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2018 Volume 46 Issue 2
2018, 46(2): 147-156
doi: 10.11895/j.issn.0253-3820.171278
Abstract:
Nitrite has been widely used in industrial and agricultural production, and is commonly found in food, drinking water, biology sample and environment. However, nitrite is a toxic inorganic pollutant that is very harmful to the health of human. A variety of strategies have been proposed for nitrite detection in recent years. Electrochemical approaches have gained more and more attention owing to simplicity, rapidity, sensitivity, low cost, etc. The research progresses of nanocomposite material sensor for electrochemical detection of nitrite based on carbon material, metal material, metal organic frameworks, and conducting polymer and enzyme in recent years are introduced from the perspective of composite electrode modification layer. The construction approaches and sensing performances of modified electrode are put special emphasis. At last, future trends of nitrite electrochemical sensor are also discussed.
Nitrite has been widely used in industrial and agricultural production, and is commonly found in food, drinking water, biology sample and environment. However, nitrite is a toxic inorganic pollutant that is very harmful to the health of human. A variety of strategies have been proposed for nitrite detection in recent years. Electrochemical approaches have gained more and more attention owing to simplicity, rapidity, sensitivity, low cost, etc. The research progresses of nanocomposite material sensor for electrochemical detection of nitrite based on carbon material, metal material, metal organic frameworks, and conducting polymer and enzyme in recent years are introduced from the perspective of composite electrode modification layer. The construction approaches and sensing performances of modified electrode are put special emphasis. At last, future trends of nitrite electrochemical sensor are also discussed.
2018, 46(2): 157-164
doi: 10.11895/j.issn.0253-3820.171139
Abstract:
Based on ultra-high-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF MS/MS), a post targeted screening strategy using high resolution mass spectrometry under data independent acquisition was established, and successfully applied to screen and identify unknown toxicants in food poisoning patients' vomit and feces. After solvent extraction, the samples were separated and analyzed on a reversed-phase C18 column using a gradient elution program of 5 mmol/L ammonium formate and 0.1% formic acid aqueous solution (A) and 0.1% formic acid in acetonitrile solution (B). All-ions MS/MS information of samples was obtained using Q-TOF MS (ESI+) in MSE mode, followed by peak recognition and library searching using the UNIFI Scientific Information System, as a result, suspected toxic compound α-solanine was primarily detected. Furthermore, the related chemicals including hydrolysates and metabolites were identified in both samples based on post-targeted screening strategy, such as α-chaconine, β-chaconine, γ-solanine/chaconine and solanidine. The concentration of α-solanine in both samples was approximately 0.1 mg/kg by one-point calibration method, the total amount of solanine analogues in two samples was about 0.5 mg/kg and 0.6 mg/kg respectively through normalization of peak area. The high resolution mass spectrometry screening strategy established here could provide efficient screening method for rapid detection and identification of toxicants in unknown food poisoning.
Based on ultra-high-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF MS/MS), a post targeted screening strategy using high resolution mass spectrometry under data independent acquisition was established, and successfully applied to screen and identify unknown toxicants in food poisoning patients' vomit and feces. After solvent extraction, the samples were separated and analyzed on a reversed-phase C18 column using a gradient elution program of 5 mmol/L ammonium formate and 0.1% formic acid aqueous solution (A) and 0.1% formic acid in acetonitrile solution (B). All-ions MS/MS information of samples was obtained using Q-TOF MS (ESI+) in MSE mode, followed by peak recognition and library searching using the UNIFI Scientific Information System, as a result, suspected toxic compound α-solanine was primarily detected. Furthermore, the related chemicals including hydrolysates and metabolites were identified in both samples based on post-targeted screening strategy, such as α-chaconine, β-chaconine, γ-solanine/chaconine and solanidine. The concentration of α-solanine in both samples was approximately 0.1 mg/kg by one-point calibration method, the total amount of solanine analogues in two samples was about 0.5 mg/kg and 0.6 mg/kg respectively through normalization of peak area. The high resolution mass spectrometry screening strategy established here could provide efficient screening method for rapid detection and identification of toxicants in unknown food poisoning.
2018, 46(2): 165-169
doi: 10.11895/j.issn.0253-3820.171011
Abstract:
Respiratory syncytial virus (RSV), which is a major cause of lower respiratory tract infections during infancy and childhood, is also an important pathogen for immunosuppression in elder and diseased areas. In order to research the pathogenesis of RSV, the matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS)was used to explore the difference between uninfected cells and virus-infected cells. The result showed that, in the molecular weight range of 5000~10000 Da, there are three component peaks expressed with significant difference in both normal group and infection group. One of the three components was up-regulated (m/z 6154.25) and the other two were down-regulated (m/z 7658.47 and 9259.82) after RSV infection. This result proved the obvious differences between the infected cells and untreated cells.The differential expression may provide a feasible method for RSV disease diagnosis and pathology research, and also provide scientific evidences for research on development of RSV therapeutic drugs.
Respiratory syncytial virus (RSV), which is a major cause of lower respiratory tract infections during infancy and childhood, is also an important pathogen for immunosuppression in elder and diseased areas. In order to research the pathogenesis of RSV, the matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS)was used to explore the difference between uninfected cells and virus-infected cells. The result showed that, in the molecular weight range of 5000~10000 Da, there are three component peaks expressed with significant difference in both normal group and infection group. One of the three components was up-regulated (m/z 6154.25) and the other two were down-regulated (m/z 7658.47 and 9259.82) after RSV infection. This result proved the obvious differences between the infected cells and untreated cells.The differential expression may provide a feasible method for RSV disease diagnosis and pathology research, and also provide scientific evidences for research on development of RSV therapeutic drugs.
