The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode.The effects of pH,scan rates,and con...The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode.The effects of pH,scan rates,and concentration of the drug on the anodic peak current were studied.Voltammograms of gemifloxacin in Tris-HCl buffer（pH 7.0） exhibited a well-defined single oxidation peak.A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity,limits of detection and quantification,accuracy,precision,specificity,and robustness.The calibration was linear from 0.5 to 10.0 μM,and the limits of detection and quantification were 0.15 and 5.0 μM.Recoveries ranging from 96.26% to 103.64% were obtained.The method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any pre-treatment.Excipients present in the tablets did not interfere in the assay.展开更多
In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The...In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The TM-AuNPs composited film had better sensitivity resulting from the gold nanoparticles amplification effect. A phase transition model analysis of TM-AuNPs films found that the TM-AuNPs films had three-phase transition intervals (<45℃, 45℃ to 80℃ and >80℃) which accommodated the temperature requirements for protein denaturation. When used to detect different concentrations of haemoglobin (Hb) solution, the TM-AuNPs modified SPCEs had a better sensitivity in detecting the different concentrations in comparison to TM and AuNP modified SPCEs which showed no clear sensitivity towards the different Hb concentrations. The dual detection and excellent sensitivity show a good application prospect for the study of the TM-AuNPs composite film.展开更多
A novel electrochemical method for the rapid detection of organophosphorus pesticide residues was realized on a dual-channel screen-printed electrode （DSPE） that was integrated with a portable smartphone-controlled ...A novel electrochemical method for the rapid detection of organophosphorus pesticide residues was realized on a dual-channel screen-printed electrode （DSPE） that was integrated with a portable smartphone-controlled potentiostat. The two carbon working channels of DSPE were first modified by electrodepositing of Prussian blue. The channels were then modified with acetylcholinesterase （ACHE） via Nation. The inhibition ratio of AChE was detected by comparing the electrical current of acetylthiocholine （ATCh） that was catalyzed by the enzyme electrodes with （channel 1） and without （channel 2） organophosphorus pesticide. Inhibition ratios were related with the negative logarithm of the organophosphorus pesticide （trichlorfon, oxamyl, and isocarbophos） concentrations at optimum experimental conditions （pH 6.9 of electrolyte, 0.2V working potential, 2.5μL AChE modification amount, and 15 min inhibition time）. The linear equations were 1%=32.301gC＋ 253.3 （R=0.9750） for isocarbophos, I% = 35.991gC＋ 270.1 （R = 0.9668） for chlorpyrifos, and 1% = 33.701gC＋ 250.5 （R = 0.9606） for trichlorfon. The detection limits were calculated as 10-7 g/mL. Given that the inhibition ratios were only related with pesticide concentration and not with pesticide species, the proposed electrodes and electrometer can rapidly detect universal organophosphorus pesticides and assess pesticide pollution.展开更多
Cadmium(Cd)and lead(Pb)in soil or water environment cause the ecological destruction and environmental deterioration when their contents exceed the natural background values.To trace the concentrations of Cd(II)and Pb...Cadmium(Cd)and lead(Pb)in soil or water environment cause the ecological destruction and environmental deterioration when their contents exceed the natural background values.To trace the concentrations of Cd(II)and Pb(II),a sensitive and selective electrode was developed using disposable screen-printed carbon electrode(SPE)immobilized with a composite film of reduced graphene oxide/carboxylation multi-walled carbon nanotubes/gold nanoparticle hybrid(RGO-MWNT-AuNP)throughπ-πbind.This highly conductive nano-composite layer,“RGO-MWNT-AuNP,”was characterized by scanning electron microscopy,UV-visible spectrometer,cyclic voltammetry,and electrochemical impedance spectroscopy.Square wave stripping voltammetry was applied to RGO-MWNT-AuNP/SPE to electroplate bismuth film and monitor the Cd(II)and Pb(II)simultaneously.To obtain high current responses,the detecting parameters were optimized.Under optimized conditions,the current responses showed a linear relationship with the concentrations of Cd(II)and Pb(II)in the range from 1.0 to 80.0μg/L with a lower detection limit of 0.7μg/L and 0.3μg/L(S/N=3),respectively.Finally,the prepared electrode was further employed to detect Cd(II)and Pb(II)in soil samples with good results.展开更多
