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2021 Volume 49 Issue 1
2021, 49(1): 1-13
doi: 10.19756/j.issn.0253-3820.201346
Abstract:
As a kind of convenient, fast and the online analysis technology, point-of-care testing (POCT) technology has been widely used in disease diagnosis, health management, environmental monitoring and emergency response analysis. To date, it is a hot spot to develop novel strategy for the detection of various targets based on the simple, rapid and sensitive signal readout and different signal production, transfer and amplification strategies in the field of POCT. The introduction of some nanozymes and functionalized nanomaterials with special catalytic properties further accelerates the application of simple analysis signal readout such as color, temperature, pressure, weight and distance, which greatly promotes the development of simple readout-based POCT methods, and expands the analytical application of such methods. In this paper, we summarize the principles, classifications and the applications of these emerging POCT methods for the analysis of life-related targets and review their current challenges and future application prospects.
As a kind of convenient, fast and the online analysis technology, point-of-care testing (POCT) technology has been widely used in disease diagnosis, health management, environmental monitoring and emergency response analysis. To date, it is a hot spot to develop novel strategy for the detection of various targets based on the simple, rapid and sensitive signal readout and different signal production, transfer and amplification strategies in the field of POCT. The introduction of some nanozymes and functionalized nanomaterials with special catalytic properties further accelerates the application of simple analysis signal readout such as color, temperature, pressure, weight and distance, which greatly promotes the development of simple readout-based POCT methods, and expands the analytical application of such methods. In this paper, we summarize the principles, classifications and the applications of these emerging POCT methods for the analysis of life-related targets and review their current challenges and future application prospects.
2021, 49(1): 14-23
doi: 10.19756/j.issn.0253-3820.201349
Abstract:
Small biomolecules in human body involve in many important life activities, especially some small reductive biomolecules, and play important roles in maintaining human health and resisting diseases. Therefore, the rapid and accurate detection of small reductive biomolecules is of great significance. The fluorescence turn-on detection is a sensitive detection method with ease of operation. Carbon quantum dots (CQDs) are a novel zero-dimensional fluorescent carbon nanomaterial, which exhibit many advantages including good biocompatibility, low toxicity, ease of fabrication, low cost, good photostability and high fluorescence quantum yield, therefore, CQDs have great potential in the fluorescence turn-on detection of small biomolecules. In this paper, we summarized the development of CQDs in fluorescence turn-on detection of glucose, ascorbic acid, dopamine, biothiols and uric acid in recent three years. Finally, we discussed the opportunities and challenges of CQDs in the fluorescence turn-on detection of these small biomolecules.
Small biomolecules in human body involve in many important life activities, especially some small reductive biomolecules, and play important roles in maintaining human health and resisting diseases. Therefore, the rapid and accurate detection of small reductive biomolecules is of great significance. The fluorescence turn-on detection is a sensitive detection method with ease of operation. Carbon quantum dots (CQDs) are a novel zero-dimensional fluorescent carbon nanomaterial, which exhibit many advantages including good biocompatibility, low toxicity, ease of fabrication, low cost, good photostability and high fluorescence quantum yield, therefore, CQDs have great potential in the fluorescence turn-on detection of small biomolecules. In this paper, we summarized the development of CQDs in fluorescence turn-on detection of glucose, ascorbic acid, dopamine, biothiols and uric acid in recent three years. Finally, we discussed the opportunities and challenges of CQDs in the fluorescence turn-on detection of these small biomolecules.
2021, 49(1): 24-33
doi: 10.19756/j.issn.0253-3820.201369
Abstract:
Post-translational modification of proteins plays an important regulatory role in the process of cell life, enabling proteins to have biological activities and perform corresponding functions. The content of post-translational modification proteins in the organism is very low, which makes it commit to a mighty challenge to accurately identify the post-translational modification proteins. The molecularly imprinted cavity, which is perfectly matched with the size, shape and functional groups of the target molecules, has shown great potential in the separation of modified proteins. In this paper, the types and characteristics of post-translational modified proteins and molecular imprinting methods are summarized. On this basis, the application of molecularly imprinted polymers in the enrichment of post-translational modified proteins is reviewed, and the prospect of its development is prospected.
Post-translational modification of proteins plays an important regulatory role in the process of cell life, enabling proteins to have biological activities and perform corresponding functions. The content of post-translational modification proteins in the organism is very low, which makes it commit to a mighty challenge to accurately identify the post-translational modification proteins. The molecularly imprinted cavity, which is perfectly matched with the size, shape and functional groups of the target molecules, has shown great potential in the separation of modified proteins. In this paper, the types and characteristics of post-translational modified proteins and molecular imprinting methods are summarized. On this basis, the application of molecularly imprinted polymers in the enrichment of post-translational modified proteins is reviewed, and the prospect of its development is prospected.
2021, 49(1): 34-41
doi: 10.19756/j.issn.0253-3820.201408
Abstract:
A coaxial sheath-flow capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS) interface based on dual capillaries was developed for performing rapid, efficient and sensitive analysis. By designing different electrode systems, the online combination between homemade interface and different ESI-MS systems was achieved. The CE-ESI-MS system utilized the suction effect to accomplish hydrodynamic injection without external force, and realized the introduction of picoliter samples. The interface had many advantages such as simple to build, low cost, good durability, minimal dead volume and low dilution effect based on optimized parameters. The spray stability was evaluated by continuous injection with a relative standard deviation (RSD) of 3.4%. Therefore, in the nine consecutive separations of reserpine, the RSD of retention time, full Width at Half Maximum and peak area were 1.9%, 9.2% and 8.2%, respectively. The present system was successfully applied to separate eighteen standard amino acids within 9 min. Moreover, the baseline separation of five standard peptides mixture was achieved within 9 min with the number of theoretical plates of 7.27×105 plates/m. The present system also performed good performance in the analysis of cytochrome C trypsin digest.
