Sputtered bismuth screen-printed electrode: A promising alternative to other bismuth modifications in the voltammetric determination of Cd(II) and Pb(II) ions in groundwater

Single-drop electrodeposition of nanoneedle-like bismuth on disposable graphene electrode for on-site electrochemical detection of cadmium and lead

A novel cost-effective disposable porous graphene electrode (P-GE) modified with bismuth nanoneedles (nano-BiNDs) is proposed as a "mercury-free" sensor for detecting heavy metals through smartphone-assisted electrochemical sensing. The P-GE was fabricated using screen-printing. Nano-BiNDs were generated on the P-GE by potentiostatic electrodeposition. Using an optimal potential of -1.20 V (vs. pseudo-Ag/AgCl) and a deposition time of 200 s, the nano-BiNDs had an average length and width of 189 ± 5 nm and 20 ± 2 nm, respectively. The analytical performances of the fabricated sensing platform were demonstrated by detecting Cd2+ and Pb2+ using square-wave anodic stripping voltammetry (SWASV) under optimized conditions. In the optimal conditions, the fabricated sensor exhibited sharp, well-defined stripping peaks for Cd2+ and Pb2+ with excellent peak-to-peak separation. The linear detection ranges were from 0.01 to 50 μg mL-1 for Cd2+ and 0.006-50 μg mL-1 for Pb2+. The detection limits for Cd2+ and Pb2+ were 3.51 and 2.10 ng mL-1, respectively. The developed portable sensor demonstrated high sensitivity, good repeatability, reproducibility, and anti-interference properties. The proposed portable sensor quantified Cd2+ and Pb2+ in commercial seaweed products with good accuracy, consistent with the results obtained using the standard ICP-OES method.

Functionalization of Screen-Printed Electrodes with Grape Stalk Waste Extract-Assisted Synthesized Silver and Gold Nanoparticles: Perspectives of Electrocatalytically Enhanced Determination of Uranyl Ion and Other Heavy Metals Ions

Recently, nanotechnology and nanoparticles (NPs) such as AgNPs and AuNPs have become important in analytical chemistry due to their great potential to improve the performance of electrochemical sensors. In this work, Ag and Au nanoparticles have been synthesized using a green route in which a grape stalk waste extract is used as a reducing agent to obtain metallic nanoparticles. These NPs were used to customize the surface of commercial screen-printed electrodes (SPCNFEs). The spin-coating method was used to modify commercial SPCNFEs under a nitrogen atmosphere. The resulting electrodes were used in a determination study of Cd(II), Pb(II), and U(VI) with differential pulse anodic stripping voltammetry (DPASV). The customized green AgNPs and AuNPs electrodes presented higher sensitivity and electroanalytical performance than the non-modified SPCNFE. The results showed that the best analytical parameters were obtained with the green, silver nanoparticle SPCNFEs, with a LOD of 0.12 μg L^-1 for Pb(II), which is a lower value compared to the most restrictive regulation guidelines. Additionally, the U(VI) ion was successfully determined using the developed G-AgNPs-SPCNFE in spiked tap water, showing comparable results with the ICP-MS technique.

Screen-printed electrochemical sensors for environmental monitoring of heavy metal ion detection

Heavy metal ions (HMIs) are known to cause severe damages to the human body and ecological environment. And considering the current alarming situation, it is crucial to develop a rapid, sensitive, robust, economical and convenient method for their detection. Screen printed electrochemical technology contributes greatly to this task, and has achieved global attention. It enabled the mass transmission rate and demonstrated ability to control the chemical nature of the measure media. Besides, the technique offers advantages like linear output, quick response, high selectivity, sensitivity and stability along with low power requirement and high signal-to-noise ratio. Recently, the performance of SPEs has been improved employing the most effective and promising method of the incorporation of different nanomaterials into SPEs. Especially, in electrochemical sensors, the incorporation of nanomaterials has gained extensive attention for HMIs detection as it exhibits outstanding features like broad electrochemical window, large surface area, high conductivity, selectivity and stability. The present review focuses on the recent progress in the field of screen-printed electrochemical sensors for HMIs detection using nanomaterials. Different fabrication methods of SPEs and their utilization for real sample analysis of HMIs using various nanomaterials have been extensively discussed. Additionally, advancement made in this field is also discussed taking help of the recent literature.

