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2017 Volume 45 Issue 8
2017, 45(8): 1103-1108
doi: 10.11895/j.issn.0253-3820.170201
Abstract:
The active copper-containing carbon nanodots were prepared by hydrothermal method, and then characterized by fluorescence spectroscopy and UV-visible absorption spectroscopy. Subsequently, a highly sensitive and selective electrochemical biosensor was fabricated on the basis of this synthesized carbon nanodots with electro-deposition technique. The electrode behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. Furthermore, the catalysis mechanism was studied. The experimental results indicated that the biosensor exhibited a strong electrocatalytic activity toward the oxidation of uric acid (UA). What's more, the interference from ascorbic acid and dopamine was eliminated effectively. Under the optimum conditions, there were linear relationships between the anodic peak current and the concentration of UA (1.00-300.0 μmol/L), and the limit detection was 0.30 μmol/L (S/N=3). The prepared biosensor had advantages such as easy fabrication, strong anti-interference ability, high sensitivity, and wide detection range, and could be used for real sample detection.
The active copper-containing carbon nanodots were prepared by hydrothermal method, and then characterized by fluorescence spectroscopy and UV-visible absorption spectroscopy. Subsequently, a highly sensitive and selective electrochemical biosensor was fabricated on the basis of this synthesized carbon nanodots with electro-deposition technique. The electrode behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. Furthermore, the catalysis mechanism was studied. The experimental results indicated that the biosensor exhibited a strong electrocatalytic activity toward the oxidation of uric acid (UA). What's more, the interference from ascorbic acid and dopamine was eliminated effectively. Under the optimum conditions, there were linear relationships between the anodic peak current and the concentration of UA (1.00-300.0 μmol/L), and the limit detection was 0.30 μmol/L (S/N=3). The prepared biosensor had advantages such as easy fabrication, strong anti-interference ability, high sensitivity, and wide detection range, and could be used for real sample detection.
2017, 45(8): 1109-1115
doi: 10.11895/j.issn.0253-3820.170198
Abstract:
A microfluidic chip with micropillar arrays for three-dimensional (3D) cell culture was designed and validated. The chip consisted of a polydimethylsiloxane (PDMS) channel plate and a glass cover plate. One cell culture chamber composed of two rows of micropillar arrays and two lateral channels for transporting the culture medium were integrated on the PDMS channel plate. The spacing between micropillars directly affects the chip performance, which is critical for the design of the chip. In this work, the spacing between micropillars was optimized by numerical simulation and experimental validation. With the optimized microfluidic chip, the mixture of cells and extracellular matrix mimics could be steadily injected into the cell culture chamber, the nutrients in the culture medium from the lateral channels could quickly diffuse into the chamber, and the cell metabolites could also timely diffuse out of the chamber. To test the stability of the microenvironment in the microfluidic chip, neural stem cells were three-dimensionally cultured.
A microfluidic chip with micropillar arrays for three-dimensional (3D) cell culture was designed and validated. The chip consisted of a polydimethylsiloxane (PDMS) channel plate and a glass cover plate. One cell culture chamber composed of two rows of micropillar arrays and two lateral channels for transporting the culture medium were integrated on the PDMS channel plate. The spacing between micropillars directly affects the chip performance, which is critical for the design of the chip. In this work, the spacing between micropillars was optimized by numerical simulation and experimental validation. With the optimized microfluidic chip, the mixture of cells and extracellular matrix mimics could be steadily injected into the cell culture chamber, the nutrients in the culture medium from the lateral channels could quickly diffuse into the chamber, and the cell metabolites could also timely diffuse out of the chamber. To test the stability of the microenvironment in the microfluidic chip, neural stem cells were three-dimensionally cultured.
2017, 45(8): 1116-1122
doi: 10.11895/j.issn.0253-3820.170306
Abstract:
A method based on gas chromatography-mass spectrometry (GC-MS) was established to analyze the changes of intracellular metabolites and study the toxic mechanisms of different concentrations of particulate matter (PM2.5) effecting the lung tissues in mice. Nasal drip experiments of PM2.5 suspensions (0, 7.5, 20.0, 37.5 g/L) for mice were carried out, and the intracellular metabolites in lung tissues were extracted, pretreated and analyzed. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) were employed for pattern recognition, and an obvious distinction among different conditions was found. According to the PLS-DA loading diagram and variable important factor (VIP) value, 7 kinds of potential biomarkers, alanine, valine, leucine, ornithine, fumaric acid, citric acid and purine (p<0.01), were determined with significant differences between four different concentrations of PM2.5. Metabolic pathway analysis indicated that the oxidative stress reactions were enhanced, and the TCA cycle and the purine metabolism in lung cells were restrained after dripping PM2.5 to the lung tissues in mice. This study could provide a new perspective and theoretical basis for the further analysis on toxic mechanisms by PM2.5.
A method based on gas chromatography-mass spectrometry (GC-MS) was established to analyze the changes of intracellular metabolites and study the toxic mechanisms of different concentrations of particulate matter (PM2.5) effecting the lung tissues in mice. Nasal drip experiments of PM2.5 suspensions (0, 7.5, 20.0, 37.5 g/L) for mice were carried out, and the intracellular metabolites in lung tissues were extracted, pretreated and analyzed. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) were employed for pattern recognition, and an obvious distinction among different conditions was found. According to the PLS-DA loading diagram and variable important factor (VIP) value, 7 kinds of potential biomarkers, alanine, valine, leucine, ornithine, fumaric acid, citric acid and purine (p<0.01), were determined with significant differences between four different concentrations of PM2.5. Metabolic pathway analysis indicated that the oxidative stress reactions were enhanced, and the TCA cycle and the purine metabolism in lung cells were restrained after dripping PM2.5 to the lung tissues in mice. This study could provide a new perspective and theoretical basis for the further analysis on toxic mechanisms by PM2.5.
