A rapid detection method for sulfur phosphorus and its application

Abstract

This invention belongs to the field of food and agricultural product safety testing technology, specifically relating to a rapid detection method for parathion and its application. Based on the parathion-induced blue shift in fluorescence of silicon nanoparticles, ascorbic acid is reacted with 3-aminopropyltriethoxysilane to generate green fluorescent silicon nanoparticles. During the formation of silicon nanoparticles, parathion can embed itself into the porous structure of the silicon nanoparticles through host-guest interactions, causing a change in the excited state of the silicon nanoparticles. This affects the fluorescence emission of the silicon nanoparticles, resulting in a blue shift in the fluorescence emission peak, changing from green fluorescence to blue fluorescence, specifically manifested as an increase in fluorescence intensity at 422 nm and a decrease in fluorescence intensity at 520 nm. By establishing the relationship between ratiometric fluorescence signal or fluorescence color change and parathion concentration, specific detection of parathion is achieved. This invention requires no enzymes or antibodies for parathion detection, is inexpensive, fast, easy to operate, highly sensitive, and has good specificity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food and agricultural product safety detection, and particularly relates to a rapid detection method for parathion and application thereof. BACKGROUND

[0002] O,O-diethyl-O-p-nitrophenyl phosphorothioate (parathion) is a highly toxic organophosphorus pesticide. It has been banned by the World Health Organization and many countries due to its high toxicity to the immune system, nervous system and reproductive system. In addition, long-term exposure to parathion can induce some medical complications such as Parkinson's disease, asthma, attention deficit and hyperactivity disorder, and even cancer. Therefore, a simple, rapid, sensitive method for detecting parathion is of great significance to food safety. Traditional chromatography or chromatography-mass spectrometry techniques, including gas chromatography, high-performance liquid chromatography, gas chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry, provide high-sensitivity, high-specificity trace analysis methods for parathion detection, and have a wide detection range. However, these detection techniques require complex sample pretreatment, professional operators and expensive instruments, and are difficult to be widely applied. Immunoassay, which utilizes the specific action of antigen and antibody, is also an important technology for rapid detection of organophosphorus pesticides. However, the preparation of immunological antibodies is complex, the technical requirements are high, and the detection cost is also high.

[0003] Currently, the simple and rapid detection of organophosphorus pesticides mainly relies on enzyme inhibition method, which depends on biological enzymes such as acetylcholine esterase and alkaline phosphatase. The principle is that organophosphorus pesticides inhibit the catalytic activity of enzymes, so the enzyme inhibition method lacks the ability to identify specific organophosphorus pesticides, such as the inability to specifically detect parathion. Moreover, the enzymes used in the enzyme inhibition method are biological active protein macromolecules, which are prone to denaturation and difficult to store for a long time. Therefore, the enzyme inhibition method has poor detection stability and is prone to false negative and false positive results. In summary, a simple, economical, accurate, reliable and highly specific rapid detection method for parathion still needs to be developed.

[0004] Silicon nanoparticles (SiNPs) have fluorescence emission characteristics and can be formed by one-step reduction of the precursor silane. As a kind of metal-free fluorescent probe, silicon nanoparticles have attracted extensive attention due to their excellent optical properties, low cost and abundant silicon source. The optical properties of silicon nanoparticles are related to their size, shape, particle crystallinity, impurity doping, surface composition and functionalization, which endow silicon nanoparticles with design flexibility as optical probes. It has great advantages to develop a rapid detection method for organophosphorus pesticides using silicon nanoparticles. SUMMARY

[0005] In order to obtain a simple, economical, accurate, reliable and highly specific rapid detection method for parathion, the following technical solutions are disclosed in the application:

[0006] A rapid detection method of parathion, the method is:

[0007] (1) ascorbic acid, 3-aminopropyl triethoxysilane, PBS buffer and the sample to be detected are mixed and incubated to generate a silicon nanoparticle reaction solution;

[0008] (2) qualitative and quantitative analysis of parathion in the sample to be detected is carried out by establishing a ratio fluorescence signal for the silicon nanoparticle reaction solution or comparing the fluorescence color change of the silicon nanoparticle reaction solution under ultraviolet radiation.

[0009] Preferably, the sample to be detected in step (1) contains 0-7.0 μg / mL of parathion.

[0010] Preferably, the concentration of ascorbic acid in step (1) is 10 mmol / L.

[0011] Preferably, the concentration of 3-aminopropyl triethoxysilane in step (1) is 0.356 mol / L.

[0012] Preferably, the concentration of PBS buffer in step (1) is 1 mmol / L, and the pH is 10.0.

[0013] Preferably, the amount-of-substance ratio of ascorbic acid to 3-aminopropyl triethoxysilane in step (1) is 10:356.

