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2023 Volume 51 Issue 6
2023, 51(6): 911-921
doi: 10.19756/j.issn.0253-3820.221589
Abstract:
The rapid and highly sensitive detection of contaminants in foods is an important strategy to prevent food safety incidents. DNA Walker is a dynamic nano-machine with a programmable structure and function. It can be moved along the designed track interface driven by free energy to carry out continuous mechanical displacement. The nuclease powered DNA walker has excellent signal amplification capabilities and reaction kinetics, and the DNA walker-based biosensor combined with aptamer has been widely used in food safety detection. This review summarized the construction strategies of nuclease powered DNA walker and its application in food safety testing, and its further prospects were also discussed.
The rapid and highly sensitive detection of contaminants in foods is an important strategy to prevent food safety incidents. DNA Walker is a dynamic nano-machine with a programmable structure and function. It can be moved along the designed track interface driven by free energy to carry out continuous mechanical displacement. The nuclease powered DNA walker has excellent signal amplification capabilities and reaction kinetics, and the DNA walker-based biosensor combined with aptamer has been widely used in food safety detection. This review summarized the construction strategies of nuclease powered DNA walker and its application in food safety testing, and its further prospects were also discussed.
2023, 51(6): 922-933
doi: 10.19756/j.issn.0253-3820.221625
Abstract:
Nanozymes, as a class of nanomaterials with enzyme-like activity, exhibit good development and application potential in the fields of analytical chemistry and disease diagnosis and treatment. Metal-organic frameworks (MOFs) materials are porous crystalline materials formed by metal nodes and organic ligands, and their structures have certain similarities with natural enzymes. At present, researchers have developed a variety of nanozymes based on MOFs, including nanozymes with peroxidase-like, oxidase-like, superoxide dismutase-like, and hydrolase-like activities, showing broad application prospects. In this paper, according to the structural characteristics of the materials, MOFs-based nanozymes were divided into four categories, including original MOFs, chemically modified MOFs, MOFs composite materials and MOFs derivatives, and the basic principles and latest developments in the preparation of these nanozymes were introduced. Based on analytical strategies such as colorimetric sensing, fluorescent sensing and electrochemical sensing, the application progress of MOFs-based nanozymes in bioanalysis was reviewed. The challenges of their practical applications and future development trends were also discussed.
Nanozymes, as a class of nanomaterials with enzyme-like activity, exhibit good development and application potential in the fields of analytical chemistry and disease diagnosis and treatment. Metal-organic frameworks (MOFs) materials are porous crystalline materials formed by metal nodes and organic ligands, and their structures have certain similarities with natural enzymes. At present, researchers have developed a variety of nanozymes based on MOFs, including nanozymes with peroxidase-like, oxidase-like, superoxide dismutase-like, and hydrolase-like activities, showing broad application prospects. In this paper, according to the structural characteristics of the materials, MOFs-based nanozymes were divided into four categories, including original MOFs, chemically modified MOFs, MOFs composite materials and MOFs derivatives, and the basic principles and latest developments in the preparation of these nanozymes were introduced. Based on analytical strategies such as colorimetric sensing, fluorescent sensing and electrochemical sensing, the application progress of MOFs-based nanozymes in bioanalysis was reviewed. The challenges of their practical applications and future development trends were also discussed.
2023, 51(6): 934-944
doi: 10.19756/j.issn.0253-3820.231008
Abstract:
Single-cell analysis is important for early diagnosis and treatment of major diseases, drug screening, and studying physiopathological processes. Microfluidic chips are capable of precisely controlling the microenvironment of single cells and monitoring their behavior in real-time, and have become a powerful tool for single-cell analysis. Single-cell capture is an important step in single-cell analysis. Till now, several microfluidic-chip-based single-cell capture methods have been reported, among which hydrodynamic microfluidicchip-based single-cell capture has the advantages such as easy operation and high-efficiency of single-cell capture, and thus has received wide attention and has been used by researchers. To comprehensively understand the research status of hydrodynamic microfluidic-chip-based single-cell capture, master the structural design of highefficiency single-cell capture microfluidic chips, and realize the accurate and rapid analysis of single cells, in this paper, the principle of efficient single-cell capture based on hydrodynamics and the structure of microfluidic chips are reviewed. There are three types of structures according to the structural design including micro-well structures, microcolumn structures and bypass channel structures. The optimization process of single-cell capture microfluidic chips is introduced. The materials, structural features, and single-cell capture efficiency of microfluidic chips are summarized, and the advantages and shortcomings of each single-cell capture structure are analyzed. Finally, the development trend of the hydrodynamic-based microfluidic chip single-cell capture method is prospected.
Single-cell analysis is important for early diagnosis and treatment of major diseases, drug screening, and studying physiopathological processes. Microfluidic chips are capable of precisely controlling the microenvironment of single cells and monitoring their behavior in real-time, and have become a powerful tool for single-cell analysis. Single-cell capture is an important step in single-cell analysis. Till now, several microfluidic-chip-based single-cell capture methods have been reported, among which hydrodynamic microfluidicchip-based single-cell capture has the advantages such as easy operation and high-efficiency of single-cell capture, and thus has received wide attention and has been used by researchers. To comprehensively understand the research status of hydrodynamic microfluidic-chip-based single-cell capture, master the structural design of highefficiency single-cell capture microfluidic chips, and realize the accurate and rapid analysis of single cells, in this paper, the principle of efficient single-cell capture based on hydrodynamics and the structure of microfluidic chips are reviewed. There are three types of structures according to the structural design including micro-well structures, microcolumn structures and bypass channel structures. The optimization process of single-cell capture microfluidic chips is introduced. The materials, structural features, and single-cell capture efficiency of microfluidic chips are summarized, and the advantages and shortcomings of each single-cell capture structure are analyzed. Finally, the development trend of the hydrodynamic-based microfluidic chip single-cell capture method is prospected.
