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2019 Volume 47 Issue 8
2019, 47(8): 1125-1133
doi: 10.19756/j.issn.0253-3820.191194
Abstract:
As a soft ionization mass spectrometry technique, matrix-assisted laser desorption/ionization mass spectrometry can quickly and reliably obtain information of molecular composition and structure from plant tissues, especially the information of component distribution through imaging. Therefore, it has attracted more and more attention in the analysis of medicinal plants. In this paper, the application of MALDI-MS imaging technology in the analysis of medicinal plants was summarized and prospected.
As a soft ionization mass spectrometry technique, matrix-assisted laser desorption/ionization mass spectrometry can quickly and reliably obtain information of molecular composition and structure from plant tissues, especially the information of component distribution through imaging. Therefore, it has attracted more and more attention in the analysis of medicinal plants. In this paper, the application of MALDI-MS imaging technology in the analysis of medicinal plants was summarized and prospected.
2019, 47(8): 1134-1144
doi: 10.19756/j.issn.0253-3820.191199
Abstract:
Lipid vesicles, composed of cell membrane components, are commonly used as an artificial cell model to mimic cell structure and functions. They have also been widely used in biological analysis. Liposome array is a high throughput platform for protein screening and bio-sensing. This review focuses on the preparation methods of homogeneous small lipid vesicle array, heterogeneous small lipid vesicle array, and giant lipid vesicle array, as well as their applications in antibiotics detection, enzymatic reactions, interactions between membrane proteins and lipid membranes. Besides, the advantages and disadvantages of the reported methods are summarized and the future directions in this field are proposed.
Lipid vesicles, composed of cell membrane components, are commonly used as an artificial cell model to mimic cell structure and functions. They have also been widely used in biological analysis. Liposome array is a high throughput platform for protein screening and bio-sensing. This review focuses on the preparation methods of homogeneous small lipid vesicle array, heterogeneous small lipid vesicle array, and giant lipid vesicle array, as well as their applications in antibiotics detection, enzymatic reactions, interactions between membrane proteins and lipid membranes. Besides, the advantages and disadvantages of the reported methods are summarized and the future directions in this field are proposed.
2019, 47(8): 1145-1152
doi: 10.19756/j.issn.0253-3820.191314
Abstract:
The triangular-electrode linear ion trap (TeLIT) has many advantages such as simple structure, easy processing and high quality analysis performance. In this work, the internal electric field composition and mass analysis ability of two asymmetric TeLIT were explored by using theoretical simulation method, including (1) two electrodes in the direction of the ion exiting had the same angle but differ with the other two identical electrodes, and (2) one electrode in the direction of the ion exiting had the different angle compared with the other three identical electrodes. The simulation results showed that when one triangular-electrode with the angle of 137° in the direction of the ion exiting and the other three with the angle of 140°, odd and even order fields were introduced simultaneously in the linear ion trap, and when the scanning speed were 1900 Da/s and at m/z 609 Da, the mass resolution could reach 7186. The sensitivity and accuracy of the linear ion trap was also improved.
The triangular-electrode linear ion trap (TeLIT) has many advantages such as simple structure, easy processing and high quality analysis performance. In this work, the internal electric field composition and mass analysis ability of two asymmetric TeLIT were explored by using theoretical simulation method, including (1) two electrodes in the direction of the ion exiting had the same angle but differ with the other two identical electrodes, and (2) one electrode in the direction of the ion exiting had the different angle compared with the other three identical electrodes. The simulation results showed that when one triangular-electrode with the angle of 137° in the direction of the ion exiting and the other three with the angle of 140°, odd and even order fields were introduced simultaneously in the linear ion trap, and when the scanning speed were 1900 Da/s and at m/z 609 Da, the mass resolution could reach 7186. The sensitivity and accuracy of the linear ion trap was also improved.
2019, 47(8): 1153-1161
doi: 10.19756/j.issn.0253-3820.191209
Abstract:
With the development of fragmentation technology for complete protein and its application in top-down (TD) proteomics, tandem mass spectrometry of complete protein ions also provides more abundant fragment information than before. Therefore, the development of algorithms for automatic analysis of fragment ions has become an indispensable part of top-down proteomics. In this study, a software, Nan Kai top-down (NKTD), was developed to analyze the top-down mass spectrometry data. The main feature of this software was to identify overlapping peaks by using the method of "one to many" to find isotope clusters. The results of postprocessing and analysis of the identified ions were helpful for investigation of the fragment ion information of protein ions produced by different fragmentation techniques. This software was used to analyze the data of ubiquitin protein ions in IRMPD and UVPD. The results showed that the fragment ions produced by the UVPD method were abundant in variety and the coverage of the cleavage site was much better than that by the IRMPD method. More importantly, the differences between the two methods made them very complementary in the top-down mass spectrometry.
With the development of fragmentation technology for complete protein and its application in top-down (TD) proteomics, tandem mass spectrometry of complete protein ions also provides more abundant fragment information than before. Therefore, the development of algorithms for automatic analysis of fragment ions has become an indispensable part of top-down proteomics. In this study, a software, Nan Kai top-down (NKTD), was developed to analyze the top-down mass spectrometry data. The main feature of this software was to identify overlapping peaks by using the method of "one to many" to find isotope clusters. The results of postprocessing and analysis of the identified ions were helpful for investigation of the fragment ion information of protein ions produced by different fragmentation techniques. This software was used to analyze the data of ubiquitin protein ions in IRMPD and UVPD. The results showed that the fragment ions produced by the UVPD method were abundant in variety and the coverage of the cleavage site was much better than that by the IRMPD method. More importantly, the differences between the two methods made them very complementary in the top-down mass spectrometry.
