A stirring-free solid phase microextraction head and application thereof

Abstract

The application discloses a kind of stirring-free solid-phase microextraction head and its application;Belong to solid-phase microextraction field.The stirring-free solid-phase microextraction head of the present application is composed of substrate and outer coating;The outer coating is made of solution of polyacrylonitrile (PAN) and dimethylformamide is mixed with C18, cation exchange particles (WCX), anion exchange particles (WAX), hydrophilic-lipophilic balance particles (HLB) one or more particles and manganese dioxide;The extraction head is contacted with sample system containing hydrogen peroxide, and hydrogen peroxide is catalyzed by manganese dioxide to generate gas, which provides the power required for extraction by continuously generating bubbles on the surface of the extraction head, realizes stirring-free extraction;Extraction method is simple, fast, time-saving;And it can also effectively improve the accuracy of target analyte detection, wide application range.

Description

Technical Field

[0001] The invention belongs to the field of solid phase microextraction, and in particular relates to a stirring-free solid phase microextraction head and applications thereof. Background Art

[0002] Potassium sorbate is a common preservative in food. Common detection methods include high-performance liquid chromatography, gas chromatography, ultraviolet spectrophotometry, and ion chromatography. Pretreatment methods generally include dilution injection, ultrasonic extraction, microextraction, and dispersive extraction. These methods all require complex sample pretreatment, resulting in time-consuming, cumbersome procedures, and high testing costs.

[0003] Solid-phase microextraction (SPM) is a simple, rapid, solvent-free, and highly sensitive sample pretreatment technology that requires a small sample volume. It has been widely used in various fields such as environment, biology, industry, food, and clinical medicine.

[0004] At present, solid phase microextraction technology is mainly divided into two methods: headspace solid phase microextraction and direct immersion solid phase microextraction. Among them, headspace solid phase microextraction is to extract compounds from the gas above the sample, while direct immersion solid phase microextraction is to extract the target by immersing the extraction head directly into the liquid sample; the direct immersion solid phase microextraction method needs to be placed on a stirrer during extraction to continuously stir the extraction to achieve equilibrium, thereby accelerating the extraction efficiency. Although this method can extract compounds in the sample, it requires a stirrer to assist in extraction. It is not only complicated to operate, time-consuming and labor-intensive, but also inconvenient to implement on-site sampling and extraction; at the same time, during the test, the matrix in the sample to be tested is easy to adhere to the extraction head, affecting the extraction effect.

[0005] Therefore, it is particularly necessary to develop an extraction head that can achieve stirring-free and efficient extraction. Summary of the Invention

[0006] In response to the defects and shortcomings of the existing technology, the present invention provides a stirring-free solid-phase microextraction head and its application. When detecting potassium sorbate, the extraction head is simple and convenient to operate, eliminating the use of a stirring aid, and can effectively improve the detection sensitivity of potassium sorbate.

[0007] The first object of the present invention is to provide a stirring-free solid-phase microextraction tip, which is composed of a substrate and an outer coating; the outer coating is composed of a polyacrylonitrile (PAN) solution mixed with one or more of C18, weak cation exchange particles (WCX), weak anion exchange particles (WAX), hydrophilic-lipophilic balance particles (HLB), and manganese dioxide.

[0008] In one embodiment, the polyacrylonitrile solution is a solution prepared from polyacrylonitrile and dimethylformamide.

[0009] In one embodiment, the substrate includes any one of stainless steel wire, wooden rod, and plastic rod.

[0010] In one embodiment, the coating is 0.11.5 cm long and 5200 μm thick.

[0011] In one embodiment, the content of manganese dioxide is 0.5-1.0% of the total mass of the coating, preferably 0.7%.

[0012] In one embodiment, the mass of PAN is 5-10% of the total mass of the coating.

[0013] In one embodiment, the mass of one or more of C18, WCX, WAX, and HLB is 5-10% of the total mass of the coating.