2018, 46(2): 170-177
doi: 10.11895/j.issn.0253-3820.170323
Abstract:
The experimental SD rats were randomly divided into normal control group (Con group), diabetic ulcer model group (DM group) and Celastrol group (Cel group). Except the control group, diabetic ulceration rat models were established by intraperitoneal injection of streptozotocin along with skin scald. And then, each group was treated by spraying the saline solution on the affected skin with (Cel group) or without (Con group and DM group) Cel (q.d.×14 d). Nuclear magnetic resonance (NMR)-based metabonomic analysis was applied to detect metabolic characteristics, accompanied by healing rate calculation and HE and Masson staining to study therapeutic effect of celastrol on accelerated healing of skin wounds of diabetic ulceration rats, which could be used to elucidate therapeutic effects of celastrol on the rat diabetic ulceration and its mechanism. The results showed that celastrol could induce epithelial regeneration of the rat ulcer wound, regulate the infiltration of inflammatory cells and the distribution of collagen fibers, and promote the healing of the ulcer wound. About 20 endogenous potential differential metabolites were screened and identified by partial least square analysis. Metabolic pathway analysis was carried out to show that celastrol can significantly recovery the level of the tricarboxylic acid cycle, promote its energy supply, accelerate the protein synthesis, improve mitochondrial dysfunction and oxidative stress, and accelerate the self-repair ability of skin tissue. Celastrol can promote the healing of ulcers skins of the diabetic rats, which contribute to experimental basis of the drugs for the treatment of diabetic ulcers.
The experimental SD rats were randomly divided into normal control group (Con group), diabetic ulcer model group (DM group) and Celastrol group (Cel group). Except the control group, diabetic ulceration rat models were established by intraperitoneal injection of streptozotocin along with skin scald. And then, each group was treated by spraying the saline solution on the affected skin with (Cel group) or without (Con group and DM group) Cel (q.d.×14 d). Nuclear magnetic resonance (NMR)-based metabonomic analysis was applied to detect metabolic characteristics, accompanied by healing rate calculation and HE and Masson staining to study therapeutic effect of celastrol on accelerated healing of skin wounds of diabetic ulceration rats, which could be used to elucidate therapeutic effects of celastrol on the rat diabetic ulceration and its mechanism. The results showed that celastrol could induce epithelial regeneration of the rat ulcer wound, regulate the infiltration of inflammatory cells and the distribution of collagen fibers, and promote the healing of the ulcer wound. About 20 endogenous potential differential metabolites were screened and identified by partial least square analysis. Metabolic pathway analysis was carried out to show that celastrol can significantly recovery the level of the tricarboxylic acid cycle, promote its energy supply, accelerate the protein synthesis, improve mitochondrial dysfunction and oxidative stress, and accelerate the self-repair ability of skin tissue. Celastrol can promote the healing of ulcers skins of the diabetic rats, which contribute to experimental basis of the drugs for the treatment of diabetic ulcers.
2018, 46(2): 178-187
doi: 10.11895/j.issn.0253-3820.170302
Abstract:
An extract method for the fingerprint feature of 49 kinds of antibiotics belonging to multiple classes in surface water was developed. Water sample was purified and concentrated by tandem dual column (MAX and HLB), and qualitatively and quantitatively analyzed by ultra-high performance liquid chromatography-tandem mass spectrometric (SPE-UPLC-MS/MS) under multiple reaction monitoring (MRM) mode. The pretreatment was optimized in types of SPE column, loading pH, eluent and redissolution for multiclass antibiotics. The results showed that the linearity of target antibiotics was good in the range of 0.001-0.5 μg/mL (0.01-5 μg/mL for streptomycin). The recoveries were from 51.7% to 94.8%, and the relative standard deviations (RSDs) ranged from 2.19% to 9.67%. The limits of detection (LOD, S/N=3) were 0.01-3.23 μg/L and 0.05-3.43 μg/L and the limits of quantification (LOQ, S/N=10) were 0.04-10.8 μg/L and 0.17-11.4 μg/L in different redissolve solutions. This method was applied to the determination of antibiotics in water samples from 9 sites of Qinhuai River and Xuanwu Lake.
An extract method for the fingerprint feature of 49 kinds of antibiotics belonging to multiple classes in surface water was developed. Water sample was purified and concentrated by tandem dual column (MAX and HLB), and qualitatively and quantitatively analyzed by ultra-high performance liquid chromatography-tandem mass spectrometric (SPE-UPLC-MS/MS) under multiple reaction monitoring (MRM) mode. The pretreatment was optimized in types of SPE column, loading pH, eluent and redissolution for multiclass antibiotics. The results showed that the linearity of target antibiotics was good in the range of 0.001-0.5 μg/mL (0.01-5 μg/mL for streptomycin). The recoveries were from 51.7% to 94.8%, and the relative standard deviations (RSDs) ranged from 2.19% to 9.67%. The limits of detection (LOD, S/N=3) were 0.01-3.23 μg/L and 0.05-3.43 μg/L and the limits of quantification (LOQ, S/N=10) were 0.04-10.8 μg/L and 0.17-11.4 μg/L in different redissolve solutions. This method was applied to the determination of antibiotics in water samples from 9 sites of Qinhuai River and Xuanwu Lake.
2018, 46(2): 188-194
doi: 10.11895/j.issn.0253-3820.171245
Abstract:
The changes of endogenous metabolites in urine samples that come from pneumonia patients of 6 months to 6 years old children were analyzed by metabolomics methods based on gas chromatography and mass spectrometry (GC-MS). The aim of this study was to analyze and study the pathogenesis of endogenous metabolites in children with pneumonia and the pathogenesis of pneumonia susceptibility. The urine samples were collected and divided into normal children group (NC group, n=29), first infection with pneumonia group (FIP group, n=35), and repeated infection with pneumonia group (RIP group, n=31). The urine metabolic profile of pneumonia was obtained by GC-MS. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to analyze the data. The results were analyzed by one-way analysis of variance and Fold change. Finally, there was significant difference between the normal group and the pneumonia group, the significant metabolites were serine, histidine, proline, norleucine, glutamine, stearic acid, valine, isoleucine with p value <0.05 and Fold change>5, and indole-3-acetic acid, creatine, ethanolamine, mannosylglycerol and fructose were significant between the two pneumonia groups with p value <0.05. The urinary metabolites demonstrated that amino acid metabolism and glucose metabolism were the main metabolic pathways and responsible for the susceptibility to pneumonia.