2019, 47(8): 1162-1169
doi: 10.19756/j.issn.0253-3820.191304
Abstract:
The method for detection of circulating tumor cells (CTCs) is considered as a promising cancer liquid biopsy technique. However, due to the rarity and heterogeneity, it is still a challenging task to capture CTCs with high purity and viability from blood for the following enumeration and molecular analysis. Herein, we fabricated a hydrogel-chitosan nanofiber substrate to effectively capture the target cancer cells, assisted by the poly(carboxybetaine methacrylate) (PCBMA) hydrogel and the anti-epithelial cell adhesion molecule (anti-EpCAM) antibody. The PCBMA hydrogel layer was fabricated by free radical polymerization to provide an antifouling surface, which could help to reduce the non-specific capture of blood cells to improve the capture purity of CTCs. Then, chitosan nanofibers were introduced onto the hydrogel layer to provide a nanostructured surface to improve the capture efficiency. Finally, the capture yield of artificial blood samples on the anti-EpCAM modified hydrogel-nanofiber substrate was up to 79.9%, revealing the potential application of the hydrogel-nanofiber substrate on efficient and sensitive capture of rare circulating tumor cells.
The method for detection of circulating tumor cells (CTCs) is considered as a promising cancer liquid biopsy technique. However, due to the rarity and heterogeneity, it is still a challenging task to capture CTCs with high purity and viability from blood for the following enumeration and molecular analysis. Herein, we fabricated a hydrogel-chitosan nanofiber substrate to effectively capture the target cancer cells, assisted by the poly(carboxybetaine methacrylate) (PCBMA) hydrogel and the anti-epithelial cell adhesion molecule (anti-EpCAM) antibody. The PCBMA hydrogel layer was fabricated by free radical polymerization to provide an antifouling surface, which could help to reduce the non-specific capture of blood cells to improve the capture purity of CTCs. Then, chitosan nanofibers were introduced onto the hydrogel layer to provide a nanostructured surface to improve the capture efficiency. Finally, the capture yield of artificial blood samples on the anti-EpCAM modified hydrogel-nanofiber substrate was up to 79.9%, revealing the potential application of the hydrogel-nanofiber substrate on efficient and sensitive capture of rare circulating tumor cells.
2019, 47(8): 1170-1179
doi: 10.19756/j.issn.0253-3820.191107
Abstract:
In recent years, perylene diimide (PDI) derivatives have attracted enormous attentions owing to their favorable properties as the alternative electron acceptor to PCBM in bulk heterojunction (BHJ) materials. It has been noted that the molecular local arrangement largely affects the performance of the BHJ devices. In this work, two PDI derivatives (named PDI and PDI) and their blends with poly(3-hexylthiophene)(P3HT) were investigated by using advanced solid state nuclear magnetic resonance(SSNMR). The 1H-1H SQ-DQ spectra revealed that both PDI and PDI molecules had ordered arrangement through π-π interaction. PDI showed higher molecular ordering than PDI. The blends of PDI and P3HT(PDI:P3HT) as well as PDI and P3HT(PDI:P3HT) were also investigated. Based on the features of 13C-1H frequency switched Lee-Goldburg heteronuclear dipolar-correlation spectroscopy (FSLG-HETOCR) spectra, we revealed the phase-segregated structures for both PDI:P3HT and PDI:P3HT. Moreover, PDI exhibited reduced local ordering when blended with P3HT. Whilst PDI demonstrated different molecular local assembling structure. By fitting the BaBa DQ sideband pattern, the inter-nuclear distance of two neighboring PDI molecules was calculated. The interfacial information of PDI:P3HT was also obtained from 1D 13C{1H} CP and 13C-1H FSLG-HETOCR spectra. Based on the 13C chemical shifts and 13C-1H correlation peaks, we suggested that in the interfacial area the PDI imide alkyl units located in the shielding zone of P3HT thiophene rings. The quantitative local mobility study was conducted through analyzing the rotor-encoded rotational echo double resonance (REREDOR) data. The deduced heteronuclear coupling constants via fitting the sideband patterns showed identical trend as the findings from the structural characterization. In addition to the structural investigation, this work suggested a possible characterizing strategy by using SSNMR techniques for the PDI based materials or other conjugated systems.
In recent years, perylene diimide (PDI) derivatives have attracted enormous attentions owing to their favorable properties as the alternative electron acceptor to PCBM in bulk heterojunction (BHJ) materials. It has been noted that the molecular local arrangement largely affects the performance of the BHJ devices. In this work, two PDI derivatives (named PDI and PDI) and their blends with poly(3-hexylthiophene)(P3HT) were investigated by using advanced solid state nuclear magnetic resonance(SSNMR). The 1H-1H SQ-DQ spectra revealed that both PDI and PDI molecules had ordered arrangement through π-π interaction. PDI showed higher molecular ordering than PDI. The blends of PDI and P3HT(PDI:P3HT) as well as PDI and P3HT(PDI:P3HT) were also investigated. Based on the features of 13C-1H frequency switched Lee-Goldburg heteronuclear dipolar-correlation spectroscopy (FSLG-HETOCR) spectra, we revealed the phase-segregated structures for both PDI:P3HT and PDI:P3HT. Moreover, PDI exhibited reduced local ordering when blended with P3HT. Whilst PDI demonstrated different molecular local assembling structure. By fitting the BaBa DQ sideband pattern, the inter-nuclear distance of two neighboring PDI molecules was calculated. The interfacial information of PDI:P3HT was also obtained from 1D 13C{1H} CP and 13C-1H FSLG-HETOCR spectra. Based on the 13C chemical shifts and 13C-1H correlation peaks, we suggested that in the interfacial area the PDI imide alkyl units located in the shielding zone of P3HT thiophene rings. The quantitative local mobility study was conducted through analyzing the rotor-encoded rotational echo double resonance (REREDOR) data. The deduced heteronuclear coupling constants via fitting the sideband patterns showed identical trend as the findings from the structural characterization. In addition to the structural investigation, this work suggested a possible characterizing strategy by using SSNMR techniques for the PDI based materials or other conjugated systems.
