CoFe2O4 decorated graphene/C18-functionalized mesoporous silica nanocomposites prepared for magnetic enrichment and electrochemical detection of promethazine in beef

Promethazine(PHZ) is used as a sedative in veterinary medicine, and its residue can threaten the health of human. The electrochemical detection of PHZ is suitable method for application in the field. However,the traditional electroanalysis is difficult to perform directly in meat samples due to matrix interference. This work integrates magnetic solid-phase extraction and differential pulse voltammetry for highly sensitive and selective determination of PHZ in beef and beef liver for the first ti...     

用对氨基苯酚改性的碳纳米管糊电极同时测定羟胺和苯酚(英文)

A carbon paste electrode that was chemically modified with multiwall carbon nanotubes and p-aminophenol was used as a selective electrochemical sensor for the simultaneous detection of hydroxylamine (HX) and phenol. Cyclic voltammetry, double potential-step chronoamperometry, square wave voltammetry (SWV), and electrochemical impedance spectroscopy were used to investigate the use of p-aminophenol in the carbon nanotubes paste matrixes as a mediator for the electrocatalytic oxidation of HX and phenol in aqueous solution. The coefficient of electron transfer and catalytic reaction rate constant were determined using the electrochemical methods. Under optimized conditions, the electrocatalytic oxidation current peaks for HX and phenol increased linearly with concentration in the range of 0.5-180.0 and 10.0-650.0 μmol/L for HX and phenol, respectively. The detection limits for HX and phenol were 0.15 and 7.1 μmol/L, respectively. The anodic potential peaks of HX and phenol were separated by 0.65 V in SWV. Because of good selectivity and sensitivity, the present method provides a simple method for the selective detection of HX and phenol in practical samples such as water samples.     

A Hydrogen Peroxide Sensor Based on Silver Nanoparticles Biosynthesized by Bacillus subtilis

In this study, silver nanoparticles （AgNPs） were biosynthesized by Bacillus subtilis and used to construct a nonenzymatic hydrogen peroxide （H202） sensor, Scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy confirmed that the AgNPs were prepared successfully with spherical morphol- ogy. The electrochemical properties of the resulted sensor were investigated by cyclic voltammetry, chronoam- perometry and electrochemical impedance spectroscopy. It was found that the sensor exhibited good electrocatalytic activity towards H202 reduction with a wider linear range from 0.05 to 120 mmol.L-1, a detection limit of 8 gmol.L-1 and a fast response time less than 2 s. The sensor exhibited good selectivity for H202 determination in the presence of glucose, acetaminophen, ascorbic acid and uric acid.     

在3,4-二羟基肉桂酸介质中以多壁碳纳米管为传感器电催化检测L-半胱氨酸(英文)

A highly sensitive electrochemical sensor was prepared for the determination of L-cysteine using a modified multiwall carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid(3,4-DHCA) as a mediator, based on an electrocatalytic process. The results indicate that the electrode is electrocatalytically efficient for the oxidation of L-cysteine in the presence of 3,4-DHCA. The interaction between the mediator and L-cysteine can be used for its sensitive and selective determination. Using chronoamperometry, the catalytic reaction rate constant was calculated to be 2.37 × 102 mol–1 L s–1. The catalytic peak current was linearly dependent on the L-cysteine concentration in the range of 0.4–115 μmol/L. The detection limit obtained by linear sweep voltammetry was 0.25 μmol/L. Finally, the modified electrode was examined as a selective, simple, and precise new electrochemical sensor for the determination of L-cysteine in real samples.     

Preparation and Electrochemical Characters of Parathion Molecule Imprinted Polymeric Sensors

A sensitive, fast and low-cost molecular imprinted polymeric sensor for quantitative determination of parathion was prepared with chitosan(CS) as function matrix and parathion(PT) as template molecule via constant potential electrochemical deposition. Sensitive response was obtained with a detection limit of 1.0×10–7 mol/L and an excellent recognition for PT was achieved due to the good memory capacity of the sensor. The developed sensor exhibited good fabrication reproducibility and acceptable stability, w...     