2017, 45(8): 1123-1128
doi: 10.11895/j.issn.0253-3820.170213
Abstract:
There are many noise signals in original laser induced breakdown spectroscopy (LIBS) spectra. To explore the effect of spectral pretreatment on LIBS information by different filter methods, the LIBS spectra of Pb-polluted cabbage in wavelength range of 400.45-410.98 nm was investigated and preprocessed by adjacent averaging, Savitzky-Golay (S-G) and fast Fourier transformation (FFT). Then partial least square (PLS) model was established for evaluating the spectral treatment effect. The result showed that the root mean square error of prediction (RMSEP) and average relative error of S-G method were 0.26 and 3.7%, suggesting a superior smoothing effect than other methods. Experimental results indicated that an appropriate filtering method could help to improve the spectral quality and raise the precision of model checkout.
There are many noise signals in original laser induced breakdown spectroscopy (LIBS) spectra. To explore the effect of spectral pretreatment on LIBS information by different filter methods, the LIBS spectra of Pb-polluted cabbage in wavelength range of 400.45-410.98 nm was investigated and preprocessed by adjacent averaging, Savitzky-Golay (S-G) and fast Fourier transformation (FFT). Then partial least square (PLS) model was established for evaluating the spectral treatment effect. The result showed that the root mean square error of prediction (RMSEP) and average relative error of S-G method were 0.26 and 3.7%, suggesting a superior smoothing effect than other methods. Experimental results indicated that an appropriate filtering method could help to improve the spectral quality and raise the precision of model checkout.
2017, 45(8): 1129-1136
doi: 10.11895/j.issn.0253-3820.170124
Abstract:
To reveal the mechanism of Cu enrichment of alfalfa, in-situ micro-X-ray fluorescence spectrometry (μ-XRF) and fractional extraction were used to explore in-situ Cu distribution information in alfalfa seedlings and different combination forms of Cu in organs. The results showed that alfalfa roots were enriched with Cu up to 12.06 mg/g, which was 8 times of stem and 4.9 times of leaves. The in-situ μ-XRF result showed that the root of alfalfa was the main site of enrichment of Cu, and there was a barrier of Cu at the rhizome junction to alleviate the toxic effect of excess Cu on the shoots. Excess Cu (more than 50 μmol/L) also inhibited the uptake of Zn and Ca in alfalfa, enhanced the uptake of Fe in alfalfa, but had no obvious effect on the uptake of K and Mn. Plant fractional extraction showed that the Cu in root cells was mainly fixed in the form of insoluble residues (41%) and cell wall chelate (20%), while in the stem, Cu existed as four forms including hydrophobic protein binding, cell wall binding state, residual state and water-soluble state, which further reduce the excess transport of Cu to the leaves. In the leaves, excess Cu in the leaf cells was mainly in the vacuole and insoluble residue to achieve tolerance and detoxification to Cun
To reveal the mechanism of Cu enrichment of alfalfa, in-situ micro-X-ray fluorescence spectrometry (μ-XRF) and fractional extraction were used to explore in-situ Cu distribution information in alfalfa seedlings and different combination forms of Cu in organs. The results showed that alfalfa roots were enriched with Cu up to 12.06 mg/g, which was 8 times of stem and 4.9 times of leaves. The in-situ μ-XRF result showed that the root of alfalfa was the main site of enrichment of Cu, and there was a barrier of Cu at the rhizome junction to alleviate the toxic effect of excess Cu on the shoots. Excess Cu (more than 50 μmol/L) also inhibited the uptake of Zn and Ca in alfalfa, enhanced the uptake of Fe in alfalfa, but had no obvious effect on the uptake of K and Mn. Plant fractional extraction showed that the Cu in root cells was mainly fixed in the form of insoluble residues (41%) and cell wall chelate (20%), while in the stem, Cu existed as four forms including hydrophobic protein binding, cell wall binding state, residual state and water-soluble state, which further reduce the excess transport of Cu to the leaves. In the leaves, excess Cu in the leaf cells was mainly in the vacuole and insoluble residue to achieve tolerance and detoxification to Cun
2017, 45(8): 1137-1142
doi: 10.11895/j.issn.0253-3820.170349
Abstract:
To improve the yield of industrial fermentation, a method based on near infrared spectroscopy was presented to predict the growth of yeast. The spectral data of fermentation sample were measured by Fourier-transform near-infrared (FT-NIR) spectrometer in the process of yeast culture. Each spectrum was acquired over the range of 10000-4000 cm-1. Meanwhile, the optical density (OD) of fermentation sample was determined with photoelectric turbidity method. After that, a method based on competitive adaptive reweighted sampling (CARS) was used to select characteristic wavelength variables of NIR data, and then extreme learning machine (ELM) algorithm was employed to develop the categorization model about the four growth processes of yeast. Experimental result showed that, only 30 characteristic wavelength variables of NIR data were selected by CRAS algorithms, and the prediction accuracies of training set and test set of the CARS-ELM model were 98.68% and 97.37%, respectively. The research showed that the near infrared spectrum analysis technology was feasible to predict the growth process of yeast.