Okadaic acid(OA),a small molecule substance derived from shellfish,is one of the most widely distributed marine toxins with acute symptoms of vomiting and diarrhea after accidental ingestion.For this,there is an urgen...Okadaic acid(OA),a small molecule substance derived from shellfish,is one of the most widely distributed marine toxins with acute symptoms of vomiting and diarrhea after accidental ingestion.For this,there is an urgently need for sensitive and reliable methods to detect OA in real shellfish samples.In this study,a simple aptasensor based on screen-printed carbon electrode(SPCE)with modification of chitosan(CS)and gold nanoparticles(Au NPs)was designed for electrochemical determination of OA,and the electrode surface was modified with Au NPs by potential-sweeping electrodeposition,which greatly improved the electrochemical response.The entire detection and characterization process were carried out by cyclic voltammetry(CV)with a linear correlation in the range of 0.01-100 ng/m L and a limit of detection(LOD)of 6.7 pg/m L.Furthermore,recovery rates of 92.3-116%were obtained demonstrating excellent accuracy through the recovery trial of mussel and scallop samples.展开更多
The zwitterionic compound,levofloxacin,was determined for the first time at different pH values in pure samples,pharmaceutical preparations and spiked serum and urine samples.Different types of potentiometric sensors ...The zwitterionic compound,levofloxacin,was determined for the first time at different pH values in pure samples,pharmaceutical preparations and spiked serum and urine samples.Different types of potentiometric sensors including poly(vinyl chloride)membrane electrode,carbon paste electrode and screen printed electrode,containing the ion pair levofloxaciniumphosphomolybdate as the electroactaive species,were used for this purpose.The effect of pH is the key factor in determining the ratio of the different species that can exist in the medium(zwitterionic,monocationic,dicationic,anionic and neutral),and so it is the controller of the electrochemical performance.The different sensors were fully characterized and optimized in terms of composition,pH effect,selectivity,response and lifetimes.The different sensors showed reliable reversibility and could be utilized for the determination of the drug in real spiked physiological fluids with reliable recovery values.展开更多
Salicylic acid(SA)is used as a preservative in food and a biocide in some consumer products.However,in some countries its use is prohibited.The main problem in the electroanalytical determination of SA is the formatio...Salicylic acid(SA)is used as a preservative in food and a biocide in some consumer products.However,in some countries its use is prohibited.The main problem in the electroanalytical determination of SA is the formation of a passive film during the electro-oxidation of SA.To alleviate the passivation during SA measurement,the experiment was conducted by screen-printed carbon electrode(SPCE).While,differential pulse voltammetry(DPV)was essential for oxidation process to provide better sensitivity.Under conditions of optimized pH and electrolyte concentration,we have calibrated SA in the range of 0.001-0.2 mM,with and LOD of 1.6μM.The relative standard deviation of the sensor responses to 40μM and 100μM SA(n=20)was<3%.SA recoveries in samples such as pickled green mustard,pickled bamboo shoots,pickled mango,pickled lime,pickle ginger and apple juice were found to be in the range of 84-113%.展开更多
