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2023 Volume 51 Issue 3
2023, 51(3): 305-315
doi: 10.19756/j.issn.0253-3820.221486
Abstract:
Beacause of the light weight, good conformability and high biosafety, flexible wearable sensors show broad application prospects in military, healthcare, medical and sports areas. Visualization is an important direction for the development of flexible wearable sensors, which is significant to enrich their functions and expand their application areas. This paper reviewed the progress of visualized flexible wearable sensors in recent years, summarized the existing types and their mechanisms, and highlighted the ones which relied on light-emitting or colour-changing materials for visualization. Finally, the opportunities and challenges of visualized flexible wearable sensors were presented.
Beacause of the light weight, good conformability and high biosafety, flexible wearable sensors show broad application prospects in military, healthcare, medical and sports areas. Visualization is an important direction for the development of flexible wearable sensors, which is significant to enrich their functions and expand their application areas. This paper reviewed the progress of visualized flexible wearable sensors in recent years, summarized the existing types and their mechanisms, and highlighted the ones which relied on light-emitting or colour-changing materials for visualization. Finally, the opportunities and challenges of visualized flexible wearable sensors were presented.
2023, 51(3): 316-330
doi: 10.19756/j.issn.0253-3820.221456
Abstract:
Converting carbon dioxide (CO2) to high-energy chemicals through electrocatalytic CO2 reduction reaction (CO2RR) is a powerful way to solve the greenhouse effect and realize the anthropogenic carbon cycle. Compared with other metal catalysts, copper (Cu)-based catalysts have attracted much attention due to the ability to generate multi-carbon products. However, it has poor selectivity for the products. Hence, efforts have been made in recent years to investigate the mechanism and influencing factors of C—C coupling in the reaction process of Cu-based catalysts, and to carry out targeted structural design and experimental synthesis of Cu-based catalysts. This paper first summarized the basic principles of electrocatalytic CO2RR. Then, the five key factors (electrocatalytic reactor, pH, pressure, temperature, CO2 flow rate and concentration) affecting electrocatalytic CO2RR were summarized. Next, related strategies (alloying, nanostructure modification, heteroatom doping, hydrophilic/hydrophobic and Single atom catalysts) for modification of Cu-based catalysts were reviewed. Finally, the current opportunities and challenges for the preparation of Cu-based catalysts for electrocatalytic CO2RR were prospected, in order to provide valuable insights and ideas for future research in related fields.
Converting carbon dioxide (CO2) to high-energy chemicals through electrocatalytic CO2 reduction reaction (CO2RR) is a powerful way to solve the greenhouse effect and realize the anthropogenic carbon cycle. Compared with other metal catalysts, copper (Cu)-based catalysts have attracted much attention due to the ability to generate multi-carbon products. However, it has poor selectivity for the products. Hence, efforts have been made in recent years to investigate the mechanism and influencing factors of C—C coupling in the reaction process of Cu-based catalysts, and to carry out targeted structural design and experimental synthesis of Cu-based catalysts. This paper first summarized the basic principles of electrocatalytic CO2RR. Then, the five key factors (electrocatalytic reactor, pH, pressure, temperature, CO2 flow rate and concentration) affecting electrocatalytic CO2RR were summarized. Next, related strategies (alloying, nanostructure modification, heteroatom doping, hydrophilic/hydrophobic and Single atom catalysts) for modification of Cu-based catalysts were reviewed. Finally, the current opportunities and challenges for the preparation of Cu-based catalysts for electrocatalytic CO2RR were prospected, in order to provide valuable insights and ideas for future research in related fields.
2023, 51(3): 331-339
doi: 10.19756/j.issn.0253-3820.221449
Abstract:
Due to advantages in high-throughput, easy reading, simple operation and low cost, enzyme linked immunosorbent assay (ELISA) plays an important role in environmental monitoring, food safety testing and medical diagnosis. However, the insufficient chromogenic part of ELISA results in high detection limit, which limits the further application of ELISA in analysis and detection. To overcome this issue, the conventional ELISA has been improved by many methods. Among them, the fluorometric method has attracted widespread attention given its high sensitivity, simple operation, and fast response. Recently, a variety of fluorescent materials have been developed to construct different types of ELISA, which promotes the application of ELISA in analytical chemistry and biomedical detection. In this paper, the ELISA constructed by fluorescent materials such as organic small molecules, silicon/carbon nanoparticles, metal nanoclusters, and quantum dots was introduced in detail. Additionally, different enzymes in ELISA, including alkaline phosphatase, horseradish peroxidase and other enzyme as labeling enzymes, were systematically reviewed. Furthermore, the prospects of ELISA based on different fluorescent materials were also discussed.
Due to advantages in high-throughput, easy reading, simple operation and low cost, enzyme linked immunosorbent assay (ELISA) plays an important role in environmental monitoring, food safety testing and medical diagnosis. However, the insufficient chromogenic part of ELISA results in high detection limit, which limits the further application of ELISA in analysis and detection. To overcome this issue, the conventional ELISA has been improved by many methods. Among them, the fluorometric method has attracted widespread attention given its high sensitivity, simple operation, and fast response. Recently, a variety of fluorescent materials have been developed to construct different types of ELISA, which promotes the application of ELISA in analytical chemistry and biomedical detection. In this paper, the ELISA constructed by fluorescent materials such as organic small molecules, silicon/carbon nanoparticles, metal nanoclusters, and quantum dots was introduced in detail. Additionally, different enzymes in ELISA, including alkaline phosphatase, horseradish peroxidase and other enzyme as labeling enzymes, were systematically reviewed. Furthermore, the prospects of ELISA based on different fluorescent materials were also discussed.