To improve the yield of industrial fermentation, a method based on near infrared spectroscopy was presented to predict the growth of yeast. The spectral data of fermentation sample were measured by Fourier-transform near-infrared (FT-NIR) spectrometer in the process of yeast culture. Each spectrum was acquired over the range of 10000-4000 cm-1. Meanwhile, the optical density (OD) of fermentation sample was determined with photoelectric turbidity method. After that, a method based on competitive adaptive reweighted sampling (CARS) was used to select characteristic wavelength variables of NIR data, and then extreme learning machine (ELM) algorithm was employed to develop the categorization model about the four growth processes of yeast. Experimental result showed that, only 30 characteristic wavelength variables of NIR data were selected by CRAS algorithms, and the prediction accuracies of training set and test set of the CARS-ELM model were 98.68% and 97.37%, respectively. The research showed that the near infrared spectrum analysis technology was feasible to predict the growth process of yeast.
2017, 45(8): 1143-1148
doi: 10.11895/j.issn.0253-3820.170049
Abstract:
Direct spray mass spectrometry was used to simply and rapidly differentiate Mutong of Aristolochiaceae from other two kinds of Mutong medicinal materials (Lardizabalaceae and Ranunculacea) by analyzing the chemical profile of Mutong of Aristolochiaceae. A novel method for determination of magnoflorine content in Mutong of Aristolochiaceae was established. The results showed that Mutong of Aristolochiaceae could be identified according to the symbolic component, magnoflorine. Under positive ion mode, semi-quantitative result based on the signal strength ratio of magnoflorine and nuciferin was obtained by choosing nuciferin as an internal standard. The method showed good linear coefficient in the concentration range of 0.50-20.00 mg/L of magnoflorine. The limit of detection was 0.1 mg/L. The method was simple and fast, and could be used for direct and rapid in-situ analysis and identification of Mutong of Aristolochiaceae from other closely related Mutong herbal species without sample pre-treatment. The results were important for the quality control of Mutong herbal medicine.
Direct spray mass spectrometry was used to simply and rapidly differentiate Mutong of Aristolochiaceae from other two kinds of Mutong medicinal materials (Lardizabalaceae and Ranunculacea) by analyzing the chemical profile of Mutong of Aristolochiaceae. A novel method for determination of magnoflorine content in Mutong of Aristolochiaceae was established. The results showed that Mutong of Aristolochiaceae could be identified according to the symbolic component, magnoflorine. Under positive ion mode, semi-quantitative result based on the signal strength ratio of magnoflorine and nuciferin was obtained by choosing nuciferin as an internal standard. The method showed good linear coefficient in the concentration range of 0.50-20.00 mg/L of magnoflorine. The limit of detection was 0.1 mg/L. The method was simple and fast, and could be used for direct and rapid in-situ analysis and identification of Mutong of Aristolochiaceae from other closely related Mutong herbal species without sample pre-treatment. The results were important for the quality control of Mutong herbal medicine.
2017, 45(8): 1149-1154
doi: 10.11895/j.issn.0253-3820.170165
Abstract:
In this study, a novel tetrapeptide hydrophilic interaction chromatography (HILIC) material was synthesized, and corresponding enrichment method for glycopeptides was developed. The tetrapeptide modified silica gel materials (denoted as Poly-DAPD) were synthesized by atom-transfer radical-polymerization (ATRP) and characterized by N2 adsorption desorption and thermometer, thermal gravimetric analyzer (TGA) and X-ray photoelectron spectrometer (XPS). The characterization results indicated that tetrapeptide had been successfully synthesized on silica gel. Poly-DAPD materials showed high enrichment selectivity toward fetuin glycopeptides under solid-phase extraction (SPE) mode. Comparing with commercialized ZIC-HILIC in glycopeptides enrichment of fetuin digest which mixed with 5 mole ratio of albumin bovine (BSA), the as-prepared materials showed higher selectivity in both aspects of the identified number of glycopeptides and anti-interference property. The SPE results demonstrated that the tetrapeptide-based HILIC materials could be a potential tool in large-scale glycosylation analysis.
In this study, a novel tetrapeptide hydrophilic interaction chromatography (HILIC) material was synthesized, and corresponding enrichment method for glycopeptides was developed. The tetrapeptide modified silica gel materials (denoted as Poly-DAPD) were synthesized by atom-transfer radical-polymerization (ATRP) and characterized by N2 adsorption desorption and thermometer, thermal gravimetric analyzer (TGA) and X-ray photoelectron spectrometer (XPS). The characterization results indicated that tetrapeptide had been successfully synthesized on silica gel. Poly-DAPD materials showed high enrichment selectivity toward fetuin glycopeptides under solid-phase extraction (SPE) mode. Comparing with commercialized ZIC-HILIC in glycopeptides enrichment of fetuin digest which mixed with 5 mole ratio of albumin bovine (BSA), the as-prepared materials showed higher selectivity in both aspects of the identified number of glycopeptides and anti-interference property. The SPE results demonstrated that the tetrapeptide-based HILIC materials could be a potential tool in large-scale glycosylation analysis.
2017, 45(8): 1155-1164
doi: 10.11895/j.issn.0253-3820.170144
Abstract:
The ionic liquid butylamine 2,5-dihydroxybenzoate (DHB-BuN) was chosen as the matrix for improving repeatability of oligosaccharides quantitation, and imaging oligosaccharides in soybean and leaf by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Using the ionic liquid matrix methanol solution (20%, V/V) to cover sample slice, and setting MS acquisition parameters including polarity as positive and laser power as 70%, the MS imaging experiment was performed to analyze oligosaccharides and their distribution in soyben and soybean leaf. As a result, the MALDI-MS analysis of 3 kinds of oligosaccharides including sucrose, raffinose and stachyose was performed using the ionic liquid matrix and the reproducibility RSDs were less than 3% for in-spot and less than 4% for spot-to-spot. The standard curves linear correlation coefficients (R2) were all no less than 0.996 between MS peak intensity and oligosaccharides concentraions in the concentration rage of 0.062-1.00 mg/mL, which showed quantitative power in MALDI-MS analysis. The matrix was used for MALDI-MS imaging analysis of soybean chips and soybean leaf surface disaccharide, trisaccharide and tetrasaccharide to obtain the soybean mass spectrum and spatial resolution of 150 μm of the three oligosaccharides imaging. Three kinds of oligosaccharides in the soybean roughly balanced distribution, and the oligosaccharides distribution in the leave was mostly at its tip part. The contents of the 3 kinds of oligosaccharides could be estimated by their MS peak intensity and above standard curve. The result suggested that the ionic liquid DHB-BuN matrix could be well applied in MALDI-MS imaging analysis of oligosaccharides in different sample.
