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2018 Volume 46 Issue 7
2018, 46(7): 995-1004
doi: 10.11895/j.issn.0253-3820.171444
Abstract:
Functional nucleic acids are natural or artificialnucleic acid sequences with specific functions and special structures. Special metal ions are essential trace elements for human health, but excessive metal ions will be harmful to human health. The functional nucleic acids are widely used in the detection of metal ions because of their advantages such as easy modification, low price, high stability and strong specificity. This review describes the function of functional nucleic acid and metal ions, mainly including cutting type, link type, metal ion-mediated base pairing, click chemical type, conformation change type, and other types. Then, biosensor of functional nucleic acid combined with different signal output is introduced. Finally, the research significance and problems of functional nucleic acid in metal ion detection are discussed, and the future development direction and application prospect of functional nucleic acid biosensor are prospected.
Functional nucleic acids are natural or artificialnucleic acid sequences with specific functions and special structures. Special metal ions are essential trace elements for human health, but excessive metal ions will be harmful to human health. The functional nucleic acids are widely used in the detection of metal ions because of their advantages such as easy modification, low price, high stability and strong specificity. This review describes the function of functional nucleic acid and metal ions, mainly including cutting type, link type, metal ion-mediated base pairing, click chemical type, conformation change type, and other types. Then, biosensor of functional nucleic acid combined with different signal output is introduced. Finally, the research significance and problems of functional nucleic acid in metal ion detection are discussed, and the future development direction and application prospect of functional nucleic acid biosensor are prospected.
2018, 46(7): 1005-1016
doi: 10.11895/j.issn.0253-3820.181110
Abstract:
Secondary ion mass spectrometry (SIMS) as a powerful surface analysis technique has been widely applied in semiconductor industry and geology research. Recently, with the development of instrumental technology, SIMS is attracting more and more attention in life sciences. SIMS can provide surface MS spectra, 2D/3D chemical images and depth profiling of substances simultaneously. The minimal lateral resolution of 2D SIMS imaging is 80 to 100 nm, and the longitudinal resolution of 3D SIMS imaging is about 1-5 nm. However, due to lack of specific ions to render the structures of organelles, SIMS imaging for single cells still has great challenges. Optical microscopy, in particular laser scanning confocal microscopy (LSCM), has been emerged to be an indispensable technique for single cell imaging and can obtain high spatial 2D/3D imaging to visualize the structures of organelles. Thus, the combinational use of SIMS and LSCM, which takes advantages of SIMS for molecular imaging and LSCM for morphological imaging, has greatly extended the application of SIMS imaging and ensured its accuracy at single cells level, providing novel insights into better understanding of the biological events inside cells. In this review, we focus on the development and application of SIMS imaging and the correlated SIMS and LSCM imaging in the research of cell biology and drug discovery. We anticipate that the combinational use of SIMS and LSCM imaging has promising future in biomedicine and life sciences.
Secondary ion mass spectrometry (SIMS) as a powerful surface analysis technique has been widely applied in semiconductor industry and geology research. Recently, with the development of instrumental technology, SIMS is attracting more and more attention in life sciences. SIMS can provide surface MS spectra, 2D/3D chemical images and depth profiling of substances simultaneously. The minimal lateral resolution of 2D SIMS imaging is 80 to 100 nm, and the longitudinal resolution of 3D SIMS imaging is about 1-5 nm. However, due to lack of specific ions to render the structures of organelles, SIMS imaging for single cells still has great challenges. Optical microscopy, in particular laser scanning confocal microscopy (LSCM), has been emerged to be an indispensable technique for single cell imaging and can obtain high spatial 2D/3D imaging to visualize the structures of organelles. Thus, the combinational use of SIMS and LSCM, which takes advantages of SIMS for molecular imaging and LSCM for morphological imaging, has greatly extended the application of SIMS imaging and ensured its accuracy at single cells level, providing novel insights into better understanding of the biological events inside cells. In this review, we focus on the development and application of SIMS imaging and the correlated SIMS and LSCM imaging in the research of cell biology and drug discovery. We anticipate that the combinational use of SIMS and LSCM imaging has promising future in biomedicine and life sciences.
2018, 46(7): 1017-1024
doi: 10.11895/j.issn.0253-3820.181158
Abstract:
Based on the electric field shielding and insulation technology, the single electrode dielectric barrier discharge ion source (DBDI) has the characteristics of uniform discharging, stability, and high ionization energy, and thus can be used to detect various samples with a large range of polarity. However, the ionization energy is too high to reduce the background signal noise, and thus affects the detection effectiveness to low polarity and low boiling point samples. To enhance the detection effectiveness to these samples, a method of eliminating electrons of single electrode DBDI by using external metal electrodes was developed in this study. Then, the single electrode DBDI was improved by an external needle electrode and an external metal net, respectively. The mechanism of those external metal electrodes was discussed, and the experimental studies were carried out. The results showed that the external metal net technology had an advantage in improving signal to noise ratio (SNR), and the enhancement of SNR for the detection of isoprocarb, perfluorooctanoic acid and Sudan Ⅲ was about 5-6 times. Based on the technology, a method for determination of Sudan Ⅲ in chili powder was developed. The recoveries, RSD and LOD were 83.7%-94.6%, 5.6%-9.0% and 23 mg/kg, respectively. The external metal electrode technique has broadened the detection range of single electrode DBDI to the field of low polarity, low boiling point and complex samples.
