A method for detecting Co in yam mixed with histidine carbon quantum dots synthesized by microwave method 2+ Method

Abstract

This invention belongs to the field of heavy metal ion detection technology, specifically relating to a method for detecting Co based on microwave-synthesized histidine carbon quantum dots from yam. 2+ The method involves adding ground yam powder and histidine to deionized water, stirring, and then microwaving. After centrifugation, the supernatant is filtered through a filter membrane, and the filtrate is the yam-doped histidine carbon quantum dot (F-CDs) mother liquor. Different concentration gradients of Co are added to the F-CDs mother liquor. 2+ Subsequently, the fluorescence intensity of the F-CDs mother liquor increased with Co. 2+ The quenching efficiency F / F0 and Co gradually decrease with increasing concentration. 2+ In 1×10 ‑6 ~9×10 ‑6 The method exhibits good linearity within the mol / L concentration range and demonstrates good selectivity, indicating that it is effective for Co. 2+ The detection is characterized by its sensitivity, speed, and high selectivity.

Description

Technical Field

[0001] This invention belongs to the field of heavy metal ion detection technology, specifically relating to a method for detecting Co based on microwave-synthesized histidine carbon quantum dots from yam. 2+ The method. Background Technology

[0002] Currently, water pollution caused by heavy metal ions has become a serious environmental problem, among which Co... 2+ Not only is it significantly toxic to aquatic organisms, but it can also accumulate in the human body through the food chain, posing a potential health risk. Therefore, the development of rapid and convenient Co... 2+ The detection method has important practical significance.

[0003] Existing detection technologies mainly include atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP-MS), spectrophotometry, and electrochemical analysis. While AAS and ICP-MS offer high detection sensitivity and accuracy, the equipment is expensive, maintenance costs are high, and the equipment is bulky. Furthermore, they place stringent demands on the testing environment and operator skills, making it difficult to meet the practical needs of rapid on-site testing and widespread application in grassroots laboratories. Spectrophotometry is relatively inexpensive, but the chromogenic reagents used have poor stability and are susceptible to interference from coexisting metal ions, resulting in insufficient selectivity. In addition, the sample pretreatment and operation procedures are cumbersome, leading to low detection efficiency. Electrochemical analysis has a fast response speed, but the electrodes are easily contaminated by the sample matrix, resulting in poor reproducibility and stability, weak anti-interference ability, and limited lifespan.

[0004] In summary, existing Co 2+ The detection methods generally suffer from drawbacks such as high equipment dependence, complex operation, insufficient anti-interference ability, and difficulty in balancing cost and efficiency, making them unsuitable for supporting the detection of Co in aquatic environments. 2+ This addresses the practical needs of real-time pollution monitoring, rapid screening of batch samples, and widespread application at the grassroots level. Therefore, it is necessary to develop a low-cost, easy-to-operate, fast-responding Co... 2+ The detection method is of great practical significance for risk warning, efficient control and management of heavy metal pollution in water environment and public health safety. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots. 2+ The method described in this invention involves preparing a mother liquor of yam-mixed histidine carbon quantum dots (F-CDs) by microwave heating and centrifugation filtration of yam powder and histidine in deionized water. The fluorescence intensity of the F-CDs mother liquor varies with the Co content. 2+ The quenching efficiency F / F0 and Co gradually decrease with increasing concentration. 2+In 1×10 -6 ~9×10 -6 It exhibits good linearity within the mol / L concentration range and is characterized by sensitivity, speed, and high selectivity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a method for detecting Co based on carbon quantum dots synthesized from yam mixed with histidine using a microwave method. 2+ The method includes the following steps: (1) Grind yam into yam powder, add yam powder and histidine to deionized water, stir and microwave heat, centrifuge and filter the supernatant through a filter membrane, the filtrate is the yam doped histidine carbon quantum dot mother liquor; (2) Take the sample to be tested and add it to the mother liquor of yam-doped histidine carbon quantum dots. Let it stand, and then test the fluorescence intensity. Based on the fluorescence intensity obtained from the pre-test, compare it with the Co... 2+ The linear equation between concentration and concentration is used to calculate the Co concentration in the sample. 2+ The concentration.