The changes of endogenous metabolites in urine samples that come from pneumonia patients of 6 months to 6 years old children were analyzed by metabolomics methods based on gas chromatography and mass spectrometry (GC-MS). The aim of this study was to analyze and study the pathogenesis of endogenous metabolites in children with pneumonia and the pathogenesis of pneumonia susceptibility. The urine samples were collected and divided into normal children group (NC group, n=29), first infection with pneumonia group (FIP group, n=35), and repeated infection with pneumonia group (RIP group, n=31). The urine metabolic profile of pneumonia was obtained by GC-MS. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to analyze the data. The results were analyzed by one-way analysis of variance and Fold change. Finally, there was significant difference between the normal group and the pneumonia group, the significant metabolites were serine, histidine, proline, norleucine, glutamine, stearic acid, valine, isoleucine with p value <0.05 and Fold change>5, and indole-3-acetic acid, creatine, ethanolamine, mannosylglycerol and fructose were significant between the two pneumonia groups with p value <0.05. The urinary metabolites demonstrated that amino acid metabolism and glucose metabolism were the main metabolic pathways and responsible for the susceptibility to pneumonia.
2018, 46(2): 195-202
doi: 10.11895/j.issn.0253-3820.171393
Abstract:
Cyclophilin A was isolated from human colorectal carcinoma tissues by ultrafiltration, affinity chromatography, and two dimensional electrophoresis. By the aid of Western blot analysis, several isoforms of cyclophilin A were detected., The tryptic digests from cyclophilin A were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry as well as electrospray tandem mass spectrometry techniques. Several different modifications such as N-terminal acetylation (Ac-1Met and Ac-2Val) and phosphorylation of 5Thr were identified from these isoforms of cyclophilin A, which represented the majority of the proteoforms of cyclophilin A in this study. In addition, other kinds of modifications such as oxidation and deamidation were also found in these proteoforms. The results indicated that the developed method could be used to rapidly and correctly identify the several proteoforms of cyclophilin A isolated from human colorectal carcinoma tissues.
Cyclophilin A was isolated from human colorectal carcinoma tissues by ultrafiltration, affinity chromatography, and two dimensional electrophoresis. By the aid of Western blot analysis, several isoforms of cyclophilin A were detected., The tryptic digests from cyclophilin A were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry as well as electrospray tandem mass spectrometry techniques. Several different modifications such as N-terminal acetylation (Ac-1Met and Ac-2Val) and phosphorylation of 5Thr were identified from these isoforms of cyclophilin A, which represented the majority of the proteoforms of cyclophilin A in this study. In addition, other kinds of modifications such as oxidation and deamidation were also found in these proteoforms. The results indicated that the developed method could be used to rapidly and correctly identify the several proteoforms of cyclophilin A isolated from human colorectal carcinoma tissues.
2018, 46(2): 203-210
doi: 10.11895/j.issn.0253-3820.171020
Abstract:
A novel polymerase-based electrochemiluminescence DNA sensor was constructed for messenger RNA (mRNA) detection by cyclic chain displacement polymerization, assisted by target mRNA cycle, and quantum dots signal amplification. Firstly, the mercapto-modified capture-type capture DNA (CP) was immobilized on the surface of a magneto-controlled glassy carbon electrode via Au-S bond. After adding the target mRNA, CP was opened and hybridized with mRNA to form dsDNA. After adding polymerase, primer chain (DNA1) and the base, the primer chain was extended to replace the target mRNA. After one cycle, the mRNA chain could open another hairpin in order to carry out next cycle of amplification. Finally, electrochemical luminescence detection was carried out by adding DNA2 labeled TGA-CdTe quantum dots. The amplification of the target mRNA by the addition of polymerase and the signal combined with the quantum dot mark improved the sensitivity of the sensor greatly. The result showed that the logarithm of target mRNA concentration had a good linear relationship with the corresponding ECL signal in the range of 1×10-15-1×10-11 mol/L, with the detection limit of 3.4×10-16 mol/L(S/N=3). Under the optimal conditions, the recoveries of mRNA spiked in human serum sample were 97.2%-102.3%. This sensor exhibited good selectivity, stability and reproducibility.
A novel polymerase-based electrochemiluminescence DNA sensor was constructed for messenger RNA (mRNA) detection by cyclic chain displacement polymerization, assisted by target mRNA cycle, and quantum dots signal amplification. Firstly, the mercapto-modified capture-type capture DNA (CP) was immobilized on the surface of a magneto-controlled glassy carbon electrode via Au-S bond. After adding the target mRNA, CP was opened and hybridized with mRNA to form dsDNA. After adding polymerase, primer chain (DNA1) and the base, the primer chain was extended to replace the target mRNA. After one cycle, the mRNA chain could open another hairpin in order to carry out next cycle of amplification. Finally, electrochemical luminescence detection was carried out by adding DNA2 labeled TGA-CdTe quantum dots. The amplification of the target mRNA by the addition of polymerase and the signal combined with the quantum dot mark improved the sensitivity of the sensor greatly. The result showed that the logarithm of target mRNA concentration had a good linear relationship with the corresponding ECL signal in the range of 1×10-15-1×10-11 mol/L, with the detection limit of 3.4×10-16 mol/L(S/N=3). Under the optimal conditions, the recoveries of mRNA spiked in human serum sample were 97.2%-102.3%. This sensor exhibited good selectivity, stability and reproducibility.
2018, 46(2): 211-216
doi: 10.11895/j.issn.0253-3820.171279
Abstract:
Graphene oxide (GO) was prepared by modified Hummers method with graphite as raw materials and used as adsorbent for sulfamethoxazole (SMZ) and sulfamerazine (SMR) in aqueous solutions. The graphene oxide was characterized by fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The effects of pH value, adsorption time, initial concentration and temperature on the adsorption property of GO to two sulfonamide antibiotics were investigated and combined with the physical and chemical properties of two kinds of antibiotics. The result showed the maximum adsorption capacity were 138.50 mg/g and 96.06 mg/g at pH=1, adsorbent dosage of 20 mg, 45℃, adsorption time of 100 min and 120 min for SMZ and SMR, respectively. The adsorption data of SMZ and SMR fitted well with the Pseudo-second-order kinetics model and the Langmuir isotherm model. The adsorption properties of GO were evaluated with lake water and tap water as real samples and good results were obtained. GO could be used as enrichment and separation materials for sample pretreatment and removing pollutant in wastewater.