[0014] In one embodiment, the solid phase microextraction head is prepared by inserting a substrate into a coating, taking it out and drying it.

[0015] A second object of the present invention is to provide a use of the above-mentioned stirring-free solid phase microextraction head in extracting target compounds in a hydrogen peroxide system.

[0016] A third object of the present invention is to provide a method for rapid detection of potassium sorbate by stirring-free solid phase microextraction, the method comprising the following steps:

[0017] (1) Constructing a quantitative relationship model

[0018] A series of potassium sorbate standard solutions are prepared, and potassium sorbate standard solutions of different concentrations are taken and added with hydrogen peroxide solution to form a standard solution system to be tested; the standard solution system to be tested is then extracted using the extraction head described above, and after the extraction is completed, the solution is washed and desorbed to obtain a test solution;

[0019] The test solution was determined by high performance liquid chromatography, with the concentration of potassium sorbate standard solution as the abscissa and the corresponding peak area as the ordinate, to construct a quantitative relationship model;

[0020] (2) Determination of potassium sorbate in the sample to be tested

[0021] A hydrogen peroxide solution is added to the sample to be tested to form a sample system to be tested, and the sample system to be tested is extracted using the extraction head described above. After the extraction is completed, the sample system is washed and desorbed to obtain a test liquid; the potassium sorbate content in the sample to be tested is determined by high performance liquid chromatography and calculated based on the quantitative relationship model constructed in step (2).

[0022] In one embodiment, the extraction time in step (1) is 10 to 30 minutes.

[0023] In one embodiment, the washing in step (1) is performed using ultrapure water for 1-2 min.

[0024] In one embodiment, the desorption in step (1) is performed by inserting the extraction head into an organic solution of methanol, ethanol or acetonitrile, and the desorption time is 1-5 min, and the volume of the organic solvent is 100-200 μL.

[0025] In one embodiment, the mass fraction of the hydrogen peroxide solution in step (1) is 3-5%.

[0026] In one embodiment, the volume ratio of the standard solution to the hydrogen peroxide solution in the standard solution system in step (1) is 1-2:1.

[0027] In one embodiment, the volume ratio of the sample solution to the hydrogen peroxide solution in the sample solution system in step (2) is 1-2:1.

[0028] In one embodiment, the high performance liquid chromatography adopts the following high performance liquid chromatography parameters: an XBridge Shield RP C18 chromatographic column (4.6*250 mm, 5 μm) is used; the flow rate is 0.2-0.6 mL / min; the column temperature is 25-30°C; the injection volume is 5-10 μL; the detection wavelength is 254 nm; and the mobile phase A is methanol, and the B is 20 mmol / L ammonium acetate, and 5% A and 95% B are used for isocratic elution. Compared with the prior art, the present application has the following beneficial effects:

[0029] (1) The present application uses manganese dioxide to prepare a stirring-free solid phase microextraction head, and the extraction head is contacted with a sample system containing hydrogen peroxide, and gas is generated by the manganese dioxide catalyzing the hydrogen peroxide reaction, so that bubbles are continuously generated on the surface of the extraction head to provide the power required for extraction, and stirring-free extraction is achieved. The extraction effect can reach the level of ordinary stirring extraction; the extraction method is simple, fast and time-saving; in addition, the bubbles continuously generated on the surface of the extraction head can also effectively prevent macromolecular substances in the sample from being adsorbed to the surface of the coating, reduce the pollution of the extraction head, and avoid affecting the enrichment of the target detection substance; and the accuracy of the detection of the target detection substance is improved;

[0030] (2) The stirring-free solid phase microextraction head of the present application can form a coating with different stationary phases and manganese dioxide to realize the extraction of different types of compounds, and has a wide range of applications;