A review on bismuth-based nanocomposites for energy and environmental applications

Bismuth, a heavy metal which is found to be inexpensive and at a reduced cost, is utilized in the synthesis of different nanomaterials with novel structure, remarkable physical and chemical properties, adjustable bandgap, notable efficiency for photothermal conversion. These characteristics have made this element desirable for various applications such as storage and conversion of energy, electronics, sensors, photocatalysis, and other biomedical applications. These review papers are the vital points for the students, this report guides them to the research papers which focus on the impressive development in the area of bismuth and similar nanostructures. The purpose of the present review is to discuss the various synthesis routes of bismuth-based nanomaterials along with green synthesis, different nanostructures of bismuth, their significant properties, diverse applications and directions for the upcoming research. Therefore, with these different tuneable synthesis methods of bismuth-based nanomaterials combined with their novel properties, would elucidate on the future devices based on various nanostructures of bismuth.

Method for analysis of environmental lead contamination in soils

A method for lead (Pb) detection in soil is presented. Pb is a dangerous environmental pollutant that is present in soils, posing a health risk to millions of people worldwide, and regular monitoring of Pb contamination in soils is essential to public health. Many sensitive methods for detection of heavy metals in solid matrices exist, but they cannot be performed on-site because they are costly (>$30 per sample), require trained personnel, and many classical sample preparation methods are not safe to bring into the field. We describe an alternative process, combining a safer sample preparation method with electrochemical analysis. The process requires minimal training, making it an attractive overall method for regular environmental screening of Pb in soils. Extract obtained from the soil is pH adjusted and analyzed using a stencil-printed carbon electrode and square wave anodic stripping voltammetry. In this work, a study of 15 neighborhood soils examining the concentration of Pb present post-extraction was performed to demonstrate the method. The limit of detection for the electrochemical analysis was calculated to be 16 ppb-well below the United States Environmental Protection Agency's action limit for Pb in soils (400 mg kg^-1 or 4000 ppb)-and third party inductively coupled plasma-optical emission spectroscopy analysis validated the results obtained in this study to within ±17% on average.

Bismuth Subcarbonate Decorated Reduced Graphene Oxide Nanocomposite for the Sensitive Stripping Voltammetry Analysis of Pb(II) and Cd(II) in Water

In this paper, bismuth subcarbonate (BiO)2CO3-reduced graphene oxide nanocomposite incorporated in Nafion matrix ((BiO)2CO3-rGO-Nafion) was synthesized and further applied, for the first time, in the sensitive detection of Pb(II) and Cd(II) by square-wave anodic stripping voltammetry (SWASV). The as-synthesized nanocomposites were characterized by energy-dispersive spectroscopy (EDS), Raman spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). (BiO)2CO3 composite plays a key role in the improvement of the detection sensitivity, which can form multicomponent alloy with cadmium and lead. Additionally, the unique structure of rGO can enlarge the surface area and provide abundant active sites. Moreover, Nafion incorporation in the nanocomposite can effectively increase the adhesion and mechanical strength of the film, and further improve the preconcetration ability due to the cation-exchange capacity of its abundant sulfonate groups. As expected, the (BiO)2CO3-rGO/Nafion nanocomposite-modified glassy carbon electrode ((BiO)2CO3-rGO-Nafion/GCE) achieved low detection limits of 0.24 μg/L for Pb(II) and 0.16 μg/L for Cd(II), in the linear range of 1.0-60 μg/L, and showed some excellent performance, such as high stability, good selectivity, and sensitivity. Finally, synthetic water samples were prepared and further used to verify the practicability of the (BiO)2CO3-rGO-Nafion/GCE with satisfactory results.

Using Electrode Made of Carbon Nanotubes and Bismuth Oxide for the Determination of Metal Concentration by Anodic Stripping Voltammetry

We have successfully manufactured a new electrode modified with bismuth oxide (Bi2O3) using carbon nanotubes (CNTs). The electrode was fabricated to detect cadmium (Cd), lead (Pb), and indium (In) by differential pulse anodic stripping voltammetry (DP-ASV). The electrode surface was studied by scanning electron microscopy (SEM), and the reduction and oxidation processes were studied by cyclic voltammetry (CV) techniques. Operational parameters such as electrode size, bismuth concentration, and electrolytic background were optimized. The DP-ASV method used fabricated electrodes with a linear response range from 1.5–20 μg·L−1 with Cd(II) and Pb(II) and 2.5–20 μg·L−1 with In(III); low detection limit (LOD) of 0.22 μg·L−1 with Cd(II), 0.65 μg·L−1 with In(III), and 0.26 μg·L−1 with Pb(II); and good repeatability with relative standard deviations (RSD) of 2.65%, 2.51%, and 3.34% with Cd(II), Pb(II), and In(III), respectively (n = 8). The electrode can be used to test the content of Cd(II), In(III), and Pb(II) in water.