2023, 51(6): 945-953
doi: 10.19756/j.issn.0253-3820.221536
Abstract:
Cardiac troponin I (cTnI) is one of the standard biomarkers of myocardial injury, and the rapid detection of its concentration in serum is crucial for the diagnosis of acute myocardial infarction (AMI). In this study, gold nanorods (GNRs) modified with mouse anti-cTnI monoclonal antibody (4T21cc-19C7cc, dAb) were used as labeling probes to prepare lateral flow immunochromatographic test strips (LFITS) by double-antibody sandwich method for rapid detection of cTnI in clinical serum samples. The GNR-labeled LFITS (termed as GNRLFITS) showed several advantages including quantitative detection, high sensitivity and good specificity. The GNR-LFITS exhibited a linearity with the concentration of cTnI in the range of 5-100 ng/mL in serum, with a low limit of detection (LOD, 1.2 ng/mL) and low values of cross reaction with other protein interfering substances (<5%). Furthermore, the practicability of as-developed GNR-LFITS was demonstrated by quantitative determination of cTnI in clinical serum samples. The results of GNR-LFITS exhibited a good correlation with those of commercial enzyme-linked immunosorbent assay (ELISA) detection kit (R2=0.989), suggesting that GNR-LFITS had great potential in the early diagnosis of AMI.
Cardiac troponin I (cTnI) is one of the standard biomarkers of myocardial injury, and the rapid detection of its concentration in serum is crucial for the diagnosis of acute myocardial infarction (AMI). In this study, gold nanorods (GNRs) modified with mouse anti-cTnI monoclonal antibody (4T21cc-19C7cc, dAb) were used as labeling probes to prepare lateral flow immunochromatographic test strips (LFITS) by double-antibody sandwich method for rapid detection of cTnI in clinical serum samples. The GNR-labeled LFITS (termed as GNRLFITS) showed several advantages including quantitative detection, high sensitivity and good specificity. The GNR-LFITS exhibited a linearity with the concentration of cTnI in the range of 5-100 ng/mL in serum, with a low limit of detection (LOD, 1.2 ng/mL) and low values of cross reaction with other protein interfering substances (<5%). Furthermore, the practicability of as-developed GNR-LFITS was demonstrated by quantitative determination of cTnI in clinical serum samples. The results of GNR-LFITS exhibited a good correlation with those of commercial enzyme-linked immunosorbent assay (ELISA) detection kit (R2=0.989), suggesting that GNR-LFITS had great potential in the early diagnosis of AMI.
2023, 51(6): 954-961
doi: 10.19756/j.issn.0253-3820.231079
Abstract:
A ratiometric colorimetric sensor for sensitive detection of paraoxon was constructed based on the organophosphorus hydrolase-like activity and oxidase-like activity of cerium oxide nanoparticles (CeO2 NPs). The CeO2 NPs with OPH-like activity catalyzed hydrolysis of paraoxon to generate yellow p-nitrophenol, which had an obvious absorption peak at 400 nm. At the same time, CeO2 NPs featured with oxidase-like activity could catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) into a blue oxidation state TMB, which had a significant absorption peak at 653 nm. In the presence of paraoxon, CeO2 nanozyme hydrolyzed paraoxon to p-nitrophenol, and the absorbance value of the system at 400 nm (A400) increased. Meanwhile, paraoxon inhibited the oxidase-like activity of CeO2 nanozyme, and the absorbance value of the TMB system at 653 nm (A653) decreased. The sensitive and accurate detection of paraoxon was realized based on the changes of A400/A653 before and after the addition of paraoxon, and the detection limit was 0.03 μmol/L (S/N=3). This method was used to detect the content of paraoxon in Chinese chives samples, and the recoveries were 92.0%-99.2%. This work developed a ratiometric colorimetric sensing method based on the dual-nanozyme activity of CeO2 NPs, providing a new strategy for the sensitive detection of paraoxon residues in food.
A ratiometric colorimetric sensor for sensitive detection of paraoxon was constructed based on the organophosphorus hydrolase-like activity and oxidase-like activity of cerium oxide nanoparticles (CeO2 NPs). The CeO2 NPs with OPH-like activity catalyzed hydrolysis of paraoxon to generate yellow p-nitrophenol, which had an obvious absorption peak at 400 nm. At the same time, CeO2 NPs featured with oxidase-like activity could catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) into a blue oxidation state TMB, which had a significant absorption peak at 653 nm. In the presence of paraoxon, CeO2 nanozyme hydrolyzed paraoxon to p-nitrophenol, and the absorbance value of the system at 400 nm (A400) increased. Meanwhile, paraoxon inhibited the oxidase-like activity of CeO2 nanozyme, and the absorbance value of the TMB system at 653 nm (A653) decreased. The sensitive and accurate detection of paraoxon was realized based on the changes of A400/A653 before and after the addition of paraoxon, and the detection limit was 0.03 μmol/L (S/N=3). This method was used to detect the content of paraoxon in Chinese chives samples, and the recoveries were 92.0%-99.2%. This work developed a ratiometric colorimetric sensing method based on the dual-nanozyme activity of CeO2 NPs, providing a new strategy for the sensitive detection of paraoxon residues in food.