The ionic liquid butylamine 2,5-dihydroxybenzoate (DHB-BuN) was chosen as the matrix for improving repeatability of oligosaccharides quantitation, and imaging oligosaccharides in soybean and leaf by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Using the ionic liquid matrix methanol solution (20%, V/V) to cover sample slice, and setting MS acquisition parameters including polarity as positive and laser power as 70%, the MS imaging experiment was performed to analyze oligosaccharides and their distribution in soyben and soybean leaf. As a result, the MALDI-MS analysis of 3 kinds of oligosaccharides including sucrose, raffinose and stachyose was performed using the ionic liquid matrix and the reproducibility RSDs were less than 3% for in-spot and less than 4% for spot-to-spot. The standard curves linear correlation coefficients (R2) were all no less than 0.996 between MS peak intensity and oligosaccharides concentraions in the concentration rage of 0.062-1.00 mg/mL, which showed quantitative power in MALDI-MS analysis. The matrix was used for MALDI-MS imaging analysis of soybean chips and soybean leaf surface disaccharide, trisaccharide and tetrasaccharide to obtain the soybean mass spectrum and spatial resolution of 150 μm of the three oligosaccharides imaging. Three kinds of oligosaccharides in the soybean roughly balanced distribution, and the oligosaccharides distribution in the leave was mostly at its tip part. The contents of the 3 kinds of oligosaccharides could be estimated by their MS peak intensity and above standard curve. The result suggested that the ionic liquid DHB-BuN matrix could be well applied in MALDI-MS imaging analysis of oligosaccharides in different sample.
2017, 45(8): 1165-1171
doi: 10.11895/j.issn.0253-3820.170006
Abstract:
In this study, the rapid resolution liquid chromatography-quadrupole time-of-flight mass spectrometry (RRLC-QTOF/MS) was used to profile the metabolites of urine samples from chronic heart failure (CHF) patients and healthy controls to find the differential metabolites which could provide the scientific evidence to explain the pathogenesis of the disease and supply a better therapy plan. Urine samples from 15 CHF patients (age (62.27±3.14) years) and 15 healthy controls (age (65.41±4.63) years) were analyzed by RRLC-QTOF/MS. After processing the data, the multivariate statistical analysis (principal component analysis, PCA) was performed to find the potential biomarkers. Result showed that urine samples of CHF patients were successfully distinguished from those of healthy controls. Two significantly differentially expressed metabolites, uridine and alanyltryptophan, were found and identified as potential biomarkers. The result showed that the LC-MS based metabolomics approach had good performance to identify potential biomarkers, and the disorder of uracil metabolism and Tryptophan metabolism may play an important role in the mechanism of CHFs
In this study, the rapid resolution liquid chromatography-quadrupole time-of-flight mass spectrometry (RRLC-QTOF/MS) was used to profile the metabolites of urine samples from chronic heart failure (CHF) patients and healthy controls to find the differential metabolites which could provide the scientific evidence to explain the pathogenesis of the disease and supply a better therapy plan. Urine samples from 15 CHF patients (age (62.27±3.14) years) and 15 healthy controls (age (65.41±4.63) years) were analyzed by RRLC-QTOF/MS. After processing the data, the multivariate statistical analysis (principal component analysis, PCA) was performed to find the potential biomarkers. Result showed that urine samples of CHF patients were successfully distinguished from those of healthy controls. Two significantly differentially expressed metabolites, uridine and alanyltryptophan, were found and identified as potential biomarkers. The result showed that the LC-MS based metabolomics approach had good performance to identify potential biomarkers, and the disorder of uracil metabolism and Tryptophan metabolism may play an important role in the mechanism of CHFs
2017, 45(8): 1172-1179
doi: 10.11895/j.issn.0253-3820.170109
Abstract:
The chelating reaction between glutathione peptides and divalent cadmium ion was used as a typical model for investigating the coordination chemistry of SH-containing peptides and heavy metal ions, which was essential to understand the mechanism of intracellular cadmium detoxification. Here, the mutant (CM113R)7 αHL protein nanopore equipped with a first synthesized per-6-quaternary ammonium-β-cyclodextrin (p-QABCD) was used as nanoreactor and detector to investigate the single-molecule reaction of GSH molecules and Cd2+ ions. Different reaction pathways, intermediates, and products could be recognized. Cd2+-GSH reaction was highly dependent on the solution pH. The Cd(GSH)2 was formed at pH 7.4, while the Cd(GSH)2 and Cd2(GSH)2 were formed at pH 9.0. Cd2(GSH)2 was formed by two possible pathways:(1) A Cd2+ ion primarily coordinated with the thiol group of two GSH molecules to form Cd(GSH)2, and then the second Cd2+ ion quickly incorporated with the deprotonated amino group of Cd(GSH)2 to form Cd2(GSH)2; (2) Two Cd2+ ions separately coordinated with the thiol and deprotonated amino group of one GSH molecule to form Cd2(GSH)1, and the second GSH molecule quickly bounded to Cd2+ ions to form Cd2(GSH)2. This work studied the chelating reaction between metal ions and bioactive glutathione at single-molecule level without labeling and chemical modification, and would be important to further understand intracellular mechanisms of detoxification of heavy metals and greatly expand the research field of nanopore single-molecule technique.