[0031] (3) The stirring-free solid phase microextraction potassium sorbate detection method of the present application has high detection sensitivity, does not require a stirrer or a vortex instrument, does not require volatile and toxic reagents, has simple, fast and time-saving operation steps, can extract samples on site, and is suitable for batch operation. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 This is a standard curve diagram of potassium sorbate in Example 1 of the present invention;

[0033] Figure 2 This is a liquid chromatogram of an actual sample of a certain brand of oyster sauce in Example 1 of the present invention;

[0034] Figure 3 This is a data graph showing the potassium sorbate content extracted by extraction heads prepared with different manganese dioxide contents in Example 3 of the present invention;

[0035] Figure 4 It is the liquid chromatogram of Comparative Example 1;

[0036] Figure 5 It is the liquid chromatogram of Comparative Example 2;

[0037] Figure 6 Schematic diagram of sample extraction by the extraction head in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] The specific preparation process of the PAN solution involved in the embodiment of the present invention is as follows:

[0040] A PAN solution was prepared by mixing 0.7 g of PAN with 10 mL of DMF and heating at 90°C for 1 hour.

[0041] Example 1

[0042] A method for rapid detection of potassium sorbate by stirring-free solid phase microextraction, comprising the following steps:

[0043] (1) 0.4 mL of potassium sorbate standard solution of different concentrations (0.3, 1.5, 7.5, 15, and 30 mg / L) and 0.4 mL of a certain brand of oyster sauce were measured and diluted to 1.2 mL with hydrogen peroxide (3 wt%). The mixture was placed in a 2 mL liquid phase sample bottle to prepare the standard samples and test samples with concentrations of 0.1, 0.5, 2.5, 5, and 10 mg / L.

[0044] (2) Extraction tip preparation: An iron wire with a diameter of 0.05 mm was immersed in the coating to form an extraction tip; the coating was 1.0 cm long and 100 μm thick, and the coating was made of 10 mL of PAN solution, 0.7 g of WAX, and 0.07 g of manganese dioxide;

[0045] (3) Extraction: The extraction head prepared in step (2) is inserted into a series of sample bottles to be tested prepared in step (1), and the coating is immersed in the sample to be tested for stirring-free extraction. The extraction time is 20 minutes; the schematic diagram is as follows Figure 6 As shown;

[0046] (4) Washing: Remove the extraction tip after extraction, wash it with ultrapure water for 1 min, and then insert it into a liquid sample bottle containing 150 μL of methanol for desorption for 1 min to form the test solution;

[0047] (5) The test solution of step (4) is measured by high performance liquid chromatography, with the concentration of potassium sorbate standard solution as the horizontal coordinate and the corresponding peak area as the vertical coordinate, to construct a quantitative relationship model (such as Figure 1 and as shown in Table 1); and based on the quantitative relationship and the peak area of ​​the sample to be tested, the content of potassium sorbate in the sample to be tested was calculated;

[0048] HPLC parameters: XBridge Shield RP C18 column (4.6×250 mm, 5 μm); flow rate: 0.5 mL / min; column temperature: 25°C; injection volume: 10 μL; detection wavelength: 254 nm; mobile phase A: methanol, mobile phase B: 20 ​​mmol / L ammonium acetate, isocratic elution: 5% A and 95% B.

[0049] The chromatogram of an actual sample of a certain brand of oyster sauce is as follows: Figure 2 As shown, the content of sorbic acid is 11.48 mg / L.

[0050] Table 1 Detection limit, quantification limit and linear regression equation of potassium sorbate

[0051]

[0052] Example 2

[0053] 0.4 mL of a certain brand of oyster sauce sample was measured as a matrix, and 0.4 mL of potassium sorbate standard solution with concentrations of 0.3, 3, and 30 mg / L was taken, and the volume was made up to 1.2 mL with hydrogen peroxide (3 wt%). The solution was placed in a 2 mL liquid phase sample bottle and prepared into samples with low (0.1 mg / L), medium (1 mg / L), and high (10 mg / L) concentrations. The recovery rate was determined according to the detection method of Example 1. The results are shown in Table 2:

[0054] Table 2 Recovery and precision analysis of spiked samples in matrix (n=3)

[0055]

[0056] It can be seen from the results in the table that the recovery rate determination data meets the national standards and can be used to determine the potassium sorbate content in samples.