Chloramphenicol(CAP)is an antifungal agent approved for use in aquarium.However,CAP residue imparts serious adverse effect on human health as well as the ecology.Thus,keeping track of CAP in aquatic products and its e...Chloramphenicol(CAP)is an antifungal agent approved for use in aquarium.However,CAP residue imparts serious adverse effect on human health as well as the ecology.Thus,keeping track of CAP in aquatic products and its environmental metabolites are of great importance.Herein,we developed a novel and neat electrochemical aptasensor for the detection of simulated CAP residual in a sandwich fashion.The screen-printed carbon electrode was employed as the sensing platform and electrodeposited with peculiar nanogolds to enhance the electrochemical performance.For the specific recognition of such small target,a pair of chloramphenicol-binding aptamers,the primary Aptl and the secondary Apt2,were tailored as an artificial single-chained antibody couple,of which the thi-olated Aptl stood on the coated working substrate to capture the analyte,while the biotinylated Apt2 rallied the signal output.In the presence of CAP,Aptl at the lower place cooperated with the upper Apt2 pinched CAP together.After that,the reporter avidin-conjugated horseradish peroxidase associated atop the mounted biotin labels,resulting in an electrocatalytic amplification.In whole,this modular biosensing construction would set a paradigm not just for practicable checkpoint quarantine or point-of-care testing,but potentially adaptable for technological fusion with“Internet Plus”and“Internet of Things”.展开更多
A disposable biosensor was fabricated using single-walled carbon nanotubes, gold nanoparticles and tyrosinase （SWCNTs-AuNPs-Tyr） modified screen-printed electrodes. The prepared biosensor was applied to the rapid de...A disposable biosensor was fabricated using single-walled carbon nanotubes, gold nanoparticles and tyrosinase （SWCNTs-AuNPs-Tyr） modified screen-printed electrodes. The prepared biosensor was applied to the rapid determination of phenolic contaminants within 15 minutes. The SWCNTs-AuNPs-Tyr bionanocomposite sensing layer was characterized with scanning electron micro- scopy, electrochemical impedance spectroscopy and cyclic voltammetry methods. The characterization results revealed that SWCNTs could lead to a high loading of tyrosinase （Tyr） with the large surface area and the porous morphology, while AuNPs could retain the bioactivity of Tyr and enhance the sensitivity. The detection conditions, including working potential, pH of supporting electrolyte and the amount of Tyr were optimumed. As an example, the biosensor for catechol determination displayed a linear range of 8.0 × 10^-8 to 2.0 × 10^- 5 mol.L-1 with a detection limit of 4.5 × 10^-8 mol.L-1 （S/N= 3）. This method has a rapid response time within 10 s, and shows excellent repeatability and stability. Moreover, the resulting biosen- sor could be disposable, low-cost, reliable and easy to carry. This kind of new Tyr biosensor provides great potential for rapid, on-site and cost-effective analysis of phenolic contaminants in environmental water samples.展开更多
文摘The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode.The effects of pH,scan rates,and concentration of the drug on the anodic peak current were studied.Voltammograms of gemifloxacin in Tris-HCl buffer（pH 7.0） exhibited a well-defined single oxidation peak.A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity,limits of detection and quantification,accuracy,precision,specificity,and robustness.The calibration was linear from 0.5 to 10.0 μM,and the limits of detection and quantification were 0.15 and 5.0 μM.Recoveries ranging from 96.26% to 103.64% were obtained.The method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any pre-treatment.Excipients present in the tablets did not interfere in the assay.
文摘In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The TM-AuNPs composited film had better sensitivity resulting from the gold nanoparticles amplification effect. A phase transition model analysis of TM-AuNPs films found that the TM-AuNPs films had three-phase transition intervals (<45℃, 45℃ to 80℃ and >80℃) which accommodated the temperature requirements for protein denaturation. When used to detect different concentrations of haemoglobin (Hb) solution, the TM-AuNPs modified SPCEs had a better sensitivity in detecting the different concentrations in comparison to TM and AuNP modified SPCEs which showed no clear sensitivity towards the different Hb concentrations. The dual detection and excellent sensitivity show a good application prospect for the study of the TM-AuNPs composite film.