Based on the electric field shielding and insulation technology, the single electrode dielectric barrier discharge ion source (DBDI) has the characteristics of uniform discharging, stability, and high ionization energy, and thus can be used to detect various samples with a large range of polarity. However, the ionization energy is too high to reduce the background signal noise, and thus affects the detection effectiveness to low polarity and low boiling point samples. To enhance the detection effectiveness to these samples, a method of eliminating electrons of single electrode DBDI by using external metal electrodes was developed in this study. Then, the single electrode DBDI was improved by an external needle electrode and an external metal net, respectively. The mechanism of those external metal electrodes was discussed, and the experimental studies were carried out. The results showed that the external metal net technology had an advantage in improving signal to noise ratio (SNR), and the enhancement of SNR for the detection of isoprocarb, perfluorooctanoic acid and Sudan Ⅲ was about 5-6 times. Based on the technology, a method for determination of Sudan Ⅲ in chili powder was developed. The recoveries, RSD and LOD were 83.7%-94.6%, 5.6%-9.0% and 23 mg/kg, respectively. The external metal electrode technique has broadened the detection range of single electrode DBDI to the field of low polarity, low boiling point and complex samples.
2018, 46(7): 1025-1031
doi: 10.11895/j.issn.0253-3820.181105
Abstract:
On the basis of the chromogenic reaction between Hg and CuI, a semi-quantitative solid sampling Hg analyzer comprising the catalytic furance, Hg testing tube, air pump and smart cellphone was developed. White carrier 101 was chosen as the adsorbent for CuI to react with Hg from the catalytic furnace. The established Hg analyzer can not only visually recognize the coloration when Hg exceeding the limit standard, but also semi-quantitatively detect the Hg content in cosmetics fast using a smart cellphone and RGB analysis software, after direct solid sampling introduction of cosmetics sample. The instrumental detection limit (LOD) of mercury was 50 ng, the linearity ranged from 50 ng to 2500 ng, the linear regression coefficient (R2) was higher than 0.97, and the RSD of the corresponding RGB values was 6% (n=11). Nine real cosmetics samples were measured by the established method, whose relative differences of Hg contents with that by the standard method (Safety Technical Specification for Cosmetics, 2015 edition) were less than 10%. The whole analytical time can be controlled within 5 min. The established instrumental method is simple, fast, accurate and visual, and extremely suitable to fast and on-site monitoring of Hg in cosmetics samples.
On the basis of the chromogenic reaction between Hg and CuI, a semi-quantitative solid sampling Hg analyzer comprising the catalytic furance, Hg testing tube, air pump and smart cellphone was developed. White carrier 101 was chosen as the adsorbent for CuI to react with Hg from the catalytic furnace. The established Hg analyzer can not only visually recognize the coloration when Hg exceeding the limit standard, but also semi-quantitatively detect the Hg content in cosmetics fast using a smart cellphone and RGB analysis software, after direct solid sampling introduction of cosmetics sample. The instrumental detection limit (LOD) of mercury was 50 ng, the linearity ranged from 50 ng to 2500 ng, the linear regression coefficient (R2) was higher than 0.97, and the RSD of the corresponding RGB values was 6% (n=11). Nine real cosmetics samples were measured by the established method, whose relative differences of Hg contents with that by the standard method (Safety Technical Specification for Cosmetics, 2015 edition) were less than 10%. The whole analytical time can be controlled within 5 min. The established instrumental method is simple, fast, accurate and visual, and extremely suitable to fast and on-site monitoring of Hg in cosmetics samples.
2018, 46(7): 1032-1038
doi: 10.11895/j.issn.0253-3820.171372
Abstract:
The low sensitivity of microbial fuel cell (MFC)-biosensor is one of the bottlenecks in its practical application. To investigate the effect of anode electrode modified with carbon nanomaterials on the sensitivity of water toxicity detection of MFC-based biosensor, graphite felts (GF) were modified using two carbon nanomaterials of multi-walled carbon nanotubes (MWNT) and conductive carbon black (GCB). MFC biosensors were started up with the anode electrodes, and the results showed that resistance of the GCB and MWNT-modified electrode was smaller than that of unmodified electrode, and the order of MFC power output was GCB/GF-MFC (2.63 W/m2) > MWNT/GF-MFC (2.56 W/m2) > GF-MFC (2.09 W/m2). Then, 3, 5-dichlorophenol poison (DCP) was used as a model toxicant in toxicity test, the order of toxicity inhibition ratios of 10 mg/L DCP to three MFC biosensor was MWNT/GF-MFC (31.8%) > GCB/GF-MFC (26.3%) > GF-MFC (20.1%). The sensitivity for toxicity detection by MFC biosensors with anode electrode modified with carbon nanomaterials was improved, and MWNT/GF-MFC had the highest sensitivity. The result of the study may promote the application of MFC biosensor in water pollution monitoring.
The low sensitivity of microbial fuel cell (MFC)-biosensor is one of the bottlenecks in its practical application. To investigate the effect of anode electrode modified with carbon nanomaterials on the sensitivity of water toxicity detection of MFC-based biosensor, graphite felts (GF) were modified using two carbon nanomaterials of multi-walled carbon nanotubes (MWNT) and conductive carbon black (GCB). MFC biosensors were started up with the anode electrodes, and the results showed that resistance of the GCB and MWNT-modified electrode was smaller than that of unmodified electrode, and the order of MFC power output was GCB/GF-MFC (2.63 W/m2) > MWNT/GF-MFC (2.56 W/m2) > GF-MFC (2.09 W/m2). Then, 3, 5-dichlorophenol poison (DCP) was used as a model toxicant in toxicity test, the order of toxicity inhibition ratios of 10 mg/L DCP to three MFC biosensor was MWNT/GF-MFC (31.8%) > GCB/GF-MFC (26.3%) > GF-MFC (20.1%). The sensitivity for toxicity detection by MFC biosensors with anode electrode modified with carbon nanomaterials was improved, and MWNT/GF-MFC had the highest sensitivity. The result of the study may promote the application of MFC biosensor in water pollution monitoring.