A coaxial sheath-flow capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS) interface based on dual capillaries was developed for performing rapid, efficient and sensitive analysis. By designing different electrode systems, the online combination between homemade interface and different ESI-MS systems was achieved. The CE-ESI-MS system utilized the suction effect to accomplish hydrodynamic injection without external force, and realized the introduction of picoliter samples. The interface had many advantages such as simple to build, low cost, good durability, minimal dead volume and low dilution effect based on optimized parameters. The spray stability was evaluated by continuous injection with a relative standard deviation (RSD) of 3.4%. Therefore, in the nine consecutive separations of reserpine, the RSD of retention time, full Width at Half Maximum and peak area were 1.9%, 9.2% and 8.2%, respectively. The present system was successfully applied to separate eighteen standard amino acids within 9 min. Moreover, the baseline separation of five standard peptides mixture was achieved within 9 min with the number of theoretical plates of 7.27×105 plates/m. The present system also performed good performance in the analysis of cytochrome C trypsin digest.
2021, 49(1): 42-49
doi: 10.19756/j.issn.0253-3820.201234
Abstract:
Conventional assays for identifying polymorphism of aldehyde dehydrogenase 2 (ALDH2) gene (rs671) are based on electrophoresis, fluorescence-labeled probes or sequencing, which are laborious and expensive. Herein, a colorimetric method was proposed for detection of ALDH2 genotype by PCR-based serial invasive reaction coupled with gold nanoparticle probe (GNP) assembling, in which the target DNAs were firstly amplified by PCR, and then the alleles on the amplicons were identified by serial invasive reaction, and finally the genotyping results could be read out with naked eyes by observing the color changes caused by gold nanoparticle assembling. If the allele-specific invasive probe matched the target sequence, the hairpin probe could be cleaved into two parts by Flap endonuclease 1 (FEN1). As a result, the GNPs could not be aggregated by the hairpin probe, keeping the solution red. Otherwise, the intact hairpin probe caused the aggregation of GNPs, leading to the color change from red to purple or clear. Therefore, the genotyping result could be read out with naked eyes by observing the color changes of the reaction. As low as 80 pg of genomic DNA could be accurately genotyped, and the genotyping results of 207 clinical samples were consisted with that of pyrosequencing, indicating that the proposed method has great potential in genotyping of personalized medicine-related single nucleotide polymorphism.
Conventional assays for identifying polymorphism of aldehyde dehydrogenase 2 (ALDH2) gene (rs671) are based on electrophoresis, fluorescence-labeled probes or sequencing, which are laborious and expensive. Herein, a colorimetric method was proposed for detection of ALDH2 genotype by PCR-based serial invasive reaction coupled with gold nanoparticle probe (GNP) assembling, in which the target DNAs were firstly amplified by PCR, and then the alleles on the amplicons were identified by serial invasive reaction, and finally the genotyping results could be read out with naked eyes by observing the color changes caused by gold nanoparticle assembling. If the allele-specific invasive probe matched the target sequence, the hairpin probe could be cleaved into two parts by Flap endonuclease 1 (FEN1). As a result, the GNPs could not be aggregated by the hairpin probe, keeping the solution red. Otherwise, the intact hairpin probe caused the aggregation of GNPs, leading to the color change from red to purple or clear. Therefore, the genotyping result could be read out with naked eyes by observing the color changes of the reaction. As low as 80 pg of genomic DNA could be accurately genotyped, and the genotyping results of 207 clinical samples were consisted with that of pyrosequencing, indicating that the proposed method has great potential in genotyping of personalized medicine-related single nucleotide polymorphism.
2021, 49(1): 50-59
doi: 10.19756/j.issn.0253-3820.201354
Abstract:
Foodborne diseases caused by pathogenic microorganisms have attracted increasing attention in the world. It is urgent to develop efficient analytical methods for simultaneous and rapid detection of foodborne pathogens. In this regard, a dual-mode sensor based on the colorimetric principle coupled with microfluidic chip was developed using magnetic aptamer capture probes. It could realize rapid qualitative and simultaneous quantitative determination of Vibrio parahaemolyticus (V.P) and Salmonella typhimurium (S.T). The probe consisted several long DNA strands containing adenosine triphosphate (ATP), analyte aptamer and repeated G-base nucleotide fragments which were labeled on the surface of magnetic beads. When the probe reacted with the target analytes, the above long DNA strands would be released. The G quadruplet formed by hemin exhibited catalytic effect on tetramethylbenzidine (TMB)-H2O2 system, which could produce visible blue color and be used for on-site analysis of two pathogenic bacteria. After the long strand of released DNA was cut by EcoRV endonuclease, different lengths of DNA were obtained corresponding to V.P and S.T respectively. By analyzing each DNA in microchips, quantitative analysis of two kinds of bacteria V.P and S.T could be realized. Under the best experimental conditions, the detection linear range for the two bacteria was 102-107 CFU/mL, and the detection limit was 30 CFU/mL. The sensor provided a reliable method for screening contamination of pathogenic bacteria and quantification of each target accurately in the laboratory.