[0014] Preferably, the incubation condition in step (1) is that the reaction is carried out at 60℃ for 80 min.

[0015] Preferably, the specific method for establishing a ratio fluorescence signal in step (2) is that the concentration of parathion pesticide is taken as the abscissa, and the fluorescence ratio F 422 nm / F 520 nm is taken as the ordinate, a linear relationship Y=0.4248X+0.6651 is established.

[0016] Preferably, the fluorescence color change of the silicon nanoparticle reaction solution under ultraviolet radiation in step (2) is that under 365 nm ultraviolet radiation, when the silicon nanoparticle reaction solution presents green fluorescence unchanged, it indicates that the solution does not contain trace parathion; when the silicon nanoparticle reaction solution presents a trend of weakening green fluorescence and enhancing blue fluorescence, it indicates that the solution contains trace parathion; when the silicon nanoparticle reaction solution presents obvious blue fluorescence, it indicates that the solution contains high-concentration parathion.

[0017] The application of a rapid detection method of parathion in detecting parathion in organophosphorus pesticides.

[0018] The advantages of the application are as follows:

[0019] The present application is very simple to operate, low in cost, low in detection limit, and excellent in selectivity, can perform qualitative analysis on parathion through fluorescence color change, and can perform quantitative analysis on parathion concentration according to fluorescence ratio. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic diagram of a rapid detection method for an organic phosphorus pesticide parathion.

[0021] Figure 2 It is (A) excitation, emission and absorption spectra of silicon nanoparticles and (B) transmission electron microscope (TEM) image.

[0022] Figure 3 It is fluorescence spectra of APTES and ascorbic acid solution respectively incubated with (A) different pesticides and (B) different ions or amino acids.

[0023] Figure 4 It is fluorescence spectra of different mixed systems of APTES, ascorbic acid and parathion.

[0024] Figure 5 It is (A) fluorescence spectra and (B) fluorescence ratio F 422 nm / F 520 nm Linear standard curve responding to parathion. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0026] Example 1

[0027] Using APTES (3-aminopropyltriethoxysilane, CAS No.: 919-30-2) as a precursor and ascorbic acid as a reducing agent, fluorescent SiNPs emitting green fluorescence can be generated. 50 μL of APTES (98 wt%, 3.56 mol / L) was added to 350 μL of PBS buffer (1 mM, pH 10.0), followed by 100 μL of ascorbic acid solution (50 mmol / L). The mixture was incubated at 60 °C for 80 min to obtain fluorescent SiNPs. During SiNP formation, if the pesticide molecule parathion is present, it will intercalate into the porous structure of the SiNPs through host-guest interactions, thus affecting the fluorescence emission of the SiNPs, causing the fluorescence of the SiNPs to change from green to blue. Figure 1 ).like Figure 2 As shown in Figure A, the optimal excitation wavelength for SiNPs is 435 nm, and the optimal emission wavelength is 525 nm. (From the photograph...) Figure 2 A) It can be clearly observed that the SiNPs solution appears pale yellow under natural light and emits bright green fluorescence under 365 nm ultraviolet light. Furthermore, from transmission electron microscopy (TEM) images (… Figure 2 According to B), SiNPs exhibit good dispersibility in water, with an average size of approximately 1.77 nm.

[0028] Example 2

[0029] 100 μL of pesticides (heptachlor, hexachlorocyclohexane, dichlorodiphenyltrichloroethane (DDT), acetamiprid, imidacloprid, dinotefuran, dimethoate, methyl parathion, malathion, acephate, profenofos, and parathion; concentration: 6 μg / mL), 50 μL of APTES (98 wt%, 3.56 mol / L), 250 μL of PBS buffer (1 mmol / L, pH 10.0) and 100 μL of ascorbic acid (10 mmol / L) were reacted at 60 °C for 80 min. Figure 3 As shown in A, only parathion can induce a blue shift in the fluorescence of SiNPs.

[0030] 100 μL of different ions or amino acids (Mg) 2+ Na + K + Ca 2+ Zn 2+ Ag + Glycine, cysteine, tyrosine, alanine, lysine; concentration: 50 μM) or parathion (6 μg / mL) with 50 μL APTES (98 wt%, 3.56 mol / L), 250 μL PBS buffer (1 mmol / L, pH 10.0) and 100 μL ascorbic acid (10 mmol / L), reacted at 60℃ for 80 min, by Figure 3B It is known that only parathion can induce the fluorescence blue shift of SiNPs.