2018, 46(7): 1039-1046
doi: 10.11895/j.issn.0253-3820.171425
Abstract:
The chemical vapor deposition grown graphene was transferred onto flexible polyethylene terephthalate surface to fabricate a graphene platform electrode (GPE), and gold nanoparticles (AuNPs) were electrodeposited on GPE to form an AuNPs modified GPE (AuNPs/GPE). The formation of AuNPs was confirmed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), high-resolution transmission electron microscope (HR-TEM), X-ray diffraction (XRD) and Raman spectra. On AuNPs/GPE, dopamine (DA) displayed a pair of well-defined redox peaks with highly enhanced peak currents compared with those on GPE. At detection potential of 0.20 V, AuNPs/GPE sensor presented a wide linear range of 0.1 μmol/L to 400.0 μmol/L of DA with a detection limit of 3.9 nmol/L (S/N=3). In addition, the proposed sensor allowed highly selective and sensitive, stable and fast amperometric sensing of DA.
The chemical vapor deposition grown graphene was transferred onto flexible polyethylene terephthalate surface to fabricate a graphene platform electrode (GPE), and gold nanoparticles (AuNPs) were electrodeposited on GPE to form an AuNPs modified GPE (AuNPs/GPE). The formation of AuNPs was confirmed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), high-resolution transmission electron microscope (HR-TEM), X-ray diffraction (XRD) and Raman spectra. On AuNPs/GPE, dopamine (DA) displayed a pair of well-defined redox peaks with highly enhanced peak currents compared with those on GPE. At detection potential of 0.20 V, AuNPs/GPE sensor presented a wide linear range of 0.1 μmol/L to 400.0 μmol/L of DA with a detection limit of 3.9 nmol/L (S/N=3). In addition, the proposed sensor allowed highly selective and sensitive, stable and fast amperometric sensing of DA.
2018, 46(7): 1047-1054
doi: 10.11895/j.issn.0253-3820.171195
Abstract:
In this paper, Fe3O4/MnO2 doped graphene molecularly imprinted hybrid material (Fe3O4/MnO2-MIP@RGO) was successfully synthesized via reversible addition fragmentation chain transfer (RAFT) molecularly imprinting technique by using methacrylic acid as functional monomer, divinylbenzene as cross-linker, Fe3O4/MnO2@RGO as carrier, and 17β-estradiol (17β-E2) as template molecule. A novel molecularly imprinting electrochemical sensor by using Fe3O4/MnO2-MIP@RGO modified electrode was constructed to specifically detect trace 17β-E2 in water. The experimental results showed that the Fe3O4/MnO2-MIP@RGO electrochemical sensor exhibited rapid and linear current response to 17β-E2 in water samples with a linear range of 4 nmol/L to 0.8 μmol/L (R=0.9852), the detection limit was 47.2 pmol/L (3σ) and the relative standard deviation (RSD) was from 2.1% to 2.5%. This study provides a simple and efficient, economical and reliable method for the monitoring of 17β-estradiol in the complex water environment.
In this paper, Fe3O4/MnO2 doped graphene molecularly imprinted hybrid material (Fe3O4/MnO2-MIP@RGO) was successfully synthesized via reversible addition fragmentation chain transfer (RAFT) molecularly imprinting technique by using methacrylic acid as functional monomer, divinylbenzene as cross-linker, Fe3O4/MnO2@RGO as carrier, and 17β-estradiol (17β-E2) as template molecule. A novel molecularly imprinting electrochemical sensor by using Fe3O4/MnO2-MIP@RGO modified electrode was constructed to specifically detect trace 17β-E2 in water. The experimental results showed that the Fe3O4/MnO2-MIP@RGO electrochemical sensor exhibited rapid and linear current response to 17β-E2 in water samples with a linear range of 4 nmol/L to 0.8 μmol/L (R=0.9852), the detection limit was 47.2 pmol/L (3σ) and the relative standard deviation (RSD) was from 2.1% to 2.5%. This study provides a simple and efficient, economical and reliable method for the monitoring of 17β-estradiol in the complex water environment.
2018, 46(7): 1055-1061
doi: 10.11895/j.issn.0253-3820.181031
Abstract:
An electrochemical analysis system for rapid determination of chemical oxygen demand (COD) in flow state was established. A planar electrode modified with GO-NiNPs was matched with a 3D printed thin-layer cell. The sample was driven smoothly through the electrode surface by a micro peristaltic pump and then measured by chronoamperometry. The effect of modified materials, dielectric and electrochemical operating conditions were investigated. The whole response time of COD was 1.5 min and the demand for the sample was about 2 mL. It turned out that the linear range of response in the low concentration region was 0.15-100 mg/L, the linear equation was i(μA)=3.974c (mg/L) + 0.2295 (r=0.9991) and the detection limit was 0.04 mg/L. The linear response range in the high concentration region was 100-450 mg/L, and the linear equation was i(μA)=1.938c (mg/L) + 230.9 (r=0.9877). Compared with the national standard method (GB11914-89) for measuring the actual water samples (Qinhuai River, Xuanwu Lake and Nanjing tap water), the correlation between them was quite good and the analysis time was dropped to 1/100. This new sensing system provided an environmentally friendly and portable method for detection of COD without using expensive, highly corrosive and toxic reagents.
An electrochemical analysis system for rapid determination of chemical oxygen demand (COD) in flow state was established. A planar electrode modified with GO-NiNPs was matched with a 3D printed thin-layer cell. The sample was driven smoothly through the electrode surface by a micro peristaltic pump and then measured by chronoamperometry. The effect of modified materials, dielectric and electrochemical operating conditions were investigated. The whole response time of COD was 1.5 min and the demand for the sample was about 2 mL. It turned out that the linear range of response in the low concentration region was 0.15-100 mg/L, the linear equation was i(μA)=3.974c (mg/L) + 0.2295 (r=0.9991) and the detection limit was 0.04 mg/L. The linear response range in the high concentration region was 100-450 mg/L, and the linear equation was i(μA)=1.938c (mg/L) + 230.9 (r=0.9877). Compared with the national standard method (GB11914-89) for measuring the actual water samples (Qinhuai River, Xuanwu Lake and Nanjing tap water), the correlation between them was quite good and the analysis time was dropped to 1/100. This new sensing system provided an environmentally friendly and portable method for detection of COD without using expensive, highly corrosive and toxic reagents.