[0007] Further, in step (1), the mass ratio of histidine to yam powder is 1:12-1:1.

[0008] Furthermore, in step (1), the mass ratio of the high histidine to the yam powder is 1:3.

[0009] Furthermore, in step (1), the microwave heating time is 6-10 minutes.

[0010] Furthermore, in step (1), the microwave heating time is 8 minutes.

[0011] Furthermore, in step (2), the excitation wavelength for testing fluorescence intensity is 390-410 nm.

[0012] Furthermore, in step (2), the excitation wavelength for testing fluorescence intensity is 406 nm.

[0013] Furthermore, in step (2), the settling time is at least 2 minutes.

[0014] Furthermore, in step (2), the settling time is 2 minutes.

[0015] Further, in step (2), the linear equation is specifically: Co 2+ Concentration at 1×10 -6 ~ 9×10 -6 The linear equation within the mol / L concentration range is y = -5060.341x + 2293221.04, R02 =0.9911.

[0016] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a simple process for preparing carbon quantum dots from yam mixed with histidine, which is beneficial for Co. 2+ The detection has high selectivity, quenching efficiency F / F0, and Co 2+ In 1×10 -6 ~9×10 -6 The method exhibits good linearity within the mol / L concentration range, indicating its suitability for Co. 2+ The detection is characterized by its sensitivity and speed. Attached Figure Description

[0017] Figure 1 The images show a TEM image of the F-CDs mother liquor and a particle size distribution diagram of F-CDs from Example 1.

[0018] Figure 2 XPS diagram of F-CDs mother liquor in Example 1.

[0019] Figure 3 The image shows the FTIR spectrum of the F-CDs mother liquor from Example 1.

[0020] Figure 4 Comparison of fluorescence intensity of F-CDs mother liquor prepared with different ratios of histidine to yam powder at an excitation wavelength of 406 nm.

[0021] Figure 5 A comparison of fluorescence intensity of F-CDs mother liquor prepared for different microwave heating times at an excitation wavelength of 406 nm.

[0022] Figure 6 This is a comparison of the fluorescence intensity of F-CDs mother liquor under different excitation wavelengths.

[0023] Figure 7 A comparative graph showing the effects of some common ions on the fluorescence intensity of F-CDs mother liquor.

[0024] Figure 8 For F-CDs mother liquor with different concentrations of Co 2+ Fluorescence quenching diagram.

[0025] Figure 9 The fluorescence intensity of F-CDs mother liquor and Co 2+ Concentration linear curve and linear equation. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0028] Example 1: Preparation of mother liquor of yam doped with histidine carbon quantum dots Grind an appropriate amount of yam into powder using a grinder. Weigh 1.2g of the ground yam powder and pour it into a 250mL beaker. Add 20mL of distilled water and 0.4g of histidine. Add a stir bar and place the beaker in a mixer. Stir for 30 minutes. Remove the stir bar and place the solution in a microwave oven. Heat for 8 minutes (microwave oven parameters: rated voltage and frequency: 220V~50Hz, rated input power: 1180W (microwave), 850W (light wave grilling), microwave output power: 700W). After heating stops, remove the yellow carbon quantum dot solution and pour it into two 100mL centrifuge tubes. Place the tubes in a centrifuge and centrifuge at 12000r / min for 10 minutes. After centrifugation, filter the supernatant using a 0.22µm filter membrane and inject it into a 15mL centrifuge tube. The dispersion obtained through the above steps is the yam-mixed histidine fluorescent carbon quantum dot (F-CDs) mother liquor, which should be stored away from light.

[0029] TEM images of F-CDs mother liquor and particle size distribution of F-CDs are shown below. Figure 1 As shown in the figure, F-CDs have uniform size and good dispersion, with an average particle size of about 2.47 nm.