Foodborne diseases caused by pathogenic microorganisms have attracted increasing attention in the world. It is urgent to develop efficient analytical methods for simultaneous and rapid detection of foodborne pathogens. In this regard, a dual-mode sensor based on the colorimetric principle coupled with microfluidic chip was developed using magnetic aptamer capture probes. It could realize rapid qualitative and simultaneous quantitative determination of Vibrio parahaemolyticus (V.P) and Salmonella typhimurium (S.T). The probe consisted several long DNA strands containing adenosine triphosphate (ATP), analyte aptamer and repeated G-base nucleotide fragments which were labeled on the surface of magnetic beads. When the probe reacted with the target analytes, the above long DNA strands would be released. The G quadruplet formed by hemin exhibited catalytic effect on tetramethylbenzidine (TMB)-H2O2 system, which could produce visible blue color and be used for on-site analysis of two pathogenic bacteria. After the long strand of released DNA was cut by EcoRV endonuclease, different lengths of DNA were obtained corresponding to V.P and S.T respectively. By analyzing each DNA in microchips, quantitative analysis of two kinds of bacteria V.P and S.T could be realized. Under the best experimental conditions, the detection linear range for the two bacteria was 102-107 CFU/mL, and the detection limit was 30 CFU/mL. The sensor provided a reliable method for screening contamination of pathogenic bacteria and quantification of each target accurately in the laboratory.
2021, 49(1): 60-67
doi: 10.19756/j.issn.0253-3820.201384
Abstract:
A colorimetric analytical method, with wavelength change as a response, was developed for the highly sensitive determination of dopamine (DA) based on gold nanorods (AuNRs) with tunable surface plasma-resonance optical properties and the fact that AuNRs could be etched by I2 generated from KIO3 reduction by DA. Even though AuNRs were unable to be etched by KIO3, however, they surrendered to I2 generated by IO3- in the presence of DA, which made their absorption peak of longitudinal localized surface plasma resonance (LSPR) a blue shift, accompanied by obvious color change from wine red to blue. The influence of KIO3 concentration, temperature, pH value and incubation time on signal responses was investigated. The results showed that under the optimized conditions including 0.7 mmol/L KIO3, reaction temperature at 50℃, pH 2.6 and incubation time of 6 min, the amount of blue shift of AuNRs absorption wavelength was linear with DA concentration in the range of 0.80-60.0 μmol/L. The detection limit was 0.62 μmol/L (3σ/k) and the matrix in urine did not interfere with the determination. The DA recovery in actual urine samples ranged from 103.0% to 110.8%.
A colorimetric analytical method, with wavelength change as a response, was developed for the highly sensitive determination of dopamine (DA) based on gold nanorods (AuNRs) with tunable surface plasma-resonance optical properties and the fact that AuNRs could be etched by I2 generated from KIO3 reduction by DA. Even though AuNRs were unable to be etched by KIO3, however, they surrendered to I2 generated by IO3- in the presence of DA, which made their absorption peak of longitudinal localized surface plasma resonance (LSPR) a blue shift, accompanied by obvious color change from wine red to blue. The influence of KIO3 concentration, temperature, pH value and incubation time on signal responses was investigated. The results showed that under the optimized conditions including 0.7 mmol/L KIO3, reaction temperature at 50℃, pH 2.6 and incubation time of 6 min, the amount of blue shift of AuNRs absorption wavelength was linear with DA concentration in the range of 0.80-60.0 μmol/L. The detection limit was 0.62 μmol/L (3σ/k) and the matrix in urine did not interfere with the determination. The DA recovery in actual urine samples ranged from 103.0% to 110.8%.
2021, 49(1): 68-75
doi: 10.19756/j.issn.0253-3820.191611
Abstract:
It is important to rapidly diagnose heavy metal toxicity of water for drinking water safety. Based on Escherichia coli (E.coli) cell damage, in this work, a new toxicity bioassay using multi-walled carbon nanotubes (MWCNTs) as bionic nanowire and K3Fe(CN)6 as electron transporter was developed. The influences of modified materials, optical density of E.coli, incubation time and K3Fe(CN)6 concentration on the respiratory inhibition of E.coil were investigated. Under the best conditions, IC50 values of single metal ions (Zn2+, Cd2+, Cu2+, Ag+ and Pb2+) were 10.72, 15.03, 6.14, 16.28 and 20.98 mg/L, respectively. This method had virtues of simple operation, low cost, short detection time, accurate and reliable results, and might serve as an early warning device for rapid warning and screening of water acute toxicity, thus avoiding environmental pollution and protecting public health.
It is important to rapidly diagnose heavy metal toxicity of water for drinking water safety. Based on Escherichia coli (E.coli) cell damage, in this work, a new toxicity bioassay using multi-walled carbon nanotubes (MWCNTs) as bionic nanowire and K3Fe(CN)6 as electron transporter was developed. The influences of modified materials, optical density of E.coli, incubation time and K3Fe(CN)6 concentration on the respiratory inhibition of E.coil were investigated. Under the best conditions, IC50 values of single metal ions (Zn2+, Cd2+, Cu2+, Ag+ and Pb2+) were 10.72, 15.03, 6.14, 16.28 and 20.98 mg/L, respectively. This method had virtues of simple operation, low cost, short detection time, accurate and reliable results, and might serve as an early warning device for rapid warning and screening of water acute toxicity, thus avoiding environmental pollution and protecting public health.