2018, 46(7): 1062-1068
doi: 10.11895/j.issn.0253-3820.171396
Abstract:
Water soluble carbon quantum dots (CQDs) were prepared by using soot as carbon source. The obtained CQDs showed an excellent intrinsic peroxidase-like activity, which could catalyze the oxidization of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 and thus resulted in color change. Glucose could react with dissolved oxygen to produce H2O2 in the presence of glucose oxidase (GOx). A colorimetric method using CQDs as peroxidase mimetic enzyme was developed for glucose determination. When TMB was acted as a substrate, the effect of a series of conditions, such as temperature and pH on the catalytic activity of the obtained CQDs, was systematically studied. Under optimal conditions, e.g. pH 3.5 and temperature 35℃, 0.5 mmol/L TMB and 1 μg/mL CQDs, the absorbance at 652 nm showed linear response with glucose concentrations ranging from 0.025 mmol/L to 0.40 mmol/L, with detection limit of 5.10 μmol/L (3σ/k). The proposed method exhibited excellent selectivity and the common substances did not interfere with detection of glucose. This method was successfully applied to detect glucose in real samples with recoveries of 95.0%-105.1%.
Water soluble carbon quantum dots (CQDs) were prepared by using soot as carbon source. The obtained CQDs showed an excellent intrinsic peroxidase-like activity, which could catalyze the oxidization of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 and thus resulted in color change. Glucose could react with dissolved oxygen to produce H2O2 in the presence of glucose oxidase (GOx). A colorimetric method using CQDs as peroxidase mimetic enzyme was developed for glucose determination. When TMB was acted as a substrate, the effect of a series of conditions, such as temperature and pH on the catalytic activity of the obtained CQDs, was systematically studied. Under optimal conditions, e.g. pH 3.5 and temperature 35℃, 0.5 mmol/L TMB and 1 μg/mL CQDs, the absorbance at 652 nm showed linear response with glucose concentrations ranging from 0.025 mmol/L to 0.40 mmol/L, with detection limit of 5.10 μmol/L (3σ/k). The proposed method exhibited excellent selectivity and the common substances did not interfere with detection of glucose. This method was successfully applied to detect glucose in real samples with recoveries of 95.0%-105.1%.
2018, 46(7): 1069-1076
doi: 10.11895/j.issn.0253-3820.171285
Abstract:
Metallothionein (MT) is a low-molecular-weight protein with high inducibility and binding ability with metal ions. Therefore, MT is often regarded as an important biomarker for assessment of heavy metal pollution in water environment. But the traditional process of its enrichment and identification is time-consuming and complicated. Herein, we prepared a core-shell nanoparticle, gold-coated iron oxide nanoparticles (Fe3O4@Au NPs). The nanoparticle possessed the advantages such as fast response to magnetic fields and optical properties attributing to Fe3O4 and Au nanoparticles separately. Fe3O4@Au nanoparticles were used to enrich MT simply through AuS interaction, and the purified proteins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The results in this work showed that the Fe3O4@Au nanoparticles could directly enrich MT from complex solutions and the detection limit could be down to 10 fg/mL.
Metallothionein (MT) is a low-molecular-weight protein with high inducibility and binding ability with metal ions. Therefore, MT is often regarded as an important biomarker for assessment of heavy metal pollution in water environment. But the traditional process of its enrichment and identification is time-consuming and complicated. Herein, we prepared a core-shell nanoparticle, gold-coated iron oxide nanoparticles (Fe3O4@Au NPs). The nanoparticle possessed the advantages such as fast response to magnetic fields and optical properties attributing to Fe3O4 and Au nanoparticles separately. Fe3O4@Au nanoparticles were used to enrich MT simply through AuS interaction, and the purified proteins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The results in this work showed that the Fe3O4@Au nanoparticles could directly enrich MT from complex solutions and the detection limit could be down to 10 fg/mL.
2018, 46(7): 1077-1083
doi: 10.11895/j.issn.0253-3820.171347
Abstract:
Molybdenum disulfide (MoS2) quantum dots (QDs) were synthesized using one-step hydrothermal method with an acceptable fluorescence property. Based on the quenching effect between doxycycline hyclate (DOX) and MoS2 QDs, a fluorescence method for detection of DOX was established. The interaction between MoS2 QDs and DOX was discussed with a final proposal of the static quenching mechanism. A good linear correlation for detection of DOX using fluorescenct MoS2 QDs was obtained in the concentration range of 0.86-55.40 μg/mL, with a detection limit of 0.023 μg/mL (S/N=3). The fabricated sensor was applied to the detection of DOX in real samples with RSDs of less than 5%. The relative error of determination results of MoS2 QDs method compared with HPLC was from -4.5% to 0.8% and -4.6% to 2.8% for DOX tablet and DOX spiked milk, respectively. The fluorescence detection of DOX in real sample using MoS2 QDs was simple, rapid and reliable.
Molybdenum disulfide (MoS2) quantum dots (QDs) were synthesized using one-step hydrothermal method with an acceptable fluorescence property. Based on the quenching effect between doxycycline hyclate (DOX) and MoS2 QDs, a fluorescence method for detection of DOX was established. The interaction between MoS2 QDs and DOX was discussed with a final proposal of the static quenching mechanism. A good linear correlation for detection of DOX using fluorescenct MoS2 QDs was obtained in the concentration range of 0.86-55.40 μg/mL, with a detection limit of 0.023 μg/mL (S/N=3). The fabricated sensor was applied to the detection of DOX in real samples with RSDs of less than 5%. The relative error of determination results of MoS2 QDs method compared with HPLC was from -4.5% to 0.8% and -4.6% to 2.8% for DOX tablet and DOX spiked milk, respectively. The fluorescence detection of DOX in real sample using MoS2 QDs was simple, rapid and reliable.