2023, 51(6): 962-971
doi: 10.19756/j.issn.0253-3820.221546
Abstract:
G-rich sequences with specific conformations (e.g. G-quadruplex and G-triplex) can interact with fluorescent dyes to enhance their fluorescence signal intensity, and are widely used for label-free fluorescent biosensing. In this study, two label-free fluorescent sensors based on G-rich sequences were constructed for detection of the gene sequence of β-amyloid protein (Aβ), a marker of Alzheimer's syndrome, using thiosemicarbazone T (ThT) as the fluorescent dye. The experimental results showed that the G-rich sequences were present as G-triplexes when the length of the hairpin stem was 4 base pairs, and the output signal of the G-triplex sensor decreased with increasing concentration of Aβ gene, with a linear detection range of 1-100 nmol/L and a detection limit of 0.3 nmol/L (S/N = 3). When the length of the hairpin stem was 8 base pairs and the base AATT was added at the 5' end, the G-rich signal decreased with the concentration of Aβ gene. The G-rich sequences were mostly present as G-quadruplexes after binding to Aβ gene, and the output signal of the G-quadruplex sensor was enhanced with increasing concentration of Aβ gene, with a linear detection range of 0.1-100 nmol/L and a detection limit of 0.04 nmol/L (S/N = 3). The two sensors were prepared in a similar process but with different detection principles, providing a basis for further research and application of G-rich sequences. It also provided a new idea for the label-free fluorescence detection of single-stranded nucleic acids.
G-rich sequences with specific conformations (e.g. G-quadruplex and G-triplex) can interact with fluorescent dyes to enhance their fluorescence signal intensity, and are widely used for label-free fluorescent biosensing. In this study, two label-free fluorescent sensors based on G-rich sequences were constructed for detection of the gene sequence of β-amyloid protein (Aβ), a marker of Alzheimer's syndrome, using thiosemicarbazone T (ThT) as the fluorescent dye. The experimental results showed that the G-rich sequences were present as G-triplexes when the length of the hairpin stem was 4 base pairs, and the output signal of the G-triplex sensor decreased with increasing concentration of Aβ gene, with a linear detection range of 1-100 nmol/L and a detection limit of 0.3 nmol/L (S/N = 3). When the length of the hairpin stem was 8 base pairs and the base AATT was added at the 5' end, the G-rich signal decreased with the concentration of Aβ gene. The G-rich sequences were mostly present as G-quadruplexes after binding to Aβ gene, and the output signal of the G-quadruplex sensor was enhanced with increasing concentration of Aβ gene, with a linear detection range of 0.1-100 nmol/L and a detection limit of 0.04 nmol/L (S/N = 3). The two sensors were prepared in a similar process but with different detection principles, providing a basis for further research and application of G-rich sequences. It also provided a new idea for the label-free fluorescence detection of single-stranded nucleic acids.
2023, 51(6): 972-981
doi: 10.19756/j.issn.0253-3820.231018
Abstract:
Bioaerosol monitoring is essential for disease prevention and control, anti-chemical and counterterrorism, and environmental and resource conservation. In this research, a tapered thin-film enhanced optical waveguide surface scattering-based sensing method was proposed for rapid bioaerosol detection. The method was implemented by measuring the scattered light intensity with time, enabling analysis of particle sedimentation process of biological aerosols on the waveguide surface and then the information on the bioaerosol sample was obtained. The formula for the relationship between the scattered light intensity and the number of particles adhered onto the waveguide surface from the bioaerosol was deduced, and a series of aqueous solutions with different concentrations of bovine serum protein (BSA) were prepared for generating the bioaerosol samples, and the singlemode glass slab waveguides made by ion-exchange were used to detect the deposition of BSA aggregates from the bioaerosol sample. A tapered thin film of Ta2O5 was locally sputtered on the glass waveguide for improving the detection sensitivity. Experimental results showed that the scattered light intensity increased with increasing the deposition time of BSA aggregates and had a good linear relationship with the BAS concentration of aqueous solution. When the glass waveguide was covered with the tapered film of Ta2O5, the BSA detection sensitivity increased by 50 times in the case of excitation of the fundamental transvers electric mode (TE0). Moreover, the sensitivity measured with the TE0 mode was 4 times higher than that with the TM0 mode in the same waveguide. The single-mode slab glass waveguides locally covered with the tapered thin films of Ta2O5 had a simple structure and a good stability and were easy to fabricate. They were convenient to use serving as the surface-scattering-based sensors, had high sensitivity and low detection cost, showing a bright application prospect in real-time detection of bioaerosols.