Graphene oxide (GO) was prepared by modified Hummers method with graphite as raw materials and used as adsorbent for sulfamethoxazole (SMZ) and sulfamerazine (SMR) in aqueous solutions. The graphene oxide was characterized by fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The effects of pH value, adsorption time, initial concentration and temperature on the adsorption property of GO to two sulfonamide antibiotics were investigated and combined with the physical and chemical properties of two kinds of antibiotics. The result showed the maximum adsorption capacity were 138.50 mg/g and 96.06 mg/g at pH=1, adsorbent dosage of 20 mg, 45℃, adsorption time of 100 min and 120 min for SMZ and SMR, respectively. The adsorption data of SMZ and SMR fitted well with the Pseudo-second-order kinetics model and the Langmuir isotherm model. The adsorption properties of GO were evaluated with lake water and tap water as real samples and good results were obtained. GO could be used as enrichment and separation materials for sample pretreatment and removing pollutant in wastewater.
2018, 46(2): 217-224
doi: 10.11895/j.issn.0253-3820.171026
Abstract:
Bismuth modified boron doped diamond (BDD) film electrode was employed for simultaneous determination of trace Zn(II), Cd(II) and Pb(II) by anodic stripping voltammetry. Bi(III) was simultaneously in-situ deposited on bismuth modified boron doped diamond electrode with Zn(II), Cd(II) and Pb(II) by pre-concentration. In the presence of Bi(III), the sensitivity for determination of Zn(II), Cd(II) and Pb(II) was remarkably enhanced. Influence factors such as bismuth concentration, boron doped concentrations of BDD electrode, pH, preconcentration potential were investigated and optimized. Under the optimal conditions, the stripping peak currents increased linearly with the increasing concentration of Zn(II), Cd(II) and Pb(II) in the range of 10-300 μg/L. The limit of detection was 0.56 μg/L for Zn(II), 0.32 μg/L for Cd(II) and 0.75 μg/L for Pb(II) (S/N=3), respectively. The interference experiments showed that common ions had little influence on the determination except Cu(II). In addition, the developed electrode displayed a good repeatability. The method was successfully applied to determination of Zn(II), Cd(II) and Pb(II) in real water samples with the standard addition recoveries of 92.0%-114.0%.
Bismuth modified boron doped diamond (BDD) film electrode was employed for simultaneous determination of trace Zn(II), Cd(II) and Pb(II) by anodic stripping voltammetry. Bi(III) was simultaneously in-situ deposited on bismuth modified boron doped diamond electrode with Zn(II), Cd(II) and Pb(II) by pre-concentration. In the presence of Bi(III), the sensitivity for determination of Zn(II), Cd(II) and Pb(II) was remarkably enhanced. Influence factors such as bismuth concentration, boron doped concentrations of BDD electrode, pH, preconcentration potential were investigated and optimized. Under the optimal conditions, the stripping peak currents increased linearly with the increasing concentration of Zn(II), Cd(II) and Pb(II) in the range of 10-300 μg/L. The limit of detection was 0.56 μg/L for Zn(II), 0.32 μg/L for Cd(II) and 0.75 μg/L for Pb(II) (S/N=3), respectively. The interference experiments showed that common ions had little influence on the determination except Cu(II). In addition, the developed electrode displayed a good repeatability. The method was successfully applied to determination of Zn(II), Cd(II) and Pb(II) in real water samples with the standard addition recoveries of 92.0%-114.0%.
2018, 46(2): 225-231
doi: 10.11895/j.issn.0253-3820.171371
Abstract:
Vertical single-walled carbon nanotubes (v-SWCNTs) array was constructed on glassy carbon electrode (GCE) by electrochemical method of electro-cyclic voltammetry (CV method). The synthesized electrode was very stable and was not easy to fall off. Via the amino groups of ethylenediamine (Ethylenediamine, EDA) and the carboxyl group of carboxylated carbon nanotubes, the SWCNTs were ordered to grow steadily on GCE(v-SWCNTs/EDA/GCE). The modified electrode was used to detect hydrochloric acid clenbuterol (CLE). The experimental results showed that the regular link of carbon nanotubes on GCE improved its utilization efficiency. The detection sensitivity of clenbuterol was 16.1 times higher than that of the bare GCE. Due to electron accelerating effect and nanometer effect of SWCNTs, the carboxyl peak current of SWCNTs was increased with the added CLE. The carboxyl peak current of SWCNTs had a good linear relationship with CLE concentration in the range of 10-120 ng/mL. The method was successfully applied to the determination of CLE in real urine samples with good recoveries. Also v-SWCNTs/EDA/GCE could be used as a new highly sensitive electrochemical sensor for CLE detection.
Vertical single-walled carbon nanotubes (v-SWCNTs) array was constructed on glassy carbon electrode (GCE) by electrochemical method of electro-cyclic voltammetry (CV method). The synthesized electrode was very stable and was not easy to fall off. Via the amino groups of ethylenediamine (Ethylenediamine, EDA) and the carboxyl group of carboxylated carbon nanotubes, the SWCNTs were ordered to grow steadily on GCE(v-SWCNTs/EDA/GCE). The modified electrode was used to detect hydrochloric acid clenbuterol (CLE). The experimental results showed that the regular link of carbon nanotubes on GCE improved its utilization efficiency. The detection sensitivity of clenbuterol was 16.1 times higher than that of the bare GCE. Due to electron accelerating effect and nanometer effect of SWCNTs, the carboxyl peak current of SWCNTs was increased with the added CLE. The carboxyl peak current of SWCNTs had a good linear relationship with CLE concentration in the range of 10-120 ng/mL. The method was successfully applied to the determination of CLE in real urine samples with good recoveries. Also v-SWCNTs/EDA/GCE could be used as a new highly sensitive electrochemical sensor for CLE detection.
2018, 46(2): 232-238
doi: 10.11895/j.issn.0253-3820.171177
Abstract:
Iron-doped titanium dioxide nanosheets was prepared by hydrothermal method using tetrabutyl titanate (C16H36O4Ti) and iron trifluoride (FeF3) and modified on ITO electrode. ITO/Fe:TiO2/CdS photoelectrochemical sensor was fabricated by successive ionic layer absorption and reaction (SILAR) method for determination of copper ion. The band gap of electode material was narrowed by iron doped TiO2 nanosheets, which made its absorption red-shifted and its response range of light was magnified. Based on the sensitization effect of CdS, the absorption and utilization of visible light of sensor was significantly enhanced and the photoelectric signal was amplified via reducing the recombination of electrons and holes.The sensor displayed excellent analytical performance for detection of copper ion with linear range of 0.2-4.0 μmol/L and 4.0-80.0 μmol/L and with the detection limit of 85 nmol/L. The sensor was used to detect copper ion in tap water, drinking water and Yongjiang river water with recoveries ranging from 94% to 111%.