2018, 46(7): 1084-1088
doi: 10.11895/j.issn.0253-3820.171422
Abstract:
Electrospray ionization is most commonly used in mass spectrometry for analysis of biological molecules such as peptides and proteins. However, peptides and proteins ions produced by electrospray ionization usually have multiple charges, and produce multiple spectrum peaks, making the mass spectrum complicated. Gas phase proton transfer ion/ion reaction can effectively regulate the charge states of peptides and proteins ions after electrospray ionization, simplifying the spectrogram, and thus is significant to the analysis of complex proteins and peptides samples. In this study, a dual-polarity linear ion trap (LIT) mass spectrometer was used to control the charge state of peptide ions by proton transfer ion/ion reaction. The detection effect of the method was verified by using glutathione (oxidation type), oxytocin and dynorphin as typical samples. The results showed that this method could remove excess charges in the positive ions. When injecting enough negative ions for eaction, peptide ions with multiple charge valence state could be reduced to the minimum, therefore simplify the spectrogram effectively.
Electrospray ionization is most commonly used in mass spectrometry for analysis of biological molecules such as peptides and proteins. However, peptides and proteins ions produced by electrospray ionization usually have multiple charges, and produce multiple spectrum peaks, making the mass spectrum complicated. Gas phase proton transfer ion/ion reaction can effectively regulate the charge states of peptides and proteins ions after electrospray ionization, simplifying the spectrogram, and thus is significant to the analysis of complex proteins and peptides samples. In this study, a dual-polarity linear ion trap (LIT) mass spectrometer was used to control the charge state of peptide ions by proton transfer ion/ion reaction. The detection effect of the method was verified by using glutathione (oxidation type), oxytocin and dynorphin as typical samples. The results showed that this method could remove excess charges in the positive ions. When injecting enough negative ions for eaction, peptide ions with multiple charge valence state could be reduced to the minimum, therefore simplify the spectrogram effectively.
2018, 46(7): 1089-1094
doi: 10.11895/j.issn.0253-3820.181099
Abstract:
Dielectric barrier discharge ion source-mass spectrometry (DBDI-MS) can achieve in-situ and efficient detection of samples without tedious pretreatment, and has become a popular analytical method. To improve the detection sensitivity, a novel mass spectrometric method based on gold nanoparticles (AuNPs)-assisted paper-based injection mode and DBDI-MS technology was developed for the fast determination of four veterinary drugs. The detection signal strength was improved by 8-31 times compared to the veterinary drugs which were tested without AuNPs-assisted paper based injection. Under the optimal conditions, the experimental data of four veterinary drugs showed a good linear relationship between the signal and the concentration in the respective range, with correlation coefficient (r) of 0.951-0.996. Moreover, the recoveries were between 79.4% and 96.5% at three spiked levels. This method has many distinct advantages, such as low detected limitation, low cost and high efficiency, and is also very suitable for fast on-site detecting, showing great potential in feed quality control.
Dielectric barrier discharge ion source-mass spectrometry (DBDI-MS) can achieve in-situ and efficient detection of samples without tedious pretreatment, and has become a popular analytical method. To improve the detection sensitivity, a novel mass spectrometric method based on gold nanoparticles (AuNPs)-assisted paper-based injection mode and DBDI-MS technology was developed for the fast determination of four veterinary drugs. The detection signal strength was improved by 8-31 times compared to the veterinary drugs which were tested without AuNPs-assisted paper based injection. Under the optimal conditions, the experimental data of four veterinary drugs showed a good linear relationship between the signal and the concentration in the respective range, with correlation coefficient (r) of 0.951-0.996. Moreover, the recoveries were between 79.4% and 96.5% at three spiked levels. This method has many distinct advantages, such as low detected limitation, low cost and high efficiency, and is also very suitable for fast on-site detecting, showing great potential in feed quality control.
2018, 46(7): 1095-1101
doi: 10.11895/j.issn.0253-3820.181142
Abstract:
A label-free and enzyme-free fluorescent DNA sensor based on hybridization chain reaction (HCR) and vacant site-binding molecule was developed. By rationally incorporating a cytosine in hairpin DNAs for HCR and utilizing vacant site-binding fluorophore ATMND, sensitive DNA detection was achieved, resulting from the large amount of vacant sites presented on the long DNA nanostructures upon HCR. Gel electrophoresis and atomic force microscopy were performed to characterize the hybridization chain reaction. Under the optimized conditions, the method could sensitively detect the target DNA with the low detection limit of 2.0 nmol/L. The method shows great potential in signal amplification for DNA detection with advantages such as simple, label-free and low-cost.
A label-free and enzyme-free fluorescent DNA sensor based on hybridization chain reaction (HCR) and vacant site-binding molecule was developed. By rationally incorporating a cytosine in hairpin DNAs for HCR and utilizing vacant site-binding fluorophore ATMND, sensitive DNA detection was achieved, resulting from the large amount of vacant sites presented on the long DNA nanostructures upon HCR. Gel electrophoresis and atomic force microscopy were performed to characterize the hybridization chain reaction. Under the optimized conditions, the method could sensitively detect the target DNA with the low detection limit of 2.0 nmol/L. The method shows great potential in signal amplification for DNA detection with advantages such as simple, label-free and low-cost.