2023, 51(3): 340-347
doi: 10.19756/j.issn.0253-3820.221110
Abstract:
Concentration calibration is the premise of accurate quantitative detection of gas analyzer, and concentration calibration cannot be separated from gas dilution system. In this work, a novel wet gas preparation method (proportion-integral (PI) two-flow method) was established, and that a simple yet accurate gas dilution system with humidity control function based on PI two-flow method was developed, which was not affected by intermediate variables. Firstly, the performance of the humidifier, an essential part of the system, was investigated. The results showed that there was a certain fluctuation (96%-103%) in the relative humidity (RH) at the outlet of the humidifier. Therefore, the PI two-flow method was developed to reduce the influence of the fluctuation on the humidity control accuracy of the whole system. A dew point transmitter was used to measure the RH at the system′s outlet as a feedback signal to automatically adjust the ratio of dry and wet gas, thereby realizing accurate control of humidity. The wet gas was prepared by the following method, the dry gas passing through a self-made bubbling humidifier. Subsequently, the system′s response characteristics were investigated by step input and sinusoidal input under different flow rates and temperature conditions. The results showed that the RH control range of the system was 5%-100%. The flow rate of the system could be up to 1000 mL/min. The RH control accuracy could realize 0.026%RH (25 °C, 100%RH) (without considering the measurement deviation of the dewpoint transmitter). The setting time reached 38 s (25 °C, 500 mL/min). The system could track the sinusoidal input when the period was more than 175 s in 1000 mL/min. Finally, the application research of the system was implemented by using proton transfer reaction mass spectrometry (PTR-MS). As the RH of sampling air of PTR-MS gradually increased, the relative ratio of H3O+ decreased, and the relative proportion of H3O+(H2O) increased. The above application showed that the new system could meet the application requirements of gas analysis instruments with large and continuous sampling flow rate in a wide humidity range (10%-100%). The new system would be expected to calibrate gas measurements instruments sensitive to humidity.
Concentration calibration is the premise of accurate quantitative detection of gas analyzer, and concentration calibration cannot be separated from gas dilution system. In this work, a novel wet gas preparation method (proportion-integral (PI) two-flow method) was established, and that a simple yet accurate gas dilution system with humidity control function based on PI two-flow method was developed, which was not affected by intermediate variables. Firstly, the performance of the humidifier, an essential part of the system, was investigated. The results showed that there was a certain fluctuation (96%-103%) in the relative humidity (RH) at the outlet of the humidifier. Therefore, the PI two-flow method was developed to reduce the influence of the fluctuation on the humidity control accuracy of the whole system. A dew point transmitter was used to measure the RH at the system′s outlet as a feedback signal to automatically adjust the ratio of dry and wet gas, thereby realizing accurate control of humidity. The wet gas was prepared by the following method, the dry gas passing through a self-made bubbling humidifier. Subsequently, the system′s response characteristics were investigated by step input and sinusoidal input under different flow rates and temperature conditions. The results showed that the RH control range of the system was 5%-100%. The flow rate of the system could be up to 1000 mL/min. The RH control accuracy could realize 0.026%RH (25 °C, 100%RH) (without considering the measurement deviation of the dewpoint transmitter). The setting time reached 38 s (25 °C, 500 mL/min). The system could track the sinusoidal input when the period was more than 175 s in 1000 mL/min. Finally, the application research of the system was implemented by using proton transfer reaction mass spectrometry (PTR-MS). As the RH of sampling air of PTR-MS gradually increased, the relative ratio of H3O+ decreased, and the relative proportion of H3O+(H2O) increased. The above application showed that the new system could meet the application requirements of gas analysis instruments with large and continuous sampling flow rate in a wide humidity range (10%-100%). The new system would be expected to calibrate gas measurements instruments sensitive to humidity.
2023, 51(3): 348-355
doi: 10.19756/j.issn.0253-3820.221368
Abstract:
Pulsed direct current electrospray ionization mass spectrometry (PDESI-MS) offers many advantages such as in situ, real-time, fast, and microvolume sample analysis. However, the current PDESI-MS system requires manual operation for sample processing and mass spectrometry injection, which have many disadvantages such as cumbersome operation, many steps, large errors and low accuracy. Herein, a high-throughput, fully automated and integrated PDESI-MS system was developed, and an in situ detection for small molecule metabolites in eukaryotes (single bladder cancer cells) and prokaryotes (single colonies of bacteria) was explored. The results showed that the automated PDESI-MS system could effectively detect metabolites of different strains and realize the classification and stereotyping of different types of Escherichia coli. In addition, the picoliter droplet generation technology allowed it to be applied to single cell detection. The automated PDESI-MS system could achieve high precision, high density, high repeatability and high automation for in situ sample extraction, especially in detection and analysis of small samples, and showed great application potential and development prospects in food safety, regenerative medicine, drug screening, clinical treatment and other fields.
