Preparation and application of green and efficient supramolecular extractant

Abstract

The invention discloses a preparation method and application of a green and efficient supramolecular solvent, and belongs to the technical field of food safety detection. The supramolecular extractant can be used for efficiently and rapidly extracting perfluorinated and polyfluoroalkyl compounds and sulfonamides in food. The supramolecular micro-extraction agent is prepared from n-heptanol, tetrahydrofuran and pure water with the pH value of 6, wherein the volume ratio of the raw materials is as follows: n-heptanol: tetrahydrofuran: pure water is 1: 4: 35. The extraction process of the supramolecular micro-extractant comprises the following steps: weighing 2 g of a food sample, putting the food sample into a 50 mL polypropylene centrifuge tube, adding 1 mL of a supramolecular solvent, then adding 0.1 g of NaCl, carrying out vortex for 5 min, carrying out centrifugation for 10 min, diluting the supernatant with methanol according to a ratio of 1: 1, and carrying out filtration with a 0.22 [mu] m organic filter membrane for LC-MS / MS analysis. The supramolecular extractant provided by the invention can replace a traditional organic solvent with high toxicity to realize rapid detection of perfluorinated and polyfluoroalkyl compounds in food. The preparation process of the supramolecular extractant is simple, the steps of purification, nitrogen blowing concentration and the like are not needed in the extraction process, and the supramolecular extractant has the advantages of being green, simple, efficient, low in cost and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of food detection, and in particular to the preparation and application of a green and efficient supramolecular extractant. Background Art

[0002] In recent years, with people's general concern about environmental issues, traditional analytical methods (alkaline digestion, solid phase extraction, ultrasonic extraction, etc.) are gradually unacceptable due to the use of toxic and harmful reagents and the generation of a large amount of waste, cumbersome operation and long time consumption. The concept of green analytical chemistry has emerged. Green analytical chemistry is the application of the principles of green chemistry to the development of new analytical methods, which can reduce and eliminate the use and generation of toxic and harmful substances in the analytical process and minimize environmental pollution. Green sample pretreatment is the basis for realizing green analytical chemistry.

[0003] Supramolecular solvents (SUPRASs) are three-dimensional aggregate solutions with unique nanostructures formed by the self-assembly of surfactants through intermolecular forces. This new supramolecular solvent microextraction (SSME) technology has the advantages of being simple, rapid, high enrichment multiples, low cost, and environmentally friendly. It is very likely to replace traditional organic extractants and achieve revolutionary breakthroughs and developments in analytical extraction processes and even separation industries. Therefore, it is urgent to study a green and efficient supramolecular extractant to simplify the pretreatment process, reduce the amount of organic solvents, improve detection efficiency, and achieve green and efficient analytical results. Summary of the invention

[0004] The main purpose of the present invention is to provide a green and efficient supramolecular extractant, which can efficiently micro-extract perfluorinated and polyfluoroalkyl compounds, sulfonamide antibiotics and other pollutants in food, and realize green and rapid detection of pollutants such as perfluorinated compounds in food.

[0005] The present invention adopts the following technical solution:

[0006] The invention provides a green and efficient supramolecular extractant, characterized in that the supramolecular extractant consists of n-heptanol, tetrahydrofuran and pure water.

[0007] The pH of the pure water used in the present invention is 6.

[0008] Furthermore, the preferred volume ratio of the supramolecular microextraction agent components is n-heptanol:tetrahydrofuran:pure water=1:4:35.

[0009] Furthermore, a preferred method for preparing the supramolecular extractant comprises: uniformly mixing n-heptanol, tetrahydrofuran and pure water (pH=6) in a volume ratio of 1:4:35, vortexing for 10 minutes, centrifuging at 4000 r / min for 10 minutes, and aspirating the supernatant.

