A nanomaterial-assisted multi-level pre-treated soil analysis and detection method

Abstract

The invention discloses a multi-level pretreatment soil analysis and detection method based on nanomaterials, which relates to the field of soil analysis and detection technology. The technical scheme is logistics pretreatment: soil particles are dispersed by mechanical vibration and ultrasonic treatment; trace elements in the soil are released by weak acid extraction in the first step, strong acid digestion in the second step, and alkaline treatment in the third step; the sample after chemical pretreatment is mixed with carbon nanotubes and modified polylactic acid-glycolic acid copolymer (PLGA) nanoparticles, reacted on a magnetic stirrer, and the adsorbed nanoparticles are separated from the sample by centrifugation; a chromatographic column is used, and the mobile phase gradient is eluted, and then detected by a detector. Through mechanical vibration and ultrasonic treatment, multi-level acid-base extraction, nanomaterial-assisted detection and chromatographic technology optimization, the sample processing efficiency and uniformity, trace element release rate, target substance enrichment ability and analysis accuracy and sensitivity are effectively improved, and the detection effect is significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil analysis and detection, and in particular to a nanomaterial-assisted multi-level pre-processed soil analysis and detection method. Background Art

[0002] In today's society, accurate assessment of soil quality is of great significance to agricultural production, environmental protection and human health. However, with the continuous development of industrialization and urbanization, soil pollution has become increasingly serious, and the accumulation of trace elements and harmful substances has become a serious problem. The presence of these trace elements and harmful substances not only threatens plant growth, soil ecosystems and crop quality, but also may pose potential risks to human health.

[0003] Traditional soil analysis methods often face many challenges and limitations. First, the complexity and diversity of soil samples make it difficult for traditional methods to meet the needs of accurate detection of trace elements and harmful substances. Second, traditional methods often require a lot of time and resources. There are many steps in the sample pretreatment, extraction and analysis process. The operation is complicated and susceptible to external interference. In addition, the sensitivity and selectivity of traditional methods are also difficult to meet the requirements of current soil analysis, and they are often unable to effectively distinguish and detect trace elements and harmful substances.

[0004] Therefore, how to improve the sensitivity, accuracy and ease of operation of soil analysis methods has become a technical problem that needs to be solved urgently. Traditional analysis methods alone can no longer meet the needs of accurate soil quality assessment, and new technical means and methods must be sought to solve this problem. Therefore, it is particularly urgent and necessary to develop a novel and efficient soil analysis and detection method.

[0005] The invention aims to improve the sensitivity and accuracy of soil analysis by introducing nanomaterial-assisted multi-level pretreatment technology to address the limitations and shortcomings of traditional soil analysis methods, simplify the operation steps, and reduce costs, thereby better meeting the demand for accurate soil quality assessment. This is of great significance for promoting the development of soil analysis technology, protecting the soil ecological environment, and maintaining human health and social stability. Summary of the invention

[0006] In order to achieve the above-mentioned invention objectives and address the above-mentioned technical problems,

[0007] The present invention provides a nanomaterial-assisted multi-level pre-treated soil analysis and detection method, comprising the following steps:

[0008] A1 Material pretreatment: Disperse soil particles through mechanical vibration and ultrasonic treatment;

[0009] A2 multi-stage acid-base extraction: through the first step of weak acid extraction, the second step of strong acid digestion, and the third step of alkaline treatment, it is used to release trace elements in the soil;

[0010] A3 Nanomaterial-assisted detection: The chemically pretreated sample was mixed with carbon nanotubes and modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles, reacted on a magnetic stirrer, and the adsorbed nanoparticles were separated from the sample by centrifugation;

[0011] A4 Optimization of chromatography technology: using a chromatographic column with a gradient elution of water and methanol as the mobile phase, followed by detection with a mass spectrometer detector.

[0012] Preferably, in step A1, the mechanical vibration is performed using a vibrating screen at a frequency of 300 rpm for 20-40 minutes; the soil sample is ultrasonically treated at a frequency of 40 kHz for 10-20 minutes to preliminarily homogenize the sample.

[0013] Preferably, in step A2, the first step of weak acid leaching is to use a 0.1M acetic acid solution with a pH of 3 to soak the sample for 1-2 hours; after the first step, concentrated nitric acid is added to the sample, and the sample is heated and digested at 150°C for 0.5-1 hour; in the third step, the digested sample is neutralized with 10% sodium hydroxide and shaken again for 10-20 minutes.

[0014] Preferably, the amount of carbon nanotubes and poly(lactic-co-glycolic acid) (PLGA) nanoparticles is 0.5-2 mg per 1 g of soil, respectively, and the reaction is carried out on a magnetic stirrer for 0.5-1 hour, and then the adsorbed nanoparticles are separated from the sample using a centrifuge, and centrifuged at 5000 rpm for 10 minutes.