Rapid detection of chlorpheniramine maleate by an electrochemical sensor based on metal-organic frameworks CHP@Cu3（BTC）2 /MWCNTsEI北大核心CSCD

Copper hydroxyphosphate@metal-organic frameworks/multi-wall carbon nanotube composites （CHP@Cu3 （BTC）2 /MWCNTs）were prepared by a new in-situ template method and then an electrochemical sensor was developed based on the composites. The crystal structure and morphology of the material were characterized by X-ray diffraction and scanning electron microscope. Cyclic voltammetry and linear sweep voltammetry were used to study the electrochemical catalytic performance，and the determination conditions were optimized. The rapid and sensitive detection of chlorphenamine maleate was realized. There was a good linear relationship between the oxidation peak current and concentration of chlorphenamine maleate in the ranges from 5 to 100 µμmol/L and from 150 to 800 µμmol/L，and the linear equations were as Ipa （µμA）=0.1559c（µμmol/L）-0.3533 （R2 =0.9973）and Ipa （µμA）=0.02328c（µμmol/L）+16.63（R2 =0.9594），and the detection limit was 1.67 µμmol/L. The recoveries of the actual drug ranged from 91.0% to 109.1%. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Construction of ceo2/rgo/gce electrochemical sensor for the determination of histamine in fishEI北大核心CSCD

By preparing nano-CeO2 (CeO2) and reduced graphene oxide (RGO), an electrochemical sensor based on CeO2/RGO composite was constructed for the detection of histamine. The morphology and structure of the composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical behavior of histamine on the sensor was studied by cyclic voltammetry (CV), and the conditions such as the type proportion and addition amount of the composite scanning rate and buffer pH were optimized. The results showed that the optimal conditions were as follows: The mass ratio was m(CeO2): M(RGO)=1: 0.25, the addition amount of composite material was 10 μL, the scanning rate was 300 mV/s and the pH of buffer solution was 8. A good linear relationship was observed between the peak current and the concentration of histamine in the range of 0.25–100 mg/L with the detection limit of 0.16 mg/L. The CeO2/RGO/GCE electrochemical sensor has been applied to the determination of histamine in fish samples with the spiked recoveries of 98.4% −104%. The method can be used to determine histamine content in fish products. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

POMs as Active Center for Sensitively Electrochemical Detection of Bisphenol A and Acetaminophen

A new type of electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs), K2H4SiW11CuO39-6H2O(SiW11Cu) and gold nanoparticles(AuNPs) was prepared for the simultaneous detection of bisphenol A and acetaminophen. Differential pulse voltammetry(DPV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were used for electrochemical characterization, and Fourier transfonn infrared spectroscopy(FTIR) was used to characterize the structure of polyoxometalates. Electrochemical experimental results show that the composite modified electrodes have good electrochemical activity as well as current response values of bisphenol A and acetaminophen when pH=7.0. At the same time, the modified electrode exhibits good stability and reproduction, and has good anti-interference ability to other substances. In practical application, the sensor obtained satisfactory results.     

A nonenzyme glucose sensor based on Cu/Ni/CMWCNTs nanocompositesEI北大核心CSCD

Copper-nickel bimetallic nanoparticles decorated on carboxylated multi-walled carbon nanotubes （Cu/Ni/CMWCNTs）were prepared by using a simple one-pot solvothermal method,which was then employed to construct a highly sensitive non-enzymatic glucose sensor. The modified electrode showed high sensitivity and stability in glucose detection,which was mainly attributed to the synergistic effect of the compact copper-nickel nanocomposite and carboxylated multi-walled carbon nanotubes that possessing high specific surface area to increase the number of active sites and to improve the electrocatalytic activity of the modified electrode. The phase structure and morphology of the material were characterized by X-ray diffraction and scanning electron microscope; the electrochemical performance of the sensor was studied by cyclic voltammetry and chronoamperometry. The sensor had a sensitivity of 1949.1 μµA·L/（mmol·cm2）for glucose detection in the linear range of 1.0-8000 μµmol/L at a potential of 0.55 V,and the detection limit was 0.2 μµmol/L. The sensor was also applied to measure the concentration of glucose in serum samples. The developed nanocomposites sensor has the potential prospect to monitor blood glucose. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Cascaded strand displacement for non-enzymatic target recycling amplification electrochemical detection of SARS-CoV-2EI北大核心CSCD