2021, 49(1): 76-84
doi: 10.19756/j.issn.0253-3820.201180
Abstract:
On the basis of fluorescence resonance energy transfer of gold nanoparticles (AuNPs) to fluorophore and the unique optical effect of AuNPs and in combination with arsenite aptamer, a dual mode of fluorescent and colorimetric detection method for inorganic arsenite was developed. In this method, the unmodified AuNPs were used as the carrier, and the aptamer of arsenic modified by FAM (FAM-Apt) as the probe was adsorbed on the surface of AuNPs. Due to the fluorescence resonance energy transfer between FAM-Apt and AuNPs, the fluorescence of FAM-Apt could be quenched by AuNPs. When arsenite was present, it combined with FAM-Apt, so that it was released from the surface of AuNPs, which induced the fluorescence recovery. And the gold nanoparticles without the protection of aptamer FAM-Apt were easily induced to aggregate, and the color changed from red into blue in the presence of salt. Thus a dual-mode detectior of fluorescence and colorimetry was developed for As(Ⅲ) detection. Both the fluorescence and colorimetric adsorption showed a good linear relationship with arsenite concentration. The fluorescence method showed a detection range of 5-800 μmol/L with a detection limit of 3.64 μmol/L (3σ), while the colorimetric method showed a detection range of 5-100 μmol/L with a detection limit of 3.42 μmol/L (3σ). And the dual-mode combined with fluorescence and colorimetry showed a linear detection range of 5-1000 μmol/L with a detection limit of 1.55 μmol/L. This method was simple, fast and easy to operate. The dual-mode method illustrated a lower detection limit and a wider detection range. The two detection modes could verify each other, and were successfully used in detection of As(Ⅲ) in fruit and vegetables. Moreover, the method could provide a general strategy for detecting other small biomolecules, metal ions and proteins.
On the basis of fluorescence resonance energy transfer of gold nanoparticles (AuNPs) to fluorophore and the unique optical effect of AuNPs and in combination with arsenite aptamer, a dual mode of fluorescent and colorimetric detection method for inorganic arsenite was developed. In this method, the unmodified AuNPs were used as the carrier, and the aptamer of arsenic modified by FAM (FAM-Apt) as the probe was adsorbed on the surface of AuNPs. Due to the fluorescence resonance energy transfer between FAM-Apt and AuNPs, the fluorescence of FAM-Apt could be quenched by AuNPs. When arsenite was present, it combined with FAM-Apt, so that it was released from the surface of AuNPs, which induced the fluorescence recovery. And the gold nanoparticles without the protection of aptamer FAM-Apt were easily induced to aggregate, and the color changed from red into blue in the presence of salt. Thus a dual-mode detectior of fluorescence and colorimetry was developed for As(Ⅲ) detection. Both the fluorescence and colorimetric adsorption showed a good linear relationship with arsenite concentration. The fluorescence method showed a detection range of 5-800 μmol/L with a detection limit of 3.64 μmol/L (3σ), while the colorimetric method showed a detection range of 5-100 μmol/L with a detection limit of 3.42 μmol/L (3σ). And the dual-mode combined with fluorescence and colorimetry showed a linear detection range of 5-1000 μmol/L with a detection limit of 1.55 μmol/L. This method was simple, fast and easy to operate. The dual-mode method illustrated a lower detection limit and a wider detection range. The two detection modes could verify each other, and were successfully used in detection of As(Ⅲ) in fruit and vegetables. Moreover, the method could provide a general strategy for detecting other small biomolecules, metal ions and proteins.
2021, 49(1): 85-94
doi: 10.19756/j.issn.0253-3820.201500
Abstract:
A Raman quantitative analysis algorithm based on genetic algorithm (GA) and linear additive model was developed. When the Raman spectrum of one main substance in a batch of mixed samples was known, the characteristic peak position of each component could be obtained by correlation analysis. Then genetic algorithm (GA) was used to fit and optimize the corresponding spectral matrix of the pure substance. Finally, the obtained spectral matrix was used to establish the Raman quantitative analysis model of various substances in the mixture. This method only required a large amount of calculation when optimizing model parameters in the model training process, and only needed to perform simple matrix operations in actual prediction, showing a small real-time calculation amount. The developed method was suitable for continuous online applications, and could be applied to the quantitative analysis of liquid and gas mixture. By taking natural gas as an example, when the Raman spectrum of the main component in methane was known, based on a set of natural gas training samples whose composition and Raman spectrum were known, a quantitative analysis model based on Raman spectrum for main components in natural gas (CH4, C2H6, C3H8, CO2, N2, H2, CO) was developed. For the test sample set, the corresponding root mean square error (RMSE) were 0.488%, 0.103%, 0.358%, 0.079%, 0.087%, 0.126% and 0.022%, and the multiple correlation coefficient (R2) were 0.995, 0.991, 0.990, 0.991, 0.998, 0.999 and 0.999, respectively. Although the result was just slightly inferior to the result when the spectra of all pure substances were known, the algorithm presented here provided a solution for the case when some pure substance spectra were unknown.
A Raman quantitative analysis algorithm based on genetic algorithm (GA) and linear additive model was developed. When the Raman spectrum of one main substance in a batch of mixed samples was known, the characteristic peak position of each component could be obtained by correlation analysis. Then genetic algorithm (GA) was used to fit and optimize the corresponding spectral matrix of the pure substance. Finally, the obtained spectral matrix was used to establish the Raman quantitative analysis model of various substances in the mixture. This method only required a large amount of calculation when optimizing model parameters in the model training process, and only needed to perform simple matrix operations in actual prediction, showing a small real-time calculation amount. The developed method was suitable for continuous online applications, and could be applied to the quantitative analysis of liquid and gas mixture. By taking natural gas as an example, when the Raman spectrum of the main component in methane was known, based on a set of natural gas training samples whose composition and Raman spectrum were known, a quantitative analysis model based on Raman spectrum for main components in natural gas (CH4, C2H6, C3H8, CO2, N2, H2, CO) was developed. For the test sample set, the corresponding root mean square error (RMSE) were 0.488%, 0.103%, 0.358%, 0.079%, 0.087%, 0.126% and 0.022%, and the multiple correlation coefficient (R2) were 0.995, 0.991, 0.990, 0.991, 0.998, 0.999 and 0.999, respectively. Although the result was just slightly inferior to the result when the spectra of all pure substances were known, the algorithm presented here provided a solution for the case when some pure substance spectra were unknown.