The chelating reaction between glutathione peptides and divalent cadmium ion was used as a typical model for investigating the coordination chemistry of SH-containing peptides and heavy metal ions, which was essential to understand the mechanism of intracellular cadmium detoxification. Here, the mutant (CM113R)7 αHL protein nanopore equipped with a first synthesized per-6-quaternary ammonium-β-cyclodextrin (p-QABCD) was used as nanoreactor and detector to investigate the single-molecule reaction of GSH molecules and Cd2+ ions. Different reaction pathways, intermediates, and products could be recognized. Cd2+-GSH reaction was highly dependent on the solution pH. The Cd(GSH)2 was formed at pH 7.4, while the Cd(GSH)2 and Cd2(GSH)2 were formed at pH 9.0. Cd2(GSH)2 was formed by two possible pathways:(1) A Cd2+ ion primarily coordinated with the thiol group of two GSH molecules to form Cd(GSH)2, and then the second Cd2+ ion quickly incorporated with the deprotonated amino group of Cd(GSH)2 to form Cd2(GSH)2; (2) Two Cd2+ ions separately coordinated with the thiol and deprotonated amino group of one GSH molecule to form Cd2(GSH)1, and the second GSH molecule quickly bounded to Cd2+ ions to form Cd2(GSH)2. This work studied the chelating reaction between metal ions and bioactive glutathione at single-molecule level without labeling and chemical modification, and would be important to further understand intracellular mechanisms of detoxification of heavy metals and greatly expand the research field of nanopore single-molecule technique.
2017, 45(8): 1180-1187
doi: 10.11895/j.issn.0253-3820.170019
Abstract:
The Au-PDA-Fe3O4 decorated graphene oxide electrode was modified with Prussion blue-secondary antibodies for determination of cancer biomarker α-fetoprotein (AFP) with great sensitivity. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet-visible absorption spectrometry were used to characterize the structure of the material. Greatly enhanced sensitivity for the cancer biomarker is based on a dual signal amplification strategy. First, Fe3O4-PDA-Au used for the biosensor platform increased the surface area to capture a large amount of primary antibodies (Ab1), which resulted in amplification of the detection response. Second, graphene oxide allowed several binding events of PB-Ab2. Enhanced sensitivity was also achieved by introducing the multibioconjugates of Ab2-PB-GO onto the electrode surface through "sandwich" immunoreactions. The test result shows that there are linear relationships between current and AFP concentrations ranging from 0.005 ng/mL to 1 ng/mL and 1 ng/mL to 20 ng/mL, with the low detection limit (LOD) of 1.0 pg/mL. This immunosensor is simple, low-cost and sensitive and shows a great potential in biomedicine, clinical diagnosis and health examination.
The Au-PDA-Fe3O4 decorated graphene oxide electrode was modified with Prussion blue-secondary antibodies for determination of cancer biomarker α-fetoprotein (AFP) with great sensitivity. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet-visible absorption spectrometry were used to characterize the structure of the material. Greatly enhanced sensitivity for the cancer biomarker is based on a dual signal amplification strategy. First, Fe3O4-PDA-Au used for the biosensor platform increased the surface area to capture a large amount of primary antibodies (Ab1), which resulted in amplification of the detection response. Second, graphene oxide allowed several binding events of PB-Ab2. Enhanced sensitivity was also achieved by introducing the multibioconjugates of Ab2-PB-GO onto the electrode surface through "sandwich" immunoreactions. The test result shows that there are linear relationships between current and AFP concentrations ranging from 0.005 ng/mL to 1 ng/mL and 1 ng/mL to 20 ng/mL, with the low detection limit (LOD) of 1.0 pg/mL. This immunosensor is simple, low-cost and sensitive and shows a great potential in biomedicine, clinical diagnosis and health examination.
2017, 45(8): 1188-1194
doi: 10.11895/j.issn.0253-3820.170207
Abstract:
A method for quantitative detection of florfenicol by colloidal gold lateral flow immunoassay was developed. The experimental conditions including pH value, concentrations of antibody in the process of conjugation between the colloidal gold and antibody, amount of gold-labeled antibody, concentration of the antigen sprayed on test lines (T line), and detection time were optimized. With a colloidal gold strip reader, the signal intensity of T lines and control lines (C line) on lateral flow strips was recorded. The T/C ratio of negative control and positive samples was defined as B0 and Bx, and the standard curve was established by plotting the Bx/B0 ratio against the concentration of florfenicol. This assay showed a good linear range from 0.1 to 1.5 ng/mL with the limit of detection of 0.08 ng/mL, while the result could be obtained within 15 min. The result showed that this quantitative method was convenient and rapid, and could be used in screening a large amount of samples on site.
A method for quantitative detection of florfenicol by colloidal gold lateral flow immunoassay was developed. The experimental conditions including pH value, concentrations of antibody in the process of conjugation between the colloidal gold and antibody, amount of gold-labeled antibody, concentration of the antigen sprayed on test lines (T line), and detection time were optimized. With a colloidal gold strip reader, the signal intensity of T lines and control lines (C line) on lateral flow strips was recorded. The T/C ratio of negative control and positive samples was defined as B0 and Bx, and the standard curve was established by plotting the Bx/B0 ratio against the concentration of florfenicol. This assay showed a good linear range from 0.1 to 1.5 ng/mL with the limit of detection of 0.08 ng/mL, while the result could be obtained within 15 min. The result showed that this quantitative method was convenient and rapid, and could be used in screening a large amount of samples on site.