2019, 47(8): 1180-1187
doi: 10.19756/j.issn.0253-3820.191250
Abstract:
The Cu metal organic framework (MOFs) material, copper-benzene-1,3,5-tricarboxylate (Cu-BTC) modified electrode was constructed by anchoring Cu-BTC on the surface of gold electrode (Au) with the aid of 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM) (Cu-BTC/MPA/Au). The direct electrochemistry of Cu-BTC was realized on the above-mentioned electrode. Fourier transform infrared spectroscopy, scanning electron spectroscopy (SEM) and powder X-ray diffraction (XRD) were used to characterize the MPA SAM and Cu-BTC. Also, SEM and energy dispersive X-ray spectrometry (EDS) were used to characterize Cu-BTC/MPA/Au. The electrochemical properties of Cu-BTC/MPA/Au were characterized by cyclic voltammetry and electrochemical impedance spectroscopy (EIS), and it was found that the electrode had a relatively higher electron transport rate. The results also showed that a short SAM, the MPA SAM, resulted in the faster direct electron transfer of Cu-BTC. The method of anchoring MOFs with self-assembled membrane provided a new insight into the direct electron-transfer process of the Cu-BTC.
The Cu metal organic framework (MOFs) material, copper-benzene-1,3,5-tricarboxylate (Cu-BTC) modified electrode was constructed by anchoring Cu-BTC on the surface of gold electrode (Au) with the aid of 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM) (Cu-BTC/MPA/Au). The direct electrochemistry of Cu-BTC was realized on the above-mentioned electrode. Fourier transform infrared spectroscopy, scanning electron spectroscopy (SEM) and powder X-ray diffraction (XRD) were used to characterize the MPA SAM and Cu-BTC. Also, SEM and energy dispersive X-ray spectrometry (EDS) were used to characterize Cu-BTC/MPA/Au. The electrochemical properties of Cu-BTC/MPA/Au were characterized by cyclic voltammetry and electrochemical impedance spectroscopy (EIS), and it was found that the electrode had a relatively higher electron transport rate. The results also showed that a short SAM, the MPA SAM, resulted in the faster direct electron transfer of Cu-BTC. The method of anchoring MOFs with self-assembled membrane provided a new insight into the direct electron-transfer process of the Cu-BTC.
2019, 47(8): 1188-1194
doi: 10.19756/j.issn.0253-3820.191231
Abstract:
A binder-free efficient sulphur indium zinc nanosheets coating titanium dioxide nanorods on conductive fluorine-doped tin oxide substrate electrode (TiO2 NRs@ZnIn2S4 NSs/FTO) was developed by simple two-steps hydrothermal method. The morphology, structure and element composition of the as-prepared materials was characterized by scanning electron microscopy, X-ray diffraction, X-ray energy-dispersive spectroscopy and UV-visible diffuse reflectance spectroscopy, respectively. A novel glutathione (GSH) photoelectrochemical (PEC) sensor was fabricated based on TiO2 NRs@ZnIn2S4 NSs/FTO modified electrode. The properties of the PEC sensor were studied via current-time curve (i-t) and electrochemical impedance spectroscopy techniques. Under the optimal conditions, GSH concentration in the range of 1-130 μmol/L had a good linear relationship with photocurrent (R=0.9919), and the detection limit was 0.1 μmol/L (S/N=3). The fabricated PEC sensor exhibited good selectivity, high stability, and high reproducibility. Moreover, This PEC sensor was successfully applied to detection of GSH in glutathione tablets and reduced GSH for injection samples with favorable recoveries of 99%-110%.
A binder-free efficient sulphur indium zinc nanosheets coating titanium dioxide nanorods on conductive fluorine-doped tin oxide substrate electrode (TiO2 NRs@ZnIn2S4 NSs/FTO) was developed by simple two-steps hydrothermal method. The morphology, structure and element composition of the as-prepared materials was characterized by scanning electron microscopy, X-ray diffraction, X-ray energy-dispersive spectroscopy and UV-visible diffuse reflectance spectroscopy, respectively. A novel glutathione (GSH) photoelectrochemical (PEC) sensor was fabricated based on TiO2 NRs@ZnIn2S4 NSs/FTO modified electrode. The properties of the PEC sensor were studied via current-time curve (i-t) and electrochemical impedance spectroscopy techniques. Under the optimal conditions, GSH concentration in the range of 1-130 μmol/L had a good linear relationship with photocurrent (R=0.9919), and the detection limit was 0.1 μmol/L (S/N=3). The fabricated PEC sensor exhibited good selectivity, high stability, and high reproducibility. Moreover, This PEC sensor was successfully applied to detection of GSH in glutathione tablets and reduced GSH for injection samples with favorable recoveries of 99%-110%.
