scholarly journals Direct Mercury Detection in Landfill Leachate Using a Novel AuNP-Biopolymer Carbon Screen-Printed Electrode Sensor

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 649
Author(s):  
Jae-Hoon Hwang ◽  
David Fox ◽  
Jordan Stanberry ◽  
Vasileios Anagnostopoulos ◽  
Lei Zhai ◽  
...  

A novel Au nanoparticle (AuNP)-biopolymer coated carbon screen-printed electrode (SPE) sensor was developed through the co-electrodeposition of Au and chitosan for mercury (Hg) ion detection. This new sensor showed successful Hg2+ detection in landfill leachate using square wave anodic stripping voltammetry (SWASV) with an optimized condition: a deposition potential of −0.6 V, deposition time of 200 s, amplitude of 25 mV, frequency of 60 Hz, and square wave step voltage of 4 mV. A noticeable peak was observed at +0.58 V associated with the stripping current of the Hg ion. The sensor exhibited a good sensitivity of ~0.09 μA/μg (~0.02 μA/nM) and a linear response over the concentration range of 10 to 100 ppb (50–500 nM). The limit of detection (LOD) was 1.69 ppb, which is significantly lower than the safety limit defined by the United States Environmental Protection Agency (USEPA). The sensor had an excellent selective response to Hg2+ in landfill leachate against other interfering cations (e.g., Zn2+, Pb2+, Cd2+, and Cu2+). Fifteen successive measurements with a stable peak current and a lower relative standard deviation (RSD = 5.1%) were recorded continuously using the AuNP-biopolymer-coated carbon SPE sensor, which showed excellent stability, sensitivity and reproducibility and consistent performance in detecting the Hg2+ ion. It also exhibited a good reliability and performance in measuring heavy metals in landfill leachate.

2019 ◽  
Vol 76 ◽  
pp. 02001
Author(s):  
Aamir Amanat Ali Khan ◽  
Huma Ajab ◽  
Asim Yaqub ◽  
Mohd Azmuddin Abdullah

Square-wave voltammetric stripping analysis is attractive for environmental monitoring and trace metal ion determination. The sensitivity is a result of analytes preconcentration steps on the electrode and advanced measurement procedures, where metal analytes are stripped away from the electrode at appropriate potential scan. Screen-printed electrode (SPE) has great advantages for in situ assays of heavy metal ions. Modification of SPE with bismuth (Bi) film improves the amalgamation of metal ions and the addition of hydroxyapatite (HA) increases the ion sorption, and enhances the current response due to the large porous structure and surface active sites for the metal ion binding. The ionization of the functional groups on the electrode surface upon contact with the aqueous system further assists the cation binding. The analytical performance of Bi and HA-modified SPE for simultaneous detection of Cd(II) and Pb(II) ions by square wave anodic stripping voltammetry (SWASV) was evaluated. Under the optimized electrochemical working conditions, calibration graph is linear for 240 s deposition time, in 0.1 M acetate buffer at pH 7.6 with the detection limit of 16.8 ppb for Pb(II). Two peaks corresponding to Cd(II) at -0.8 V and Pb(II) at -0.6 V can be discerned suggesting that Bi-HA modification had increased the current responses.


2011 ◽  
Vol 76 (3) ◽  
pp. 159-176 ◽  
Author(s):  
Ibrahim Hüdai Taşdemir ◽  
Orhan Çakirer ◽  
Nevin Erk ◽  
Esma Kiliç

Electrochemical properties and diffusion-adsorption behavior of risperidone (RPN), an antiphyscotic drug, on hanging mercury drop electrode (HMDE) were carried out in Britton–Robinson (BR) buffer. Some electrochemical parameters such as diffusion coefficient, number of transferred electrons and proton participated to its reduction mechanism and surface coverage coefficient were calculated from the results of cyclic voltammetry, square-wave voltammetry and constant potential electrolysis. RPN was found to be reduced with single two-electron/two-proton quasi-reversible mechanism controlled mainly by adsorption with some diffusion contribution at the potential about –1.58 V (vs Ag|AgCl electrode). Experimental parameters were optimized to develop a new, accurate, rapid, selective and simple square-wave cathodic adsorptive stripping voltammetric (SWCAdSV) method for direct determination of RPN in pharmaceutical dosage forms, spiked human urine and human serum samples without time-consuming steps prior to drug assay. This method was based on the relation between the peak current and the concentration of RPN and it was recognized that peak current of reduction wave linearly changes with the concentration of RPN in the concentration range of 1.5–150 nM, when optimum preconcentration potential –0.65 V and optimum preconcentration time 60 s were applied. In this method, limit of detection (LOD) was found as 5.18 nM (2.12 ppb). The method was successfully applied to determine the RPN content of commercial pharmaceutical preparations, spiked human serum and spiked human urine. The method was found to be highly accurate and precise, having a relative standard deviation of less than 4.80% for all applications.


Author(s):  
Abolfazl Darroudi ◽  
Saeid Nazari ◽  
Seyed Ali Marashi ◽  
Mahdi Karimi-Nazarabad

Abstract An accurate, rapid, simple, and novel technique was developed to determine simvastatin (SMV). In this research, a screen-printed electrode (SPE) was deposited with graphene oxide (GO) and sodium dodecyl sulfate (SDS), respectively. For the first time, the handmade modified SPE measured the SMV by differential pulse voltammetry (DPV) with high sensitivity and selectivity. The results of cyclic voltammetry indicated the oxidation irreversible process of SMV. Various parameters (pH, concentration, scan rate, support electrolyte) were performed to optimize the conditions for the determination of SMV. Under the optimum experiment condition of 0.1 M KNO3 as support electrolyte and pH 7.0, the linear range was achieved for SMV concentration from 1.8 to 36.6 µM with a limit of detection (LOD), and a limit of quantitation (LOQ) of 0.06 and 1.8 µM, respectively. The proposed method was successfully utilized to determine SMV in tablets and urine samples with a satisfactory recovery in the range of 96.2 to 103.3%.


