Electrochemical sensor for the detection of lead ions
24 Jul 2013-pp 367-370
TL;DR: In this paper, a glutathione stabilized silver nanoparticles (GSH-AgNPs) modified screen printed electrode was proposed to determine the trace levels of Pb(II) by using cyclic voltammetry.
Abstract: The development of practical sensors for the detection and quantification of heavy metals ions in the samples is the subject of considerable research. A glutathione stabilized silver nanoparticles (GSH-AgNPs) modified screen printed electrode was proposed to determine the trace levels of Pb(II) by using cyclic voltammetry. Maximum current was obtained at the potential range of 0.263 V. The electrostatic redox peak current shows a linear response towards the concentration of Pb(II) and linear calibration curves were obtained. The limit of detection was determined as 4.963×10-8 M and the sensitivity response is 10-5 mV with a scanning rate of 100 mV/s.
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TL;DR: In this paper, a colloidal silver solution was synthesized by reducing silver nitrate using sodium borohydride and starch as a stabilizer agent, which exhibited a strong antibacterial activity against Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S.aureus).
Abstract: The colloidal silver solution was synthesized by reducing silver nitrate () using sodium borohydride () and starch as a stabilizer agent. The size and optical properties of synthesized AgNPs were characterized by UV-Vis spectroscopy, Fourier transform-infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The effects of several parameters on AgNPs were also investigated. The results have shown that the size of synthesized spherical silver nanoparticles was and disperse in water. The synthesized AgNPs of his study exhibited a strong antibacterial activity against Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The average zones of inhibition of AgNPs were of 7.7 mm for bacteria E. coli and 7.0 mm for S. aureus. In this study, the zone of inhibition of AgNPs was also compared to the reference antibiotics drug.
60 citations
TL;DR: In this article, the iminephthalocyanine derivative displayed redox peaks ascribed to cobalt (Co+2/Co+1) metal and phthalocyanin ligand (Pc−2/Pc+3).
21 citations
01 Jan 2012
TL;DR: In this article, the authors present a range of on-going projects with an emphasis on environmental sensing; relevant literature pertaining to sensor networks is reviewed, validated sensing applications are described and the contribution of high-resolution temporal data to better decision-making is discussed.
Abstract: With the increasingly ubiquitous use of web-based technologies in modern society, autonomous sensor networks represent the future in large-scale information acquisition for applications ranging from environmental monitoring to in-vivo sensing. This chapter presents a range of on-going projects with an emphasis on environmental sensing; relevant literature pertaining to sensor networks is reviewed, validated sensing applications are described and the contribution of high-resolution temporal data to better decision-making is discussed.
14 citations
TL;DR: In this paper, the authors proposed a new microfluidic portable experimental platform for quick detection of heavy metal ions (HMIs) in picomolar range using a microfabricated piezoresistive sensor (MPS) array of eight cantilevers with ion-selective self-assembled monolayer's (SAM).
Abstract: This paper aims to propose a new microfluidic portable experimental platform for quick detection of heavy metal ions (HMIs) in picomolar range. The experimental setup uses a microfabricated piezoresistive sensor (MPS) array of eight cantilevers with ion-selective self-assembled monolayer's (SAM).,Most of the components used in this experimental setup are battery operated and, hence, portable to perform the on-field experiments. HMIs (antigen) and thiol-based SAM (antibody) interaction start bending the microcantilever. This results in a change of resistance, which is directly proportional to the surface stress produced due to the mass of targeted HMIs. The authors have used Cysteamine and 4-Mercaptobenzoic acid as a thiol for creating SAM to test the sensitivity and identify the suitable thiol. Some of the cantilevers are blocked using acetyl chloride to use as a reference for error detection.,The portable experimental platform achieves very small detection time of 10-25 min with a lower limit of detection (LOD) 0.762 ng (6.05 pM) for SAM of Cysteamine and 4-Mercaptobenzoic acid to detect Mn2+ ions. This technique has excellent potential and capability to selectively detect Hg2+ ions as low as 2.43 pM/mL using SAM of Homocysteine (Hcys)-Pyridinedicarboxylic acid (PDCA).,As microcantilever is very thin and fragile, it is challenging to apply a surface coating to have selective detection using Nanadispenser. Some of the cantilevers get broken during this process.,The excessive use and commercialization of NPs are quickly expanding their toxic impact on health and the environment. Also, LOD is limited to nanomolar range. The proposed method used the combination of thin-film, NPs, and MEMS-based technology to overcome the limitation of NPs-based technique and have picomolar range of HMIs detection.
11 citations
TL;DR: In this article, the use of newly developed composite materials (organic-inorganic hybrid) based on PANI-GO-APTES for electrochemical detection of Pb2+ in aqueous solution was explored.