2017, 45(8): 1195-1202
doi: 10.11895/j.issn.0253-3820.170132
Abstract:
A method for simultaneous determination of 25 kinds of fungicides in cereals, vegetables and fruits using SPE-LC-Q-TOF/MS technique was developed. The samples were extracted with acetonitrile containing 1% (V/V) acetic acid, purified by solid phase extraction (SPE) with a Crabon/NH2 cartridge, eluted with acetonitrile-toluene(3:1, V/V), separated by a reversed phase C18 column, gradiently eluted with acetonitrile and 0.1% formic acid solution (Containing 5 mmol/L ammonium acetate), determined by LC-Q-TOF/MS, and quantified by external standard method. A data base of the accurate mass numbers and a library which contains 25 kinds of fungicides were established. The automatic retrieval of detection results was carried on according to the characteristics of the compound, such as accurate mass, retention time, isotope peak distribution, isotopic ratios, and so on. Based on the above results, the qualitative identifications of the 25 new fungicides were accomplished without the contrast of standard substances. The results indicated that 25 fungicides showed good linearity in the range of 0.02-200 μg/L, and the limits of detection (LOD) and the limits of quantification (LOQ) were 0.01-5.00 μg/kg and 0.02-20.00 μg/kg, respectively. The linear relative coefficients were greater than 0.995. The recoveries were in the range 71.8%-114.0% and the relative standard deviations (RSD) were ranged from 0.1% to 21.3% (n=3). The method has some advantages such as simplicity, rapidity and high sensitivity, and is suitable for the rapid determination of the common fungicides in cereals, vegetables and fruits.
A method for simultaneous determination of 25 kinds of fungicides in cereals, vegetables and fruits using SPE-LC-Q-TOF/MS technique was developed. The samples were extracted with acetonitrile containing 1% (V/V) acetic acid, purified by solid phase extraction (SPE) with a Crabon/NH2 cartridge, eluted with acetonitrile-toluene(3:1, V/V), separated by a reversed phase C18 column, gradiently eluted with acetonitrile and 0.1% formic acid solution (Containing 5 mmol/L ammonium acetate), determined by LC-Q-TOF/MS, and quantified by external standard method. A data base of the accurate mass numbers and a library which contains 25 kinds of fungicides were established. The automatic retrieval of detection results was carried on according to the characteristics of the compound, such as accurate mass, retention time, isotope peak distribution, isotopic ratios, and so on. Based on the above results, the qualitative identifications of the 25 new fungicides were accomplished without the contrast of standard substances. The results indicated that 25 fungicides showed good linearity in the range of 0.02-200 μg/L, and the limits of detection (LOD) and the limits of quantification (LOQ) were 0.01-5.00 μg/kg and 0.02-20.00 μg/kg, respectively. The linear relative coefficients were greater than 0.995. The recoveries were in the range 71.8%-114.0% and the relative standard deviations (RSD) were ranged from 0.1% to 21.3% (n=3). The method has some advantages such as simplicity, rapidity and high sensitivity, and is suitable for the rapid determination of the common fungicides in cereals, vegetables and fruits.
2017, 45(8): 1203-1208
doi: 10.11895/j.issn.0253-3820.170142
Abstract:
A method for simultaneous determination of 12 kinds of chlorinated disinfection byproducts (DBPs) in drinking water was developed based on liquid-liquid extraction gas chromatography equipped with electron capture detector (GC/ECD). The procedural standard calibration was adopted to eliminate the interference of different matrix. The method detection limits for 12 DBPs were 0.08-0.21 μg/L and the entire analytical procedure was finished in 21.50 min. The recoveries were in the range of 80.9%-115.7% and the relative standard deviations (RSD) were between 0.9% and 9.9% at different concentration levels (5 and 50 μg/L) in tap water and surface water. The correlation coefficients for all 12 kinds of DBPs were greater than 0.99 in the linearity range of 0.5-200 μg/L. The method was applied to determine DBPs in drinking water and source water. This method was rapid and competent for detection of volatile DBPs in drinking water.
A method for simultaneous determination of 12 kinds of chlorinated disinfection byproducts (DBPs) in drinking water was developed based on liquid-liquid extraction gas chromatography equipped with electron capture detector (GC/ECD). The procedural standard calibration was adopted to eliminate the interference of different matrix. The method detection limits for 12 DBPs were 0.08-0.21 μg/L and the entire analytical procedure was finished in 21.50 min. The recoveries were in the range of 80.9%-115.7% and the relative standard deviations (RSD) were between 0.9% and 9.9% at different concentration levels (5 and 50 μg/L) in tap water and surface water. The correlation coefficients for all 12 kinds of DBPs were greater than 0.99 in the linearity range of 0.5-200 μg/L. The method was applied to determine DBPs in drinking water and source water. This method was rapid and competent for detection of volatile DBPs in drinking water.
2017, 45(8): 1209-1214
doi: 10.11895/j.issn.0253-3820.160865
Abstract:
A new type of fluorescent gold nanoclusters (MU-Au NCs) was prepared by hydrothermal synthesis method using ammonium benzoate murexide (MU) as reducing agent and protecting agent. The synthesis method was simple and rapid. Based on the fluorescence quenching ability of spermine, a "turn off" type fluorescence analysis method was established for rapid and ultra sensitive detection of spermine. The linear range for detection of spermine was 0.003-300 μmol/L and the detection limit was 1 nmol/L (S/N=3). The established analytical method of spermine provided theoretical basis and reference for construction of spermine biosensor and actual sample detection.