Pulsed direct current electrospray ionization mass spectrometry (PDESI-MS) offers many advantages such as in situ, real-time, fast, and microvolume sample analysis. However, the current PDESI-MS system requires manual operation for sample processing and mass spectrometry injection, which have many disadvantages such as cumbersome operation, many steps, large errors and low accuracy. Herein, a high-throughput, fully automated and integrated PDESI-MS system was developed, and an in situ detection for small molecule metabolites in eukaryotes (single bladder cancer cells) and prokaryotes (single colonies of bacteria) was explored. The results showed that the automated PDESI-MS system could effectively detect metabolites of different strains and realize the classification and stereotyping of different types of Escherichia coli. In addition, the picoliter droplet generation technology allowed it to be applied to single cell detection. The automated PDESI-MS system could achieve high precision, high density, high repeatability and high automation for in situ sample extraction, especially in detection and analysis of small samples, and showed great application potential and development prospects in food safety, regenerative medicine, drug screening, clinical treatment and other fields.
2023, 51(3): 356-363
doi: 10.19756/j.issn.0253-3820.221167
Abstract:
Surface-enhanced Raman scattering (SERS) nanotip is a kind of new technique for single cell analysis, which shows excellent application potential in detection of intracellular environment and study of cell physiological function. Due to the small number of noble metal particles that can be loaded on SERS nanotips, screening and modifying nanoparticles with high SERS enhancement ability is the key to ensure their detection sensitivity. In this study, core-satellite Au nanoparticles were prepared, and the single particle signal was significantly higher than that of traditional Au nanospheres and Au nanostars. The particle was coated on the surface of glass capillary with tip diameter of about 200 nm to form SERS nanotips, which further functionalized and modified with target-sensitive Raman reporter molecules, enabling them to detect pH value and O2 content in micro-area environment. As application performance investigation, SERS nanotips realized pH value and anoxic state monitoring in single HL-7702 cell. This study solved the bottleneck issues such as random aggregation and difficulty in precise localization faced by traditional granular SERS probes for cell analysis, providing a new analytical tool for detection and analysis of single cell environment.
Surface-enhanced Raman scattering (SERS) nanotip is a kind of new technique for single cell analysis, which shows excellent application potential in detection of intracellular environment and study of cell physiological function. Due to the small number of noble metal particles that can be loaded on SERS nanotips, screening and modifying nanoparticles with high SERS enhancement ability is the key to ensure their detection sensitivity. In this study, core-satellite Au nanoparticles were prepared, and the single particle signal was significantly higher than that of traditional Au nanospheres and Au nanostars. The particle was coated on the surface of glass capillary with tip diameter of about 200 nm to form SERS nanotips, which further functionalized and modified with target-sensitive Raman reporter molecules, enabling them to detect pH value and O2 content in micro-area environment. As application performance investigation, SERS nanotips realized pH value and anoxic state monitoring in single HL-7702 cell. This study solved the bottleneck issues such as random aggregation and difficulty in precise localization faced by traditional granular SERS probes for cell analysis, providing a new analytical tool for detection and analysis of single cell environment.
2023, 51(3): 364-372
doi: 10.19756/j.issn.0253-3820.221207
Abstract:
Based on the target recognition ability of aptamer and the excellent fluorescence performance of copper nanoclusters (CuNCs), a label-free fluorescent probe was developed for rapid detection of isocarbophos (ISO). In the absence of target molecule, the aptamer DNA and complementary DNA in the solution formed double-stranded DNA, which could mediate the synthesis of fluorescent CuNCs and showed a high fluorescence signal. When ISO was present, it would form aptamer-target complex, and released the complementary DNA. Free single stranded DNA could not mediate the synthesis of CuNCs, resulting in weak fluorescence signal in solution. Under the optimal conditions, the fluorescence inhibition rate of the system showed a linear relationship with the logarithm of concentration of ISO within the concentration range of 0.05-25 mg/L, and the detection limit was 47 μg/L (3σ). The method showed a high selectivity in detection of ISO with little interference. In addition, the probe was successfully used for detection of ISO in water samples with the recoveries of 80.3%-108.0%. These results indicated that the developed method could be used to effectively detect ISO residues in actual samples.
Based on the target recognition ability of aptamer and the excellent fluorescence performance of copper nanoclusters (CuNCs), a label-free fluorescent probe was developed for rapid detection of isocarbophos (ISO). In the absence of target molecule, the aptamer DNA and complementary DNA in the solution formed double-stranded DNA, which could mediate the synthesis of fluorescent CuNCs and showed a high fluorescence signal. When ISO was present, it would form aptamer-target complex, and released the complementary DNA. Free single stranded DNA could not mediate the synthesis of CuNCs, resulting in weak fluorescence signal in solution. Under the optimal conditions, the fluorescence inhibition rate of the system showed a linear relationship with the logarithm of concentration of ISO within the concentration range of 0.05-25 mg/L, and the detection limit was 47 μg/L (3σ). The method showed a high selectivity in detection of ISO with little interference. In addition, the probe was successfully used for detection of ISO in water samples with the recoveries of 80.3%-108.0%. These results indicated that the developed method could be used to effectively detect ISO residues in actual samples.