[0057] Example 3

[0058] Referring to the detection method of Example 1, the amount of manganese dioxide added during the preparation of the extraction head in step (2) was adjusted to 0 g (0%), 0.05 g (0.5%), 0.06 g (0.6%), 0.07 g (0.7%), and 0.08 g (0.8%); 0.6 mL of potassium sorbate standard solution (2 mg / L) was used to determine the volume to 1.2 mL with hydrogen peroxide (3 wt%) and placed in a 2 mL liquid sample bottle to form a sample to be tested. The test results (peak area of ​​the standard sample) were as follows: Figure 3 shown.

[0059] The results show that during the preparation of the extraction head, the amount of manganese dioxide added has a relatively large impact on the extraction effect of potassium sorbate. As the amount of manganese dioxide added increases, the corresponding peak area of ​​potassium sorbate also continues to increase; this shows that the prepared extraction head can extract more potassium sorbate from the sample. However, when the manganese dioxide content continues to increase (exceeding the addition amount of 0.7%), the peak area of ​​potassium sorbate decreases instead, indicating that during the preparation of the extraction head, excessive manganese dioxide is not conducive to the effective extraction of potassium sorbate from the sample.

[0060] Comparative Example 1

[0061] A method for rapid detection of potassium sorbate by solid phase microextraction, comprising the following steps:

[0062] (1) Measure 0.6 mL of potassium sorbate standard solution (2 mg / L), dilute to 1.2 mL with hydrogen peroxide (3 wt%), and place in a 2 mL liquid phase sample bottle to form the sample to be tested;

[0063] (2) Extraction head preparation: An iron wire with a diameter of 0.05 mm was immersed in the coating to form an extraction head; the coating was 1.0 cm long and 100 μm thick, and the coating was made of 10 mL PAN and 0.7 g WAX;

[0064] (3) Extraction: insert the extraction head prepared in step (2) into the liquid sample bottle of step (1), immerse the coating in the sample to be tested and perform extraction without stirring, the extraction time is 20 minutes;

[0065] (4) Washing: Remove the extraction tip after extraction, wash it with ultrapure water for 1 min, and then insert it into a liquid sample bottle containing 150 μL of methanol for desorption for 1 min to form the test solution;

[0066] (5) using high performance liquid chromatography to measure the test solution of step (4);

[0067] Among them, the high performance liquid chromatography parameters are as follows: XBridge Shield RP C18 column (4.6×250 mm, 5 μm) was used for analysis; flow rate: 0.5 mL / min; column temperature: 25°C; injection volume: 10 μL; detection wavelength: 254 nm; mobile phase A was methanol, B was 20 mmol / L ammonium acetate, and 5% A and 95% B were used for isocratic elution.

[0068] The results are as follows Figure 4 As shown in the figure: when the extraction head without manganese dioxide was used for extraction, the average recovery rate of potassium sorbate was only 52.37%, and the relative standard deviation was 8.28%.

[0069] Comparative Example 2

[0070] A method for rapid detection of potassium sorbate by solid phase microextraction, comprising the following steps:

[0071] (1) Measure 0.6 mL of potassium sorbate standard solution (2 mg / L), dilute to 1.2 mL with hydrogen peroxide (3 wt%), and place in a 2 mL liquid phase sample bottle to form the sample to be tested;

[0072] (2) Extraction tip preparation: An iron wire with a diameter of 0.05 mm was immersed in the coating to form an extraction tip; the coating was 1.0 cm long and 100 μm thick, and the coating was made of 10 mL PAN and 0.7 g WAX;