2019 ◽  
Vol 9 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Sayed Zia Mohammadi ◽  
Hadi Beitollahi ◽  
Tahereh Rohani ◽  
Hossein Allahabadi

Electrochemical characteristics of carvacrol were investigated on a screen-printed electrode (SPE) modified with La2O3/Co3O4 nanocomposite by using voltammetric techniques, which displayed a well-defined peak for sensitive carvacrol determination in phosphate buffer solution (PBS) at pH 7.0. La2O3/Co3O4 nanoparticles demonstrated suitable catalytic activity for carvacrol determination by differential pulse voltammetry (DPV) technique. Besides, determination of carvacrol in a real samples was recognized in the light of electrochemical findings and a validated voltammetric technique for quantitative analysis of carvacrol in a real formulation was proposed. The DPV peak currents were found to be linear in the concentration range of 10.0 to 800.0 μM. The limit of detection (LOD) was found to be 1.0 μM.


2020 ◽  
Vol 34 (1) ◽  
pp. 25-39
Author(s):  
Denekew Alemayehu ◽  
Bhagwan Singh Chandravanshi Chandravanshi ◽  
Tesfu Hailu ◽  
Merid Tessema

A new method has been developed for the electrochemical determination of Hg(II) with N-p-chlorophenylcinnamohydroxamic acid (CPCHA) modified carbon paste electrode by square wave anodic stripping voltammetry (SWASV). Hg(II) was accumulated on the electrode surface by the formation of the complex in an open circuit and the resulting surface was characterized by electrochemical reduction and stripping. The optimum voltammetric response was observed using a carbon paste composition of 7.5% (w/w) CPCHA and preconcentration time of 210 s in 0.1 M sodium acetate at pH 8 followed by electrochemical SWASV in 0.3 M NH4Cl solution at pH 4 at a reduction potential of -0.6 V. The voltammetric signals were linear in the range of 1-25 µM Hg(II) with a detection limit of 12.9 nM. The voltammetric response for six replicate measurements of 15 µM Hg(II) was reproduced with 3.8% relative standard deviation (RSD). Many coexisting metal ions had little or no effect on the determination of Hg(II). Five spiked samples of water were evaluated by using the developed method giving recoveries of Hg(II) in the range 98-105%.   Bull. Chem. Soc. Ethiop. 2020, 34(1), 25-39. DOI: https://dx.doi.org/10.4314/bcse.v34i1.3


Toxins ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 317 ◽  
Author(s):  
Xian Zhang ◽  
Zuohuan Wang ◽  
Hui Xie ◽  
Renjie Sun ◽  
Tong Cao ◽  
...  

A rapid and sensitive electrochemical biosensor based on magnetic nanoparticles and screen-printed electrodes (MNPs-SPEs sensor) was developed for the detection of ochratoxin A (OTA) in cereal and feed samples. Different types of magnetic nanoparticles-based ELISA (MNPs-ELISA) were optimized, and the signal detection, as well as sensitivity, was enhanced by the combined use of screen-printed electrodes (SPEs). Under the optimized conditions, the calibration curve of the MNPs-SPEs sensor was y = 0.3372x + 0.8324 (R2 = 0.9805). The linear range of detection and the detection limit were 0.01–0.82 ng/mL and 0.007 ng/mL, respectively. In addition, 50% inhibition (IC50) was detectable at 0.10 ng/mL. The limit of detection (LOD) of this MNPs-SPEs sensor in cereal and feed samples was 0.28 μg/kg. The recovery rates in spiked samples were between 78.7% and 113.5%, and the relative standard deviations (RSDs) were 3.6–9.8%, with the coefficient of variation lower than 15%. Parallel analysis of commercial samples (corn, wheat, and feedstuff) showed a good correlation between MNPs-SPEs sensor and liquid chromatography tandem mass spectrometry (LC/MS-MS). This new method provides a rapid, highly sensitive, and less time-consuming method to determine levels of ochratoxin A in cereal and feedstuff samples.


The Analyst ◽  
2015 ◽  
Vol 140 (22) ◽  
pp. 7522-7526 ◽  
Author(s):  
A. M. Vinu Mohan ◽  
Barbara Brunetti ◽  
Andrea Bulbarello ◽  
Joseph Wang

Distinct electrochemical signatures of multivitamins using cyclic square wave voltammetry at a disposable screen printed electrode.


2012 ◽  
Vol 452-453 ◽  
pp. 909-912
Author(s):  
Saithip Pakapongpan ◽  
Surachai Thachepan ◽  
Yingyot Poo-Arporn ◽  
Rungtiva Palangsuntikul

Multi-walled carbon nanotubes (MWNTs) were coated first with methylene blue (MB) by noncovalent adsorption and then by horseradish peroxidase (HRP) and glucose oxidase (GOD) by covalent-linking. The MB-MWNTs/GOD/HRP composites formed stable films on screen-printed electrodes (SPE). The electrochemical and electrocatalytic behaviors of the bienzyme modified SPE were studied using cyclic voltammetry (CV) and amperometry. Using the MB-MWNT/GOD/HRP composites, glucose could be calibrated by amperometry at −0.35 V vs. SCE. The optimized response (at pH 7.0) had a sensitivity of 2.4 mA.M−1 and a limit of detection (3×S/N) of 35 µM. Tests of the portable bienzyme sensor demonstrate its imperviousness to the effects of ascorbic acid, uric acid and p-acetaminophen, as well as its ability to measure glucose concentrations ranging from 0.25 to 2 mM.


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