An electrochemical biosensor for low cost and highly sensitive and selective detection of SARS-CoV-2 target nucleic acid was developed based on two cascaded toehold-mediated strand displacement reactions (TSDRs). Driven by thermodynamic entropy, the target nucleic acid bound to the first toehold region of the probes, leading to the first TSDR and the second toehold region exposed. Subsequently, the methylene blue (MB)-modified signal probe triggered the second TSDR and led to cyclic reuse of the target nucleic acid. Based on cascaded TSDRs, a large number of signal probes were combined on the sensor surface to produce significantly enhanced square wave voltammetry (SWV)electrochemical signals. The results showed that the SWV signal intensity was proportional to the logarithm of the target nucleic acid concentration, and had a good linear relationship in the range of 5×10-14-5×10-10 mol/L with a detection limit of 1.8×10-14 mol/L. Moreover, the sensor could be employed to monitor SARS-CoV-2 nucleic acid in 10% serum samples. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

4D-proteomics-based breast cancer progressionEI北大核心CSCD

：The occurrence and development of breast cancer go through multiple processes，and the protein molecular information in its evolution is intricate and complex. The 4D-proteomics technique was used to investigate the tumor progression of MMTV-PyMT transgenic mice. The results of protein identification and differential expression analysis showed that a total of 5819 proteins were identified in 4D-proteomics analysis and 5667 proteins were quantifiable. Compared with 3-week-old tumors，a total of 270 differentially expressed proteins were found in the 5-week-old tumors，while 255 proteins in the 7-week-old tumors. We also detected 23 of proteins （such as，Srpk11 and Tinagl1）with gradual up-regulation and 35 of proteins （such as，Pdgfrb， Col1a2 and Col1a1）with gradual down-regulation during the tumor progression，including 3-，5-and 7-weeks. We also performed bioinformatics analysis，including subcellular localization，GO function analysis and pathway enrichment analysis. The results showed that the biological processes（immune regulation and lipid metabolism） and enrichment pathways （metabolic pathway）involved in differentially expressed proteins remained the same during the tumor progression，but some cellular components and molecular functions changed，such as，protein locations were extracellular region and membrane in 5-weeks-old tumors as well as cytoplasm in 7-weeks-old tumors. And important protein functions were protein binding functions in 5-weeks-old tumors as well as nucleotide binding in 7-weeks-old tumors. The acquired protein biomarkers and pathways could help with the accurate exploration of molecular mechanisms of tumor progression，screening of molecular targets of breast cancer，and evaluation of personalized treatment programs. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

氯离子加速的铜基芬顿反应用于对多巴胺的比色检测EI北大核心CSCD

基于氯离子加速的铜基芬顿反应构建了一种便捷、快速、无标记的比色分析方法并将其应用于多巴胺(DA)的快速检测。Cl^(-)可以加速Cu^(2+)催化过氧化氢(H_(2)O_(2))产生羟基自由基,进而氧化3,3′,5,5′-四甲基联苯胺(TMB)显色,而DA可以与Cu^(2+)配位,使反应速率减慢。基于此,可以利用检测液的颜色及TMB^(2+)在452 nm处吸光度的变化来实现对DA的检测。DA的浓度在0~10μmol/L及10~50μmol/L范围内与TMB^(2+)在452 nm处的吸光度呈线性相关,检出限为0.5μmol/L。本方法已用于实际样品的检测。     

Effect of metal ions on enantioseparation of five amino acids by ligand exchange capillary zone electrophoresisEI北大核心CSCD