2021, 49(1): 95-102
doi: 10.19756/j.issn.0253-3820.201477
Abstract:
The recognition and discrimination of chirality is of great significance for further understanding the pharmaceutical mechanism of chiral drugs. Ibuprofen is a well-popular clinically used anti-inflammatory drug in the world. However, in R-ibuprofen and S-ibuprofen enantiomers, only S-ibuprofen is responsible for the anti-inflammatory effects. In this work, a novel discrimination method for chiral ibuprofen was investigated. A stoichiometric R- and S-Ibuprofen were mixed with γ-cyclodextrin and barium chloride to obtain the noncovalent complexes in methanol aqueous solution, and the ion mobility of the complexes was measured by trapped ion mobility spectrometry-time-of-flight mass spectrometry (TIMS-TOF-MS). The formed diastereomeric ions of[γ-CD+R-ibuprofen+Ba(BaCl)-H]2+ and[γ-CD+S-ibuprofen+Ba(BaCl)-H]2+ were successfully separated in ion mobility spectra and the collision cross section difference (ΔCCS) reached 0.07 nm2.Additionally, the experimental data indicated that the fractions of mobility peak intensities for[γ-CD+S-ibuprofen+Ba(BaCl)-H]2+ and their molar fractions exhibited a great linear relationship. Due to that no complicate pre-treatment or chemical derivation was needed, this method could discriminate chiral molecules rapidly and efficiently.
The recognition and discrimination of chirality is of great significance for further understanding the pharmaceutical mechanism of chiral drugs. Ibuprofen is a well-popular clinically used anti-inflammatory drug in the world. However, in R-ibuprofen and S-ibuprofen enantiomers, only S-ibuprofen is responsible for the anti-inflammatory effects. In this work, a novel discrimination method for chiral ibuprofen was investigated. A stoichiometric R- and S-Ibuprofen were mixed with γ-cyclodextrin and barium chloride to obtain the noncovalent complexes in methanol aqueous solution, and the ion mobility of the complexes was measured by trapped ion mobility spectrometry-time-of-flight mass spectrometry (TIMS-TOF-MS). The formed diastereomeric ions of[γ-CD+R-ibuprofen+Ba(BaCl)-H]2+ and[γ-CD+S-ibuprofen+Ba(BaCl)-H]2+ were successfully separated in ion mobility spectra and the collision cross section difference (ΔCCS) reached 0.07 nm2.Additionally, the experimental data indicated that the fractions of mobility peak intensities for[γ-CD+S-ibuprofen+Ba(BaCl)-H]2+ and their molar fractions exhibited a great linear relationship. Due to that no complicate pre-treatment or chemical derivation was needed, this method could discriminate chiral molecules rapidly and efficiently.
2021, 49(1): 103-112
doi: 10.19756/j.issn.0253-3820.201391
Abstract:
The effect of matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) in analysis of small molecule compounds including amino acid, oligosaccharide and triglyceride was studied using nano triiron tetraoxide (Fe3O4) matrix. By comparing with other nanoparticle matrices and organic-inorganic binary matrices in the MALDI-MS analysis of D,L-pyroglutamic acid, D,L-aspartic acid, L-proline, L-phenylalanine, sucrose, raffinose, tripalmitin and triolein, the Fe3O4 nanoparticles were selected as matrix, and the effects of MALDI-MS experimental conditions on MS peak noise and signal intensity were investigated. As a result, Fe3O4 presented the characteristics of increasing the MS peak strength and reducing background noise. Using nano Fe3O4 matrix to cover sample, and setting MS acquisition parameters including polarity as positive and laser power of 70%, the results showed that the nano Fe3O4 was an ideal matrix for the detection of amino acids, oligosaccharide and triglycerides with good reproducibility and sensitivity. The MALDI-MS analysis of D,L-pyroglutamic acid, sucrose and triolein were performed using the nano Fe3O4 matrix and the in-spot repeatability RSDs were less than 3.2% and the spot-to-spot repeatability RSDs were less than 6.0%. The linear correlation coefficients (R2) between MS peak intensity and concentrations were determined as no less than 0.997 in the concentration range of 0.05-1.00 mg/mL, which showed potential quantitative power of the MALDI-MS analysis.