Iron-doped titanium dioxide nanosheets was prepared by hydrothermal method using tetrabutyl titanate (C16H36O4Ti) and iron trifluoride (FeF3) and modified on ITO electrode. ITO/Fe:TiO2/CdS photoelectrochemical sensor was fabricated by successive ionic layer absorption and reaction (SILAR) method for determination of copper ion. The band gap of electode material was narrowed by iron doped TiO2 nanosheets, which made its absorption red-shifted and its response range of light was magnified. Based on the sensitization effect of CdS, the absorption and utilization of visible light of sensor was significantly enhanced and the photoelectric signal was amplified via reducing the recombination of electrons and holes.The sensor displayed excellent analytical performance for detection of copper ion with linear range of 0.2-4.0 μmol/L and 4.0-80.0 μmol/L and with the detection limit of 85 nmol/L. The sensor was used to detect copper ion in tap water, drinking water and Yongjiang river water with recoveries ranging from 94% to 111%.
2018, 46(2): 239-245
doi: 10.11895/j.issn.0253-3820.171039
Abstract:
In2O3 nanoparticles-modified multiwalled carbon nanotubes (In2O3-MWCNTs) were successfully prepared as solid phase extraciton (SPE) adsorbent for the determination of three food preservatives (benzoic acid, sorbic acid, and methylparaben) in beverage samples coupled with high performance liquid chromatography (HPLC). Because of the large surface area and amount of hydroxyl groups on the surface of In2O3 nanoparticles, In2O3 nanoparticles could interact with specific functional groups. In2O3-MWCNTs adsorbent was prepared based on the large surface area of In2O3 and superior thermal and chemical stability of MWCNTs. The obtained adsorbent was characterized via transmission electron microscope (TEM), thermogravimetric analysis (TGA), and Fourier transform-infrared (FT-IR) spectroscopy. Several experimental parameters affecting the extraction efficiency were investigated by single-factor experiments, such as adsorbents amount, sample volume, eluent volume, sample pH, and eluent type. The first four factors were then further evaluated by means of a Taguchi's L16 (44) orthogonal array experimental design. According to the results of orthogonal array experiment, the optimal conditions were chosen as follows:0.15 g of adsorbent amount, 5.0 mL of sample volume, 0.6 mL of ACN-H2O (60:40, 0.1% formic acid, V/V) as eluent, and sample pH 4.0. Under the optimum conditions, the LODs (S/N=3) and LOQs (S/N=10) for three preservatives were in the range of 0.004-0.012 μg/mL and 0.012-0.038 μg/mL, respectively. The recoveries ranged from 70.2% to 109.4%. The method is rapid, sensitive, and suitable for the determination of preservatives in food samples.
In2O3 nanoparticles-modified multiwalled carbon nanotubes (In2O3-MWCNTs) were successfully prepared as solid phase extraciton (SPE) adsorbent for the determination of three food preservatives (benzoic acid, sorbic acid, and methylparaben) in beverage samples coupled with high performance liquid chromatography (HPLC). Because of the large surface area and amount of hydroxyl groups on the surface of In2O3 nanoparticles, In2O3 nanoparticles could interact with specific functional groups. In2O3-MWCNTs adsorbent was prepared based on the large surface area of In2O3 and superior thermal and chemical stability of MWCNTs. The obtained adsorbent was characterized via transmission electron microscope (TEM), thermogravimetric analysis (TGA), and Fourier transform-infrared (FT-IR) spectroscopy. Several experimental parameters affecting the extraction efficiency were investigated by single-factor experiments, such as adsorbents amount, sample volume, eluent volume, sample pH, and eluent type. The first four factors were then further evaluated by means of a Taguchi's L16 (44) orthogonal array experimental design. According to the results of orthogonal array experiment, the optimal conditions were chosen as follows:0.15 g of adsorbent amount, 5.0 mL of sample volume, 0.6 mL of ACN-H2O (60:40, 0.1% formic acid, V/V) as eluent, and sample pH 4.0. Under the optimum conditions, the LODs (S/N=3) and LOQs (S/N=10) for three preservatives were in the range of 0.004-0.012 μg/mL and 0.012-0.038 μg/mL, respectively. The recoveries ranged from 70.2% to 109.4%. The method is rapid, sensitive, and suitable for the determination of preservatives in food samples.
2018, 46(2): 246-253
doi: 10.11895/j.issn.0253-3820.170031
Abstract:
Hydrophobic medicine carbendazim, come into inclusion compounds with β-cyclodextrin (β-CD), 2-hydroxypropyl-β-CD (2-Hp-β-CD) and 2,6-dimethyl-β-CD (Me-β-CD), were made by solvent method. By investigating the inclusion behaviors of these three cyclodextrins combined with carbendazim using 1H NMR, 2D rotating frame overhause effect spectroscopy (ROESY) and diffusion ordered spectroscopy, the possible ways of combinations and the recognition ratio of this three inclusion compounds, Dβ-CD=2.516×10-10 m2/s, D2-Hp-β-CD=1.676×10-10 m2/s, DMe-β-CD=2.046×10-10 m2/s, were obtained. According to X-ray power diffraction, thermogravimetric analysis, infrared spectroscopy and scanning electron spectroscopy characterization, it was found that the characteristic diffraction peaks changed after carbendazim and cyclodextrin formed into inclusion compounds, and the characteristic diffraction peak of carbendazim at 10.4°, 21.2°, 25.8°, 31.5°(2θ) lost or disappear. The pyrolysis temperature of carbendazim was 197.5℃, and would be higher than 260℃ after it formed inclusion complex. The infrared spectrum also showed that the oscillation peaks of inner cyclodextrin cavum apparently reduced after carbendazim combined, which demonstrated that the position of water molecules inside cyclodextrin cavum were occupied by the carbendazim molecules. With the help of SEM, the appearances of inclusion were different from a single carbendazim molecule, which manifested a new structure appeared.