Bioaerosol monitoring is essential for disease prevention and control, anti-chemical and counterterrorism, and environmental and resource conservation. In this research, a tapered thin-film enhanced optical waveguide surface scattering-based sensing method was proposed for rapid bioaerosol detection. The method was implemented by measuring the scattered light intensity with time, enabling analysis of particle sedimentation process of biological aerosols on the waveguide surface and then the information on the bioaerosol sample was obtained. The formula for the relationship between the scattered light intensity and the number of particles adhered onto the waveguide surface from the bioaerosol was deduced, and a series of aqueous solutions with different concentrations of bovine serum protein (BSA) were prepared for generating the bioaerosol samples, and the singlemode glass slab waveguides made by ion-exchange were used to detect the deposition of BSA aggregates from the bioaerosol sample. A tapered thin film of Ta2O5 was locally sputtered on the glass waveguide for improving the detection sensitivity. Experimental results showed that the scattered light intensity increased with increasing the deposition time of BSA aggregates and had a good linear relationship with the BAS concentration of aqueous solution. When the glass waveguide was covered with the tapered film of Ta2O5, the BSA detection sensitivity increased by 50 times in the case of excitation of the fundamental transvers electric mode (TE0). Moreover, the sensitivity measured with the TE0 mode was 4 times higher than that with the TM0 mode in the same waveguide. The single-mode slab glass waveguides locally covered with the tapered thin films of Ta2O5 had a simple structure and a good stability and were easy to fabricate. They were convenient to use serving as the surface-scattering-based sensors, had high sensitivity and low detection cost, showing a bright application prospect in real-time detection of bioaerosols.
2023, 51(6): 982-993
doi: 10.19756/j.issn.0253-3820.231142
Abstract:
The development of a smart hydrogel platform with shape adaptability and excellent antibacterial activity for treating bacteria-infected wound is highly demanded in practical applications. Herein, an injectable thermosensitive hydrogel with adhesive and photothermal antibacterial activity was prepared by combination of biocompatible chitosan (CS), β-sodium glycerophosphate (β-GP) and polydopamine nanoparticles (PDA NPs) via hydrogen bonding and Schiff base bond. It was noted that catechol groups were grafted on the chitosan backbone to improve the adhesive activity between hydrogel and tissues. Catechol-modified chitosan (CHI-C), β-GP and PDA NPs could form a crosslinked network by simple stirring at physiological temperature within 1.5 min. Furthermore, the introduction of PDA NPs with efficient photothermal conversion ability not only endowed the hydrogel with excellent antibacterial ability, but also enhanced the mechanical property of the hydrogel network. The as-prepared CHI-C/β-GP/PDA hydrogel with good biocompatibility, excellent photothermal conversion ability, and fantastic antibacterial effect could be injected directly in the irregular wounds of mice to form the hydrogel in situ. The experimental results demonstrated that the as-prepared smart hydrogel could be expected to serve as a promising wound to promote bacteria-infected wound healing.
The development of a smart hydrogel platform with shape adaptability and excellent antibacterial activity for treating bacteria-infected wound is highly demanded in practical applications. Herein, an injectable thermosensitive hydrogel with adhesive and photothermal antibacterial activity was prepared by combination of biocompatible chitosan (CS), β-sodium glycerophosphate (β-GP) and polydopamine nanoparticles (PDA NPs) via hydrogen bonding and Schiff base bond. It was noted that catechol groups were grafted on the chitosan backbone to improve the adhesive activity between hydrogel and tissues. Catechol-modified chitosan (CHI-C), β-GP and PDA NPs could form a crosslinked network by simple stirring at physiological temperature within 1.5 min. Furthermore, the introduction of PDA NPs with efficient photothermal conversion ability not only endowed the hydrogel with excellent antibacterial ability, but also enhanced the mechanical property of the hydrogel network. The as-prepared CHI-C/β-GP/PDA hydrogel with good biocompatibility, excellent photothermal conversion ability, and fantastic antibacterial effect could be injected directly in the irregular wounds of mice to form the hydrogel in situ. The experimental results demonstrated that the as-prepared smart hydrogel could be expected to serve as a promising wound to promote bacteria-infected wound healing.
2023, 51(6): 994-1002
doi: 10.19756/j.issn.0253-3820.231062
Abstract:
A new experimental set-up for highly sensitive detection of transient radicals was established based on cavity ring-down spectroscopy (CRDS) combined with flash photolysis. The mode coupling between the laser and the cavity was achieved by scanning the cavity length of the self-designed optical resonant cavity, and the ringdown time was obtained by fitting the decay curve based on the linear regression summation (LRS) algorithm. The minimum detectable absorption of the system of 5.05×10-11 cm-1 was achieved with effective optical path of 20.3 km and acquiring time of 6.25 s. HO2 radicals were generated by using a 266 nm Nd∶YAG laser photolysis of O3/C2H2 mixtures. The characteristic absorption of HO2 radicals at 6638.203 cm-1 was measured, and the absorption spectrum with a resolution of 0.002 cm-1 was obtained. Under the condition of 2 kPa, the absorption cross section of HO2 radicals at 6638.203 cm-1 was 3.3×10-19 cm2/molecule by measuring the decay of the HO2 radicals self-reaction, and the corresponding absorption line strength was 6.02×10-21 cm-1/(molecule/cm2).