[0073] (3) Extraction: insert the extraction head prepared in step (2) into the liquid sample bottle of step (1), immerse the coating in the sample to be tested and stir and extract at a stirring speed of 500 rpm for 20 min;

[0074] (4) Washing: Remove the extraction tip after extraction, wash it with ultrapure water for 1 min, and then insert it into a liquid sample bottle containing 150 μL of methanol for desorption for 1 min to form the test solution;

[0075] (5) using high performance liquid chromatography to measure the test solution of step (4);

[0076] Among them, the high performance liquid chromatography parameters are as follows: XBridge Shield RP C18 column (4.6×250 mm, 5 μm) was used for analysis; flow rate: 0.5 mL / min; column temperature: 25°C; injection volume: 10 μL; detection wavelength: 254 nm; mobile phase A was methanol, B was 20 mmol / L ammonium acetate, and 5% A and 95% B were used for isocratic elution.

[0077] The results are as follows Figure 5As shown, when an extraction head without manganese dioxide was used and the extraction was performed under stirring conditions, the average recovery rate of potassium sorbate was determined to be 99.54% and the relative standard deviation was 3.97%.

Claims

1. A method for rapid detection of potassium sorbate by stirring-free solid phase microextraction, characterized in that: The method comprises the following steps: (1) Constructing a quantitative relationship model A series of potassium sorbate standard solutions are prepared, and hydrogen peroxide solution is added to potassium sorbate standard solutions of different concentrations to form a standard solution system to be tested; the standard solution system to be tested is then extracted using a stirring-free solid phase microextraction head, and after the extraction is completed, the solution is washed and desorbed to obtain a test solution; The test solution was determined by high performance liquid chromatography, with the concentration of potassium sorbate standard solution as the abscissa and the corresponding peak area as the ordinate, to construct a quantitative relationship model; (2) Determination of potassium sorbate in the sample to be tested A hydrogen peroxide solution is added to the sample to be tested to form a sample system to be tested, and the sample system to be tested is extracted using a stirring-free solid phase microextraction head. After the extraction is completed, washing and desorption are performed to obtain a test solution; Determine by high performance liquid chromatography and calculate the content of potassium sorbate in the sample according to the quantitative relationship model constructed in step (2); The stirring-free solid phase microextraction head consists of a substrate and an outer coating; the outer coating is a mixture of polyacrylonitrile (PAN) solution and one or more of C18, weak cation exchange particles WCX, weak anion exchange particles WAX, hydrophilic-lipophilic balance particles HLB, and manganese dioxide.

2. The method according to claim 1, characterized in that The content of the manganese dioxide is 0.5-1.0% of the total mass of the coating.

3. The method according to claim 1, characterized in that The base material includes any one of stainless steel wire, wooden rod and plastic rod.

4. The method according to claim 1, wherein The coating has a length of 0.1-1.5 cm and a thickness of 5-200 μm.

5. The method according to claim 1, wherein The mass of PAN is 5-10% of the total mass of the coating.

6. The method according to claim 1, characterized in that In step (1), the volume ratio of the standard solution to the hydrogen peroxide solution in the standard solution system to be tested is 1-2:1; and the mass fraction of the hydrogen peroxide solution is 3-5%.

7. The method according to claim 1, characterized in that The desorption in step (1) is specifically performed by inserting the extraction head into an organic solution of methanol, ethanol or acetonitrile for desorption, the desorption time is 1 to 5 minutes, and the volume of the organic solvent is 100 to 200 μL.

8. The method according to claim 1, wherein The HPLC parameters used in the HPLC method are as follows: an XBridge Shield RP C18 column 4.6×250 mm, 5 μm; a flow rate of 0.2-0.6 mL / min; a column temperature of 25-30°C; an injection volume of 5-10 μL; a detection wavelength of 254 nm; and mobile phases A and B of 20 mmol / L ammonium acetate, with isocratic elution of 5% A and 95% B.

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