2023, 51(3): 373-382
doi: 10.19756/j.issn.0253-3820.221006
Abstract:
To establish a novel and simple method for screening glycosidase inhibitors from traditional Chinese medicine, a nickel-based nanomaterial modified electrode (Ni(OH)2/NF) was prepared on nickel foam (NF) in one step by multi-cycle electrochemical cyclic voltammetry, which was used to construct a highly sensitive and selective electrochemical sensor for evaluating the inhibitory activity of α-glycosidase inhibitors. The structure and surface morphology of the modified electrode were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and its sensing performance was investigated by cyclic voltammetry and chronoamperometry. The results showed that the Ni(OH)2/NF sensor had a high electrochemical response to glucose in complex enzyme reaction system, and the sensitivity was 3222 μA·mmol/(L·cm2) in the linear range of 3.0-6000 μmol/L, with a detection limit as low as 0.9 μmol/L (S/N = 3). The feasibility of the sensor for detecting α-glycosidase activity was verified by a clinical hypoglycemic drug acarbose. The nanosensor was also applied to evaluate the inhibitory effect of lotus stamen extract. It was found that lotus stamen had a certain α-glycosidase inhibitory activity, with its half inhibition concentration IC50 = 3.31 g/L. The experimental results showed that the developed sensor was suitable for analysis of α-glycosidase inhibitory activity, providing a novel method for screening natural hypoglycemic chemicals.
To establish a novel and simple method for screening glycosidase inhibitors from traditional Chinese medicine, a nickel-based nanomaterial modified electrode (Ni(OH)2/NF) was prepared on nickel foam (NF) in one step by multi-cycle electrochemical cyclic voltammetry, which was used to construct a highly sensitive and selective electrochemical sensor for evaluating the inhibitory activity of α-glycosidase inhibitors. The structure and surface morphology of the modified electrode were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and its sensing performance was investigated by cyclic voltammetry and chronoamperometry. The results showed that the Ni(OH)2/NF sensor had a high electrochemical response to glucose in complex enzyme reaction system, and the sensitivity was 3222 μA·mmol/(L·cm2) in the linear range of 3.0-6000 μmol/L, with a detection limit as low as 0.9 μmol/L (S/N = 3). The feasibility of the sensor for detecting α-glycosidase activity was verified by a clinical hypoglycemic drug acarbose. The nanosensor was also applied to evaluate the inhibitory effect of lotus stamen extract. It was found that lotus stamen had a certain α-glycosidase inhibitory activity, with its half inhibition concentration IC50 = 3.31 g/L. The experimental results showed that the developed sensor was suitable for analysis of α-glycosidase inhibitory activity, providing a novel method for screening natural hypoglycemic chemicals.
2023, 51(3): 383-389
doi: 10.19756/j.issn.0253-3820.221384
Abstract:
Peptide mapping currently serves as the primary means for quality control of protonic drugs through employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the workhorse. Although being versatile, LC-MS/MS still suffers from shortcomings in terms of time-consuming, solvent-intensive and sophisticated instrumentation. Because of the extraordinary merit namely high throughput, the potential of direct infusion (DI) coupled to tandem mass spectrometry towards the tryptic peptide mapping was evaluated, and particularly, a new technique termed as MS/MSALL program was implemented to acquire MS2 spectrum for each nominal m/z value, attributing to the involvement of the robust gas phase ion fractionation technique. Human hemoglobin (Hb) was utilized as a proof-of-concept target molecule. After thorough tryptic digestion, the peptide pool was directly injected into the ion source of mass spectrometer through an infusion pump, and MS/MSALL was programmed to record all desired MS2 spectra, because the whole ion population was fractionated into sequential ion currents with 1 Da mass window. After matching the acquired MS1 and MS2 spectral information, 20 over 21 theoretical peptides that were suggested by Skyline software, were successfully captured, whilst all 21 peptides were detected by the well-defined LC-MS/MS program. Moreover, similar MS1 spectra (average spectrum for LC-MS/MS) occurred between the two means, primarily including quasi-molecular ions bearing the charged states amongst 1-4. Either analytical method dominantly gave out characteristic y+ ions. Thereafter, comparable potential towards tryptic peptide mapping was yielded from DI-MS/MSALL in comparison with LC-MS/MS, and the DI-MS/MSALL exhibited many advantages including high throughput, solvent-saving and low-costing measurement. The results demonstrated that the DI-MS/MSALL could be an alternative analytical tool for LC-MS/MS.
Peptide mapping currently serves as the primary means for quality control of protonic drugs through employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the workhorse. Although being versatile, LC-MS/MS still suffers from shortcomings in terms of time-consuming, solvent-intensive and sophisticated instrumentation. Because of the extraordinary merit namely high throughput, the potential of direct infusion (DI) coupled to tandem mass spectrometry towards the tryptic peptide mapping was evaluated, and particularly, a new technique termed as MS/MSALL program was implemented to acquire MS2 spectrum for each nominal m/z value, attributing to the involvement of the robust gas phase ion fractionation technique. Human hemoglobin (Hb) was utilized as a proof-of-concept target molecule. After thorough tryptic digestion, the peptide pool was directly injected into the ion source of mass spectrometer through an infusion pump, and MS/MSALL was programmed to record all desired MS2 spectra, because the whole ion population was fractionated into sequential ion currents with 1 Da mass window. After matching the acquired MS1 and MS2 spectral information, 20 over 21 theoretical peptides that were suggested by Skyline software, were successfully captured, whilst all 21 peptides were detected by the well-defined LC-MS/MS program. Moreover, similar MS1 spectra (average spectrum for LC-MS/MS) occurred between the two means, primarily including quasi-molecular ions bearing the charged states amongst 1-4. Either analytical method dominantly gave out characteristic y+ ions. Thereafter, comparable potential towards tryptic peptide mapping was yielded from DI-MS/MSALL in comparison with LC-MS/MS, and the DI-MS/MSALL exhibited many advantages including high throughput, solvent-saving and low-costing measurement. The results demonstrated that the DI-MS/MSALL could be an alternative analytical tool for LC-MS/MS.