[0030] The elemental composition of F-CDs was characterized by X-ray photoelectron spectroscopy, and the experimental results are as follows: Figure 2 As shown in the XPS image, fluorescent carbon quantum dots with an O1s peak appear at 530.74 eV, fluorescent carbon quantum dots with an N1s peak appear at 399.58 eV, and fluorescent carbon quantum dots with a C1s peak appear at 284.55 eV. This indicates that the surface of this material contains three elements: C, N, and O, with mass fractions of 61.77%, 17.07%, and 21.16%, respectively.

[0031] The chemical bonds of F-CDs were characterized by FTIR spectroscopy, such as... Figure 3 As shown. Infrared spectroscopy analysis indicates that this compound is at 2023 cm⁻¹. -1A strong absorption peak appears at 652 and 683 cm⁻¹, attributed to the stretching vibration of the nitrile group (-C≡N); -1 The strong absorption peak at 833 and 776 cm⁻¹ corresponds to the stretching vibration of the C-Cl bond; simultaneously, the absorption peaks at 833 and 776 cm⁻¹ correspond to the stretching vibration of the C-Cl bond; -1 The absorption peak at [value missing] indicates the presence of a para-disubstituted benzene ring in the molecule. Furthermore, the absorption peak at 1060-1111 cm⁻¹... -1 The absorption in the region suggests the possible presence of a COC ether bond structure.

[0032] Test Example 1: Effect of the mass ratio of histidine to yam powder on the fluorescence intensity of carbon quantum dots The mass ratio of histidine to yam powder in Example 1 was changed from 1:3 to 0, 1 / 12, 2 / 12, 3 / 12, 5 / 12, 6 / 12, 7 / 12, 8 / 12, 9 / 12, 10 / 12, 11 / 12, and 12 / 12, while other aspects remained the same as in Example 1. The fluorescence intensity of the F-CDs mother liquor prepared with different histidine to yam powder mass ratios was tested at an excitation wavelength of 406 nm. The results are as follows: Figure 4 As shown, the fluorescence intensity of carbon quantum dots from yam without histidine doping is significantly reduced. The maximum fluorescence intensity can be obtained when the mass ratio of histidine to yam powder is controlled at 1:3.

[0033] Test Example 2: Effect of different microwave heating times on the fluorescence intensity of carbon quantum dots The microwave heating time in Example 1 was changed from 8 min to 6 min, 7 min, 9 min, and 10 min, respectively, while the rest remained the same as in Example 1. The fluorescence intensity of the F-CDs mother liquor prepared with different microwave heating times was tested at an excitation wavelength of 406 nm. The results are as follows: Figure 5 As shown, the F-CDs mother liquor prepared by microwave heating time of 8-10 min has a higher fluorescence intensity, and the differences among the three are not significant. Considering all factors, 8 min is the optimal microwave heating time.

[0034] Test Example 3: Effect of different excitation wavelengths on the fluorescence intensity of carbon quantum dots The fluorescence intensity of the F-CDs mother liquor prepared in Example 1 was measured at excitation wavelengths of 390 nm, 394 nm, 398 nm, 402 nm, 406 nm, and 410 nm, respectively. The results are as follows: Figure 6 As shown, the fluorescence intensity of the F-CDs mother liquor is the highest at an excitation wavelength of 406 nm. Therefore, the optimal excitation wavelength is 406 nm.