2019, 47(8): 1195-1204
doi: 10.19756/j.issn.0253-3820.181714
Abstract:
Cobaltosic oxide (Co3O4) nanoparticles were synthesized by solvothermal method, which were applied to prepare Co3O4-MWCNTs nanocomposites multi-walled carbon nanotubes (MWCNTs) by ultrasonic assisted method. Then, glassy carbon electrode (GCE) was modified with the nanocomposites (Co3O4-MWCNTs/GCE) as anode for the preparation of phenol/O2 fuel cell. The morphology of the prepared materials was characterized by scanning electron microscopy, transmission electron microscopy and X-ray powder diffraction. In addition, the cyclic voltammetric response characteristics of phenol on different electrodes (GCE, MWCNTs/GCE, Co3O4/GCE and Co3O4-MWCNTs/GCE) were investigated. The electrochemical response signals at different scan rates (20-120 mV/s) and different concentrations (60-300 mg/L) of phenol on Co3O4-MWCNTs modified electrodes were also investigated. The results of electrochemical test showed that Co3O4-MWCNTs nanocomposites had better electrocatalytic performance for the oxidization of phenol than that of simplex Co3O4 or MWCNTs. The platinum film was electrodeposited by cyclic voltammetry as a cathode oxygen reduction catalyst, and a platinum film-modified glassy carbon electrode (Pt/GCE) was obtained after 30 CV deposition cycles. A phenol/O2 biofuel cell was thus constructed with Co3O4-MWCNTs/GCE as anode and Pt/GCE as cathode. The open circuit potential (OCP) of the fuel cell was 0.44 V and the maximal power density (Pmax) measured at 0.35 V was 0.27 mW/cm2 when the phenol concentration was 500 mg/L, exhibiting good application potential.
Cobaltosic oxide (Co3O4) nanoparticles were synthesized by solvothermal method, which were applied to prepare Co3O4-MWCNTs nanocomposites multi-walled carbon nanotubes (MWCNTs) by ultrasonic assisted method. Then, glassy carbon electrode (GCE) was modified with the nanocomposites (Co3O4-MWCNTs/GCE) as anode for the preparation of phenol/O2 fuel cell. The morphology of the prepared materials was characterized by scanning electron microscopy, transmission electron microscopy and X-ray powder diffraction. In addition, the cyclic voltammetric response characteristics of phenol on different electrodes (GCE, MWCNTs/GCE, Co3O4/GCE and Co3O4-MWCNTs/GCE) were investigated. The electrochemical response signals at different scan rates (20-120 mV/s) and different concentrations (60-300 mg/L) of phenol on Co3O4-MWCNTs modified electrodes were also investigated. The results of electrochemical test showed that Co3O4-MWCNTs nanocomposites had better electrocatalytic performance for the oxidization of phenol than that of simplex Co3O4 or MWCNTs. The platinum film was electrodeposited by cyclic voltammetry as a cathode oxygen reduction catalyst, and a platinum film-modified glassy carbon electrode (Pt/GCE) was obtained after 30 CV deposition cycles. A phenol/O2 biofuel cell was thus constructed with Co3O4-MWCNTs/GCE as anode and Pt/GCE as cathode. The open circuit potential (OCP) of the fuel cell was 0.44 V and the maximal power density (Pmax) measured at 0.35 V was 0.27 mW/cm2 when the phenol concentration was 500 mg/L, exhibiting good application potential.
2019, 47(8): 1205-1211
doi: 10.19756/j.issn.0253-3820.191177
Abstract:
Attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) has attracted more and more attention in many fields due to its unique advantages. However, the lack of simple-preparation, low-cost and high-sensitivity enhancing substrates limits the further development and wider application of surface-enhanced infrared spectroscopy technology. In this study, a mountain-like silver nanostructure was prepared by chemical deposition of silver nanoparticles followed by a simple ligand inducing. Theoretical electromagnetic field simulation by finite difference time domain (FDTD) revealed that as-prepared nanostructure could effectively couple with infrared photon and produce a strong local electromagnetic field, showing great potential of serving as enhancing substrate in infrared spectroscopy. SEIRAS results showed that the enhancement factor of as-prepared substrate to the model molecule (p-aminothiophenol) was higher than that of the traditional widely used gold nano-island film, and could be used to in situ quantitatively analyze bovine serum albumin in solution in the range of 5×10-10 mol/L-4×10-7 mol/L, showing great potential in infrared sensor.
Attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) has attracted more and more attention in many fields due to its unique advantages. However, the lack of simple-preparation, low-cost and high-sensitivity enhancing substrates limits the further development and wider application of surface-enhanced infrared spectroscopy technology. In this study, a mountain-like silver nanostructure was prepared by chemical deposition of silver nanoparticles followed by a simple ligand inducing. Theoretical electromagnetic field simulation by finite difference time domain (FDTD) revealed that as-prepared nanostructure could effectively couple with infrared photon and produce a strong local electromagnetic field, showing great potential of serving as enhancing substrate in infrared spectroscopy. SEIRAS results showed that the enhancement factor of as-prepared substrate to the model molecule (p-aminothiophenol) was higher than that of the traditional widely used gold nano-island film, and could be used to in situ quantitatively analyze bovine serum albumin in solution in the range of 5×10-10 mol/L-4×10-7 mol/L, showing great potential in infrared sensor.