Hydrophobic medicine carbendazim, come into inclusion compounds with β-cyclodextrin (β-CD), 2-hydroxypropyl-β-CD (2-Hp-β-CD) and 2,6-dimethyl-β-CD (Me-β-CD), were made by solvent method. By investigating the inclusion behaviors of these three cyclodextrins combined with carbendazim using 1H NMR, 2D rotating frame overhause effect spectroscopy (ROESY) and diffusion ordered spectroscopy, the possible ways of combinations and the recognition ratio of this three inclusion compounds, Dβ-CD=2.516×10-10 m2/s, D2-Hp-β-CD=1.676×10-10 m2/s, DMe-β-CD=2.046×10-10 m2/s, were obtained. According to X-ray power diffraction, thermogravimetric analysis, infrared spectroscopy and scanning electron spectroscopy characterization, it was found that the characteristic diffraction peaks changed after carbendazim and cyclodextrin formed into inclusion compounds, and the characteristic diffraction peak of carbendazim at 10.4°, 21.2°, 25.8°, 31.5°(2θ) lost or disappear. The pyrolysis temperature of carbendazim was 197.5℃, and would be higher than 260℃ after it formed inclusion complex. The infrared spectrum also showed that the oscillation peaks of inner cyclodextrin cavum apparently reduced after carbendazim combined, which demonstrated that the position of water molecules inside cyclodextrin cavum were occupied by the carbendazim molecules. With the help of SEM, the appearances of inclusion were different from a single carbendazim molecule, which manifested a new structure appeared.
2018, 46(2): 254-259
doi: 10.11895/j.issn.0253-3820.171382
Abstract:
In this work, a highly sensitive electrochemical biosensor for the detection of trace adenosine triphosphate (ATP) was proposed. The biosensor was based on porous anodic alumina (PAA) and SiO2 nanoparticles combining with several oligonucleotides to construct sandwich structure. It was characterized by scanning electron microscopy, fluorescence microscopy, differential pulse voltammetry and electrochemical impedance spectroscopy, which conformed to the reliability of the biosensor fabrication and the feasibility of the detection. In the presence of ATP, the sandwich structures could be destroyed. The variation of the current was directly corresponding to the amount of the ATP. The application of SiO2 nanoparticles could effectively reduce the background and increase the sensitivity of the biosensor. The calibration curve of ATP was obtained in the range of 0.025-0.900 nmol/L with the detection limit of 13 pmol/L (S/N=3). Also, the biosensor exhibited a good specificity. Besides, the sensor was constructed easily and possessed excellent regeneration ability. The proposed biosensor was applied in detection of real sample such as mice blood. Therefore, the proposed ATP-sensing biosensor could be expected to be applied in clinical, pharmaceutical and environmental detection.
In this work, a highly sensitive electrochemical biosensor for the detection of trace adenosine triphosphate (ATP) was proposed. The biosensor was based on porous anodic alumina (PAA) and SiO2 nanoparticles combining with several oligonucleotides to construct sandwich structure. It was characterized by scanning electron microscopy, fluorescence microscopy, differential pulse voltammetry and electrochemical impedance spectroscopy, which conformed to the reliability of the biosensor fabrication and the feasibility of the detection. In the presence of ATP, the sandwich structures could be destroyed. The variation of the current was directly corresponding to the amount of the ATP. The application of SiO2 nanoparticles could effectively reduce the background and increase the sensitivity of the biosensor. The calibration curve of ATP was obtained in the range of 0.025-0.900 nmol/L with the detection limit of 13 pmol/L (S/N=3). Also, the biosensor exhibited a good specificity. Besides, the sensor was constructed easily and possessed excellent regeneration ability. The proposed biosensor was applied in detection of real sample such as mice blood. Therefore, the proposed ATP-sensing biosensor could be expected to be applied in clinical, pharmaceutical and environmental detection.
2018, 46(2): 260-264
doi: 10.11895/j.issn.0253-3820.170330
Abstract:
A new method for simultaneous determination of six benzoic acid esters and their metabolite p-hydroxybenzoic acid (p-HB) in sediments was developed. The samples were extracted with methanol and water, and then the extraction was purified by Oasis MCX solid phase column. The separation of targets was conducted by passing through a UPLC® HSS T3 column with a methanol-0.1% acid aqueous solution as the mobile phase under gradient elution. The qualitative analysis of the analytes was measured by Ultra performance liquid chromatography-Triple quadrupole tandem mass under multiple reaction monitoring mode (MRM) and the internal standard method was applied for quantitative analysis. The results indicated that seven target substances had a good linear relationship in the range of 0.1-500 μg/L with correlation coefficients above 0.9995 and the detection limits of 0.75-1.23 ng/g. The recoveries ranged from 65.5% to 88.3% and the relative standard deviation was 7.4%-13.6%. This method was suitable for the measurement of benzoic acid esters with the advantages such as simple processing, good selectivity and high sensitivity.
A new method for simultaneous determination of six benzoic acid esters and their metabolite p-hydroxybenzoic acid (p-HB) in sediments was developed. The samples were extracted with methanol and water, and then the extraction was purified by Oasis MCX solid phase column. The separation of targets was conducted by passing through a UPLC® HSS T3 column with a methanol-0.1% acid aqueous solution as the mobile phase under gradient elution. The qualitative analysis of the analytes was measured by Ultra performance liquid chromatography-Triple quadrupole tandem mass under multiple reaction monitoring mode (MRM) and the internal standard method was applied for quantitative analysis. The results indicated that seven target substances had a good linear relationship in the range of 0.1-500 μg/L with correlation coefficients above 0.9995 and the detection limits of 0.75-1.23 ng/g. The recoveries ranged from 65.5% to 88.3% and the relative standard deviation was 7.4%-13.6%. This method was suitable for the measurement of benzoic acid esters with the advantages such as simple processing, good selectivity and high sensitivity.