Enantioseparation of five amino acids was conducted by chiral ligand exchange capillary zone electrophoresis (CLE-CZE). L-His and different metal ions in a certain proportion were used to form chiral recognition complexes. The enantiomers were exchanged with L-His ligands in the complex. Then, the separation of enantiomers was obtained according to the different ligand exchange ability. Effects of the valence and the electron layers of metal ions on the resolution were investigated systemically. Baseline separation of D, L-Phe, D, L-Tyr and D, L-Trp was obtained within 12 min when 4 mmol/L Co(Ⅱ) and 8 mmol/L L-His were added to the phosphate buffer solution (20 mmol/L, pH 8.0). The resolutions of D, L-Phe, D, L-Tyr and D, L-Trp were 1.53, 2.04, and 1.58, respectively. Partial chiral separation of D, L-Ser and D, L-Val was achieved under the same conditions. When Co(II) was used as the central ion, the resolution was better than that of Cu(II) and Zn(II), although they had the same number of electron layers and valence. The resolution of amino acids with Ag(I) as the central ion was not as good as that of divalent metal ions. Metal ions with three electron layers had better separation results than that with four electron layers. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

超高效液相色谱-三重四极杆质谱法测定化妆品中秋水仙碱、秋水仙胺和秋水仙碱苷EI北大核心CSCD

建立了一种同时测定化妆品中秋水仙碱、秋水仙胺和秋水仙碱苷的超高效液相色谱-三重四极杆质谱分析方法。试样经正己烷饱和的甲醇-乙腈(1∶1,V/V)混合溶剂超声提取,蜡基类样品经正己烷溶解分散后提取,膏霜类样品在提取液中加入乙酸铵以改善样品乳化情况,提取液离心过滤后,以5 mmol/L乙酸铵(含0.1%甲酸)-甲醇作为流动相梯度洗脱,经ACQUITY UPLC BEH C_(18)色谱柱分离后,采用超高效液相色谱-三重四极杆质谱在电喷雾正离子电离模式和多反应监测(MRM)模式检测。3种化合物在0.5~10μg/L范围内线性关系良好,相关系数大于0.995,检出限为3.0μg/kg,定量限为10.0μg/kg,在10.0,20.0,100μg/kg 3个加标水平下的平均回收率为81.5%~109.2%,相对标准偏差为0.5%~8.7%。该方法适用于化妆品中秋水仙碱、秋水仙胺和秋水仙碱苷的测定。     

Pd nanoparticles on boron doped graphene catalyst for electrochemical detection of hydrogen peroxide prepared by electroless deposition methodEI北大核心CSCD

Taking advantage of large conjugated structure and reductivity of boron-doped graphenethe palladium nanoparticles/boron-doped graphene catalyst was prepared by electroless deposition method using boron-doped graphene as reductant and stabilizer. The average size of palladium nanoparticles highly dispersed on the surface of boron-doped graphene was about 6.5 nm. The electrochemical sensor was prepared by modifying the as-formed catalyst on the surface of glassy carbon electrode. The obtained electrochemical sensor exhibited an excellent electrochemical catalytic activity for H2 O2 . It exhibited high sensitivity with the detection limit as low as 830 nmol/L and good linearity in the range of 2.5-300 μµmol/L for detection of H2 O2 . It could be utilized for the determination of H2 O2 in milk samples. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Determination of 15 polycyclic aromatic hydrocarbons in lotus root by QuEChERS-high performance liquid chromatographyEI北大核心CSCD