The effect of matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) in analysis of small molecule compounds including amino acid, oligosaccharide and triglyceride was studied using nano triiron tetraoxide (Fe3O4) matrix. By comparing with other nanoparticle matrices and organic-inorganic binary matrices in the MALDI-MS analysis of D,L-pyroglutamic acid, D,L-aspartic acid, L-proline, L-phenylalanine, sucrose, raffinose, tripalmitin and triolein, the Fe3O4 nanoparticles were selected as matrix, and the effects of MALDI-MS experimental conditions on MS peak noise and signal intensity were investigated. As a result, Fe3O4 presented the characteristics of increasing the MS peak strength and reducing background noise. Using nano Fe3O4 matrix to cover sample, and setting MS acquisition parameters including polarity as positive and laser power of 70%, the results showed that the nano Fe3O4 was an ideal matrix for the detection of amino acids, oligosaccharide and triglycerides with good reproducibility and sensitivity. The MALDI-MS analysis of D,L-pyroglutamic acid, sucrose and triolein were performed using the nano Fe3O4 matrix and the in-spot repeatability RSDs were less than 3.2% and the spot-to-spot repeatability RSDs were less than 6.0%. The linear correlation coefficients (R2) between MS peak intensity and concentrations were determined as no less than 0.997 in the concentration range of 0.05-1.00 mg/mL, which showed potential quantitative power of the MALDI-MS analysis.
2021, 49(1): 113-120
doi: 10.19756/j.issn.0253-3820.201308
Abstract:
Zinc oxide exhibits high chemical and thermal stability as well as desired adsorption, and can be used as excellent fiber coating of solid phase microextraction (SPME). In this study, the crosslinked titanium and nickel oxide composite nanoflakes (TiO2@NiOCNFs) coating was in situ grown on nitinol (NiTi) wire by hydrothermal treatment, and then the flower-like zinc oxide nanoflakes (ZnONFs) coating was successfully modified onto the hydrothermally treated NiTi surface via potentiostatic method. Coupled to high performance liquid chromatography (HPLC), the extraction performance of the new ZnONFs-TiO2@NiOCNFs-NiTi fiber was estimated by using typical aromatic compounds as model analytes. The fabricated fiber showed excellent extraction selectivity and high extraction capability for 5 kinds of benzotriazole ultraviolet filters (BUVFs) in food packaging materials. Under the optimized conditions such as pH=7.0, extraction temperature of 30℃, extraction time of 40 min, desorption time of 3 min, stirring rate at 500 r/min and 5% (w/V) NaCl, the proposed SPME-HPLC methods with ZnONFs-TiO2@NiOCNFs-NiTi fiber showed a linearity from 0.05 to 200 μg/L with correlation coefficient (R) of higher than 0.9988. The limit of detection (LOD) ranged from 0.042 to 0.230 μg/kg, and the relative standard deviations (RSDs) were below 6.4% and 7.5% for intra-day and inter-day analysis of the 5 kinds of BUVFs at the spiking level of 50 μg/L using a single fiber, respectively. The developed SPME-HPLC method was successfully applied to selective extraction and determination of BUVFs in different types of food packaging materials with recovery of 83.6%-104.0% and RSDs of 5.5%-8.3%. Moreover, the novel fiber possessed good stability and repeatability, and the single fiber could finish all of analysis in the whole sequence.
Zinc oxide exhibits high chemical and thermal stability as well as desired adsorption, and can be used as excellent fiber coating of solid phase microextraction (SPME). In this study, the crosslinked titanium and nickel oxide composite nanoflakes (TiO2@NiOCNFs) coating was in situ grown on nitinol (NiTi) wire by hydrothermal treatment, and then the flower-like zinc oxide nanoflakes (ZnONFs) coating was successfully modified onto the hydrothermally treated NiTi surface via potentiostatic method. Coupled to high performance liquid chromatography (HPLC), the extraction performance of the new ZnONFs-TiO2@NiOCNFs-NiTi fiber was estimated by using typical aromatic compounds as model analytes. The fabricated fiber showed excellent extraction selectivity and high extraction capability for 5 kinds of benzotriazole ultraviolet filters (BUVFs) in food packaging materials. Under the optimized conditions such as pH=7.0, extraction temperature of 30℃, extraction time of 40 min, desorption time of 3 min, stirring rate at 500 r/min and 5% (w/V) NaCl, the proposed SPME-HPLC methods with ZnONFs-TiO2@NiOCNFs-NiTi fiber showed a linearity from 0.05 to 200 μg/L with correlation coefficient (R) of higher than 0.9988. The limit of detection (LOD) ranged from 0.042 to 0.230 μg/kg, and the relative standard deviations (RSDs) were below 6.4% and 7.5% for intra-day and inter-day analysis of the 5 kinds of BUVFs at the spiking level of 50 μg/L using a single fiber, respectively. The developed SPME-HPLC method was successfully applied to selective extraction and determination of BUVFs in different types of food packaging materials with recovery of 83.6%-104.0% and RSDs of 5.5%-8.3%. Moreover, the novel fiber possessed good stability and repeatability, and the single fiber could finish all of analysis in the whole sequence.
2021, 49(1): 121-127
doi: 10.19756/j.issn.0253-3820.201544
Abstract:
The adsorption behavior of proteins in blood on the surface of the contact material is an important factor affecting the blood compatibility of the implanted material. In order to establish the relationship between protein conformation and blood compatibility, the surfaces of amino and carboxyl groups on the titanium dioxide nanotubes were fabricated by grafting silane coupling agent, and bovine serum albumin (BSA) and fibrinogen (Fib) were fixed to the surface through EDC/NHS chemical crosslinking. The relationship between the secondary structure changes of BSA and Fib and platelet adhesion behavior was investigated by studying protein adsorption and surface platelet adhesion behavior. The results showed that the ratios of β-sheet to β-turn in the secondary structure of proteins on the surface of carboxyl immobilized-BSA and amino immobilized Fib were higher, and the blood compatibility was better. Furthermore, BSA adhesion to platelets was selective, the amino-binding protein led to exposure of specific receptors that recognize platelets, and platelet activation increased.