A new experimental set-up for highly sensitive detection of transient radicals was established based on cavity ring-down spectroscopy (CRDS) combined with flash photolysis. The mode coupling between the laser and the cavity was achieved by scanning the cavity length of the self-designed optical resonant cavity, and the ringdown time was obtained by fitting the decay curve based on the linear regression summation (LRS) algorithm. The minimum detectable absorption of the system of 5.05×10-11 cm-1 was achieved with effective optical path of 20.3 km and acquiring time of 6.25 s. HO2 radicals were generated by using a 266 nm Nd∶YAG laser photolysis of O3/C2H2 mixtures. The characteristic absorption of HO2 radicals at 6638.203 cm-1 was measured, and the absorption spectrum with a resolution of 0.002 cm-1 was obtained. Under the condition of 2 kPa, the absorption cross section of HO2 radicals at 6638.203 cm-1 was 3.3×10-19 cm2/molecule by measuring the decay of the HO2 radicals self-reaction, and the corresponding absorption line strength was 6.02×10-21 cm-1/(molecule/cm2).
2023, 51(6): 1003-1012
doi: 10.19756/j.issn.0253-3820.221186
Abstract:
UiO-66(OH)@Fe2O3 synthesized by hydrothermal method was used for adsorption of As(Ⅲ) and As(V). results showed that the optimal pH value for As (Ⅲ) removal by UiO-66(OH)@Fe2O3 was pH=11, the equilibrium adsorption time was 180 min, and the maximum adsorption amount was 140.0 mg/g. At this time, the main form of As(Ⅲ) removal was H2AsO3-. Meanwhile, the optimal pH value for As(V) removal by UiO-66(OH)@Fe2O3 was pH=9, the equilibrium adsorption time was 90 min, and the maximum adsorption amount was 260.0 mg/g. At this pH value, the main form of As(V) removal was HAsO42-. The adsorption kinetics, thermodynamic, co-existing ions and repeatability of UiO-66(OH)@Fe2O3 were also investigated. It was shown that the adsorption fitted well with pseudo second-order kinetic model and Langmuir isotherm, and the ΔG° was less than zero under different temperatures, indicating that the entire adsorption process belongs to spontaneous monolayer chemical adsorption. Except PO43-, other co-existing ions had little effects on adsorption. The adsorbed material was eluted with 0.25 mol/L Na2SO4. Through five times of adsorption and desorption experiments, it was shown that the removal rate of As(Ⅲ) and As(V) were more than 60% and 80%, respectively. The characterization results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) showed that the adsorption of arsenic by this adsorbent was mainly a chemical process, including the formation of Zr—O—As and the co-precipitation of ferric hydroxide produced by Fe2O3 hydrolysis. The prepared UiO-66(OH)@Fe2O3 had good adsorption activity for removing arsenic in different forms, and provided a theoretical reference for the development of composite materials with zirconium-based frame materials as the basic materials.
UiO-66(OH)@Fe2O3 synthesized by hydrothermal method was used for adsorption of As(Ⅲ) and As(V). results showed that the optimal pH value for As (Ⅲ) removal by UiO-66(OH)@Fe2O3 was pH=11, the equilibrium adsorption time was 180 min, and the maximum adsorption amount was 140.0 mg/g. At this time, the main form of As(Ⅲ) removal was H2AsO3-. Meanwhile, the optimal pH value for As(V) removal by UiO-66(OH)@Fe2O3 was pH=9, the equilibrium adsorption time was 90 min, and the maximum adsorption amount was 260.0 mg/g. At this pH value, the main form of As(V) removal was HAsO42-. The adsorption kinetics, thermodynamic, co-existing ions and repeatability of UiO-66(OH)@Fe2O3 were also investigated. It was shown that the adsorption fitted well with pseudo second-order kinetic model and Langmuir isotherm, and the ΔG° was less than zero under different temperatures, indicating that the entire adsorption process belongs to spontaneous monolayer chemical adsorption. Except PO43-, other co-existing ions had little effects on adsorption. The adsorbed material was eluted with 0.25 mol/L Na2SO4. Through five times of adsorption and desorption experiments, it was shown that the removal rate of As(Ⅲ) and As(V) were more than 60% and 80%, respectively. The characterization results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) showed that the adsorption of arsenic by this adsorbent was mainly a chemical process, including the formation of Zr—O—As and the co-precipitation of ferric hydroxide produced by Fe2O3 hydrolysis. The prepared UiO-66(OH)@Fe2O3 had good adsorption activity for removing arsenic in different forms, and provided a theoretical reference for the development of composite materials with zirconium-based frame materials as the basic materials.
2023, 51(6): 1013-1023
doi: 10.19756/j.issn.0253-3820.211239
Abstract:
A imidazolium ionic liquid-functionalized silica (Sil-IL) was synthesized and used as mixed-mode sorbent for solid phase extraction (SPE) of non-steroidal anti-inflammatory drugs (NSAIDs, naproxen, ketoprofen, indoometacin and tolfenamic acid) residues from bovine milk. A method combining this mixed-mode SPE and high performance liquid chromatography-ultraviolet detector (HPLC-UV) was established for simultaneous analysis of four kinds of NSAIDs residues in bovine milk. The prepared Sil-IL was characterized by Fourier transform infrared spectra, Raman spectra and elemental analysis. Then the retention mechanism of NSAIDs on Sil-IL sorbent was explored and the parameters affecting the extraction efficiency were optimized. Experimental results showed that Sil-IL had good extraction selectivity and high extraction efficiency towards four kinds of NSAIDs. Meanwhile, the interaction between Sil-IL and NSAIDs was mainly hydrophobic and anion exchange interactions. Under optimal SPE conditions, good sensitivity was achieved with a limit of detection of 1.2-1.9 μg/kg. The method displayed good linear relationship in the concentration range of 3-1000 μg/L for ketoprofen, naproxen, indomethacin and 4-1000 μg/L for tolfenamic acid, with the correlation coefficient (R2) of 09996-0.9998. The intra-day and inter-day precision were 1.0%-3.0% and 1.9%-6.3%, respectively. The recoveries of four kinds of NSAIDs in bovine milk at two spiked levels were 90.8%-105.3% with relative standard deviations less than 6.1%. The established method was proved to be accurate, reliable, simple, sensitive and selective, and could be used for determination of NSAIDs residues in milk sample.