2018, 46(2): 265-272
doi: 10.11895/j.issn.0253-3820.171040
Abstract:
Laser-induced breakdown spectroscopy (LIBS) was used for analysis of the distribution of S, Mn, Fe, Cr, Mo, Si, Al in a 34CrNiMo6 steel sample cut from a main shaft of wind driven generator. The MnS inclusion area in each ablation craters cover zone was extracted in the way of comparing the metallograph captured by optical microscopy before and after LIBS scanning ablation. The statistic relation between MnS inclusion area and signal intensity of S and Mn was analyzed. The result showed that the abnormal signal of S and Mn occurred at the same position with the existence of MnS inclusion, and their signal intensity showed linear relationship. The abnormal signal of S and Mn were triggered mainly by MnS inclusion. The statistic result also showed linear relationship between signal intensity and MnS inclusion area both for S and Mn. It was possible to determine the inclusion type, size and distribution by analyzing abnormal signal. A simplified ablation model was established to calculate the relation of S and Mn content to MnS inclusion area. The arithmetic result showed a linear relation between the content and MnS inclusion area both for S and Mn. The calculation confirmed the linear relationship between signal intensity and inclusion area observed in experiment. The linear relationship could be interfered by macro-segregation, micro-segregation, deviation in measuring inclusion area, and inclusion spatter in pre-ablation.
Laser-induced breakdown spectroscopy (LIBS) was used for analysis of the distribution of S, Mn, Fe, Cr, Mo, Si, Al in a 34CrNiMo6 steel sample cut from a main shaft of wind driven generator. The MnS inclusion area in each ablation craters cover zone was extracted in the way of comparing the metallograph captured by optical microscopy before and after LIBS scanning ablation. The statistic relation between MnS inclusion area and signal intensity of S and Mn was analyzed. The result showed that the abnormal signal of S and Mn occurred at the same position with the existence of MnS inclusion, and their signal intensity showed linear relationship. The abnormal signal of S and Mn were triggered mainly by MnS inclusion. The statistic result also showed linear relationship between signal intensity and MnS inclusion area both for S and Mn. It was possible to determine the inclusion type, size and distribution by analyzing abnormal signal. A simplified ablation model was established to calculate the relation of S and Mn content to MnS inclusion area. The arithmetic result showed a linear relation between the content and MnS inclusion area both for S and Mn. The calculation confirmed the linear relationship between signal intensity and inclusion area observed in experiment. The linear relationship could be interfered by macro-segregation, micro-segregation, deviation in measuring inclusion area, and inclusion spatter in pre-ablation.
2018, 46(2): 273-280
doi: 10.11895/j.issn.0253-3820.170285
Abstract:
The non-covalent interactions between 18-crown-6 (18c6) and 20 common types of protonated amino acids were explored by electrospray ionization mass spectrometry (ESI-MS). The mass spectra showed the formation of 1:1 stoichiometric non-covalent complexes between 18c6 and amino acids. The calibration curves and linear equations for the complexes of L-Phe, L-Tyr, L-Lys and L-Asp with 18c6 were established by mass spectrometric titration and used as reference values for competitive ESI-MS. Through competitive equilibrium, the binding constants for the complexes of 18c6 with other L-amino acids and their D-isomers were derived. It was found, as a general trend, lgKa for the complexes of 18c6 with the basic amino acid and the amino acid with alkyl side chain were larger than other complexes, and among the amino acids with alkyl side chain, Gly and Ala exhibited greater 18c6 binding affinities. As for Ser and Thr, the intramolecular hydrogen bond between the nitrogen atom from terminal NH2 and the oxygen atom from carboxyl may impede their protonated amino-group to attack the 18c6. Furthermore, Gln and Asn exhibited lower 18c6 binding affinities probably due to effects of electron-withdrawing group of acylamide. Finally, the chiral selectivity of 18c6 for 19 L-, or D-amino acids was measured by ESI-MS, indicating 18c6 could only recognize some neutral amino acid isomers.
The non-covalent interactions between 18-crown-6 (18c6) and 20 common types of protonated amino acids were explored by electrospray ionization mass spectrometry (ESI-MS). The mass spectra showed the formation of 1:1 stoichiometric non-covalent complexes between 18c6 and amino acids. The calibration curves and linear equations for the complexes of L-Phe, L-Tyr, L-Lys and L-Asp with 18c6 were established by mass spectrometric titration and used as reference values for competitive ESI-MS. Through competitive equilibrium, the binding constants for the complexes of 18c6 with other L-amino acids and their D-isomers were derived. It was found, as a general trend, lgKa for the complexes of 18c6 with the basic amino acid and the amino acid with alkyl side chain were larger than other complexes, and among the amino acids with alkyl side chain, Gly and Ala exhibited greater 18c6 binding affinities. As for Ser and Thr, the intramolecular hydrogen bond between the nitrogen atom from terminal NH2 and the oxygen atom from carboxyl may impede their protonated amino-group to attack the 18c6. Furthermore, Gln and Asn exhibited lower 18c6 binding affinities probably due to effects of electron-withdrawing group of acylamide. Finally, the chiral selectivity of 18c6 for 19 L-, or D-amino acids was measured by ESI-MS, indicating 18c6 could only recognize some neutral amino acid isomers.
2018, 46(2): 281-287
doi: 10.11895/j.issn.0253-3820.171056
Abstract:
The chemical structure of fatty acid has a great influence on the relaxation characteristic of lipid. In this work, the low-field nuclear magnetic resonance (LF-NMR) relaxation characteristics of fatty acids with different chain lengths or degree of saturation were investigated firstly, and then the relaxation characteristics of binary or ternary fatty acid mixtures were studied. The result showed that except acetic acid, the T2 relaxation time and T2W decreased as the carbon chain length increased; but as the unsaturated degree increased, these measures all increased. For the binary fatty acid system, the T2 relaxation time and T2W of palmitic acid-oleic acid and stearic acid-oleic acid all increased as oleic acid ratio increased. While for the linoleic acid-oleic acid system, only when the oleic acid ratio was above 40%, the relaxation response changed significantly. For the ternary fatty acid system, the T2 relaxation time of each linoleic acid/oleic acid/stearic acid system increased with the increase of linoleic acid ratio, while the area ratio S21 decreased, and S22 increased. The higher ratio of oleic acid and the change of the peak area ratio were relatively reduced, and the relative increases of T2W changed more slowly.