The adsorption behavior of proteins in blood on the surface of the contact material is an important factor affecting the blood compatibility of the implanted material. In order to establish the relationship between protein conformation and blood compatibility, the surfaces of amino and carboxyl groups on the titanium dioxide nanotubes were fabricated by grafting silane coupling agent, and bovine serum albumin (BSA) and fibrinogen (Fib) were fixed to the surface through EDC/NHS chemical crosslinking. The relationship between the secondary structure changes of BSA and Fib and platelet adhesion behavior was investigated by studying protein adsorption and surface platelet adhesion behavior. The results showed that the ratios of β-sheet to β-turn in the secondary structure of proteins on the surface of carboxyl immobilized-BSA and amino immobilized Fib were higher, and the blood compatibility was better. Furthermore, BSA adhesion to platelets was selective, the amino-binding protein led to exposure of specific receptors that recognize platelets, and platelet activation increased.
2021, 49(1): 128-136
doi: 10.19756/j.issn.0253-3820.201555
Abstract:
A novel method for determination of seven kinds of alkaloids (isoquinoline, nicotine, 3-(2-pyrrolidinyl) plridine nornicotine, myosmine, b-nicotyrine, Anabasine, 2,3'-bipyridine, and anabaseine) and nine kinds of flavor compounds (hydrocoumarin, vanillin, coumadin, ethyl vanillin, methyl vanillin, 7-methyl coumarin, 7-methoxycoumarin, 7-ethoxy-4-methylcoumarin, and pyranocoumarin) in cigarette by thermal desorption-cooled injection system coupled with gas chromatography-mass spectrometry (TDU-CIS-GC-MS) was developed. By optimizing the conditions such as TDU (time, temperature, and flow rate of helium gas), CIS temperature, vent time and purge time, the cigarette alkaloid compound could be completely thermal desorption, and the volatile alkaloids and coumarin substances were enriched using the cold injection system. A DB-5 MS chromatographic column was used for separation, and a matrix curve external label method was used to quantify the matrix effect under the selected ion monitoring mode (SIM). The results showed that the linear range of 7 kinds of alkaloids and 9 kinds of flavors was 1-500 μg/L, the linear correlation coefficient (R2) was greater than 0.993, and the limits of detection (LOD) and limits of quantitation (LOQ) were 0.02-0.50 μg/kg and 0.1-2.0 μg/kg, respectively. This method was simple, safe with high sensitivity and accuracy, and suitable for the determination of alkaloids and flavor compounds in cigarette, which was very important for the analysis of complex volatile trace substances in heated non-burning cigarette.
A novel method for determination of seven kinds of alkaloids (isoquinoline, nicotine, 3-(2-pyrrolidinyl) plridine nornicotine, myosmine, b-nicotyrine, Anabasine, 2,3'-bipyridine, and anabaseine) and nine kinds of flavor compounds (hydrocoumarin, vanillin, coumadin, ethyl vanillin, methyl vanillin, 7-methyl coumarin, 7-methoxycoumarin, 7-ethoxy-4-methylcoumarin, and pyranocoumarin) in cigarette by thermal desorption-cooled injection system coupled with gas chromatography-mass spectrometry (TDU-CIS-GC-MS) was developed. By optimizing the conditions such as TDU (time, temperature, and flow rate of helium gas), CIS temperature, vent time and purge time, the cigarette alkaloid compound could be completely thermal desorption, and the volatile alkaloids and coumarin substances were enriched using the cold injection system. A DB-5 MS chromatographic column was used for separation, and a matrix curve external label method was used to quantify the matrix effect under the selected ion monitoring mode (SIM). The results showed that the linear range of 7 kinds of alkaloids and 9 kinds of flavors was 1-500 μg/L, the linear correlation coefficient (R2) was greater than 0.993, and the limits of detection (LOD) and limits of quantitation (LOQ) were 0.02-0.50 μg/kg and 0.1-2.0 μg/kg, respectively. This method was simple, safe with high sensitivity and accuracy, and suitable for the determination of alkaloids and flavor compounds in cigarette, which was very important for the analysis of complex volatile trace substances in heated non-burning cigarette.
2021, 49(1): 137-143
doi: 10.19756/j.issn.0253-3820.201363
Abstract:
Generally, the off-line method is used to characterize the carbon isotopic composition of CO2 enclosed in the mineral fluid inclusions. The enclosed CO2 is first released by mechanical crushing or thermal decrepitation, and then is collected, purified and measured by isotope ratio mass spectrometer (IRMS). Here, an on-line continuous flow analytic system was developed by linking the thermal decrepitation device and IRMS with Conflo Ⅳ. The gas-liquid inclusions were heated and burst out and the released gas was quickly taken away from the high-temperature area by using high-purity He as carrier gas to reduce the isotope exchange. The gas of CO2 was collected after cooling with liquid nitrogen and then separated by chromatographic column. The separated CO2 was analyzed by IRMS with an analysis accuracy of 0.2‰ (1σ). By connecting the measurement needle to the system, it could be used to collect and test CO2 produced by carbonate reference materials. The results showed that the linear correlation of the calibration curves established by several standards was significant, and the carbon isotopic composition of CO2 within fluid inclusions could be accurately determined. By using this online method, the operation process was simplified, and the experimental efficiency was greatly improved.