[0010] The present invention also provides an application method of the supramolecular extractant, which comprises the following steps:

[0011] Weigh 2 g of food sample into a 50 mL polypropylene centrifuge tube, add 1 mL of supramolecular solvent, then add 0.1 g of NaCl, vortex for 5 min, and centrifuge for 10 min. The supernatant is diluted 1:1 with methanol and filtered through a 0.22 μm organic filter for LC-MS / MS analysis.

[0012] The components and application method of the supramolecular extractant of the present invention are obtained by the applicant through a large number of repeated practices. The advantages and positive effects of the supramolecular extractant of the present invention are:

[0013] The supramolecular extractant of the present invention can efficiently microextract pollutants such as perfluorinated compounds in food, realize green and rapid detection of 23 kinds of pollutants such as perfluorinated compounds in food, and solve the problems of high toxicity, environmental pollution and low extraction efficiency of traditional organic solvents;

[0014] The supramolecular extractant of the present invention has a strong enrichment ability and can efficiently extract pollutants such as perfluorinated compounds in food under trace conditions;

[0015] The supramolecular extractant of the present invention does not require purification, nitrogen blowing and concentration steps during the extraction process, which can simplify the operation steps and greatly improve the analysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0017] Figure 1 Screening of supramolecular solvent alkyl alcohols;

[0018] Figure 2 n-Heptanol volume optimization;

[0019] Figure 3 THF volume optimization;

[0020] Figure 4 The effect of vortex time on the extraction efficiency of PFASs;

[0021] Figure 5 The effect of extraction salt on the extraction efficiency of PFASs;

[0022] Figure 6 Effect of matrix sample weight on PFASs extraction efficiency. DETAILED DESCRIPTION

[0023] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0024] Taking the trace presence of perfluorinated and polyfluorinated alkyl compounds in hairy crabs as an example, a green and efficient supramolecular extraction agent was optimized and screened to achieve the green and efficient extraction of perfluorinated and polyfluorinated alkyl compounds in hairy crabs.

[0025] Example 1

[0026] Screening of components for supramolecular preparation

[0027] Select the conventionally purchased n-heptanol, n-octanol and dodecanol, mix them with tetrahydrofuran and pure water respectively, then vortex for 10 minutes, centrifuge at 4000r / min for 10 minutes, and absorb the supernatant to obtain the supramolecular extractant.

[0028] Extraction: Accurately weigh 2g of crab sample and place it in a 50mL polypropylene centrifuge tube, add 1mL of supramolecular solvent, then add 0.1g NaCl, vortex for 5min, and centrifuge for 10min. Aspirate the supernatant, add methanol in a 1:1 ratio, vortex and mix, pass through a 0.22μm organic filter membrane, and provide LC-MS / MS analysis. The extraction recovery rate of 23 perfluorinated and polyfluorinated alkyl compounds was used as the basis for the evaluation of supramolecular extractants.

[0029] Depend on Figure 1 It can be seen that the extraction efficiency of short-chain perfluoro and polyfluoroalkyl compounds increases with the increase of the carbon chain of alkyl alcohol, while the extraction efficiency of long-chain perfluoro and polyfluoroalkyl compounds gradually decreases with the increase of the carbon chain of alkyl alcohol. Among the three alkyl alcohols tested, the extraction effect and recovery rate of n-heptanol are relatively good. Comprehensive analysis of the results shows that n-heptanol is preferred as the raw material for the preparation of supramolecular solvents.

[0030] Screening of supramolecular component ratios

[0031] Example 1.1

[0032] n-Heptanol, tetrahydrofuran and pure water were mixed evenly according to the volume ratios of 1:4:35, 2:4:34, 3:4:33 and 4:4:32, respectively, and then vortexed for 10 minutes, centrifuged at 4000 r / min for 10 minutes, and the supernatant was aspirated to obtain the supramolecular extractant.

[0033] Extraction: Accurately weigh 2g crab sample and place it in a 50mL polypropylene centrifuge tube, add 1mL supramolecular solvent, then add 0.1g NaCl, vortex for 5min, centrifuge for 10min. Aspirate the supernatant, add methanol in a 1:1 ratio, vortex and mix, pass through a 0.22μm organic filter membrane, and prepare for LC-MS / MS analysis.