The chemical structure of fatty acid has a great influence on the relaxation characteristic of lipid. In this work, the low-field nuclear magnetic resonance (LF-NMR) relaxation characteristics of fatty acids with different chain lengths or degree of saturation were investigated firstly, and then the relaxation characteristics of binary or ternary fatty acid mixtures were studied. The result showed that except acetic acid, the T2 relaxation time and T2W decreased as the carbon chain length increased; but as the unsaturated degree increased, these measures all increased. For the binary fatty acid system, the T2 relaxation time and T2W of palmitic acid-oleic acid and stearic acid-oleic acid all increased as oleic acid ratio increased. While for the linoleic acid-oleic acid system, only when the oleic acid ratio was above 40%, the relaxation response changed significantly. For the ternary fatty acid system, the T2 relaxation time of each linoleic acid/oleic acid/stearic acid system increased with the increase of linoleic acid ratio, while the area ratio S21 decreased, and S22 increased. The higher ratio of oleic acid and the change of the peak area ratio were relatively reduced, and the relative increases of T2W changed more slowly.
2018, 46(2): 288-292
doi: 10.11895/j.issn.0253-3820.171299
Abstract:
The macroporous microspheres were prepared through suspension polymerization and based on a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate. The effect of porogen on the microspheres structure was evaluated in terms of pore size and surface area. Porogen contained dichloromethane (δ=9.7 (cal/cm3)1/2) and N-octanol (δ=10.3 (cal/cm3)1/2) which corresponded to a good and poor solvent, respectively. The solubility parameter of porogen was controlled in the range of 9.89-10.09 (cal/cm3)1/2. The pore size of microspheres increased with the difference value of solubility parameter between the polymer and the porogen. On the contrary, the surface area of microspheres decreased in this study. The anion exchange media was prepared through coupling poly(ethylene imine) in the microspheres, and the proteins transport was determined by frontal analysis method. The macroporous microspheres with 257 nm pore size could still afford a high proteins capacity (45.1 mg/mL). These macroporous supports showed a large potential in a rapid separation of proteins.
The macroporous microspheres were prepared through suspension polymerization and based on a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate. The effect of porogen on the microspheres structure was evaluated in terms of pore size and surface area. Porogen contained dichloromethane (δ=9.7 (cal/cm3)1/2) and N-octanol (δ=10.3 (cal/cm3)1/2) which corresponded to a good and poor solvent, respectively. The solubility parameter of porogen was controlled in the range of 9.89-10.09 (cal/cm3)1/2. The pore size of microspheres increased with the difference value of solubility parameter between the polymer and the porogen. On the contrary, the surface area of microspheres decreased in this study. The anion exchange media was prepared through coupling poly(ethylene imine) in the microspheres, and the proteins transport was determined by frontal analysis method. The macroporous microspheres with 257 nm pore size could still afford a high proteins capacity (45.1 mg/mL). These macroporous supports showed a large potential in a rapid separation of proteins.
2018, 46(2): 293-299
doi: 10.11895/j.issn.0253-3820.170295
Abstract:
To measure particle size distribution of phenols in mainstream cigarette smoke aerosol, the particles of cigarette smoke aerosol were divided into 12 stages using single channel smoking machine coupled electrical low-pressure impactor (ELPI) and collected by 12 polyester films. The collected particles were weighted and then analyzed by ultra-high performance liquid chromatography-fluorescence detection (UPLC-FLD) to determine the 14 phenols in the different size particles. The results showed that the aerosols collecting method had good stability with relative standard deviation (RSD) of collected particles mass less than 10%. The analyzing results of 14 phenols by UPLC-FLD showed that the linear correlation coefficients (R2) were greater than 0.9959, with detection limits were less than 1.2 ng/cig and recoveries were 80.1%-115.0%. The distributions of 14 phenols with respect to smoke aerosol particle size were investigated. The results indicated that except 4-ethyl-2-methoxy-phenol not detected, the other 13 phenols were detected in mainstream cigarette smoke aerosol. The content of 13 phenols appeared increasing at first and then decreasing with increase of the particle size which distributed in a pattern similar to that of particle mass. All of 13 phenols were present in higher amounts in the medium size particles (0.261-0.722 μm) with peak content in particles 0.431 μm. The distribution of concentrations (ratio of content to particle mass) of 13 phenols in different size particles was different. The concentrations of phenol and mono-substituted phenol appeared to first increase and then decrease with increasing smoke aerosol particle size and were higher in medium size particles (0.261-0.772 μm). The concentrations of benzenediol and mono-substituted benzenediol were uniformly distributed in medium size particles (0.144-1.166 μm), and the concentration of disubstituted phenol was uniform throughout the particles of varying sizes.
To measure particle size distribution of phenols in mainstream cigarette smoke aerosol, the particles of cigarette smoke aerosol were divided into 12 stages using single channel smoking machine coupled electrical low-pressure impactor (ELPI) and collected by 12 polyester films. The collected particles were weighted and then analyzed by ultra-high performance liquid chromatography-fluorescence detection (UPLC-FLD) to determine the 14 phenols in the different size particles. The results showed that the aerosols collecting method had good stability with relative standard deviation (RSD) of collected particles mass less than 10%. The analyzing results of 14 phenols by UPLC-FLD showed that the linear correlation coefficients (R2) were greater than 0.9959, with detection limits were less than 1.2 ng/cig and recoveries were 80.1%-115.0%. The distributions of 14 phenols with respect to smoke aerosol particle size were investigated. The results indicated that except 4-ethyl-2-methoxy-phenol not detected, the other 13 phenols were detected in mainstream cigarette smoke aerosol. The content of 13 phenols appeared increasing at first and then decreasing with increase of the particle size which distributed in a pattern similar to that of particle mass. All of 13 phenols were present in higher amounts in the medium size particles (0.261-0.722 μm) with peak content in particles 0.431 μm. The distribution of concentrations (ratio of content to particle mass) of 13 phenols in different size particles was different. The concentrations of phenol and mono-substituted phenol appeared to first increase and then decrease with increasing smoke aerosol particle size and were higher in medium size particles (0.261-0.772 μm). The concentrations of benzenediol and mono-substituted benzenediol were uniformly distributed in medium size particles (0.144-1.166 μm), and the concentration of disubstituted phenol was uniform throughout the particles of varying sizes.