Generally, the off-line method is used to characterize the carbon isotopic composition of CO2 enclosed in the mineral fluid inclusions. The enclosed CO2 is first released by mechanical crushing or thermal decrepitation, and then is collected, purified and measured by isotope ratio mass spectrometer (IRMS). Here, an on-line continuous flow analytic system was developed by linking the thermal decrepitation device and IRMS with Conflo Ⅳ. The gas-liquid inclusions were heated and burst out and the released gas was quickly taken away from the high-temperature area by using high-purity He as carrier gas to reduce the isotope exchange. The gas of CO2 was collected after cooling with liquid nitrogen and then separated by chromatographic column. The separated CO2 was analyzed by IRMS with an analysis accuracy of 0.2‰ (1σ). By connecting the measurement needle to the system, it could be used to collect and test CO2 produced by carbonate reference materials. The results showed that the linear correlation of the calibration curves established by several standards was significant, and the carbon isotopic composition of CO2 within fluid inclusions could be accurately determined. By using this online method, the operation process was simplified, and the experimental efficiency was greatly improved.
2021, 49(1): 144-150
doi: 10.19756/j.issn.0253-3820.201537
Abstract:
Raman spectroscopic technique is powerful to obtain microscopic information of tissue lesions at molecular level. In this study, Raman microspectroscopy system was used to collect in situ Raman spectra of the healthy breast and breast cancer tissues of 20 patients to investigate the biochemical composition changes. By comparing the average Raman spectra of healthy and cancerous breast tissues, it was clearly shown that the spectral intensity of cancerous tissues was significantly lower than that of healthy breast tissues. As comparing Raman intensity ratios of the protein and lipid components between the two types of tissues, it was found that the lipid content decreased and the protein content increased in cancerous tissues. In the meantime, saturated fatty acids were converted into unsaturated fatty acids in the process of tissue canceration. And it was further found that polyunsaturated fatty acids increased in content and monounsaturated fatty acids decreased in content after tissue canceration. This study revealed many biochemical component changes in the canceration process of breast tissue, especially the changes in fatty acid content, which was of great significance for the study of the biochemical mechanism of breast cancer, and was helpful for early monitoring and spectroscopic diagnosis of breast cancer.
Raman spectroscopic technique is powerful to obtain microscopic information of tissue lesions at molecular level. In this study, Raman microspectroscopy system was used to collect in situ Raman spectra of the healthy breast and breast cancer tissues of 20 patients to investigate the biochemical composition changes. By comparing the average Raman spectra of healthy and cancerous breast tissues, it was clearly shown that the spectral intensity of cancerous tissues was significantly lower than that of healthy breast tissues. As comparing Raman intensity ratios of the protein and lipid components between the two types of tissues, it was found that the lipid content decreased and the protein content increased in cancerous tissues. In the meantime, saturated fatty acids were converted into unsaturated fatty acids in the process of tissue canceration. And it was further found that polyunsaturated fatty acids increased in content and monounsaturated fatty acids decreased in content after tissue canceration. This study revealed many biochemical component changes in the canceration process of breast tissue, especially the changes in fatty acid content, which was of great significance for the study of the biochemical mechanism of breast cancer, and was helpful for early monitoring and spectroscopic diagnosis of breast cancer.
2021, 49(1): 151-158
doi: 10.19756/j.issn.0253-3820.201535
Abstract:
Surface enhanced Raman spectroscopy (SERS) is an excellent platform for the rapid and non-destructive detection of biochemical substances at monomolecular level. However, this detection technique is limited by the substrate. In this work, a substrate based on the adjustable coffee ring effect was used to improve the sensitivity and simplicity of SERS in determination of trace analytes. The coffee ring shape of the dye was regulated by the surface hydrophilicity of polydimethylsiloxane (PDMS) substrate. Meanwhile, coffee rings with different morphologies would influence the Raman signal, which indirectly explained the influence of substrates on Raman signals. Silver nanoparticles (AgNPs) were mixed with the Congo Red solution and deposited on the PDMS substrate to form a coffee ring, which was used to explore the enhancement effect of Raman signal. The results showed that the coffee rings had smaller size and higher compactness with the increase of hydrophobicity. Besides, the Raman signal was mainly concentrated on the ring and exhibited high sensitivity, excellent repeatability and small relative standard deviation (5%). The coffee ring enhanced the hot spot effect by concentrating the gap between the analyzer and AgNPs, which significantly improved the SERS sensitivity and the detection limit reached 1×10-6 mol/L. This SERS based on the coffee ring effect provided a sensitive and environmentally friendly method for dyes detection in wastewater, and had a broad application prospect.
Surface enhanced Raman spectroscopy (SERS) is an excellent platform for the rapid and non-destructive detection of biochemical substances at monomolecular level. However, this detection technique is limited by the substrate. In this work, a substrate based on the adjustable coffee ring effect was used to improve the sensitivity and simplicity of SERS in determination of trace analytes. The coffee ring shape of the dye was regulated by the surface hydrophilicity of polydimethylsiloxane (PDMS) substrate. Meanwhile, coffee rings with different morphologies would influence the Raman signal, which indirectly explained the influence of substrates on Raman signals. Silver nanoparticles (AgNPs) were mixed with the Congo Red solution and deposited on the PDMS substrate to form a coffee ring, which was used to explore the enhancement effect of Raman signal. The results showed that the coffee rings had smaller size and higher compactness with the increase of hydrophobicity. Besides, the Raman signal was mainly concentrated on the ring and exhibited high sensitivity, excellent repeatability and small relative standard deviation (5%). The coffee ring enhanced the hot spot effect by concentrating the gap between the analyzer and AgNPs, which significantly improved the SERS sensitivity and the detection limit reached 1×10-6 mol/L. This SERS based on the coffee ring effect provided a sensitive and environmentally friendly method for dyes detection in wastewater, and had a broad application prospect.