Nafion-Protected Sputtered-Bismuth Screen-Printed Electrode for On-site Voltammetric Measurements of Cd(II) and Pb(II) in Natural Water Samples

In this work, we explore the protection with Nafion of commercial sputtered-bismuth screen-printed electrodes (Bi_SPSPEs), to improve its ability for on-site determination of Cd(II) and Pb(II) ions in ambient water samples. The modified screen-printed platform was coupled with a miniaturized cell, in combination with a battery-operated stirring system and a portable potentiostat operated by a laptop for decentralized electrochemical measurements using Square-Wave Anodic Stripping Voltammetry (SWASV). We also describe a detailed electrode surface characterization by microscopy and surface analysis techniques, before and after the modification with Nafion, to get insight about modification effect on signal size and stability. Optimization of the chemical composition of the medium including the optimization of pH, and instrumental parameters, resulted in a method with detection limits in the low ng/mL range (3.62 and 3.83 ng·mL⁻¹ for Cd and Pb respectively). Our results show an improvement of the sensitivity and stability for Nafion-protected Bi_SPSPEs in pH = 4.4 medium, and similar or lower detection limits than comparable methods on commercial Bi_SPSPEs. The values obtained for Pb(II) and Cd(II) in natural water samples agreed well with those obtained by the much more costly Inductively Coupled Plasma Mass Spectrometry, ICP-MS, technique as a reference method (recoveries from 75% to 111%).

Screen-Printed Electrodes Modified with "Green" Metals for Electrochemical Stripping Analysis of Toxic Elements

This work reviews the field of screen-printed electrodes (SPEs) modified with “green” metals for electrochemical stripping analysis of toxic elements. Electrochemical stripping analysis has been established as a useful trace analysis technique offering many advantages compared to competing optical techniques. Although mercury has been the preferred electrode material for stripping analysis, the toxicity of mercury and the associated legal requirements in its use and disposal have prompted research towards the development of “green” metals as alternative electrode materials. When combined with the screen-printing technology, such environment-friendly metals can lead to disposable sensors for trace metal analysis with excellent operational characteristics. This review focuses on SPEs modified with Au, Bi, Sb, and Sn for stripping analysis of toxic elements. Different modification approaches (electroplating, bulk modification, use of metal precursors, microengineering techniques) are considered and representative applications are described. A developing related field, namely biosensing based on stripping analysis of metallic nanoprobe labels, is also briefly mentioned.

Multifunctional Bismuth Oxychloride/Mesoporous Silica Composites for Photocatalysis, Antibacterial Test, and Simultaneous Stripping Analysis of Heavy Metals

The increasing complexity of environmental pollution nowadays poses a severe threat to the public health, which attracts considerable attentions in searching for nanomaterials of multiproperty. In this study, mesoporous silica of KIT-6-encapsulated bismuth oxychloride (BiOCl), an intrinsically multifunctional material exhibiting bunched structure in the composites, are facilely prepared under hydrothermal conditions. Subsequently, the produced materials of multifunctionality were applied for photocatalysis, antibacterial test, and simultaneous determination of heavy metals including lead and cadmium. A combination of physiochemical characterizations have revealed that the BiOCl-KIT-6 composites exhibit enlarged yet refined surface morphology contributing to the improved photocatalytic ability with a band gap of 3.06 eV at a molecular ratio of 8Bi-Si. Moreover, the antibacterial activities of our BiOCl-KIT-6 composites were explored, and possible antimicrobial mechanism related to the production of reactive oxygen species was discussed. Furthermore, a sensitive electrochemical determination of heavy metals of lead and cadmium using square-wave anodic stripping voltammetry was also achieved. The composites-modified glassy carbon electrode displays a linear range of calibration curve from 0.2 to 300 μg/L with a detection limit of 0.05 μg/L (Pb2+) and 0.06 μg/L (Cd2+), respectively.

Disposable sputtered-bismuth screen-printed sensors for voltammetric monitoring of cadmium and lead in atmospheric particulate matter samples

We report here the use of commercial screen-printed disposable sensors comprising a sputtered bismuth working electrode, a silver pseudo reference electrode and a carbon auxiliary electrode (whole set referred as Bi_spSPE), as a new and advantageous alternative for reliable and convenient monitoring of Cd and Pb in atmospheric particulate matter (PM10 fraction) by anodic stripping voltammetry after acid digestion. After a detailed exploration of surface composition and depth profiles of the Bi_spSPE by SEM, EDX, XPS and EIS, chemical and instrumental variables have been optimized to develop a reliable method capable of measuring Cd and Pb with detection limits of 11.8ngmL^-1 and 6.1ngmL^-1 respectively. These detection limits are useful for pollution monitoring of these elements in ambient air under the requirements of international health and environmental protection standards. The accuracy of the method was assessed by voltammetric measurements of Cd and Pb in ERM®-CZ120 Fine dust (PM10-like) and ERM® 1648a Urban Particulate Matter certified reference materials. The applicability of the method to Cd and Pb determination in real samples was demonstrated by analysis of PM10 samples from the air quality network in Extremadura, with a good correlation respect to the standard ICP-MS methodology. Our work constitutes the first reference about the use of disposable sensors based on Bi_spSPE for the determination of heavy metals in atmospheric particulate matter samples.