Abstract: Lead is a potentially toxic element (PTE) that has several adverse medical effects in humans. Its presence in the environment became prominent due to anthropogenic activities. The current study explores the use of newly developed composite materials (organic-inorganic hybrid) based on PANI-GO-APTES for electrochemical detection of Pb2+ in aqueous solution. The composite material (PANI-GO-APTES) was synthesized by chemical method and was characterized with SEM, XPS, XEDS, XRD, TGA, FTIR, EIS and CV. The result of characterization indicates the successful synthesis of the intended material. The PANI-GO-APTES was successfully applied for electrochemical detection of Pb2+ using cyclic voltammetry and linear sweep voltammetry method. The limit of detection of Pb2+ was 0.0053 µM in the linear range of 0.01 µM to 0.4 µM. The current response produced during the electrochemical reduction of Pb2+ catalyzed by PANI-GO-APTES was also very repeatable, reproducible and rapid. The application of PANI-GO-APTES-modified GCE in real sample analysis was also established. Therefore, PANI-GO-APTES is presented as a potential Pb2+ sensor for environmental and human health safety.
10 citations
References
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TL;DR: Traditional analytical protocols in current use are presented, and the influence of confounding variables on BPb levels are assessed and the significance of Pb determinations in human specimens including hair, nails, saliva, bone, blood, urine, feces, and exfoliated teeth are discussed.
Abstract: Lead concentration in whole blood (BPb) is the primary biomarker used to monitor exposure to this metallic element. The U.S. Centers for Disease Control and Prevention and the World Health Organization define a BPb of 10 microg/dL (0.48 micromol/L) as the threshold of concern in young children. However, recent studies have reported the possibility of adverse health effects, including intellectual impairment in young children, at BPb levels < 10 microg/dL, suggesting that there is no safe level of exposure. It appears impossible to differentiate between low-level chronic Pb exposure and a high-level short Pb exposure based on a single BPb measurement; therefore, serial BPb measurements offer a better estimation of possible health outcomes. The difficulty in assessing the exact nature of Pb exposure is dependent not so much on problems with current analytical methodologies, but rather on the complex toxicokinetics of Pb within various body compartments (i.e., cycling of Pb between bone, blood, and soft tissues). If we are to differentiate more effectively between Pb stored in the body for years and Pb from recent exposure, information on other biomarkers of exposure may be needed. None of the current biomarkers of internal Pb dose have yet been accepted by the scientific community as a reliable substitute for a BPb measurement. This review focuses on the limitations of biomarkers of Pb exposure and the need to improve the accuracy of their measurement. We present here only the traditional analytical protocols in current use, and we attempt to assess the influence of confounding variables on BPb levels. Finally, we discuss the interpretation of BPb data with respect to both external and endogenous Pb exposure, past or recent exposure, as well as the significance of Pb determinations in human specimens including hair, nails, saliva, bone, blood (plasma, whole blood), urine, feces, and exfoliated teeth.
627 citations
TL;DR: A unique strategy for the selective detection of micromolar concentrations of cysteine/glutathione in the presence of various other alpha-amino acids through the plasmon coupling of Au nanorods is reported.
Abstract: A unique strategy for the selective detection of micromolar concentrations of cysteine/glutathione in the presence of various other α-amino acids through the plasmon coupling of Au nanorods is reported.
577 citations
TL;DR: It is expected this Au NPs-based Hg(2+) sensor will be a promising candidate for field detection of environmentally toxic mercury and exhibits excellent selectivity over a spectrum of interference metal ions.
Abstract: We report a highly sensitive electrochemical sensor for the detection of Hg2+ ions in aqueous solution by using a thymine (T)-rich, mercury-specific oligonucleotide (MSO) probe and gold nanoparticles (Au NPs)-based signal amplification. The MSO probe contains seven thymine bases at both ends and a “mute” spacer in the middle, which, in the presence of Hg2+, forms a hairpin structure via the Hg2+-mediated coordination of T−Hg2+−T base pairs. The thiolated MSO probe is immobilized on Au electrodes to capture free Hg2+ in aqueous media, and the MSO-bound Hg2+ can be electrochemically reduced to Hg+, which provides a readout signal for quantitative detection of Hg2+. This direct immobilization strategy leads to a detection limit of 1 μM. In order to improve the sensitivity, MSO probe-modified Au NPs are employed to amplify the electrochemical signals. Au NPs are comodified with the MSO probe and a linking probe that is complementary to a capture DNA probe immobilized on gold electrodes. We demonstrated that t...
409 citations
TL;DR: It was observed that the rate of release of fluorescein-tagged ligand was determined by the surface charge of the AuNPs, with cationic particles much more labile than anionic analogues.
84 citations
TL;DR: In this article, a novel fluorescence chemical sensor for the highly sensitive and selective determination of mercury(II) ions in aqueous solutions is prepared by incorporating 1-(dansylamidopropyl)-1-aza-4,10-dithia-7-oxacyclododecane (L) as a neutral Hg 2+ -selective fluoroionophore in the plasticized PVC membrane containing potassium tetrakis( p -chlorophenyl)-borate as a liphophilic anionic additive.
81 citations