2019, 47(8): 1212-1218
doi: 10.19756/j.issn.0253-3820.191118
Abstract:
The emodin and its metabolites in serum of renal interstitial fibrosis rats were separated on a Thermo Scientific Hypersil GLOD column with the mixture of 0.1% formic acid water and acetonitrile as the mobile phase, and then analyzed by ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). In this study, an integrated qualitative strategy was proposed to identify the target metabolites of active pharmaceutical ingredients in vivo, which combined mass defect, neutral loss, and diagnostic fragment ion filtering. The method was applied to the identification of metabolites of emodin in rat blood, and 11 metabolites were determined accurately, 39 possible metabolites were tentatively identified. The result shows that the metabolism pathways of emodin in rats were mainly oxidation and hydroxylation in phase Ι, and sulfation and glucuronidation in phase Ⅱ. The integrated qualitative strategy proposed here could effectively reduce matrix interference and interfering ions in the qualitative process, thus improveing the efficiency and accuracy of qualitative analysis of metabolites.
The emodin and its metabolites in serum of renal interstitial fibrosis rats were separated on a Thermo Scientific Hypersil GLOD column with the mixture of 0.1% formic acid water and acetonitrile as the mobile phase, and then analyzed by ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). In this study, an integrated qualitative strategy was proposed to identify the target metabolites of active pharmaceutical ingredients in vivo, which combined mass defect, neutral loss, and diagnostic fragment ion filtering. The method was applied to the identification of metabolites of emodin in rat blood, and 11 metabolites were determined accurately, 39 possible metabolites were tentatively identified. The result shows that the metabolism pathways of emodin in rats were mainly oxidation and hydroxylation in phase Ι, and sulfation and glucuronidation in phase Ⅱ. The integrated qualitative strategy proposed here could effectively reduce matrix interference and interfering ions in the qualitative process, thus improveing the efficiency and accuracy of qualitative analysis of metabolites.
2019, 47(8): 1219-1226
doi: 10.19756/j.issn.0253-3820.191056
Abstract:
Four chiral bifunctional squaramide fluorescent probes were synthesized, including new compounds 1 and 3, and known compounds 2 and 4, and their structure were confirmed by 1H NMR, 13C NMR and HRMS spectra. The fluorescence chiral recognition effects of these four probes on Boc-phenylalanine, phenylalanine, phenylglycine, proline, valine, tartaric acid, mandelic acid, and binaphthol were systematically investigated by fluorescence spectroscopy. By combinatorial screening, it was found that the probe 4 had good recognition effect on valine. Further research showed that the fluorescence peak showed a sharp blue shift and the fluorescence intensity was greatly reduced after addition of L-valine at 1:2 molar ratio of probe 4 to valine. By contrast, there was no obvious change on the fluorescence intensity after addition of D-valine, and the fluorescence intensity ratio (ID/IL) value was up to 1.35. Based on this, a two-chiral-centers recognition mechanism was proposed. The tertiary amine and squaramide group of the probe 4 separately combined with one molecule of L-valine by electrostatic and hydrogen bonding interactions.
Four chiral bifunctional squaramide fluorescent probes were synthesized, including new compounds 1 and 3, and known compounds 2 and 4, and their structure were confirmed by 1H NMR, 13C NMR and HRMS spectra. The fluorescence chiral recognition effects of these four probes on Boc-phenylalanine, phenylalanine, phenylglycine, proline, valine, tartaric acid, mandelic acid, and binaphthol were systematically investigated by fluorescence spectroscopy. By combinatorial screening, it was found that the probe 4 had good recognition effect on valine. Further research showed that the fluorescence peak showed a sharp blue shift and the fluorescence intensity was greatly reduced after addition of L-valine at 1:2 molar ratio of probe 4 to valine. By contrast, there was no obvious change on the fluorescence intensity after addition of D-valine, and the fluorescence intensity ratio (ID/IL) value was up to 1.35. Based on this, a two-chiral-centers recognition mechanism was proposed. The tertiary amine and squaramide group of the probe 4 separately combined with one molecule of L-valine by electrostatic and hydrogen bonding interactions.
2019, 47(8): 1227-1234
doi: 10.19756/j.issn.0253-3820.181816
Abstract:
A new method for screening pesticide residues in agricultural products by gas chromatography-electrostatic field orbitrap high resolution mass spectrometry (Orbitrap GC-MS) was developed. The samples were extracted with acetonitrile (dry sample soaked in water first), and then purified with SinChERS-Nano column. Accurate mass measurements of the target pesticide compounds in full scan mode could eliminate matrix interference effectively. A total of 12 kinds of typical samples (leek, rape, cucumber, cabbage, citrus, apple, grape, tomato, mushroom, rice, soybean and peanut) were evaluated. The linear ranges of the 70 kinds of pesticides were form 0.5 to 200 μg/kg with good correlation coefficients of greater than 0.9950. The limits of detection (LODs) were 0.3-3.0 μg/kg and the limits of quantification (LOQs) were 1.0-10.0 μg/kg. The average recoveries at three spiked levels were in the range of 73.2%-123.4%, 72.4%-121.3%, 73.8%-112.6% and 73.5%-122.3% in leek, mushroom, rice and peanut, respectively, with relative standard deviations (RSDs) of 2.2%-11.3%, 2.4%-11.1%, 3.2%-11.3% and 3.3%-11.1%. The method was simple and sensitive, and suitable for the rapid screening and confirmation of multi-residue pesticides in agricultural products.