2023, 51(3): 390-396
doi: 10.19756/j.issn.0253-3820.221436
Abstract:
Artemisia rupestris L. (A. rupestris) is a kind of commonly used medicinal plant in Uygur medicine. Due to its unique ecological characteristics, it is extremely difficult to reproduce naturally, and wild resources have been scarce in recent years. Therefore, conducting introduction, domestication and artificial cultivation researches are the most effective means to realize the sustainable utilization of resources. The material basis of medicinal plants is usually specific for the period of growth and development. Thus, an in-depth study of the correlation between the growth period and the metabolic patterns of key components will help to reveal the physiological and metabolic adaptation mechanism of A. rupestris. In this study, plant metabolomics strategy based on liquid chromatography-mass spectrometry technique was applied to analyze A. rupestris samples of different growth periods, including seedling stage, development phase, and full-bloom stage, which were collected from Xinjiang Altay Fuyun and Hami regions. Twenty-four metabolites that were closely related to the plant growth and development were screened by integrated analysis of the two regions data and dynamic regulation description. Furthermore, a Bayesian discriminant analysis model based on 24 key growth components was constructed, which could be used to discriminate the harvesting period of unknown samples. This study provided new reference information for quality control and rational utilization of A. rupestris., and also provided research ideas for other medicinal plants.
Artemisia rupestris L. (A. rupestris) is a kind of commonly used medicinal plant in Uygur medicine. Due to its unique ecological characteristics, it is extremely difficult to reproduce naturally, and wild resources have been scarce in recent years. Therefore, conducting introduction, domestication and artificial cultivation researches are the most effective means to realize the sustainable utilization of resources. The material basis of medicinal plants is usually specific for the period of growth and development. Thus, an in-depth study of the correlation between the growth period and the metabolic patterns of key components will help to reveal the physiological and metabolic adaptation mechanism of A. rupestris. In this study, plant metabolomics strategy based on liquid chromatography-mass spectrometry technique was applied to analyze A. rupestris samples of different growth periods, including seedling stage, development phase, and full-bloom stage, which were collected from Xinjiang Altay Fuyun and Hami regions. Twenty-four metabolites that were closely related to the plant growth and development were screened by integrated analysis of the two regions data and dynamic regulation description. Furthermore, a Bayesian discriminant analysis model based on 24 key growth components was constructed, which could be used to discriminate the harvesting period of unknown samples. This study provided new reference information for quality control and rational utilization of A. rupestris., and also provided research ideas for other medicinal plants.
2023, 51(3): 397-404
doi: 10.19756/j.issn.0253-3820.221227
Abstract:
With the increasing public concern on food quality, especially the zero-tolerance of illegal additives, the rapid qualitative and quantitative analysis of trace banned substances in food is in a prosperity stage in the field of food safety. Here, by combining with a self-developed rapid pretreatment kit, an on-site, rapid and sensitive detection strategy for trace antibiotics such as enrofloxacin and ciprofloxacin, two typical abused antibiotics in livestock and other industries, by surface-enhanced Raman spectroscopy (SERS) technique was developed. The abused quinolones residues in chicken meat (3 kinds of silky chicken meat and 2 kinds of plain chicken meat) were successfully screened by the developed SERS method, which showed an accurate qualification and a reliable quantitation in comparison with that by standard high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) technique. The proposed SERS-based strategy may provide a practical and simple method for rapid detection of other quinolones in real samples.
With the increasing public concern on food quality, especially the zero-tolerance of illegal additives, the rapid qualitative and quantitative analysis of trace banned substances in food is in a prosperity stage in the field of food safety. Here, by combining with a self-developed rapid pretreatment kit, an on-site, rapid and sensitive detection strategy for trace antibiotics such as enrofloxacin and ciprofloxacin, two typical abused antibiotics in livestock and other industries, by surface-enhanced Raman spectroscopy (SERS) technique was developed. The abused quinolones residues in chicken meat (3 kinds of silky chicken meat and 2 kinds of plain chicken meat) were successfully screened by the developed SERS method, which showed an accurate qualification and a reliable quantitation in comparison with that by standard high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) technique. The proposed SERS-based strategy may provide a practical and simple method for rapid detection of other quinolones in real samples.
2023, 51(3): 405-411
doi: 10.19756/j.issn.0253-3820.221376
Abstract:
Scanning electron microscopy (SEM) coupled with energy spectrometry (EDS), quantitative proton nuclear magnetic resonance (1H NMR) and two-dimensional diffusion-ordered spectroscopy (DOSY) techniques were applied to analyze the composition of blooming. The EDS results indicated that the elements in the blooming were carbon, oxygen, sulfur and zinc with the mass ratio of 6∶1∶1∶1. Quantitative 1H NMR combined with DOSY strongly convinced that the main precipitates of the blooming were zinc stearate, zinc dimethyl dithiocarbamate (ZDMC), 2-mercaptobenzothiazole (MBT) and rubber protective wax. Their corresponding mass content ratio was 38.9% : 31.5% : 14.4% : 15.2%, based on which the content ratio of element C, O, S and Zn was estimated as 5.70 ∶0.44 ∶1.28∶1. Then the possible formation mechanism of blooming was proposed. ZnO reacted with S to form ZnS, followed by the reaction of ZnS and stearic acid to generate zinc stearate. Moreover, tetramethyl thiuram disulfide (TMTD) could react with ZnO to produce ZDMC during the vulcanization stage. The DOSY and quantitative 1H NMR spectroscopy were used together for the first time to analyze the components of blooming mixture on the surface of rubber products, which opened a new avenue to analyze unknown mixtures.