2018, 46(7): 1102-1108
doi: 10.11895/j.issn.0253-3820.181008
Abstract:
A method for short-chain chlorinated paraffins (SCCPs) analysis in water samples based on solid-phase extraction (SPE) was developed using gas chromatography coupled with electron capture negative chemical ionization mass spectrometry (GC-ENCI-MS). SPE parameters including the sorbent, elution solvent and elution volume were optimized. Agilent Bond Elut-C18 was precleaned with 3 mL of hexane, 3 mL of methanol and conditioned with 3 mL of H2O before use. After enriched by the cartridge, the sample was washed by 3 mL of methanol (10%, V/V) and eluted by 3 mL of mixture of hexane and dichloromethane (1:1, V/V). The results showed that the limits of detection (LOD) of SCCPs were 18 ng/L, and the corresponding limits of quantitation of SCCPs were 60 ng/L. Recovery experiment showed that, for the water samples spiked with 1 μg/L, the recoveries were in the range of 90%-135% and the relative standard deviations were less than ±10%. Finally, the SCCPs in 20 surficial water samples collected in Beijing were analyzed using the method proposed here. The range of the concentrations of SCCPs was
A method for short-chain chlorinated paraffins (SCCPs) analysis in water samples based on solid-phase extraction (SPE) was developed using gas chromatography coupled with electron capture negative chemical ionization mass spectrometry (GC-ENCI-MS). SPE parameters including the sorbent, elution solvent and elution volume were optimized. Agilent Bond Elut-C18 was precleaned with 3 mL of hexane, 3 mL of methanol and conditioned with 3 mL of H2O before use. After enriched by the cartridge, the sample was washed by 3 mL of methanol (10%, V/V) and eluted by 3 mL of mixture of hexane and dichloromethane (1:1, V/V). The results showed that the limits of detection (LOD) of SCCPs were 18 ng/L, and the corresponding limits of quantitation of SCCPs were 60 ng/L. Recovery experiment showed that, for the water samples spiked with 1 μg/L, the recoveries were in the range of 90%-135% and the relative standard deviations were less than ±10%. Finally, the SCCPs in 20 surficial water samples collected in Beijing were analyzed using the method proposed here. The range of the concentrations of SCCPs was
2018, 46(7): 1109-1115
doi: 10.11895/j.issn.0253-3820.171532
Abstract:
Based on the modification of inlet of a proton transfer reaction time of flight mass spectrometry (PTR-TOF-MS) instrument developed in our laboratory, a new method for real-time and on-line quantitation of volatile organic compounds (VOCs) from human exhalation was established. A 28-day real-time and on-line monitoring of exhaled breath from 23 volunteers (11 male healthy subjects, 11 female healthy subjects and 1 stomach-sick patient) was carried out and the experimental results showed that the major potential VOCs markers were identified as formaldehyde, propylene, acetone, acetaldehyde, isopropanol and isoprene, and their concentrations obeyed the Normal Distribution. The concentrations of formaldehyde, propylene and isopropanol were mainly in the range of 40 to 100 ppb, acetaldehyde in the range of 80 to 180 ppb, acetone in the range of 500 to 1500 ppb, and isoprene in the range of 8 to 20 ppb. Meanwhile, the concentrations for some compounds were different for men and women. Men have higher level of acetone, and women have higher levels of acetaldehyde and isopropanol. In addition, the concentrations of formaldehyde and acetone in the exhaled breath of stomach sicknesses were significantly higher than that in healthy people. Ethanol and acetaldehyde were the main potential markers of exhale breath after drinking alcohol. The acetaldehyde was the major metabolite of ethanol, and the concentration of acetaldehyde changed with the concentration variation of ethanol in degradation process.
Based on the modification of inlet of a proton transfer reaction time of flight mass spectrometry (PTR-TOF-MS) instrument developed in our laboratory, a new method for real-time and on-line quantitation of volatile organic compounds (VOCs) from human exhalation was established. A 28-day real-time and on-line monitoring of exhaled breath from 23 volunteers (11 male healthy subjects, 11 female healthy subjects and 1 stomach-sick patient) was carried out and the experimental results showed that the major potential VOCs markers were identified as formaldehyde, propylene, acetone, acetaldehyde, isopropanol and isoprene, and their concentrations obeyed the Normal Distribution. The concentrations of formaldehyde, propylene and isopropanol were mainly in the range of 40 to 100 ppb, acetaldehyde in the range of 80 to 180 ppb, acetone in the range of 500 to 1500 ppb, and isoprene in the range of 8 to 20 ppb. Meanwhile, the concentrations for some compounds were different for men and women. Men have higher level of acetone, and women have higher levels of acetaldehyde and isopropanol. In addition, the concentrations of formaldehyde and acetone in the exhaled breath of stomach sicknesses were significantly higher than that in healthy people. Ethanol and acetaldehyde were the main potential markers of exhale breath after drinking alcohol. The acetaldehyde was the major metabolite of ethanol, and the concentration of acetaldehyde changed with the concentration variation of ethanol in degradation process.
2018, 46(7): 1116-1121
doi: 10.11895/j.issn.0253-3820.181216
Abstract:
A novel polydimethylsiloxane (PDMS)-poly-L-lysine (PLL) microfluidic chip, comprised of 24 reaction channels with 2.5 μL volume of each reaction channel only, was proposed for quantitative analysis of methamphetamine (MET) based on time-resolved immunoassay techniques. The chip utilized the adsorption characteristics of PDMS and PLL towards proteins to immobilize MET complete antigens (MET-BSA) on the surface of reaction channel. Then the competition reaction could happen between MET-Ag in the sample solution and MET-BSA on the inner surfaces of the reaction channels with MET-Ab in the reagent. The surface of latex microspheres was labeled by lanthanide, which could emit red fluorescence under the exposure of ultraviolet (UV). Based on the principle of competitive immunoassay, the more MET-Ag, the less the fluorescence intensity in the reaction channel. The detection results of this chip were acquired using UV-irradiation fluorescence imaging method. With this method, 24 samples could be detected and analyzed simultaneously on a chip by just taking the fluorescence image of the chip. The method allows the detection of MET antigens ranging from 100 ng/mL to 3000 ng/mL, with less sample consumption and high-throughput. This chip is suitable for the police preliminary screening work and has a good application prospects.