A new method for screening pesticide residues in agricultural products by gas chromatography-electrostatic field orbitrap high resolution mass spectrometry (Orbitrap GC-MS) was developed. The samples were extracted with acetonitrile (dry sample soaked in water first), and then purified with SinChERS-Nano column. Accurate mass measurements of the target pesticide compounds in full scan mode could eliminate matrix interference effectively. A total of 12 kinds of typical samples (leek, rape, cucumber, cabbage, citrus, apple, grape, tomato, mushroom, rice, soybean and peanut) were evaluated. The linear ranges of the 70 kinds of pesticides were form 0.5 to 200 μg/kg with good correlation coefficients of greater than 0.9950. The limits of detection (LODs) were 0.3-3.0 μg/kg and the limits of quantification (LOQs) were 1.0-10.0 μg/kg. The average recoveries at three spiked levels were in the range of 73.2%-123.4%, 72.4%-121.3%, 73.8%-112.6% and 73.5%-122.3% in leek, mushroom, rice and peanut, respectively, with relative standard deviations (RSDs) of 2.2%-11.3%, 2.4%-11.1%, 3.2%-11.3% and 3.3%-11.1%. The method was simple and sensitive, and suitable for the rapid screening and confirmation of multi-residue pesticides in agricultural products.
Preparation and Properties Study of Inclusion Complex of Triptonide with 2,6-Dimethyl-β-cyclodextrin
2019, 47(8): 1235-1242
doi: 10.19756/j.issn.0253-3820.191112
Abstract:
The inclusion complex of triptonide (TN) and 2,6-dimethyl-β-cyclodextrin (DM-β-CD) was prepared by saturated aqueous solution method. The TN/DM-β-CD inclusion complex was characterized by FTIR, XRD, SEM, and TG, the possible inclusion mode was inferred by 1H NMR and 2D ROESY. The Job's plot showed that the inclusion ratio of host and guest was 1:1. The stability constant was determined by UV absorbance spectra as 2891 L/mol. The result showed that the DM-β-CD was able to solubilize TN to level as high as 2.7 mg/mL. The water solubility of inclusion complex increased 150 times. In vitro release experiments showed that the cumulative release rate of the inclusion complex reached 70% in 12 h, while the cumulative release rate of TN reached 70% in 120 h. The inclusion complex would have important applications in medical field with higher activity, higher solubility and lower toxicity.
The inclusion complex of triptonide (TN) and 2,6-dimethyl-β-cyclodextrin (DM-β-CD) was prepared by saturated aqueous solution method. The TN/DM-β-CD inclusion complex was characterized by FTIR, XRD, SEM, and TG, the possible inclusion mode was inferred by 1H NMR and 2D ROESY. The Job's plot showed that the inclusion ratio of host and guest was 1:1. The stability constant was determined by UV absorbance spectra as 2891 L/mol. The result showed that the DM-β-CD was able to solubilize TN to level as high as 2.7 mg/mL. The water solubility of inclusion complex increased 150 times. In vitro release experiments showed that the cumulative release rate of the inclusion complex reached 70% in 12 h, while the cumulative release rate of TN reached 70% in 120 h. The inclusion complex would have important applications in medical field with higher activity, higher solubility and lower toxicity.
2019, 47(8): 1243-1248
doi: 10.19756/j.issn.0253-3820.191020
Abstract:
In the purification process of zinc hydrometallurgy, the concentration ratio of zinc to trace nickel ion may reach up to as high as 105, and the overlap peaks of zinc and nickel ions are serious, so that the signal of nickel ion is completely masked by the signal of high concentrated zinc ion, resulting in low sensitivity in detection of nickel ion, and the absorbance and concentration of nickel ion exhibit a strong nonlinear relationship. In this work, aiming at the issue of difficult detection of nickel ion in high concentrated zinc ion solution, an extended Kalman filter (EKF) optimum method based on UV-vis spectrometry for determination of trace nickel in high concentrated zinc ion solution was proposed. Firstly, the standard solution of nickel was prepared, and the nonlinear model of nickel ion was established to obtain the absorption coefficient matrix. Then the filter interval was selected by setting the threshold of correlation coefficient. Finally, the concentration of nickel ion was detected by EKF method. The detection range of nickel ion was 0.3-6.0 mg/L, the RMSEP of nickel was 0.145, and the average relative deviation was 3.9%. The results showed that the method was fast, easy to operate and suitable for real-time detection and control of nickel ion quanlification in the purification process of zinc hydrometallurgy.
In the purification process of zinc hydrometallurgy, the concentration ratio of zinc to trace nickel ion may reach up to as high as 105, and the overlap peaks of zinc and nickel ions are serious, so that the signal of nickel ion is completely masked by the signal of high concentrated zinc ion, resulting in low sensitivity in detection of nickel ion, and the absorbance and concentration of nickel ion exhibit a strong nonlinear relationship. In this work, aiming at the issue of difficult detection of nickel ion in high concentrated zinc ion solution, an extended Kalman filter (EKF) optimum method based on UV-vis spectrometry for determination of trace nickel in high concentrated zinc ion solution was proposed. Firstly, the standard solution of nickel was prepared, and the nonlinear model of nickel ion was established to obtain the absorption coefficient matrix. Then the filter interval was selected by setting the threshold of correlation coefficient. Finally, the concentration of nickel ion was detected by EKF method. The detection range of nickel ion was 0.3-6.0 mg/L, the RMSEP of nickel was 0.145, and the average relative deviation was 3.9%. The results showed that the method was fast, easy to operate and suitable for real-time detection and control of nickel ion quanlification in the purification process of zinc hydrometallurgy.