Scanning electron microscopy (SEM) coupled with energy spectrometry (EDS), quantitative proton nuclear magnetic resonance (1H NMR) and two-dimensional diffusion-ordered spectroscopy (DOSY) techniques were applied to analyze the composition of blooming. The EDS results indicated that the elements in the blooming were carbon, oxygen, sulfur and zinc with the mass ratio of 6∶1∶1∶1. Quantitative 1H NMR combined with DOSY strongly convinced that the main precipitates of the blooming were zinc stearate, zinc dimethyl dithiocarbamate (ZDMC), 2-mercaptobenzothiazole (MBT) and rubber protective wax. Their corresponding mass content ratio was 38.9% : 31.5% : 14.4% : 15.2%, based on which the content ratio of element C, O, S and Zn was estimated as 5.70 ∶0.44 ∶1.28∶1. Then the possible formation mechanism of blooming was proposed. ZnO reacted with S to form ZnS, followed by the reaction of ZnS and stearic acid to generate zinc stearate. Moreover, tetramethyl thiuram disulfide (TMTD) could react with ZnO to produce ZDMC during the vulcanization stage. The DOSY and quantitative 1H NMR spectroscopy were used together for the first time to analyze the components of blooming mixture on the surface of rubber products, which opened a new avenue to analyze unknown mixtures.
2023, 51(3): 412-420
doi: 10.19756/j.issn.0253-3820.221072
Abstract:
The existence of low concentration of lead ion (Pb2+) in nature water has great harm to the environment and human body, so it is of great significance to remove Pb2+ from the environment. In this work, an porous ion imprinting adsorbent (IIP) based on epoxy resin was prepared by curing and polymerization of epoxy resin with Pb2+ as template ion, PEG-600 as porogen, and 1,6-hexanediamine as curing agent. The effects of pH value, initial Pb2+ concentration, adsorption temperature and adsorption time on adsorption of Pb2+ on IIPs were studied by static adsorption method. The IIP before and after adsorption was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that when pH=4.5 and T=293 K, the adsorption capacity of Pb2+ reached 149.01 mg/g, the adsorption kinetics followed the quasi second-order kinetic model, and the isothermal curve conformed to the Langmuir adsorption model. It was found that the IIP had good adsorption capacity and reusability. The selectivity investigation showed that the adsorption of Pb2+ upon IIP was significantly greater than that of competitive ions. The prepared IIP material had certain advantages in the treatment of wastewater containing low concentration of Pb2+ and had a good application prospect.
The existence of low concentration of lead ion (Pb2+) in nature water has great harm to the environment and human body, so it is of great significance to remove Pb2+ from the environment. In this work, an porous ion imprinting adsorbent (IIP) based on epoxy resin was prepared by curing and polymerization of epoxy resin with Pb2+ as template ion, PEG-600 as porogen, and 1,6-hexanediamine as curing agent. The effects of pH value, initial Pb2+ concentration, adsorption temperature and adsorption time on adsorption of Pb2+ on IIPs were studied by static adsorption method. The IIP before and after adsorption was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that when pH=4.5 and T=293 K, the adsorption capacity of Pb2+ reached 149.01 mg/g, the adsorption kinetics followed the quasi second-order kinetic model, and the isothermal curve conformed to the Langmuir adsorption model. It was found that the IIP had good adsorption capacity and reusability. The selectivity investigation showed that the adsorption of Pb2+ upon IIP was significantly greater than that of competitive ions. The prepared IIP material had certain advantages in the treatment of wastewater containing low concentration of Pb2+ and had a good application prospect.
2023, 51(3): 421-428
doi: 10.19756/j.issn.0253-3820.221583
Abstract:
A novel fluorescence probe SAM-S with near infrared emission (675 nm) was synthesized by a two-step reaction using dicyanoisophorone and 4-diethylaminosalicylaldehyde as raw materials. The probe showed a weak fluorescence in CH3OH/HEPES buffer (1∶1, V/V, pH = 7.4) solution, and the fluorescence was significantly enhanced only after adding Hg2+. Therefore, a new method for detecting Hg2+ was established. SAM-S for detection of Hg2+ possessed many advantages such as good selectivity, strong anti-interference ability, and low detection limit (0.49 μmol/L). The content of Hg2+ in lake water and tap water was determined by this method, and the recoveries were between 99.9% and 104.8%. In addition, the probe SAM-S could be produced into fluorescent ink, which was expected to be used for trademark packaging. Meanwhile, because of the low toxicity of SAM-S, probe SAM-S could perform fluorescence imaging of Hg2+ in living cells.