A novel polydimethylsiloxane (PDMS)-poly-L-lysine (PLL) microfluidic chip, comprised of 24 reaction channels with 2.5 μL volume of each reaction channel only, was proposed for quantitative analysis of methamphetamine (MET) based on time-resolved immunoassay techniques. The chip utilized the adsorption characteristics of PDMS and PLL towards proteins to immobilize MET complete antigens (MET-BSA) on the surface of reaction channel. Then the competition reaction could happen between MET-Ag in the sample solution and MET-BSA on the inner surfaces of the reaction channels with MET-Ab in the reagent. The surface of latex microspheres was labeled by lanthanide, which could emit red fluorescence under the exposure of ultraviolet (UV). Based on the principle of competitive immunoassay, the more MET-Ag, the less the fluorescence intensity in the reaction channel. The detection results of this chip were acquired using UV-irradiation fluorescence imaging method. With this method, 24 samples could be detected and analyzed simultaneously on a chip by just taking the fluorescence image of the chip. The method allows the detection of MET antigens ranging from 100 ng/mL to 3000 ng/mL, with less sample consumption and high-throughput. This chip is suitable for the police preliminary screening work and has a good application prospects.
2018, 46(7): 1122-1128
doi: 10.11895/j.issn.0253-3820.171448
Abstract:
Laser induced breakdown spectroscopy (LIBS) was proposed to rapidly discriminate microbe species. Ten species of microbes were prepared in lab. Filter papers were selected as substrate for enriching bacteria and enhancing the quality of LIBS. The images of plasma were collected by ICCD camera and LIBS spectra were obtained by spectrometers. The results displayed that the images and spectra were different from 10 bacteria. It was demonstrated that this method was feasible to discriminate bacteria species by analyzing image and/or spectroscopy. Furthermore, nine smooth and multiple scattering correction (MSC) were utilized to preprocess the LIBS full-spectrum data in the wavelength range of 200-420 nm and 560-680 nm. And principal component analysis (PCA) and PCA-RF (Random forest) were compared to validate the accuracy of discrimination. The investigation showed that the PCA-RF model coupled with suitable methods in preprocessing data could identify bacteria. The accuracy was 99.6% for ten species of microbes by evaluating LIBS spectra in training set, and 96.7% in predicting set. This report indicated that it is feasible to differentiate bacteria species by analyzing LIBS spectras
Laser induced breakdown spectroscopy (LIBS) was proposed to rapidly discriminate microbe species. Ten species of microbes were prepared in lab. Filter papers were selected as substrate for enriching bacteria and enhancing the quality of LIBS. The images of plasma were collected by ICCD camera and LIBS spectra were obtained by spectrometers. The results displayed that the images and spectra were different from 10 bacteria. It was demonstrated that this method was feasible to discriminate bacteria species by analyzing image and/or spectroscopy. Furthermore, nine smooth and multiple scattering correction (MSC) were utilized to preprocess the LIBS full-spectrum data in the wavelength range of 200-420 nm and 560-680 nm. And principal component analysis (PCA) and PCA-RF (Random forest) were compared to validate the accuracy of discrimination. The investigation showed that the PCA-RF model coupled with suitable methods in preprocessing data could identify bacteria. The accuracy was 99.6% for ten species of microbes by evaluating LIBS spectra in training set, and 96.7% in predicting set. This report indicated that it is feasible to differentiate bacteria species by analyzing LIBS spectras
2018, 46(7): 1129-1136
doi: 10.11895/j.issn.0253-3820.181038
Abstract:
An enzyme cascade strategy was introduced for sensitive detection of acid phosphatase (ACP). Pyrophosphate ions (PPi) can strongly bound Fe3+ and thus hinders the production of Prussian blue nanoparticles (PBNPs). ACP can hydrolyze PPi to form phosphate ions, and the released Fe3+ reacts with potassium ferrocyanide (K4[Fe(CN)6]) to form PBNPs. The formed PBNPs have high peroxidase-like activity, which can decompose hydrogen peroxide (H2O2) to produce hydroxyl radical (·OH) for oxidizing the typical substrate of 3,3',5,5'-tetramethylbenzidine (TMB). Therefore, a novel sensing strategy for detecting ACP based on the high signal amplification of enzyme cascade was constructed. The results showed that there was a good linear relationship between the absorbance of oxidized TMB (oxTMB) and the concentration of ACP in the range of 3-20 U/L, with a detection limit of 0.8 U/L. Different from the conventional enzyme cascades in which the product of one enzyme is the substrate of the other, this study opens up a new way to construct novel enzyme cascade system.
An enzyme cascade strategy was introduced for sensitive detection of acid phosphatase (ACP). Pyrophosphate ions (PPi) can strongly bound Fe3+ and thus hinders the production of Prussian blue nanoparticles (PBNPs). ACP can hydrolyze PPi to form phosphate ions, and the released Fe3+ reacts with potassium ferrocyanide (K4[Fe(CN)6]) to form PBNPs. The formed PBNPs have high peroxidase-like activity, which can decompose hydrogen peroxide (H2O2) to produce hydroxyl radical (·OH) for oxidizing the typical substrate of 3,3',5,5'-tetramethylbenzidine (TMB). Therefore, a novel sensing strategy for detecting ACP based on the high signal amplification of enzyme cascade was constructed. The results showed that there was a good linear relationship between the absorbance of oxidized TMB (oxTMB) and the concentration of ACP in the range of 3-20 U/L, with a detection limit of 0.8 U/L. Different from the conventional enzyme cascades in which the product of one enzyme is the substrate of the other, this study opens up a new way to construct novel enzyme cascade system.
2018, 46(7): 1137-1144
doi: 10.11895/j.issn.0253-3820.181098
Abstract:
An analytical method was developed for determination of low-level uranium isotopes in vegetation samples. Dry ashing method was employed to decompose organic matters of vegetation. The sample ash was further digested using multiple acids. Uranium in the prepared sample solution was separated and purified by an extraction chromatography using UTEVA resin. The chemical recovery of uranium in the separation procedure was more than 94%, and more than 99% of Na, K, Ca and other matrix elements and interfering elements were removed. Three natural uranium isotopes were finally measured with high sensitivity ICP-MS/MS. The detection limits of the method for 238U, 235U, 234U were 3.05, 0.34 and 0.04 pg/g, respectively. The detection limits for 238U and 235U were 10 times better than the reported values. Analysis result of U in GBW-10046 standard reference material was in good agreement with reference value, indicating that this method was reliable. The method was successfully applied to determination of uranium isotopes in the vegetation samples collected in Xi'an region, and it was found that the uranium concentrations and isotopic ratios in these vegetation samples fall well into natural level, and there was no significant artificial uranium contamination. This was the first survey of the three natural uranium isotopes in vegetation samples in this region.