[0035] Test Example 4: Selectivity Test Solutions of ZnCl2, NiCl, KCl, NaCl, HgCl2, CaCl2, CdCl2, CoCl2, CuCl2, FeCl3, VCl2, and CrCl2 with concentrations of 0.1 mol / L were prepared as interfering agents. First, 3 mL of the F-CDs stock solution prepared in Example 1 was added to a fluorescent cuvette, and the emission spectrum and fluorescence intensity of the blank sample were measured using an excitation wavelength of 406 nm. Then, 30 μL of each of the above solutions were added to a fluorescent cuvette containing 3 mL of F-CDs stock solution, mixed thoroughly for 2 min, and then fluorescence detection was performed. The fluorescence intensity of the F-CDs stock solution with added interfering agents was compared with the fluorescence intensity of the corresponding blank F-CDs stock solution, and the results are shown below. Figure 7 As shown, according to Figure 7 Analysis, Fe 3+ Co 2+ The quenching effect of F-CDs on the fluorescence intensity is very good, while the quenching effect of other interfering substances is not obvious or even enhances fluorescence. Therefore, it can be concluded that F-CDs have a good quenching effect on the fluorescence intensity of Fe. 3 + Co 2+ It offers a good selection.

[0036] Test Example 5: Detection of Co in F-CDs Mother Liquor 2+ To achieve Co 2+ Quantitative detection of Co, establishing a rapid detection method 2+ The method was used to determine 1×10 -6 ~ 9×10 -6 Within a concentration range of mol / L, different concentration gradients of Co were added to the F-CDs mother liquor. 2+ Co 2+ After 2 min of treatment with the F-CDs mother liquor, the fluorescence intensity changed as follows: Figure 8 As shown, the fluorescence intensity of the F-CDs mother liquor increases with Co 2+ The concentration gradually decreases as it increases. The curve fitted to the value is as follows: Figure 9 As shown, Co 2+ Concentration at 1×10 -6 ~ 9×10 -6 Within the range of mol / L, the fluorescence intensity of histidine carbon quantum dots doped in yam increased with Co. 2+ The fluorescence intensity decreased with increasing concentration, showing an overall downward trend. The fluorescence intensity ratio of yam-doped histidine carbon quantum dots was related to that of Co. 2+ The concentrations showed a good linear correlation. Co 2+ Concentration at 1×10 -6 ~ 9×10 -6The linear equation within the mol / L concentration range is y = -5060.341x + 2293221.04, R0 2 =0.9911.

[0037] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots. 2+ The method is characterized by, Includes the following steps: (1) Grind yam into yam powder, add yam powder and histidine to deionized water, stir and microwave heat, centrifuge and filter the supernatant through a filter membrane, the filtrate is the yam doped histidine carbon quantum dot mother liquor; (2) Take the sample to be tested and add it to the mother liquor of yam-doped histidine carbon quantum dots. Let it stand, and then test the fluorescence intensity. Based on the fluorescence intensity obtained from the pre-test, compare it with the Co... 2+ The linear equation between concentration and concentration is used to calculate the Co concentration in the sample. 2+ The concentration.

2. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 1. 2+ The method is characterized by, In step (1), the mass ratio of histidine to yam powder is 1:12-1:

1.

3. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 2. 2+ The method is characterized by, In step (1), the mass ratio of the high histidine to the yam powder is 1:

3.

4. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 1. 2+ The method is characterized by, In step (1), the microwave heating time is 6-10 minutes.

5. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 4. 2+ The method is characterized by, In step (1), the microwave heating time is 8 minutes.

6. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 1. 2+ The method is characterized by, In step (2), the excitation wavelength for testing fluorescence intensity is 390-410 nm.

7. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 6. 2+ The method is characterized by, In step (2), the excitation wavelength for testing fluorescence intensity is 406 nm.

8. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 1. 2+ The method is characterized by, In step (2), the settling time is at least 2 minutes.

9. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 8. 2+ The method is characterized by, In step (2), the settling time is 2 minutes.

10. The method for detecting Co based on microwave-synthesized yam mixed with histidine carbon quantum dots according to claim 1. 2+ The method is characterized by, In step (2), the linear equation is specifically: Co 2+ Concentration at 1×10 -6 ~ 9×10 -6 The linear equation within the mol / L concentration range is y = -5060.341x + 2293221.04, R0 2 =0.9911.

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