A new type of fluorescent gold nanoclusters (MU-Au NCs) was prepared by hydrothermal synthesis method using ammonium benzoate murexide (MU) as reducing agent and protecting agent. The synthesis method was simple and rapid. Based on the fluorescence quenching ability of spermine, a "turn off" type fluorescence analysis method was established for rapid and ultra sensitive detection of spermine. The linear range for detection of spermine was 0.003-300 μmol/L and the detection limit was 1 nmol/L (S/N=3). The established analytical method of spermine provided theoretical basis and reference for construction of spermine biosensor and actual sample detection.
2017, 45(8): 1215-1221
doi: 10.11895/j.issn.0253-3820.170094
Abstract:
A method for the determination of three volatile elements (mercury, arsenic and selenium) in soils by one-time digestion was established. The digestion of samples was carried out in an automatic program temperature controlled graphite digestion instrument by aqua regia + hydrofluoric acid+boric acid. Hydride generation atomic fluorescence spectrometry (HG-AFS) was used to determine the contents of mercury, arsenic and selenium in the same digestion solution. The accuracy of the method was verified by the results of the soil environment samples of certified reference materials GSS-1-GSS-8 from the Center of the National Standard. The contents of soil mercury, arsenic and selenium obtained by this method were consistent with the standard values of these elements provided by the Center of the National Standard. In comparison with the current standard methods, the one-time digestion method was simplified, the pre-processing time was saved, and the reagent consumption was reduced. The method had wide range of application, high sensitivity, low detection limit, which was especially suitable for trace analysis of bulk samples, and also it could be used as a rapid digestion method for the measurement and governance of heavy metals in polluted soils.
A method for the determination of three volatile elements (mercury, arsenic and selenium) in soils by one-time digestion was established. The digestion of samples was carried out in an automatic program temperature controlled graphite digestion instrument by aqua regia + hydrofluoric acid+boric acid. Hydride generation atomic fluorescence spectrometry (HG-AFS) was used to determine the contents of mercury, arsenic and selenium in the same digestion solution. The accuracy of the method was verified by the results of the soil environment samples of certified reference materials GSS-1-GSS-8 from the Center of the National Standard. The contents of soil mercury, arsenic and selenium obtained by this method were consistent with the standard values of these elements provided by the Center of the National Standard. In comparison with the current standard methods, the one-time digestion method was simplified, the pre-processing time was saved, and the reagent consumption was reduced. The method had wide range of application, high sensitivity, low detection limit, which was especially suitable for trace analysis of bulk samples, and also it could be used as a rapid digestion method for the measurement and governance of heavy metals in polluted soils.
2017, 45(8): 1222-1226
doi: 10.11895/j.issn.0253-3820.170220
Abstract:
An analytical method was developed for determination of P and Si in edible vegetable oil using inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS). The microwave-assisted acid digestion of vegetable oil using HNO3 + H2O2 was carried out in closed vessels. The mass spectral interferences were eliminated by O2 mass shift when promoting reaction with O2 inside the collision reaction cell (CRC), and the monitoring of P as 31P16O+ product ion significantly improved the accuracy of the analysis. H2 was added into the CRC for H2 on-mass reaction. The interferences were eliminated by the quadrupole analyzer to accurately identify 28Si+. The effects of the flow rate of O2 and H2 in ORS3 on the signal intensities and BECs of 31P16O+ and 28Si+ were investigated. The optimum O2 and H2 flow rate was determined. Under the optimized conditions, the limits of detection were 0.043 and 0.66 μg/L for 31P16O+ and 28Si+, respectively. The accuracy of the analytical method was assessed by the analysis of the standard reference materials lubricant oil (SRM 1848) from the National Institute of Standard and Technology. No significant differences were observed between the certified values and measured values. This method was used to analyze 5 kinds of edible vegetable oils (rapeseed oil, sunflower oil, peanut oil, corn oil and soybean oil) from different regions of China, and it was found that the content of P was the highest in peanut oil, and Si showed the highest content in soybean oil.
An analytical method was developed for determination of P and Si in edible vegetable oil using inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS). The microwave-assisted acid digestion of vegetable oil using HNO3 + H2O2 was carried out in closed vessels. The mass spectral interferences were eliminated by O2 mass shift when promoting reaction with O2 inside the collision reaction cell (CRC), and the monitoring of P as 31P16O+ product ion significantly improved the accuracy of the analysis. H2 was added into the CRC for H2 on-mass reaction. The interferences were eliminated by the quadrupole analyzer to accurately identify 28Si+. The effects of the flow rate of O2 and H2 in ORS3 on the signal intensities and BECs of 31P16O+ and 28Si+ were investigated. The optimum O2 and H2 flow rate was determined. Under the optimized conditions, the limits of detection were 0.043 and 0.66 μg/L for 31P16O+ and 28Si+, respectively. The accuracy of the analytical method was assessed by the analysis of the standard reference materials lubricant oil (SRM 1848) from the National Institute of Standard and Technology. No significant differences were observed between the certified values and measured values. This method was used to analyze 5 kinds of edible vegetable oils (rapeseed oil, sunflower oil, peanut oil, corn oil and soybean oil) from different regions of China, and it was found that the content of P was the highest in peanut oil, and Si showed the highest content in soybean oil.
2017, 45(8): 1227-1232
doi: 10.11895/j.issn.0253-3820.170335
Abstract:
The graphene prepared by chemical vapor deposition onto copper foils was transferred onto a poly(ethylene terephthalate) (PET) soft substrate by the aid of poly-methyl methacrylate (PMMA). The soft G/AuNPs/GOD composite electrode based on PET substrate was fabricated using a protocol in which the uniform distribution of Au nanoparticles (AuNPs) was firstly obtained by controlling the evaporation of gold sol on a graphene surface, then thioglycolic acid (TGA) was modified on the AuNPs through Au-S bond, and finally glucose oxidase (GOD) was immobilized on the surface of AuNPs through acylation reaction between TGA and the GOD. Glucose was detected in the linear range from 0.05 to 10.55 mmol/L with a linear correlation coefficient (r) of 0.9955. The detection was performed in phosphate buffer solution (pH 7) at 25℃ with a working potential of 0.6 V (vs.SCE electrode), and the detection limit was 1 μmol/L (3σ). The G/AuNPs/GOD flexible electrode based on PET substrate provided a new pathway to detect glucose in special environments using wearable equipment, which enlarged the applied field of glucose detection.