An analytical method was developed for determination of low-level uranium isotopes in vegetation samples. Dry ashing method was employed to decompose organic matters of vegetation. The sample ash was further digested using multiple acids. Uranium in the prepared sample solution was separated and purified by an extraction chromatography using UTEVA resin. The chemical recovery of uranium in the separation procedure was more than 94%, and more than 99% of Na, K, Ca and other matrix elements and interfering elements were removed. Three natural uranium isotopes were finally measured with high sensitivity ICP-MS/MS. The detection limits of the method for 238U, 235U, 234U were 3.05, 0.34 and 0.04 pg/g, respectively. The detection limits for 238U and 235U were 10 times better than the reported values. Analysis result of U in GBW-10046 standard reference material was in good agreement with reference value, indicating that this method was reliable. The method was successfully applied to determination of uranium isotopes in the vegetation samples collected in Xi'an region, and it was found that the uranium concentrations and isotopic ratios in these vegetation samples fall well into natural level, and there was no significant artificial uranium contamination. This was the first survey of the three natural uranium isotopes in vegetation samples in this region.
2018, 46(7): 1145-1151,1159
doi: 10.11895/j.issn.0253-3820.171510
Abstract:
Molecular mechanisms whereby H2S influences its targets have been of intriguing interest. In this work, L-lactic dehydrogenase (L-LDH) was used as the protein target, and three kinds of H2S-donor reagents (NaHS, Na2S, and polysulfide) were chosen. The interactions of these H2S-donor reagents with L-LDH were disclosed by molecular fluorescent assays for real-time monitoring of L-LDH activity. The results of the SDS-PAGE showed that H2S might not interact with L-LDH to form disulfide/trisulfide bonding. Circular dichroism spectra assays revealed that H2S reagents could be likely to react with cysteine thiols to yield sulfurated thiol (-SSH) derivatives in L-LDH, and sulfur-containing PS (polysulfide) was a stronger protein S-sulfurating agent than the other two sulfides. Matrix assisted laser desorptionionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) study showed partial S-sulfuration of the active cysteine sites existed in L-LDH. In conclusion, H2S exerts its biological effects as a gasotransmitter through its reactions with cysteine thiols in proteins by S-sulfuration.
Molecular mechanisms whereby H2S influences its targets have been of intriguing interest. In this work, L-lactic dehydrogenase (L-LDH) was used as the protein target, and three kinds of H2S-donor reagents (NaHS, Na2S, and polysulfide) were chosen. The interactions of these H2S-donor reagents with L-LDH were disclosed by molecular fluorescent assays for real-time monitoring of L-LDH activity. The results of the SDS-PAGE showed that H2S might not interact with L-LDH to form disulfide/trisulfide bonding. Circular dichroism spectra assays revealed that H2S reagents could be likely to react with cysteine thiols to yield sulfurated thiol (-SSH) derivatives in L-LDH, and sulfur-containing PS (polysulfide) was a stronger protein S-sulfurating agent than the other two sulfides. Matrix assisted laser desorptionionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) study showed partial S-sulfuration of the active cysteine sites existed in L-LDH. In conclusion, H2S exerts its biological effects as a gasotransmitter through its reactions with cysteine thiols in proteins by S-sulfuration.
2018, 46(7): 1152-1159
doi: 10.11895/j.issn.0253-3820.171394
Abstract:
Differential proteomics analysis of Sika deer antlers at rapid growth stage (60 d) and ossification stage (90 d) was performed by isobaric tags for relative and absolute quantitation (iTRAQ), ultra high performance liquid chromatography and mass spectrometry technologies. A total of 127 differential proteins were identified. Compared with the ossification stage, 80 differential proteins were significantly up-regulated and 47 differential proteins were significantly down-regulated at the rapid growth stage. These differential proteins were mainly distributed in the regions of extracellular matrix, nucleosome, haptoglobin-hemoglobin complex, actin filament, endoplasmic reticulum-Golgi intermediate compartment, endoplasmic reticulum lumen, and endometrium, etc. The up-regulated differential proteins were mainly involved in the regulations of oxygen transport in the blood, nerve growth and regeneration, cartilage and bone development and ATP synthesis compared with ossification stage, and the down-regulated differential proteins were mainly involved in the endochondral ossification process. The changes of protein expression at different growth stages were closely related to antler rapid growth and ossification. Therefore, the results of this study provided a basic data for discovering the molecular mechanisms of antler rapid growth and ossification, and it was of great significance for further study of the pharmacological basis and clinical application of antlers.
Differential proteomics analysis of Sika deer antlers at rapid growth stage (60 d) and ossification stage (90 d) was performed by isobaric tags for relative and absolute quantitation (iTRAQ), ultra high performance liquid chromatography and mass spectrometry technologies. A total of 127 differential proteins were identified. Compared with the ossification stage, 80 differential proteins were significantly up-regulated and 47 differential proteins were significantly down-regulated at the rapid growth stage. These differential proteins were mainly distributed in the regions of extracellular matrix, nucleosome, haptoglobin-hemoglobin complex, actin filament, endoplasmic reticulum-Golgi intermediate compartment, endoplasmic reticulum lumen, and endometrium, etc. The up-regulated differential proteins were mainly involved in the regulations of oxygen transport in the blood, nerve growth and regeneration, cartilage and bone development and ATP synthesis compared with ossification stage, and the down-regulated differential proteins were mainly involved in the endochondral ossification process. The changes of protein expression at different growth stages were closely related to antler rapid growth and ossification. Therefore, the results of this study provided a basic data for discovering the molecular mechanisms of antler rapid growth and ossification, and it was of great significance for further study of the pharmacological basis and clinical application of antlers.
