method (i.e. the slope of the calibration curve);

[0103] K——Generally take 3 when calculating;

[0104] According to the above formula, it can be calculated that the detection limit of BPA in the concentration range of 1-10nmol / L is L=0.16nmol / L.

[0105] This application establishes a nano-gold particle coagulation system to detect BPA, and uses a method of detecting the content of bisphenol A by temperature change of the system, which is suitable for detecting trace amounts of BPA (1-10nmol / L). The method is simple to operate, rapid, accurate in qualitative and quantitative analysis, and can detect trace amounts of bisphenol A.

[0106] If the detection method of this application is applied and the BPA content is detected to be >10nmol / L or the BPA content is <1nmol / L, other detection methods need to be used for verification.

[0107] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A rapid quantitative detection method for bisphenol A, characterized in that: The following steps are involved: Preparation of the test solution: Mix the nano-gold and bisphenol A nucleic acid aptamer and add the test solution, stir for 60 minutes, then add the metal salt solution and stir for more than 3 minutes to obtain the test solution; Infrared irradiation: irradiate the test liquid with an infrared laser, record the temperatures T1 and T2 of the test liquid at 0 min and 5 min of infrared irradiation, and calculate ΔT=T2-T1; Analysis and calculation: Through the linear regression equation △T=1.1234C BPA +3.8923 for analysis and calculation, and the concentration of bisphenol A in the test solution C is obtained. BPA .

2. The detection method according to claim 1, characterized in that: The correlation coefficient of the linear regression equation is R 2 =0.9884, minimum detection limit 0.16nmol / L.

3. The detection method according to claim 1, characterized in that: The concentration of bisphenol A C BPA ≦10nmol / L.

4. The detection method according to claim 1, characterized in that: The nucleic acid aptamer is the nucleotide sequence shown in SEQ ID NO.

1.

5. The detection method according to claim 1, characterized in that: The metal salt solution is a NaCl solution.

6. The detection method according to claim 1, characterized in that: In the detection solution, the concentration of the metal salt is ≥30 mmol / L, the concentration of the bisphenol A nucleic acid aptamer is ≥100 nmol / L, and the concentration of the nano-gold is 2 mmol / L.

7. The detection method according to claim 6, characterized in that: In the detection solution, the concentration of the metal salt is 30 mmol / L, and the concentration of the bisphenol A nucleic acid aptamer is 100 nmol / L.

8. The detection method according to claim 1, characterized in that: The infrared laser irradiation adopts a point laser with an operating wavelength of 808nm and a power of 1W.

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