2019, 47(8): 1249-1257
doi: 10.19756/j.issn.0253-3820.191208
Abstract:
To monitor illegally added Tadalafil and its analogues in health food, polyclonal antibody was obtained by immunizing New Zealand white rabbits with a common skeleton structure hapten combined with an unsaturated linear alkyl arm hapten strategy, which could simultaneously recognize Tadalafil, Amino Tadalafil and N-Desmethyl Tadalafil. A microwell lateral flow immunochromatographic assay (mwLFIA) combined with simple sample pretreatment was developed. The LOD of mwLFIA for three Tadalafil drugs was between 0.05 and 0.30 ng/mL, the cut-off values were between 50 and 100 ng/mL, and the detection time was less than 10 min. Cross-reactivity test showed no interference from substances with similar structures, indicating a good specificity of the method against Tadalafil, Amino Tadalafil and N-Desmethyl Tadalafil. The average recoveries of three drugs in spiked health wine and oral liquid ranged from 78.7% to 117.8% with RSDs less than 15%, which had a good aggrement with the results of HPLC-MS/MS. The developed mwLFIA strip was suitable for the rapid detection of Tadalafil and its analogues in health wine and oral liquid samples.
To monitor illegally added Tadalafil and its analogues in health food, polyclonal antibody was obtained by immunizing New Zealand white rabbits with a common skeleton structure hapten combined with an unsaturated linear alkyl arm hapten strategy, which could simultaneously recognize Tadalafil, Amino Tadalafil and N-Desmethyl Tadalafil. A microwell lateral flow immunochromatographic assay (mwLFIA) combined with simple sample pretreatment was developed. The LOD of mwLFIA for three Tadalafil drugs was between 0.05 and 0.30 ng/mL, the cut-off values were between 50 and 100 ng/mL, and the detection time was less than 10 min. Cross-reactivity test showed no interference from substances with similar structures, indicating a good specificity of the method against Tadalafil, Amino Tadalafil and N-Desmethyl Tadalafil. The average recoveries of three drugs in spiked health wine and oral liquid ranged from 78.7% to 117.8% with RSDs less than 15%, which had a good aggrement with the results of HPLC-MS/MS. The developed mwLFIA strip was suitable for the rapid detection of Tadalafil and its analogues in health wine and oral liquid samples.
2019, 47(8): 1258-1266
doi: 10.19756/j.issn.0253-3820.191137
Abstract:
A new magnetic sorbent named as ferromagnetic fluorinated graphene (FG@Fe3O4) was prepared for extraction and enrichment of 10 kinds of fluorine-containing pesticides in tea soups, which were then detected by gas chromatography tandem triple quadrupole mass spectrometer (GC-MS/MS). The transfer rate of fluorine-containing was also investigated. Due to the π electrons and F atoms, FG@Fe3O4 could form π-π conjugation and fluorous-fluorous interaction with fluorine-containing pesticides, and the magnetic sorbent displayed excellent adsorption performance for 10 kinds of fluorine-containing pesticides. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry and vibrating sample magnetometer were used to characterize the sorbents. The main parameters, such as sorbent amount, desorption solvent, extraction time were investigated. The adsorption properties of different sorbents and the recycle times of FG@Fe3O4 were also investigated. Under the optimum conditions, the linear relations were good in the corresponding concentration range with the correlation coefficients of more than 0.998. The method limits of detection (S/N=3) and method limits of quantitation (S/N=10) ranged from 0.3 μg/kg to 6.0 μg/kg and 1.0 μg/kg to 20.0 μg/kg, respectively. The average recoveries ranged from 71.2% to 108.4% and the intra-day precisions were 2.6%-8.7% at three standard spiked levels. This developed method was successfully applied for the detection of 10 tea soup samples, among which flubendiamide was detected in 2 samples, flufenoxuron was detected in 2 samples, and triflumizole was detected in one sample. The transfer rate of different fluorine-containing pesticide from teas to infusion was different.
A new magnetic sorbent named as ferromagnetic fluorinated graphene (FG@Fe3O4) was prepared for extraction and enrichment of 10 kinds of fluorine-containing pesticides in tea soups, which were then detected by gas chromatography tandem triple quadrupole mass spectrometer (GC-MS/MS). The transfer rate of fluorine-containing was also investigated. Due to the π electrons and F atoms, FG@Fe3O4 could form π-π conjugation and fluorous-fluorous interaction with fluorine-containing pesticides, and the magnetic sorbent displayed excellent adsorption performance for 10 kinds of fluorine-containing pesticides. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry and vibrating sample magnetometer were used to characterize the sorbents. The main parameters, such as sorbent amount, desorption solvent, extraction time were investigated. The adsorption properties of different sorbents and the recycle times of FG@Fe3O4 were also investigated. Under the optimum conditions, the linear relations were good in the corresponding concentration range with the correlation coefficients of more than 0.998. The method limits of detection (S/N=3) and method limits of quantitation (S/N=10) ranged from 0.3 μg/kg to 6.0 μg/kg and 1.0 μg/kg to 20.0 μg/kg, respectively. The average recoveries ranged from 71.2% to 108.4% and the intra-day precisions were 2.6%-8.7% at three standard spiked levels. This developed method was successfully applied for the detection of 10 tea soup samples, among which flubendiamide was detected in 2 samples, flufenoxuron was detected in 2 samples, and triflumizole was detected in one sample. The transfer rate of different fluorine-containing pesticide from teas to infusion was different.