[0034] Example 1.2

[0035] n-Heptanol, tetrahydrofuran and pure water were mixed evenly according to the volume ratios of 1:2:37, 1:4:35, 1:6:33 and 1:8:31 respectively, and then vortexed for 10 minutes, centrifuged at 4000 r / min for 10 minutes, and the supernatant was aspirated to obtain the supramolecular extractant.

[0036] Extraction: Accurately weigh 2g crab sample and place it in a 50mL polypropylene centrifuge tube, add 1mL supramolecular solvent, then add 0.1g NaCl, vortex for 5min, centrifuge for 10min. Aspirate the supernatant, add methanol in a 1:1 ratio, vortex and mix, pass through a 0.22μm organic filter membrane, and prepare for LC-MS / MS analysis.

[0037] The supramolecular solvents prepared in Comparative Examples 1 and 2 are Figure 2 and Figure 3 The results show that the volume of n-heptanol has no significant effect on the extraction recovery of 23 perfluoro and polyfluoroalkyl compounds. As the volume ratio of tetrahydrofuran increases, the extraction recovery of 23 perfluoro and polyfluoroalkyl compounds gradually increases. The extraction recovery rate is the highest under the ratio of 1:4:35, and the extraction efficiency does not increase at last. In summary, it is preferred to prepare supramolecular solvents with a ratio of n-heptanol, tetrahydrofuran and pure water of 1:4:35.

[0038] Example 2 Optimization of the extraction process

[0039] Example 2.1

[0040] n-Heptanol, tetrahydrofuran and pure water were mixed evenly in a volume ratio of 1:4:35, then vortexed for 10 minutes, centrifuged at 4000 r / min for 10 minutes, and the supernatant was aspirated to obtain a supramolecular extractant.

[0041] Extraction: Accurately weigh 2g crab sample and put it into a 50mL polypropylene centrifuge tube, add 1mL supramolecular solvent, then add 0.1g NaCl, vortex for 2min, 5min and 10min respectively, centrifuge for 10min. Aspirate the supernatant, add methanol in a 1:1 ratio, vortex and mix, pass through a 0.22μm organic filter membrane, and prepare for LC-MS / MS analysis.

[0042] Example 2.2

[0043] n-Heptanol, tetrahydrofuran and pure water were mixed evenly in a volume ratio of 1:4:35, then vortexed for 10 minutes, centrifuged at 4000 r / min for 10 minutes, and the supernatant was aspirated to obtain a supramolecular extractant.

[0044] Extraction: Accurately weigh 2 g of crab sample and place it in a 50 mL polypropylene centrifuge tube. Add 1 mL of supramolecular solvent and 0.1 g of NaCl, CaCl 2NH 4 Cl 3 kinds of extraction salts, vortex for 5 minutes, centrifuge for 10 minutes. Aspirate the supernatant, add methanol in a ratio of 1:1, vortex mix, pass through a 0.22μm organic filter membrane, and prepare for LC-MS / MS analysis.

[0045] Example 2.3

[0046] n-Heptanol, tetrahydrofuran and pure water were mixed evenly in a volume ratio of 1:4:35, then vortexed for 10 minutes, centrifuged at 4000 r / min for 10 minutes, and the supernatant was aspirated to obtain a supramolecular extractant.

[0047] Extraction: Accurately weigh 1g, 2g, 3g, and 5g of crab samples respectively and put them into 50mL polypropylene centrifuge tubes, add 1mL of supramolecular solvent, add 0.1g of NaCl respectively, vortex for 5min, centrifuge for 10min, aspirate the supernatant, add methanol in a 1:1 ratio, vortex mix, and pass through a 0.22μm organic filter membrane for LC-MS / MS analysis.