基金financially supported by the Natural Science Foundation of Zhejiang Province(No.LQ17B050002)Analysis and Measurement Foundation of Zhejiang Province(No.2015C37068)
文摘A novel electrochemical method for the rapid detection of organophosphorus pesticide residues was realized on a dual-channel screen-printed electrode （DSPE） that was integrated with a portable smartphone-controlled potentiostat. The two carbon working channels of DSPE were first modified by electrodepositing of Prussian blue. The channels were then modified with acetylcholinesterase （ACHE） via Nation. The inhibition ratio of AChE was detected by comparing the electrical current of acetylthiocholine （ATCh） that was catalyzed by the enzyme electrodes with （channel 1） and without （channel 2） organophosphorus pesticide. Inhibition ratios were related with the negative logarithm of the organophosphorus pesticide （trichlorfon, oxamyl, and isocarbophos） concentrations at optimum experimental conditions （pH 6.9 of electrolyte, 0.2V working potential, 2.5μL AChE modification amount, and 15 min inhibition time）. The linear equations were 1%=32.301gC＋ 253.3 （R=0.9750） for isocarbophos, I% = 35.991gC＋ 270.1 （R = 0.9668） for chlorpyrifos, and 1% = 33.701gC＋ 250.5 （R = 0.9606） for trichlorfon. The detection limits were calculated as 10-7 g/mL. Given that the inhibition ratios were only related with pesticide concentration and not with pesticide species, the proposed electrodes and electrometer can rapidly detect universal organophosphorus pesticides and assess pesticide pollution.
基金This work was supported by the International Research Exchange Scheme of the Marie Curie Program of the 7th Framework Program(Ref.PIRSES-GA-2013-612659)Chinese National Natural Science Foundation(No.31671578)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2016 XD001)the Shandong Provincial Natural Science Foundation of China(No.ZR2015CM016).
文摘Cadmium(Cd)and lead(Pb)in soil or water environment cause the ecological destruction and environmental deterioration when their contents exceed the natural background values.To trace the concentrations of Cd(II)and Pb(II),a sensitive and selective electrode was developed using disposable screen-printed carbon electrode(SPE)immobilized with a composite film of reduced graphene oxide/carboxylation multi-walled carbon nanotubes/gold nanoparticle hybrid(RGO-MWNT-AuNP)throughπ-πbind.This highly conductive nano-composite layer,“RGO-MWNT-AuNP,”was characterized by scanning electron microscopy,UV-visible spectrometer,cyclic voltammetry,and electrochemical impedance spectroscopy.Square wave stripping voltammetry was applied to RGO-MWNT-AuNP/SPE to electroplate bismuth film and monitor the Cd(II)and Pb(II)simultaneously.To obtain high current responses,the detecting parameters were optimized.Under optimized conditions,the current responses showed a linear relationship with the concentrations of Cd(II)and Pb(II)in the range from 1.0 to 80.0μg/L with a lower detection limit of 0.7μg/L and 0.3μg/L(S/N=3),respectively.Finally,the prepared electrode was further employed to detect Cd(II)and Pb(II)in soil samples with good results.
基金supported by Beijing University of Chemical Technology-China-Japan Friendship Hospital Biomedical Translation Engineering Research Center Joint Project(RZ2020-02)the National Key Research and Development Program of China(2016YFF0203703)
文摘Okadaic acid(OA),a small molecule substance derived from shellfish,is one of the most widely distributed marine toxins with acute symptoms of vomiting and diarrhea after accidental ingestion.For this,there is an urgently need for sensitive and reliable methods to detect OA in real shellfish samples.In this study,a simple aptasensor based on screen-printed carbon electrode(SPCE)with modification of chitosan(CS)and gold nanoparticles(Au NPs)was designed for electrochemical determination of OA,and the electrode surface was modified with Au NPs by potential-sweeping electrodeposition,which greatly improved the electrochemical response.The entire detection and characterization process were carried out by cyclic voltammetry(CV)with a linear correlation in the range of 0.01-100 ng/m L and a limit of detection(LOD)of 6.7 pg/m L.Furthermore,recovery rates of 92.3-116%were obtained demonstrating excellent accuracy through the recovery trial of mussel and scallop samples.
文摘The zwitterionic compound,levofloxacin,was determined for the first time at different pH values in pure samples,pharmaceutical preparations and spiked serum and urine samples.Different types of potentiometric sensors including poly(vinyl chloride)membrane electrode,carbon paste electrode and screen printed electrode,containing the ion pair levofloxaciniumphosphomolybdate as the electroactaive species,were used for this purpose.The effect of pH is the key factor in determining the ratio of the different species that can exist in the medium(zwitterionic,monocationic,dicationic,anionic and neutral),and so it is the controller of the electrochemical performance.The different sensors were fully characterized and optimized in terms of composition,pH effect,selectivity,response and lifetimes.The different sensors showed reliable reversibility and could be utilized for the determination of the drug in real spiked physiological fluids with reliable recovery values.