[0015] Preferably, the carbon nanotubes have a purity of 95% to 99%, a length of 10 to 500 nanometers, and a diameter of 10 to 20 nanometers.

[0016] Preferably, the modified poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles are prepared by the following method:

[0017] B1: PLGA was dissolved in ethyl acetate to a concentration of 10 mg / mL, and then added dropwise into deionized water, emulsified by ultrasound, and stirred continuously to evaporate the ethyl acetate to form PLGA nanoparticles;

[0018] B2 immersing the PLGA nanoparticles obtained in step B1 into a crosslinker solution and stirring at room temperature for 1-2 hours to activate the particle surface;

[0019] B3 Mix the activated particles with the chelating agent solution and continue stirring for usually 0.5 hours.

[0020] B4 uses a centrifuge to centrifuge the mixed solution, the centrifuge speed is 5000 rpm, and the centrifugation time is 10 minutes.

[0021] B5 The separated nanoparticles are properly washed and dried to obtain modified polylactic acid-glycolic acid copolymer (PLGA) nanoparticle products.

[0022] Preferably, the cross-linking agent is glutaraldehyde at a concentration of 2-7 mg / ml.

[0023] Preferably, the chelating agent is ethylenediaminetetraacetic acid (EDTA) at a concentration of 5-15 mM.

[0024] Preferably, in step A4, a C18 chromatographic column is used with a flow rate of 1.0 mL / min and a mass spectrometer detector is used for scanning.

[0025] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0026] Improve sample processing efficiency and uniformity: Through mechanical vibration and ultrasonic treatment, soil particles are effectively dispersed, making the sample more uniform, speeding up the sample pre-treatment, improving the efficiency of sample processing, and being able to more thoroughly break up soil agglomerates, making the sample easier to handle.

[0027] Improve the release rate of trace elements: The multi-stage acid-base extraction method can effectively release the trace elements in the soil and improve the release rate and solubility of the trace elements. The combined application of weak acid extraction, strong acid digestion and alkaline treatment allows the trace elements in the soil to be released more fully, providing a more reliable sample basis for subsequent analysis.

[0028] Enhance the enrichment capacity of target substances: Using carbon nanotubes and modified PLGA nanoparticles as adsorbents can effectively enrich trace elements and harmful substances in the soil. These nanomaterials have a high specific surface area and adsorption performance, can quickly and efficiently adsorb target substances, and improve the enrichment capacity of target substances in samples.

[0029] Improve the accuracy and sensitivity of analysis: Through the optimization of chromatography technology, trace elements and harmful substances in samples can be separated and detected efficiently, quickly and accurately. The combined application of chromatographic columns and mass spectrometers improves the accuracy and sensitivity of analysis, making the analysis results more reliable and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the spectrum of Example 1 of the present invention.

[0031] Figure 2 This is the spectrum of Example 7 of the present invention.

[0032] Figure 3 This is the spectrum of Example 15 of the present invention.

[0033] Figure 4 This is the spectrum of Example 2 of the present invention.

[0034] Figure 5 This is the spectrum of Example 11 of the present invention.

[0035] Figure 6 This is the spectrum of Example 4 of the present invention.

[0036] Figure 7 This is the spectrum of Example 6 of the present invention.

[0037] Figure 8 It is the spectrum of comparative example 1 of the present invention.

[0038] Fig. 9 It is the spectrum of comparative example 3 of the present invention.

[0039] Fig.10 It is the spectrum of comparative example 4 of the present invention.

[0040] Fig.11 It is the spectrum of Comparative Example 2 of the present invention.

[0041] Fig.12 It is the spectrum of comparative example 5 of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0043] Example 1

[0044] A nanomaterial-assisted multi-level pre-processed soil analysis and detection method comprises the following steps:

[0045] The soil samples were mechanically vibrated using a vibrating screen at a frequency of 300 rpm for 30 min, and then ultrasonicated at a frequency of 40 kHz for 15 min to ensure initial homogenization of the samples.

[0046] The mechanically treated samples were subjected to multi-stage acid-base leaching:

[0047] The first step of weak acid extraction used 0.1 M acetic acid solution with a pH of 3 and an immersion time of 1.5 h.

[0048] After the first step, concentrated nitric acid was added and the sample was heated for digestion at 150°C for 40 minutes.

[0049] The digested samples were neutralized in the third step using 10% sodium hydroxide with a shaking time of 15 min.

[0050] Nanomaterials assisted detection:

[0051] Carbon nanotubes and PLGA nanoparticles were used at a dosage of 1 mg to 1 g of soil, respectively.

[0052] The reaction time was 45 min on a magnetic stirrer.