A imidazolium ionic liquid-functionalized silica (Sil-IL) was synthesized and used as mixed-mode sorbent for solid phase extraction (SPE) of non-steroidal anti-inflammatory drugs (NSAIDs, naproxen, ketoprofen, indoometacin and tolfenamic acid) residues from bovine milk. A method combining this mixed-mode SPE and high performance liquid chromatography-ultraviolet detector (HPLC-UV) was established for simultaneous analysis of four kinds of NSAIDs residues in bovine milk. The prepared Sil-IL was characterized by Fourier transform infrared spectra, Raman spectra and elemental analysis. Then the retention mechanism of NSAIDs on Sil-IL sorbent was explored and the parameters affecting the extraction efficiency were optimized. Experimental results showed that Sil-IL had good extraction selectivity and high extraction efficiency towards four kinds of NSAIDs. Meanwhile, the interaction between Sil-IL and NSAIDs was mainly hydrophobic and anion exchange interactions. Under optimal SPE conditions, good sensitivity was achieved with a limit of detection of 1.2-1.9 μg/kg. The method displayed good linear relationship in the concentration range of 3-1000 μg/L for ketoprofen, naproxen, indomethacin and 4-1000 μg/L for tolfenamic acid, with the correlation coefficient (R2) of 09996-0.9998. The intra-day and inter-day precision were 1.0%-3.0% and 1.9%-6.3%, respectively. The recoveries of four kinds of NSAIDs in bovine milk at two spiked levels were 90.8%-105.3% with relative standard deviations less than 6.1%. The established method was proved to be accurate, reliable, simple, sensitive and selective, and could be used for determination of NSAIDs residues in milk sample.
2023, 51(6): 1024-1032
doi: 10.19756/j.issn.0253-3820.231040
Abstract:
Dispersive solid phase extraction (DSPE) using nitro modified zirconium-based metal organic framework (NO2-MOF) as adsorbent for determination of bongkrekic acid in food was developed. The synthesized NO2-MOF were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), infrared spectroscopy (IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption experiment, etc, indicating that a structural stable MOF material with large BET surface area was obtained. There existed electrostatic interaction, π-π stacking, hydrogen bond and other weak intermolecular interactions between MOF and bongkrekic acid molecules to achieve selective adsorption of target molecules. Main experimental factors affecting DSPE were optimized, including pH value, amount of the adsorbent, extraction time, and type of desorption solvent. The established method was applied to detection of bongkrekic acid in auricularia auricula and rice flour, with limit of quantification of 1.6 μg/kg, and limit of detection of 0.5 μg/kg. In conclusion, the established method for determination of bongkrekic acid in food by DSPE had the advantages such as short pretreatment time, high sensitivity and precision with satisfactory recoveries of 75%-96%, and was environmentally friendly. This work provided a more reliable technique for determination of extremely trace amount of bongkrekic acid in related food such as auricularia auricula, tremella and rice flour.
Dispersive solid phase extraction (DSPE) using nitro modified zirconium-based metal organic framework (NO2-MOF) as adsorbent for determination of bongkrekic acid in food was developed. The synthesized NO2-MOF were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), infrared spectroscopy (IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption experiment, etc, indicating that a structural stable MOF material with large BET surface area was obtained. There existed electrostatic interaction, π-π stacking, hydrogen bond and other weak intermolecular interactions between MOF and bongkrekic acid molecules to achieve selective adsorption of target molecules. Main experimental factors affecting DSPE were optimized, including pH value, amount of the adsorbent, extraction time, and type of desorption solvent. The established method was applied to detection of bongkrekic acid in auricularia auricula and rice flour, with limit of quantification of 1.6 μg/kg, and limit of detection of 0.5 μg/kg. In conclusion, the established method for determination of bongkrekic acid in food by DSPE had the advantages such as short pretreatment time, high sensitivity and precision with satisfactory recoveries of 75%-96%, and was environmentally friendly. This work provided a more reliable technique for determination of extremely trace amount of bongkrekic acid in related food such as auricularia auricula, tremella and rice flour.