基金support provided by Agricultural Research Development Agency(Grant no.CRP5507010820)the King Mongkut’s University of Technology Thonburi through the“KMUTT 55th Anniversary Commemorative Fund”(Grant number 60000331).
文摘Salicylic acid(SA)is used as a preservative in food and a biocide in some consumer products.However,in some countries its use is prohibited.The main problem in the electroanalytical determination of SA is the formation of a passive film during the electro-oxidation of SA.To alleviate the passivation during SA measurement,the experiment was conducted by screen-printed carbon electrode(SPCE).While,differential pulse voltammetry(DPV)was essential for oxidation process to provide better sensitivity.Under conditions of optimized pH and electrolyte concentration,we have calibrated SA in the range of 0.001-0.2 mM,with and LOD of 1.6μM.The relative standard deviation of the sensor responses to 40μM and 100μM SA(n=20)was<3%.SA recoveries in samples such as pickled green mustard,pickled bamboo shoots,pickled mango,pickled lime,pickle ginger and apple juice were found to be in the range of 84-113%.
基金Supported by the National Natural Science Foundation of China(Nos.21874071,21775072)the Outstanding Youth Foundation of Jiangsu Province,China(No.BK20170093)+1 种基金the Fundamental Research Funds for the Central Universities of China(Nos.30916011201,309171A8803)the National Key Research and Development Program of China for International Science&Innovation Cooperation Major Project Between Govemments(No.2018YFE0113200).
文摘Chloramphenicol(CAP)is an antifungal agent approved for use in aquarium.However,CAP residue imparts serious adverse effect on human health as well as the ecology.Thus,keeping track of CAP in aquatic products and its environmental metabolites are of great importance.Herein,we developed a novel and neat electrochemical aptasensor for the detection of simulated CAP residual in a sandwich fashion.The screen-printed carbon electrode was employed as the sensing platform and electrodeposited with peculiar nanogolds to enhance the electrochemical performance.For the specific recognition of such small target,a pair of chloramphenicol-binding aptamers,the primary Aptl and the secondary Apt2,were tailored as an artificial single-chained antibody couple,of which the thi-olated Aptl stood on the coated working substrate to capture the analyte,while the biotinylated Apt2 rallied the signal output.In the presence of CAP,Aptl at the lower place cooperated with the upper Apt2 pinched CAP together.After that,the reporter avidin-conjugated horseradish peroxidase associated atop the mounted biotin labels,resulting in an electrocatalytic amplification.In whole,this modular biosensing construction would set a paradigm not just for practicable checkpoint quarantine or point-of-care testing,but potentially adaptable for technological fusion with“Internet Plus”and“Internet of Things”.
文摘A disposable biosensor was fabricated using single-walled carbon nanotubes, gold nanoparticles and tyrosinase （SWCNTs-AuNPs-Tyr） modified screen-printed electrodes. The prepared biosensor was applied to the rapid determination of phenolic contaminants within 15 minutes. The SWCNTs-AuNPs-Tyr bionanocomposite sensing layer was characterized with scanning electron micro- scopy, electrochemical impedance spectroscopy and cyclic voltammetry methods. The characterization results revealed that SWCNTs could lead to a high loading of tyrosinase （Tyr） with the large surface area and the porous morphology, while AuNPs could retain the bioactivity of Tyr and enhance the sensitivity. The detection conditions, including working potential, pH of supporting electrolyte and the amount of Tyr were optimumed. As an example, the biosensor for catechol determination displayed a linear range of 8.0 × 10^-8 to 2.0 × 10^- 5 mol.L-1 with a detection limit of 4.5 × 10^-8 mol.L-1 （S/N= 3）. This method has a rapid response time within 10 s, and shows excellent repeatability and stability. Moreover, the resulting biosen- sor could be disposable, low-cost, reliable and easy to carry. This kind of new Tyr biosensor provides great potential for rapid, on-site and cost-effective analysis of phenolic contaminants in environmental water samples.