A novel fluorescence probe SAM-S with near infrared emission (675 nm) was synthesized by a two-step reaction using dicyanoisophorone and 4-diethylaminosalicylaldehyde as raw materials. The probe showed a weak fluorescence in CH3OH/HEPES buffer (1∶1, V/V, pH = 7.4) solution, and the fluorescence was significantly enhanced only after adding Hg2+. Therefore, a new method for detecting Hg2+ was established. SAM-S for detection of Hg2+ possessed many advantages such as good selectivity, strong anti-interference ability, and low detection limit (0.49 μmol/L). The content of Hg2+ in lake water and tap water was determined by this method, and the recoveries were between 99.9% and 104.8%. In addition, the probe SAM-S could be produced into fluorescent ink, which was expected to be used for trademark packaging. Meanwhile, because of the low toxicity of SAM-S, probe SAM-S could perform fluorescence imaging of Hg2+ in living cells.
2023, 51(3): 429-435
doi: 10.19756/j.issn.0253-3820.221492
Abstract:
The miniaturization of gas chromatographic columns is beneficial to the miniaturization of gas chromatographic systems. The separation of light alkanes is a challenge for micro gas chromatographic columns (μGCC). Metal organic framework material is a new type of porous material that has been developed rapidly in the last two decades, and has attracted a lot of attention from researchers as stationary phases for gas chromatography. In this study, a μGCC was prepared based on MEMS technology, and a metal organic framework material HKUST-1 was synthesized at room temperature. HKUST-1 was coated into the μGCC as a stationary phase by dynamic coating method. The testing result of the μGCC with HKUST-1 stationary phase showed that the μGCC could completely separate light alkanes mixtures (methane, ethane, propane and n-butane), and the resolution of methane and ethane that were difficult to separate was 9.2.
The miniaturization of gas chromatographic columns is beneficial to the miniaturization of gas chromatographic systems. The separation of light alkanes is a challenge for micro gas chromatographic columns (μGCC). Metal organic framework material is a new type of porous material that has been developed rapidly in the last two decades, and has attracted a lot of attention from researchers as stationary phases for gas chromatography. In this study, a μGCC was prepared based on MEMS technology, and a metal organic framework material HKUST-1 was synthesized at room temperature. HKUST-1 was coated into the μGCC as a stationary phase by dynamic coating method. The testing result of the μGCC with HKUST-1 stationary phase showed that the μGCC could completely separate light alkanes mixtures (methane, ethane, propane and n-butane), and the resolution of methane and ethane that were difficult to separate was 9.2.
2023, 51(3): 436-444
doi: 10.19756/j.issn.0253-3820.221309
Abstract:
Chiral covalent organic frameworks (CCOFs) have important applications in many fields such as asymmetric catalysis and chiral recognition. Chiral separation has become one of the most important applications of CCOFs due to its convenience, rapidity and high efficiency. To further develop the application value of CCOFs in chromatographic chiral separation, three kinds of CCOFs were obtained by post-synthetic modification method, e.g. L-valine was modified on covalent organic frameworks (COFs) TpPa(NH2)2, L-isoleucine was modified on COFs TpPa(NH2)2 and TpBD(NH2)2, respectively. The three CCOFs were used as gas chromatography chiral stationary phases(CSPs), and mixed with polysiloxane OV-1701 at a mass ratio of 3∶7 to prepare a 4.5 mg/mL coating solution. Three capillary chromatographic columns were prepared by dynamic coating method for chiral separation and analysis. The results showed that the chromatographic columns coated with three kinds of CCOFs had good chiral selectivity and repeatability, which could be used for rapid separation of 25 kinds of chiral compounds such as amino acids, alcohols, aldehydes, esters, ethers, acids and ketones, as well as n-alkanes, n-alkanols, aromatic mixtures and Grob mixtures. Among them, the three CCOFs had wide chiral selectivity and good complementarity in gas chromatography chiral separation, which broadened the range of CCOFs used as gas chromatography CSPs to separate chiral compounds to some extent. This study provided an example of the synthesis of CCOFs by postsynthetic modification, expanded the application of COFs in the field of chiral separation, and showed that CCOFs as a new CSPs had a good application prospect in chromatographic chiral separation.
Chiral covalent organic frameworks (CCOFs) have important applications in many fields such as asymmetric catalysis and chiral recognition. Chiral separation has become one of the most important applications of CCOFs due to its convenience, rapidity and high efficiency. To further develop the application value of CCOFs in chromatographic chiral separation, three kinds of CCOFs were obtained by post-synthetic modification method, e.g. L-valine was modified on covalent organic frameworks (COFs) TpPa(NH2)2, L-isoleucine was modified on COFs TpPa(NH2)2 and TpBD(NH2)2, respectively. The three CCOFs were used as gas chromatography chiral stationary phases(CSPs), and mixed with polysiloxane OV-1701 at a mass ratio of 3∶7 to prepare a 4.5 mg/mL coating solution. Three capillary chromatographic columns were prepared by dynamic coating method for chiral separation and analysis. The results showed that the chromatographic columns coated with three kinds of CCOFs had good chiral selectivity and repeatability, which could be used for rapid separation of 25 kinds of chiral compounds such as amino acids, alcohols, aldehydes, esters, ethers, acids and ketones, as well as n-alkanes, n-alkanols, aromatic mixtures and Grob mixtures. Among them, the three CCOFs had wide chiral selectivity and good complementarity in gas chromatography chiral separation, which broadened the range of CCOFs used as gas chromatography CSPs to separate chiral compounds to some extent. This study provided an example of the synthesis of CCOFs by postsynthetic modification, expanded the application of COFs in the field of chiral separation, and showed that CCOFs as a new CSPs had a good application prospect in chromatographic chiral separation.