A method for the determination of 15 priority polycyclic aromatic hydrocarbonsPAHsin lotus root by QuEChERS technique combined with high performance liquid chromatography HPLC was established. Lotus root samples were extracted by acetonitrilefiltrated after salting out and purified by C18 and primary secondary aminePSAsorbent. Then the 15 kinds of PAHs were analyzed by HPLC with diode array detector or fluorescence detector after being separated by Athena PAHs column. When the 15 kinds of PAHs were analyzed by diode array detectorthe linear relationships were good between 0.02 and 1.0 mg/L with the correlation coefficients above 0.99 for all the 15 kinds of PAHs. The limits of quantitation were 0.02 mg/kg for allthe average recoveries of the 15 kinds of PAHs were 84.7%-117.1%and the relative standard deviations were 0.73%-11%. When the 14 kinds of PAHsexcept for acenaphthyleneanalyzed by fluorescence detectorthe linear relationships were good between 0.001 and 1.0 mg/L with the correlation coefficients above 0.99 for all the 14 kinds of PAHs except for acenaphthylene. The limits of quantitation were 5 μµg/kg for allthe average recoveries of the 14 kinds of PAHsexcept for acenaphthylenewere 69.1%-111.8%and the relative standard deviations were 0.18%-9.7%. Diode array detector and fluorescence detector are complementary. Diode array detector can analyze all the PAHsbut its sensitivity is relatively low. Fluorescence detector is not suitable for acenaphthylene with weak fluorescence signalbut its sensitivity is much higher than that of diode array detector. This method is suitable for simultaneously and quickly determination of 15 kinds of PAHs in lotus root. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

高效液相色谱-紫外检测法测定水产品中氨苯砜及其代谢物残留量EI北大核心CSCD

建立了水产品中氨苯砜及其代谢产物N-乙酰氨苯砜残留量同时测定的高效液相色谱-紫外检测法(HPLC-UV)。样品经1%氨化乙腈提取,正己烷去脂,MCX阳离子固相萃取柱富集净化,氮吹浓缩,定容过膜后测定。以甲醇和水为流动相,ZORBAX SB-C_(18)色谱柱梯度洗脱分离,采用保留时间定性,外标法定量。在最佳检测条件下,目标化合物质量浓度在5~200 ng/mL范围内线性关系良好(R^(2)> 0.999),检出限(LOD)为10.0μg/kg,定量限(LOQ)为20.0μg/kg。以不同类型的水产品为空白基质,在20,50,100μg/kg加标水平下,氨苯砜的回收率为70.1%~81.7%,N-乙酰氨苯砜的回收率为84.2%~109.5%,相对标准偏差(RSD)均小于10%。该方法能够实现大批量水产品中氨苯砜及其代谢物残留量的检测。     

Simultaneous determination of 73 fragrance allergens and 4 pesticides in silicone mosquito repellent products by ultrasonic solvent extraction combined with gas chromatography-tandem mass spectrometryEI北大核心CSCD

以73种致敏性芳香剂与4种农药为目标化合物,建立了硅胶驱蚊手环中致敏性芳香剂与农药同时测定的气相色谱-串联质谱(GC-MS/MS)方法。DB-17MS色谱柱分离,动态多反应监测模式(dMRM),外标法定量。采用阳性样品优化前处理条件,结果显示,以无水乙醇为提取溶剂、密闭控温超声提取可以有效提取硅胶样品中农药与致敏性芳香剂。最佳条件下,77种目标分析物在0.1~100 mg/L范围内线性良好(R^(2)>0.9920),定量限0.02~5.0 mg/kg,回收率66%~120%,相对标准偏差0.2%~9.8%。采用上述方法对14个驱蚊手环样品进行检测,共检出31种目标化合物。该方法可用于硅胶样品中致敏性芳香剂和农药高通量定向筛查。     

Determination of cobalt ion based on polyethyleneimine modified silver nanoclustersEI北大核心CSCD

PolyethyleneiminePEImodified silver nanoclustersAg NCswere synthesized through chemical reduction method by using PEI as stabilizerAgNO3 as silve source and ascorbic acid as reducing agentand it was applied to the detection of cobalt ions. It was found that the fluorescence of the silver nanoclusters was quenched by Co2+ for the aggregation of PEI-Ag NCs caused by the coordination between cobalt ion and amino group on polyethyleneimine. Under the optimized experimental conditionsthe fluorescence quenching degree of PEI-Ag NCs was piecewise linear with the concentration of cobalt ion in the range of 8.30×10-7-4.17×10-4 mol/L and the detection limit was 0.41 μµmol/L. © 2022, Youke Publishing Co.,Ltd. All rights reserved.