[0031] Example 3

[0032] The curve a) in Fig. 1 was obtained by adding 50 μL APTES (98 wt%, 3.56 mol / L), 350 μL PBS buffer (1 mmol / L, pH 10.0) and 100 μL ascorbic acid (10 mmol / L) into 250 μL parathion (5 μg / mL) and reacting at 60 °C for 80 min. Figure 4 The curve b) in Fig. 1 was obtained by adding 100 μL parathion (6 μg / mL), 50 μL APTES (98 wt%, 3.56 mol / L), 250 μL PBS buffer (1 mmol / L, pH 10.0) and 100 μL ascorbic acid (10 mmol / L) and reacting at 60 °C for 80 min. Figure 4 The curve c) in Fig. 1 was obtained by adding 50 μL APTES (98 wt%, 3.56 mol / L), 350 μL PBS buffer (1 mmol / L, pH 10.0) and 100 μL ascorbic acid (10 mmol / L) into 100 μL parathion (6 μg / mL) and reacting at 60 °C for 80 min. Figure 4 It is known that parathion, ascorbic acid and APTES must be reacted simultaneously to induce the fluorescence blue shift of SiNPs.

[0033] Example 4

[0034] Different volumes (40-80 μL) of APTES (98 wt%, 3.56 mol / L) and 100 μL ascorbic acid (10 mmol / L) were added into PBS buffer (1 mmol / L) to make the total reaction system 500 μL, and the reaction was carried out at 60 °C for 80 min. 40-60 μL of APTES (98 wt%, 3.56 mol / L) had no effect on the fluorescence of SiNPs. For convenience, 50 μL of APTES (98 wt%, 3.56 mol / L) was selected for the experiment.

[0035] Different pH values (pH: 7.0, 8.0, 9.0, 10.0, 11.0; concentration: 1 mmol / L) of PBS were used to add 50 μL APTES (98 wt%, 3.56 mol / L), 100 μL parathion (5 μg / mL) and 100 μL ascorbic acid (10 mmol / L) into 250 μL PBS buffer and the reaction was carried out at 60 °C for 80 min. The effect of parathion on the fluorescence blue shift of SiNPs was best at pH 10.

[0036] Add 50 μL of APTES (98 wt%, 3.56 mol / L) and 10 mmol / L ascorbic acid to 350 μL of PBS buffer (1 mmol / L, pH 10.0). Incubate at different temperatures (37, 40, 50, 60, 70, 80 °C) for 80 min. At temperatures below or equal to 60 °C, fluorescence intensity increases with increasing temperature. When the temperature is above or equal to 70 °C, fluorescence exhibits a blue shift; therefore, 60 °C is the optimal reaction temperature. Alternatively, add 50 μL of APTES (98 wt%, 3.56 mol / L) and 100 μL of ascorbic acid (10 mmol / L) to 350 μL of PBS buffer (1 mmol / L, pH 10.0). React at 60 °C for different times (10-100 min), with 80 min being the optimal reaction time.

[0037] Example 5

[0038] 100 μL of parathion of different concentrations (0-9.0 μg / mL), 50 μL of APTES (98 wt%, 3.56 mol / L), 250 μL of PBS buffer (1 mmol / L, pH 10.0), and 100 μL of ascorbic acid (10 mmol / L) were reacted at 60 °C for 80 min. The fluorescence spectra are as follows. Figure 5 As shown in Figure A, the fluorescence intensity (F) at 422 nm increases with increasing parathion concentration. 422 nm The fluorescence intensity at 520 nm gradually increases, with the fluorescence intensity (F) gradually increasing. 520 nm The fluorescence ratio F gradually decreased. Plotting parathion pesticide concentration on the x-axis, the fluorescence ratio F... 422 nm / F 520 nm Using the ordinate, the linear relationship within the parathion concentration range of 0-7.0 μg / mL can be expressed as F 422 nm / F 520 nm = 0.4248 [parathion] (μg / mL) + 0.6651 (e.g.) Figure 5 As shown in B, the limit of detection (LOD) was calculated to be 0.037 μg / mL using 3σ / k (σ is the standard deviation of the background signal, and k is the slope of the fitted linearity).

[0039] Example 6

[0040] The rapid detection method is applied to the detection of parathion in baby bok choy. The stains on the surface of the leaves are wiped and weighed, and then the leaves are completely immersed in 1 mmol / L PBS buffer (5 mL PBS / 1 g baby bok choy) and ultrasonicated for 10 min. The supernatant is collected after filtration. After 100 μL of the supernatant of baby bok choy, 50 μL of APTES (98 wt%, 3.56 mol / L), 250 μL of PBS buffer (1 mmol / L, pH 10.0) and 100 μL of ascorbic acid (10 mmol / L) are reacted at 60°C for 80 min, the obtained F 422 nm / F 520 nm The fluorescence ratio value is substituted into the linear equation F 422 nm / F 520 nm = 0.4248 [parathion] (μg / mL) + 0.6651, and the concentration of parathion in the actual sample can be calculated.