Multi-element determination of metals and metalloids in waters and wastewaters, at trace concentration level, using electroanalytical stripping methods with environmentally friendly mercury free-electrodes: A review

Nowadays, water is no longer regarded as an inexhaustible resource and the excessive release and proliferation of toxic metal(loid)s into aquatic environments has become a critical issue. Therefore, fast, accurate, simple, selective, sensitive and portable methodologies to detect multiple elements in natural waters is of paramount importance. Electrochemical stripping analysis is an efficient tool for trace metal(loid)s determinations and bring new prospects for answering the current environmental concerns. This review presents a survey of the advancements made between 2003 and 2016 on the development and application of non-toxic mercury free electrodes on the simultaneous analysis of metals and metalloids in waters and wastewaters by means of electroanalytical stripping techniques. The advantages, limitations, improvements and real applications of these "green" sensors are discussed from a critical point of view.

Application of screen-printed carbon electrode modified with lead in stripping analysis of Cd(II)

In the work presented, a lead film electrode was prepared in situ on a screen-printed carbon support using a reversibly deposited mediator (Zn) and applied to the determination of Cd(II) by anodic stripping voltammetry. The electrochemical method for lead film formation is based on a co-deposition of a metal of interest (Pb), with a reversibly deposited zinc mediator, followed by oxidation of zinc, with additional deposition of lead at the appropriate potential. It serves to increase the density of lead particles, promoting lead film growth, and consequently helps to improve the electrochemical properties of the electrode. This was confirmed by microscopic and voltammetric studies. The obtained detection limit of Cd(II) is equal to 6.6 × 10−9 mol L−1 (−1.6 V for 180 s and then −0.95 V for 5 s). The presented procedure was successfully applied to cadmium determination in Bystrzyca River water samples.

An electrochemiluminescence sensor with dual signal amplification of Ru(bpy)32+based on PtNPs and glucose dehydrogenase for diagnosis of gas gangrene

Gas gangrene is a bacterial infection that produces gas in tissues in gangrene.C. perfringenswith alpha-toxin plays a key role in gas gangrene. Detection ofC. perfringensis highly important in clinical diagnosis of gas gangrene.

Monodisperse magnetic ion imprinted polymeric microparticles prepared by RAFT polymerization based on γ-Fe2O3@meso-SiO2nanospheres for selective solid-phase extraction of Cu(ii) in water samples

Utilising a general protocol for making surface-imprinted core–shell microparticlesviaa RAFT-mediated approach, we developed a Cu(ii) imprinted polymer with a novel magnetic nanosphere, γ-Fe₂O₃@meso-SiO₂, as support.

Antimony film screen-printed carbon electrode for stripping analysis of Cd(II), Pb(II), and Cu(II) in natural samples

An in-situ antimony film screen-printed carbon electrode (in-situ SbSPCE) was successfully used for the determination of Cu(II) simultaneously with Cd(II) and Pb(II) ions, by means of differential pulse anodic stripping voltammetry (DPASV), in a certified reference groundwater sample with a very high reproducibility and good trueness. This electrode is proposed as a valuable alternative to in-situ bismuth film electrodes, since no competition between the electrodeposited copper and antimony for surface sites was noticed. In-situ SbSPCE was microscopically characterized and experimental parameters such as deposition potential, accumulation time and pH were optimized. The best voltammetric response for the simultaneous determination of Cd(II), Pb(II) and Cu(II) ions was achieved when deposition potential was -1.2 V, accumulation time 120 s and pH 4.5. The detection and quantification limits at levels of μg L(-1) suggest that the in-situ SbSPCE could be fully suitable for the determination of Cd(II), Pb(II) and Cu(II) ions in natural samples.

An electrochemical strategy with molecular beacon and hemin/G-quadruplex for the detection of Clostridium perfringens DNA on screen-printed electrodes

An electrochemical strategy based on molecular beacon, hemin/G-quadruplex, and SA/ADH/Fe₃O₄nanocomposites.