2019, 47(8): 1267-1275
doi: 10.19756/j.issn.0253-3820.181312
Abstract:
An analytical method based on online solid-phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry was established for determination of biological potency of heparin, including anti-Factor Ⅱa activity and anti-Factor Xa activity. The online SPE was conducted with ten-port switching valve by equipping a C18 column as the SPE column, where the samples were cleaned up in on-line mode. Subsequently, the analyte was eluted from the SPE column onto the analytical column (C18 column) by water-acetonitrile for LC-MS/MS analysis performed in the positive mode and multiple reaction monitoring (MRM) mode. The analytical method was validated to demonstrate specificity, linearity, accuracy, precision, LLOQ, stability and matrix effect. In the linearity range of 3-1000 μg/L, the LLOQ for p-nitroaniline (pNA) in the enzyme reaction were 3 μg/L, the intra-day and inter-day precisions were 1.1%-5.4% (n=6) and 3.8%-10.9% (n=18), respectively, and the accuracy was 88.8%-100.6%. Minimal ion suppression was observed for pNA. Comparing to the reference standard, the biological potencies of two heparin sodium samples were assessed using this method. The method showed better sensitivity, no need for large of enzyme and substrate, and good reproducibility than UV spectrophotometry method. Therefore, it could be applied to the determination of biological potency of heparin, contributing to the quality control of pharmaceutical products.
An analytical method based on online solid-phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry was established for determination of biological potency of heparin, including anti-Factor Ⅱa activity and anti-Factor Xa activity. The online SPE was conducted with ten-port switching valve by equipping a C18 column as the SPE column, where the samples were cleaned up in on-line mode. Subsequently, the analyte was eluted from the SPE column onto the analytical column (C18 column) by water-acetonitrile for LC-MS/MS analysis performed in the positive mode and multiple reaction monitoring (MRM) mode. The analytical method was validated to demonstrate specificity, linearity, accuracy, precision, LLOQ, stability and matrix effect. In the linearity range of 3-1000 μg/L, the LLOQ for p-nitroaniline (pNA) in the enzyme reaction were 3 μg/L, the intra-day and inter-day precisions were 1.1%-5.4% (n=6) and 3.8%-10.9% (n=18), respectively, and the accuracy was 88.8%-100.6%. Minimal ion suppression was observed for pNA. Comparing to the reference standard, the biological potencies of two heparin sodium samples were assessed using this method. The method showed better sensitivity, no need for large of enzyme and substrate, and good reproducibility than UV spectrophotometry method. Therefore, it could be applied to the determination of biological potency of heparin, contributing to the quality control of pharmaceutical products.
2019, 47(8): 1276-1282
doi: 10.19756/j.issn.0253-3820.191117
Abstract:
Titania (TiO2) has high thermal and chemical stability, unique nanostructure-forming ability and good adsorption, and can be used as a solid-phase microextraction (SPME) fiber coating. In this work, TiO2 nanowires (TiO2NWs) were in-situ grown on Ti wire by electrochemical anodization. Thereafter, the Ti@TiO2NWs fiber was annealed at 800℃ and the nanoparticle-like TiO2NWs coating was obtained on the Ti fiber substrate. Coupled to high-performance liquid chromatography with ultraviolet detection (HPLC-UV), SPME performance of the annealed Ti@TiO2NWs fiber was evaluated using typical aromatic compounds as model analytes. As compared with the commercial polyacrylate fiber, the annealed Ti@TiO2NWs fiber showed good extraction selectivity and high extraction capability for ultraviolet filters (UVFs). The experimental conditions for the extraction of UVFs were optimized. The established SPME-HPLC-UV method with the annealed Ti@TiO2NWs fiber presented linear ranges from 0.05 μg/L to 300 μg/L with correlation coefficients (R2)>0.999 and limits of detection from 0.005 μg/L to 0.045 μg/L. Relative standard deviations (RSDs) were below 5.4% and 6.4% for intra-day and inter-day analyses of UVFs at the spiking level of 50 μg/L with the single fiber (n=5), respectively. The developed method was successfully applied to the selective enrichment and sensitive determination of target UVFs in environmental water samples with recoveries from 85.0% to 113% and RSDs from 4.2% to 7.8%. Moreover, the annealed Ti@TiO2NWs fiber was fabricated in a precise controllable manner and stable for at least 200 extraction and desorption cycles.
Titania (TiO2) has high thermal and chemical stability, unique nanostructure-forming ability and good adsorption, and can be used as a solid-phase microextraction (SPME) fiber coating. In this work, TiO2 nanowires (TiO2NWs) were in-situ grown on Ti wire by electrochemical anodization. Thereafter, the Ti@TiO2NWs fiber was annealed at 800℃ and the nanoparticle-like TiO2NWs coating was obtained on the Ti fiber substrate. Coupled to high-performance liquid chromatography with ultraviolet detection (HPLC-UV), SPME performance of the annealed Ti@TiO2NWs fiber was evaluated using typical aromatic compounds as model analytes. As compared with the commercial polyacrylate fiber, the annealed Ti@TiO2NWs fiber showed good extraction selectivity and high extraction capability for ultraviolet filters (UVFs). The experimental conditions for the extraction of UVFs were optimized. The established SPME-HPLC-UV method with the annealed Ti@TiO2NWs fiber presented linear ranges from 0.05 μg/L to 300 μg/L with correlation coefficients (R2)>0.999 and limits of detection from 0.005 μg/L to 0.045 μg/L. Relative standard deviations (RSDs) were below 5.4% and 6.4% for intra-day and inter-day analyses of UVFs at the spiking level of 50 μg/L with the single fiber (n=5), respectively. The developed method was successfully applied to the selective enrichment and sensitive determination of target UVFs in environmental water samples with recoveries from 85.0% to 113% and RSDs from 4.2% to 7.8%. Moreover, the annealed Ti@TiO2NWs fiber was fabricated in a precise controllable manner and stable for at least 200 extraction and desorption cycles.