[0053] The adsorbed nanoparticles were separated from the sample using a centrifuge at a speed of 5000 rpm for 10 min.

[0054] Optimization of chromatography techniques:

[0055] A C18 column was used and the flow rate was set at 1.0 mL / min.

[0056] Mass spectrometer detector scan.

[0057] Carbon nanotube parameters:

[0058] Purity is 98%; length is 200 nanometers; diameter is 15 nanometers.

[0059] Preparation of modified PLGA nanoparticles:

[0060] B1: The concentration of PLGA solution was 10 mg / mL, and ethyl acetate was evaporated by ultrasonic emulsification to form nanoparticles.

[0061] B2: Use 5 mg / ml glutaraldehyde as a cross-linking agent and stir for 1.5 hours to activate the particle surface.

[0062] B3: Use 10 mM EDTA as chelating agent and stir for 0.5 hours.

[0063] B4: Use a centrifuge for centrifugal separation at a speed of 5000 rpm for 10 minutes.

[0064] B5: The separated nanoparticles are properly washed and dried.

[0065] Example 2

[0066] The same detection method as in Example 1 was followed, except that the mechanical vibration time was 20 minutes and the ultrasonic treatment time was 10 minutes.

[0067] Example 3

[0068] The same detection method as in Example 1 was followed, except that the mechanical vibration time was 40 minutes and the ultrasonic treatment time was 20 minutes.

[0069] Example 4

[0070] The same detection method as in Example 1 was used, except that the weak acid extraction time was 1 hour, the strong acid digestion time was 30 minutes, and the alkali treatment time was 10 minutes.

[0071] Example 5

[0072] The same detection method as in Example 1 was used, except that the weak acid extraction time was 2 hours, the strong acid digestion time was 60 minutes, and the alkali treatment time was 20 minutes.

[0073] Example 6

[0074] The same detection method as in Example 1 was used, except that the amount of nanomaterial used was 0.5 mg.

[0075] Example 7

[0076] The same detection method as in Example 1 was used, except that the amount of nanomaterial used was 2 mg.

[0077] Example 8

[0078] The same detection method as in Example 1 was used, except that the magnetic stirring time was 30 minutes, the centrifuge speed was 3000 rpm, and the time was 10 minutes.

[0079] Example 9

[0080] The same detection method as in Example 1 was used, except that the magnetic stirring time was 60 minutes, the centrifuge speed was 7000 rpm, and the time was 20 minutes.

[0081] Example 10

[0082] The same detection method as in Example 1 was used, except that the purity of the carbon nanotubes was 95%.

[0083] Embodiment 11

[0084] The detection method is the same as that in Example 1, except that the length of the carbon nanotubes is 500 nanometers.

[0085] Example 12

[0086] The detection method was the same as in Example 1, except that the concentration of the cross-linking agent was 2 mg / ml.

[0087] Embodiment 13

[0088] The same detection method as in Example 1 was followed, except that the cross-linking agent concentration was 7 mg / ml.

[0089] Embodiment 14

[0090] The same detection method as in Example 1 was followed, except that the concentration of the chelating agent was 5 mM.

[0091] Embodiment 15

[0092] The same detection method as in Example 1 was followed, except that the concentration of the chelating agent was 15 mM.

[0093] Comparative Example 1

[0094] The same detection method as in Example 1 was used, except that the samples were not subjected to mechanical shaking.

[0095] Comparative Example 2

[0096] The same detection method as in Example 1 was used, except that the samples were not subjected to acid or alkali treatment.

[0097] Comparative Example 3

[0098] The same detection method as in Example 1 was followed, except that no carbon nanotubes were added.

[0099] Comparative Example 4

[0100] The same detection method as in Example 1 was used except that PLGA nanoparticles were not added.

[0101] Comparative Example 5

[0102] The same detection method as in Example 1 is used, except that no nanomaterial is used to assist in the detection.

[0103] Experimental test: Agilent, DESKTOP-J446SVU\GC-MS was used for detection

[0104] Testing items: soil VOC testing

[0105] Table 1 Example 1 Test results

[0106] Table 2 Test results of Example 7

[0107]

[0108] Table 3 Test results of Example 15

[0109]

[0110] Table 4 Test data of Example 2

[0111] Table 5 Test data of Example 11

[0112]

[0113] Table 6 Test data of Example 4

[0114]

[0115] Table 7 Test data of Example 6

[0116]

[0117] Table 8 Test data of comparative example 1

[0118]

[0119]

[0120] Table 9 Test data of comparative example 3

[0121] Table 10 Test data of comparative example 4

[0122]

[0123] Table 11 Test data of comparative example 2

[0124] Table 12 Test data of comparative example 5

[0125] in conclusion:

[0126] Mechanical vibration and ultrasonic treatment: provide effective sample homogenization, make soil particles more uniform, and improve detection sensitivity. Comparison of Example 1 with Comparative Example 1 shows that mechanical vibration treatment significantly improves detection sensitivity.