The graphene prepared by chemical vapor deposition onto copper foils was transferred onto a poly(ethylene terephthalate) (PET) soft substrate by the aid of poly-methyl methacrylate (PMMA). The soft G/AuNPs/GOD composite electrode based on PET substrate was fabricated using a protocol in which the uniform distribution of Au nanoparticles (AuNPs) was firstly obtained by controlling the evaporation of gold sol on a graphene surface, then thioglycolic acid (TGA) was modified on the AuNPs through Au-S bond, and finally glucose oxidase (GOD) was immobilized on the surface of AuNPs through acylation reaction between TGA and the GOD. Glucose was detected in the linear range from 0.05 to 10.55 mmol/L with a linear correlation coefficient (r) of 0.9955. The detection was performed in phosphate buffer solution (pH 7) at 25℃ with a working potential of 0.6 V (vs.SCE electrode), and the detection limit was 1 μmol/L (3σ). The G/AuNPs/GOD flexible electrode based on PET substrate provided a new pathway to detect glucose in special environments using wearable equipment, which enlarged the applied field of glucose detection.
2017, 45(8): 1233-1237
doi: 10.11895/j.issn.0253-3820.170129
Abstract:
Based on melamine-Cu conjugate and subsequent interruption of formation of polythymine (Poly T)-templated copper nanoclusters (CuNCs), a novel fluorescent strategy was developed for detection of melamine. The method relied on the principle that the coordination of melamine to copper would be unfavorable for the reduction of Cu2+ in the poly T-CuNCs synthesis process, and thereby resulting in the decrease of fluorescence intensity of CuNCs. By this method, the fluorescence response of CuNCs displayed an linear relationship with melamine concentration in the range from 5 μmol/L to 120 μmol/L. The detection limit was 1.5 μmol/L. Furthermore, the assay was successfully applied in the detection of melamine in milk samples with good recoveries.
Based on melamine-Cu conjugate and subsequent interruption of formation of polythymine (Poly T)-templated copper nanoclusters (CuNCs), a novel fluorescent strategy was developed for detection of melamine. The method relied on the principle that the coordination of melamine to copper would be unfavorable for the reduction of Cu2+ in the poly T-CuNCs synthesis process, and thereby resulting in the decrease of fluorescence intensity of CuNCs. By this method, the fluorescence response of CuNCs displayed an linear relationship with melamine concentration in the range from 5 μmol/L to 120 μmol/L. The detection limit was 1.5 μmol/L. Furthermore, the assay was successfully applied in the detection of melamine in milk samples with good recoveries.
2017, 45(8): 1238-1247
doi: 10.11895/j.issn.0253-3820.170159
Abstract:
Magnetic manipulation of particles/cells in microfluidic chips is a promising research field. This paper stated the operation mechanism and the main means of manipulation, including separation, concentration, capture, arrangement and assembly. Especially, the concept of particles/cells separation was emphasized with different criteria, like sizes, shapes, and magnetic properties. In addition, the effects of the channel geometry, the intensity and distribution of the magnetic field, and the types of magnetic liquid (paramagnetic salt solutions and ferrofluids) on the performance of the magnetic manipulation were also compared. The prospective to the prospect of magnetic manipulation about particles/cells in microfluidic chip was also depicted.
Magnetic manipulation of particles/cells in microfluidic chips is a promising research field. This paper stated the operation mechanism and the main means of manipulation, including separation, concentration, capture, arrangement and assembly. Especially, the concept of particles/cells separation was emphasized with different criteria, like sizes, shapes, and magnetic properties. In addition, the effects of the channel geometry, the intensity and distribution of the magnetic field, and the types of magnetic liquid (paramagnetic salt solutions and ferrofluids) on the performance of the magnetic manipulation were also compared. The prospective to the prospect of magnetic manipulation about particles/cells in microfluidic chip was also depicted.
2017, 45(8): 1248-1257
doi: 10.11895/j.issn.0253-3820.170098
Abstract:
The hydrogen sulfate plays an important role in biological and environmental areas and can contaminate the environment, which will cause harm to human body. Thus it is of primary importance to detect hydrogen sulfate with high selectivity and sensitivity. Among these methods for detection of hydrogen sulfate, the optical chemosensor based on molecular recognition is desirable with unique advantage. Anions optical sensing systems are predominantly attractive due to their simplicity, high degree of specificity, low detection limits, easy on-line analysis and especial colorimetric recognition and in situ detection. Herein, the progress during the last decades of optical chemosensors and probes for hydrogen sulfate based on the recognizing mechanism is summarized. The further research orientations are also prospected.
The hydrogen sulfate plays an important role in biological and environmental areas and can contaminate the environment, which will cause harm to human body. Thus it is of primary importance to detect hydrogen sulfate with high selectivity and sensitivity. Among these methods for detection of hydrogen sulfate, the optical chemosensor based on molecular recognition is desirable with unique advantage. Anions optical sensing systems are predominantly attractive due to their simplicity, high degree of specificity, low detection limits, easy on-line analysis and especial colorimetric recognition and in situ detection. Herein, the progress during the last decades of optical chemosensors and probes for hydrogen sulfate based on the recognizing mechanism is summarized. The further research orientations are also prospected.