2023, 51(6): 1033-1041
doi: 10.19756/j.issn.0253-3820.221372
Abstract:
A headspace solid-phase microextraction coupled with gas chromatography-mass spectrometric (GCMS) method was developed for analysis of 8 kinds of benzenes (BTEX) and 17 kinds of volatile halogenated hydrocarbons (VHC) in urine samples. The effects of extraction fiber, extraction temperature, extraction time, urine pH, stirring speed and salt effect on the experimental results were investigated by single-factor experiments, followed by the interaction analysis between factors based on the Box-Behnken experimental design principle with the total peak areas of the chromatograms of 25 kinds of target compounds as the response values. The optimized conditions were as follows: 2 mL of urine sample adjusted to pH=4, 40 μL of internal standard (fluorobenzene and chlorobenzene-d5, 500 μg/L) and 0.55 g NaCl were added to a 40-mL headspace vial; 75 μm Carboxen/ polydimethylsiloxane (Carboxen/PDMS) fiber was selected for headspace extraction at 51℃ with stirring speed of 400 r/min for 35 min. The calibration curves showed good linearity (R2 > 0.990) in the range of 0.05-50 μg/L for the 25 kinds of targets, with the detection limits of 0.008-5.780 ng/L and the lower limits of quantification of 0.027-19.268 ng/L. The recoveries of the 25 kinds of stargets ranged from 78.9% to 115.2% and the relative standard deviations were 0.7%-16.2%. The method was applied to determination of urine samples from the healthy population in Lai Yang, Shandong Province. The results showed that 20 kinds of target compounds were detected in 15 human urine samples, with total concentrations ranging from 3.13 to 43.17 μg/L and a median content of 5.78 μg/L. 1,2,4-Trimethylbenzene (1,2,4-TMB) was the compound with the highest median content of BTEX and 1,3-dichlorobenzene (1,3-DCB) was the compound with the highest median content of VHC. The method was sensitive and reproducible for simultaneous determination of BTEX and VHC in urine samples and might provide an important methodological basis for human exposure studies of these two compounds.
A headspace solid-phase microextraction coupled with gas chromatography-mass spectrometric (GCMS) method was developed for analysis of 8 kinds of benzenes (BTEX) and 17 kinds of volatile halogenated hydrocarbons (VHC) in urine samples. The effects of extraction fiber, extraction temperature, extraction time, urine pH, stirring speed and salt effect on the experimental results were investigated by single-factor experiments, followed by the interaction analysis between factors based on the Box-Behnken experimental design principle with the total peak areas of the chromatograms of 25 kinds of target compounds as the response values. The optimized conditions were as follows: 2 mL of urine sample adjusted to pH=4, 40 μL of internal standard (fluorobenzene and chlorobenzene-d5, 500 μg/L) and 0.55 g NaCl were added to a 40-mL headspace vial; 75 μm Carboxen/ polydimethylsiloxane (Carboxen/PDMS) fiber was selected for headspace extraction at 51℃ with stirring speed of 400 r/min for 35 min. The calibration curves showed good linearity (R2 > 0.990) in the range of 0.05-50 μg/L for the 25 kinds of targets, with the detection limits of 0.008-5.780 ng/L and the lower limits of quantification of 0.027-19.268 ng/L. The recoveries of the 25 kinds of stargets ranged from 78.9% to 115.2% and the relative standard deviations were 0.7%-16.2%. The method was applied to determination of urine samples from the healthy population in Lai Yang, Shandong Province. The results showed that 20 kinds of target compounds were detected in 15 human urine samples, with total concentrations ranging from 3.13 to 43.17 μg/L and a median content of 5.78 μg/L. 1,2,4-Trimethylbenzene (1,2,4-TMB) was the compound with the highest median content of BTEX and 1,3-dichlorobenzene (1,3-DCB) was the compound with the highest median content of VHC. The method was sensitive and reproducible for simultaneous determination of BTEX and VHC in urine samples and might provide an important methodological basis for human exposure studies of these two compounds.
2023, 51(6): 1042-1050
doi: 10.19756/j.issn.0253-3820.221388
Abstract:
As an important ingredient of fried food, the quality of oil is of great significance to product safety and industry development. To explore the feasibility of synchronous evaluation of oil frying quality indexes based on low-field nuclear magnetic resonance (LF-NMR) technology, rapeseed oil was taken as the research object, and the changes of quality indexes as well as the variations on LF-NMR relaxation signals during frying were systematically analyzed. Then, the correlation between the quality indexes and the relaxation properties of rapeseed oil was studied. At last, the synchronous evaluation model for rapeseed oil frying quality indexes was established by LF-NMR relaxation properties combined with multiple linear regression, and the influence of the number of independent variables on the model performance was also investigated. The experimental results showed that the acid value, polar component, p-anisidine value, carbonyl value, viscosity and the absorbance of rapeseed oil increased with the increase of frying time, while the iodine value gradually decreased. During frying, the attenuation rate of the Carr-Purcell-Meiboom-Gill (CPMG) echo attenuation curve of rapeseed oil gradually increased. In addition, the relaxation parameters (T2w, T21, T22, S22, S23) were significantly related to the frying quality indexes of rapeseed oil (Acid value, polar component, p-anisidine value, carbonyl value, viscosity, absorbance and iodine value) with p<0.05. Moreover, the determination coefficient (R2) of the LF-NMR-based synchronous prediction model for frying quality indexes of rapeseed oil was greater than 0.93, and the relative average deviation (RAD) was less than 0.15. Compared with the univariate model, except p-anisidine value, the RAD and the root mean square error of prediction (RMSEP) value of other indexes were reduced by more than 55%. It could be seen that it was feasible to synchronously detect multiple indicators of oil frying quality based on LF-NMR, and this technique could also provide the theoretical basis and technical support for rapid online monitoring of complex systems.