[0127] Multi-stage acid-base extraction: effectively release trace elements in the soil and improve detection sensitivity. Compared with Example 1 and Comparative Example 2, the lack of acid-base treatment leads to a significant decrease in sensitivity, indicating that multi-stage acid-base extraction is crucial.

[0128] Nanomaterial-assisted detection: Carbon nanotubes and PLGA nanoparticles significantly improve sensitivity.

[0129] Comparison of Example 1 with Comparative Examples 3 and 4 shows that the lack of any nanomaterial will significantly reduce the sensitivity.

[0130] Optimization parameters: Various parameters such as vibration and ultrasonic time, acid-base treatment time, and nanomaterial dosage have a significant impact on sensitivity. In Example 7, the sensitivity is further improved by increasing the nanomaterial dosage; in Example 6, the sensitivity is significantly reduced by reducing the nanomaterial dosage.

[0131] Comparative Example 5: No nanomaterial-assisted detection. The sensitivity is extremely low and the detection effect is the worst. The comparison of no nanomaterial-assisted detection clearly shows the key role of nanomaterials in improving detection sensitivity.

[0132] Comparative Example 2 Analysis Sensitivity: Very low, lowest sensitivity, lacks the comparison of acid-base treatment steps, emphasizing the importance of acid-base treatment in releasing trace elements in soil and improving sensitivity.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A nanomaterial-assisted multi-level pre-treated soil analysis and detection method, characterized in that: The following steps are involved: A1 Material pretreatment: Soil particles are dispersed by mechanical vibration and ultrasonic treatment. Mechanical vibration uses a vibrating screen at a frequency of 300 rpm for 20-40 minutes. Soil samples are treated with ultrasonic waves at a frequency of 40 kHz for 10-20 minutes to make the samples preliminarily homogenized. A2 multi-stage acid-base extraction: through the first step of weak acid extraction, the second step of strong acid digestion, and the third step of alkaline treatment, it is used to release trace elements in the soil. The first step of weak acid leaching is to use 0.1M acetic acid solution with a pH of 3 to soak the sample for 1-2 hours; after the first step, concentrated nitric acid is added to the sample and the sample is heated and digested at 150°C for 0.5-1 hour; In the third step, the digested sample was neutralized with 10% sodium hydroxide and shaken again for 10-20 minutes; A3 Nanomaterial-assisted detection: The chemically pretreated sample was mixed with carbon nanotubes and modified polylactic acid-co-glycolic acid nanoparticles, reacted on a magnetic stirrer, and the adsorbed nanoparticles were separated from the sample by centrifugation. The amount of carbon nanotubes and polylactic acid-co-glycolic acid nanoparticles used was 0.5-2 mg per 1 g of soil, respectively. The reaction was carried out on a magnetic stirrer for 0.5-1 hour, and then the adsorbed nanoparticles were separated from the sample using a centrifuge, centrifuged at 5000 rpm for 10 minutes. The modified polylactic acid-glycolic acid copolymer nanoparticles are prepared by the following method: B1: Poly(lactic acid-co-glycolic acid) copolymer is dissolved in ethyl acetate to a concentration of 10 mg / mL, and then added dropwise into deionized water, emulsified by ultrasound, and stirred continuously to evaporate the ethyl acetate to form poly(lactic acid-co-glycolic acid) copolymer nanoparticles; B2 immersing the polylactic acid-co-glycolic acid nanoparticles obtained in step B1 into a crosslinking agent solution, stirring at room temperature for 1-2 hours to activate the particle surface; B3: Mix the activated particles with the chelating agent solution and continue stirring for usually 0.5 hours; B4 uses a centrifuge to centrifuge the mixed solution, the centrifuge speed is 5000 rpm, and the centrifugation time is 10 minutes; B5 The separated nanoparticles are properly washed and dried to obtain modified polylactic acid-glycolic acid copolymer nanoparticle products. A4 Optimization of chromatography technology: using a chromatographic column, gradient elution with mobile phase, and then detection with a detector.

2. The soil analysis and detection method according to claim 1, characterized in that: The carbon nanotube parameter range is 95% - 99% purity, 10 - 500 nanometers in length, and 10 - 20 nanometers in diameter.

3. The soil analysis and detection method according to claim 1, characterized in that: The cross-linking agent is glutaraldehyde with a concentration of 2-7 mg / ml.

4. The soil analysis and detection method according to claim 1, characterized in that: The chelating agent is ethylenediaminetetraacetic acid, and the concentration is 5-15 mM.

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