2023, 51(3): 445-453
doi: 10.19756/j.issn.0253-3820.221534
Abstract:
X-ray diffraction (XRD) has been widely used in the field of analytical chemistry because it can quickly analyze the composition of materials and the structure and morphology of atoms or molecules inside materials. However, due to the influence of instrument vibration, electromagnetic interference and other factors, the XRD spectrum measured by X-ray diffractometer is extremely noisy. Therefore, in this study, empirical mode decomposition (EMD) combined with t-test was introduced for XRD spectral denoising. Firstly, the XRD spectrum was decomposed by EMD to obtain a series of intrinsic mode function (IMF) components. The high frequency components represented noise and the low frequency components represented useful information. However, sometimes the noise was indistinguishable from useful information. Therefore, the statistical t-test method was introduced in this study to determine the significant difference between the mean of IMFs and zero. Finally, the components with no significant difference were deleted, and the components with significant difference were reconstructed to obtain denosied XRD spectrum. The feasibility of this method was verified by a simulated XRD spectrum and two measured XRD spectrum. The results showed that EMD combined with t-test could effectively remove the noise in XRD spectrum in comparison with Savitzky-Golay (SG) smoothing.
X-ray diffraction (XRD) has been widely used in the field of analytical chemistry because it can quickly analyze the composition of materials and the structure and morphology of atoms or molecules inside materials. However, due to the influence of instrument vibration, electromagnetic interference and other factors, the XRD spectrum measured by X-ray diffractometer is extremely noisy. Therefore, in this study, empirical mode decomposition (EMD) combined with t-test was introduced for XRD spectral denoising. Firstly, the XRD spectrum was decomposed by EMD to obtain a series of intrinsic mode function (IMF) components. The high frequency components represented noise and the low frequency components represented useful information. However, sometimes the noise was indistinguishable from useful information. Therefore, the statistical t-test method was introduced in this study to determine the significant difference between the mean of IMFs and zero. Finally, the components with no significant difference were deleted, and the components with significant difference were reconstructed to obtain denosied XRD spectrum. The feasibility of this method was verified by a simulated XRD spectrum and two measured XRD spectrum. The results showed that EMD combined with t-test could effectively remove the noise in XRD spectrum in comparison with Savitzky-Golay (SG) smoothing.
2023, 51(3): 454-462
doi: 10.19756/j.issn.0253-3820.221405
Abstract:
利用近红外(Near infrared,NIR)漫反射光谱法结合化学计量学定量分析技术开展了平谷产大桃品质的无损检测研究。使用手持式近红外光谱仪采集7个不同品种平谷产大桃的近红外漫反射光谱,采用系统抽样法将其划分为验证集和验证集,结合Savitzky-Golay卷积平滑法(Savitzky-Golay Smoothing,S-G)、标准正态变换法(Standard normal variation,SNV)和多元散射校正法(Multivariate scattering correction,MSC)3种预处理方法以及偏最小二乘回归(Partial least square regression,PLSR)与随机森林(Random forest,RF)两种建模算法,分别建立了大桃中的糖度(Soluble solids content,SSC)、酸度、硬度和水分定量模型。结果表明,非线性RF模型优于线性PLSR模型,对于SSC,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集决定系数(Coefficient of determination,R2)和预测均方根误差(Root mean squared error prediction,RMSEP)分别为0.79和0.77° Brix;对于硬度,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集R2和RMSEP分别为0.90和0.55 N;对于酸度,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集R2和RMSEP分别为0.71和0.18;对于水分,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集R2和RMSEP分别为0.80和0.64%。本研究采用近红外光谱结合化学计量学算法建立的方法可实现平谷大桃品质的快速无损检测。
利用近红外(Near infrared,NIR)漫反射光谱法结合化学计量学定量分析技术开展了平谷产大桃品质的无损检测研究。使用手持式近红外光谱仪采集7个不同品种平谷产大桃的近红外漫反射光谱,采用系统抽样法将其划分为验证集和验证集,结合Savitzky-Golay卷积平滑法(Savitzky-Golay Smoothing,S-G)、标准正态变换法(Standard normal variation,SNV)和多元散射校正法(Multivariate scattering correction,MSC)3种预处理方法以及偏最小二乘回归(Partial least square regression,PLSR)与随机森林(Random forest,RF)两种建模算法,分别建立了大桃中的糖度(Soluble solids content,SSC)、酸度、硬度和水分定量模型。结果表明,非线性RF模型优于线性PLSR模型,对于SSC,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集决定系数(Coefficient of determination,R2)和预测均方根误差(Root mean squared error prediction,RMSEP)分别为0.79和0.77° Brix;对于硬度,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集R2和RMSEP分别为0.90和0.55 N;对于酸度,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集R2和RMSEP分别为0.71和0.18;对于水分,一阶导数光谱结合MSC预处理建立的RF模型效果最佳,验证集R2和RMSEP分别为0.80和0.64%。本研究采用近红外光谱结合化学计量学算法建立的方法可实现平谷大桃品质的快速无损检测。