As an important ingredient of fried food, the quality of oil is of great significance to product safety and industry development. To explore the feasibility of synchronous evaluation of oil frying quality indexes based on low-field nuclear magnetic resonance (LF-NMR) technology, rapeseed oil was taken as the research object, and the changes of quality indexes as well as the variations on LF-NMR relaxation signals during frying were systematically analyzed. Then, the correlation between the quality indexes and the relaxation properties of rapeseed oil was studied. At last, the synchronous evaluation model for rapeseed oil frying quality indexes was established by LF-NMR relaxation properties combined with multiple linear regression, and the influence of the number of independent variables on the model performance was also investigated. The experimental results showed that the acid value, polar component, p-anisidine value, carbonyl value, viscosity and the absorbance of rapeseed oil increased with the increase of frying time, while the iodine value gradually decreased. During frying, the attenuation rate of the Carr-Purcell-Meiboom-Gill (CPMG) echo attenuation curve of rapeseed oil gradually increased. In addition, the relaxation parameters (T2w, T21, T22, S22, S23) were significantly related to the frying quality indexes of rapeseed oil (Acid value, polar component, p-anisidine value, carbonyl value, viscosity, absorbance and iodine value) with p<0.05. Moreover, the determination coefficient (R2) of the LF-NMR-based synchronous prediction model for frying quality indexes of rapeseed oil was greater than 0.93, and the relative average deviation (RAD) was less than 0.15. Compared with the univariate model, except p-anisidine value, the RAD and the root mean square error of prediction (RMSEP) value of other indexes were reduced by more than 55%. It could be seen that it was feasible to synchronously detect multiple indicators of oil frying quality based on LF-NMR, and this technique could also provide the theoretical basis and technical support for rapid online monitoring of complex systems.
2023, 51(6): 1051-1058
doi: 10.19756/j.issn.0253-3820.231052
Abstract:
Protein phosphorylation is one of the most important and common post-translational modifications, and the determination of protein phosphorylation is essential for comprehensive understanding of phosphorylation pathways in biological processes. Mass spectrometric technique has become an important method to analyze protein phosphorylation. However, the low abundance, low ionization efficiency of phosphopeptides and their coexistence with non-phosphopeptides seriously affect the direct analysis of phosphopeptides by mass spectrometry. To solve this issue, selective enrichment of phosphopeptides is usually required before the analysis step. Functional magnetic materials have good magnetic responsiveness and can be quickly separated from solution with the help of external magnets. In the present work, a new method based on quaternarized magnetic chitosan composite as the adsorbent was developed for enrichment of phosphopeptides combined with matrixassisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The magnetic material had the advantages such as rapid magnetic response, good biocompatibility, positive electricity, cheap availability, and good enrichment selectivity for phosphopeptides. The detection limit of β-casein was 0.4 fmol after enrichment. This method was successfully applied to detection of phosphopeptides in actual skim milk samples, indicating that the synthesized magnetic material had high application potential in detection of phosphopeptides in complex samples.
Protein phosphorylation is one of the most important and common post-translational modifications, and the determination of protein phosphorylation is essential for comprehensive understanding of phosphorylation pathways in biological processes. Mass spectrometric technique has become an important method to analyze protein phosphorylation. However, the low abundance, low ionization efficiency of phosphopeptides and their coexistence with non-phosphopeptides seriously affect the direct analysis of phosphopeptides by mass spectrometry. To solve this issue, selective enrichment of phosphopeptides is usually required before the analysis step. Functional magnetic materials have good magnetic responsiveness and can be quickly separated from solution with the help of external magnets. In the present work, a new method based on quaternarized magnetic chitosan composite as the adsorbent was developed for enrichment of phosphopeptides combined with matrixassisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The magnetic material had the advantages such as rapid magnetic response, good biocompatibility, positive electricity, cheap availability, and good enrichment selectivity for phosphopeptides. The detection limit of β-casein was 0.4 fmol after enrichment. This method was successfully applied to detection of phosphopeptides in actual skim milk samples, indicating that the synthesized magnetic material had high application potential in detection of phosphopeptides in complex samples.
2023, 51(6): 1059-1065
doi: 10.19756/j.issn.0253-3820.231035
Abstract:
A new method for analysis of metal-doped polystyrene microplastics in biological samples by single particle-inductively coupled plasma time-of-flight mass spectrometry (SP-ICP-TOF-MS) was developed. Mouse liver samples spiked with the particles were successfully digested using tetramethylammonium hydroxide and hydrogen peroxide. Centrifugal concentration method was used to remove the matrix from the digested solution and to meet the analytical requirements of SP-ICP-TOF-MS. The method achieved recoveries of 102%±11% for microplastic particles. The SP-ICP-TOF-MS achieved detection limits of 0.004-0.026 fg for Ce, Eu, Ho, and Lu in microplastics, and 37 particles/mL for particle number concentration. The developed method provided a new approach to study the environmental impact and toxicology of microplastics.
A new method for analysis of metal-doped polystyrene microplastics in biological samples by single particle-inductively coupled plasma time-of-flight mass spectrometry (SP-ICP-TOF-MS) was developed. Mouse liver samples spiked with the particles were successfully digested using tetramethylammonium hydroxide and hydrogen peroxide. Centrifugal concentration method was used to remove the matrix from the digested solution and to meet the analytical requirements of SP-ICP-TOF-MS. The method achieved recoveries of 102%±11% for microplastic particles. The SP-ICP-TOF-MS achieved detection limits of 0.004-0.026 fg for Ce, Eu, Ho, and Lu in microplastics, and 37 particles/mL for particle number concentration. The developed method provided a new approach to study the environmental impact and toxicology of microplastics.