[0041] Example 7

[0042] The rapid detection method is applied to the detection of parathion in baby bok choy. The stains on the surface of the leaves are wiped and weighed, and then the leaves are completely immersed in 1 mmol / L PBS buffer (5 mL PBS / 1 g baby bok choy) and ultrasonicated for 10 min. The supernatant is collected after filtration. After 100 μL of the supernatant of baby bok choy, 50 μL of APTES (98 wt%, 3.56 mol / L), 250 μL of PBS buffer (1 mmol / L, pH 10.0) and 100 μL of ascorbic acid (10 mmol / L) are reacted at 60°C for 80 min, the obtained F 422 nm / F 520nm The fluorescence ratio value is substituted into the linear equation F 422 nm / F 520 nm = 0.4248 [parathion] (μg / mL) + 0.6651, and the concentration of parathion in the actual sample can be calculated.

[0043] Example 8

[0044] When the rapid detection method is applied to the detection of parathion in fresh tea leaves, the stains on the surface of the fresh tea leaves are wiped off, 1 g of fresh tea leaves is weighed and completely immersed in 5 mL of 1 mmol / L PBS buffer solution and ultrasonicated for 10 min, and then the supernatant is collected after filtration. After 100 μL of the tea leaf supernatant, 50 μL of APTES (98 wt%, 3.56 mol / L), 250 μL of PBS buffer solution (1 mmol / L, pH 10.0) and 100 μL of ascorbic acid (10 mM) are reacted at 60°C for 80 min, the obtained F 422 nm / F 520 nm The fluorescence ratio value is substituted into the linear equation F 422 nm / F 520nm = 0.4248 [parathion] (μg / mL) + 0.6651, and the concentration of parathion in the actual sample can be calculated.

[0045] Example 9

[0046] In addition, qualitative analysis and semi-quantitative analysis can be performed by the fluorescence color emitted by the solution after the reaction under 365 nm ultraviolet radiation. After 100 μL of the sample supernatant after pretreatment, 50 μL of APTES (98 wt%, 3.56 mol / L), 250 μL of PBS buffer solution (1 mmol / L, pH 10.0) and 100 μL of ascorbic acid (10 mmol / L) are reacted at 60°C for 80 min, the fluorescence color emitted by the solution after the reaction and the control solution (50 μL of APTES (98 wt%, 3.56 mol / L), 350 μL of PBS buffer solution (1 mmol / L, pH 10.0) and 100 μL of ascorbic acid (10 mmol / L) are reacted at 60°C for 80 min) under 365 nm ultraviolet radiation is compared. When the solution is compared with the control solution, the green fluorescence is weakened and the blue fluorescence is enhanced, which indicates that the solution contains trace amounts of parathion, and when the solution color presents obvious blue fluorescence, it indicates that the solution contains a higher concentration of parathion.

Claims

1. A method for rapid detection of parathion, characterized by, The method is: (1) mixing ascorbic acid, 3-aminopropyl triethoxysilane, PBS buffer and the sample to be detected to generate a silicon nanoparticle reaction solution; the concentration of ascorbic acid is 10 mmol / L; the concentration of 3-aminopropyl triethoxysilane is 0.356 mol / L; the concentration of the PBS buffer is 1 mmol / L, and pH is 10.0; the molar ratio of ascorbic acid to 3-aminopropyl triethoxysilane is 10:356; the incubation condition is that the reaction is carried out at 60℃ for 80 min; (2) The parathion in the sample is quantitatively analyzed by establishing a ratio fluorescence signal of the silicon nanoparticle reaction solution, and the specific method of establishing the ratio fluorescence signal is as follows: taking the parathion pesticide concentration as the abscissa and the fluorescence ratio F 422nm / F 520nm as the ordinate, a linear relationship Y=0.4248X+0.6651 is established. or comparing the fluorescence color change of the contrast silicon nanoparticle reaction solution under ultraviolet radiation to qualitatively analyze parathion in the sample to be detected, wherein the fluorescence color change of the contrast silicon nanoparticle reaction solution under ultraviolet radiation is that, under 365 nm ultraviolet radiation, when the silicon nanoparticle reaction solution presents unchanged green fluorescence, it indicates that the silicon nanoparticle reaction solution does not contain trace parathion; when the silicon nanoparticle reaction solution presents a trend of weakened green fluorescence and enhanced blue fluorescence, it indicates that the silicon nanoparticle reaction solution contains trace parathion; when the silicon nanoparticle reaction solution presents obvious blue fluorescence, it indicates that the silicon nanoparticle reaction solution contains high-concentration parathion.

2. The application of the method in claim 1 in detecting the organophosphorus pesticide parathion.

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