[0048] The extraction process of comparative examples 1 to 3 is as follows: Figure 4-Figure 6 The results showed that the extraction efficiency increased with the increase of vortex time during 2-10 min vortex extraction, but there was no significant difference between 5 min and 10 min extraction. 2 When used as an extraction salt, the extraction efficiency of per- and polyfluoroalkyl compounds is the lowest, and NH 4 The extraction efficiency of perfluorinated and polyfluorinated alkyl compounds was unstable when Cl was used as the extraction salt; the extraction efficiency continued to decrease with the increase of sample weight, but there was no significant difference between 1g and 2g. In summary, the preferred extraction method was to weigh 2g crab sample, add 1mL supramolecular solvent, add 0.1g NaCl, vortex for 5min, and centrifuge for 10min.

[0049] Example 3

[0050] The optimal supramolecular preparation method and extraction method optimized in the examples were used to extract and detect trace amounts of perfluoroalkyl and polyfluoroalkyl compounds and sulfonamide antibiotic pollutants in hairy crabs.

[0051] (1) Preparation of supramolecular extractant: n-heptanol, tetrahydrofuran and pure water were mixed uniformly in a volume ratio of 1:4:35, and then vortexed for 10 minutes and centrifuged at 4000 r / min for 10 minutes. The supernatant was aspirated to obtain the supramolecular extractant.

[0052] (2) Extraction process: Accurately weigh 2 g of crab sample and put it into a 50 mL polypropylene centrifuge tube, add 10 ng of perfluoroalkyl and polyfluoroalkyl compounds as internal standard and 50 ng of sulfonamide antibiotics as internal standard, add 1 mL of supramolecular solvent, add 0.1 g of NaCl respectively, vortex for 5 min, centrifuge for 10 min, aspirate the supernatant, add methanol in a 1:1 ratio, vortex mix, and filter through a 0.22 μm organic filter membrane for LC-MS / MS analysis.

[0053] As shown in the results of Table 1 and Table 2, within the range of spiked concentrations, the average recoveries of 23 perfluorinated and polyfluorinated alkyl compounds were 70.1-129%, with RSDs of 3.40-19.9%, and the average recoveries of 12 sulfonamide antibiotics were 70.5-98.2%, with RSDs of 6.9-19.1%, which met the standard requirements for recovery and precision, indicating that the method has good accuracy and repeatability. This detection method has the advantages of simplicity, high efficiency, low cost, and environmental friendliness. It uses trace amounts of green and efficient supramolecular solvents to replace traditional highly toxic organic extractants, and does not require purification, nitrogen blowing, and concentration steps, greatly improving the analysis efficiency.

[0054] Table 1 Average recoveries and relative standard deviations (RSDs) of per- and polyfluoroalkyl compounds in hairy crabs

[0055]

[0056]

[0057] Table 2 Recovery and relative standard deviation (RSD) of sulfonamide antibiotics in hairy crabs

[0058]

[0059] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A green and efficient supramolecular extractant, characterized in that: The supramolecular extractant components include n-heptanol, tetrahydrofuran and pure water, wherein the volume ratio of the component raw materials is as follows: n-heptanol: tetrahydrofuran: pure water is 1:4:35; the pH of the pure water is 6; and efficient extraction of a variety of perfluorinated and polyfluorinated alkyl compounds and sulfonamide drugs can be achieved.

2. The method for preparing the supramolecular extractant according to claim 1, characterized in that: The preparation method of the supramolecular microextractant comprises: preparing n-heptanol, tetrahydrofuran and pure water, vortexing for 10 minutes, centrifuging at 4000 r / min for 10 minutes, and absorbing the supernatant.

3. The use of the supramolecular extractant according to claim 1, characterized in that: Weigh 2 g of food sample into a 50 mL polypropylene centrifuge tube, add 1 mL of supramolecular solvent, then add 0.1 g of NaCl, vortex for 5 min, and centrifuge for 10 min. The supernatant is diluted 1:1 with methanol and filtered through a 0.22 μm organic filter for LC-MS / MS analysis.

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