Voltammetry Peak Research Articles

A High Voltage Aqueous Zinc–Organic Hybrid Flow Battery

AbstractWater‐soluble redox‐active organic molecules have attracted extensive attention as electrical energy storage alternatives to redox‐active metals that are low in abundance and high in cost. Here an aqueous zinc–organic hybrid redox flow battery (RFB) is reported with a positive electrolyte comprising a functionalized 1,4‐hydroquinone bearing four (dimethylamino)methyl groups dissolved in sulfuric acid. By utilizing a three‐electrolyte, two‐membrane configuration this acidic positive electrolyte is effectively paired with an alkaline negative electrolyte comprising a Zn/[Zn(OH)4]2− redox couple and a hybrid RFB is operated at a high operating voltage of 2.0 V. It is shown that the electrochemical reversibility and kinetics of the organic redox species can be enhanced by an electrocatalyst, leading to a cyclic voltammetry peak separation as low as 35 mV and enabling an enhanced rate capability.

Structure, Shift in Redox Potential and Li-Ion Diffusion Behavior in Tavorite LiFe1−xVxPO4F Solid-Solution Cathodes

Solid-solution Li-ion cathode materials transform through a single-phase reaction thus leading to a long-term structural stability and improved cyclability. In this work, a two- to single-phase Li+-extraction/insertion mechanism is studied through tuning the stoichiometry of transition-metal Fe/V cations to trigger a transition in the chemical reactivity path. Tavorite triclinic-structured LiFe1−xVxPO4F (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) solid-solution powders were prepared by a facile one-step solid-state method from hydrothermal-synthesized and commercial raw materials. The broad shape of cyclic voltammetry (CV) peaks, sloping charge/discharge profiles and sloping open-circuit voltage (OCV) profiles were observed in LiFe1−xVxPO4F solid-solution cathodes while 0 < x < 1. These confirm strongly a single-phase behavior which is different from the two-phase behavior in the end-members (x = 0 or 1). The electronegativity of M (M = Fe1−xVx) for the redox potential of Fe2+/3+ couple or the M–O4F2 bond length for the V3+/4+ couple plays respectively a dominant role in LiFe1−xVxPO4F solid-solution cathodes.

Electrochemical oxidation of 2,5-diethoxy 4-morpholinoaniline in the presence of thiobarbituric acid: present an ECCCEC Mechanism

The electrochemical oxidation of 2,5-diethoxy-4-morpholinoaniline has been studied in the presence of thiobarbituric acid by the use of experimental and calculation methods. Cyclic voltammetry, controlled-potential coulometry and density functional theory (DFT) were used in this study. By the use of the cyclic voltammetry, the best condition of synthesis was obtained, and controlled-potential coulometry was performed under this condition. The results indicated that the produced p-benzoquinonediimine is unstable, and it was hydrolyzed in the experimental condition. It was found that the produced p-quinoneimine from oxidation/hydrolysis of 2,5-diethoxy-4-morpholinoaniline reacts with the thiobarbituric acid as a nucleophile and via an ECCCEC mechanism converts to the product. Also, computational calculations were used to analyze oxidation peaks in voltammetry. DFT, BP86 level of theory and 6-31G(p,d) basis set, was used to obtain the theoretical results.

Cyclic voltammetry measurements of electroactive surface area of porous nickel: Peak current and peak charge methods and diffusion layer effect

Surface area is a key parameter for porous metals for electrode applications. Here we measured the electroactive surface area of porous nickel samples using the cyclic voltammetry peak current and peak charge methods. The peak current method measures the contributions from primary pores, while the peak charge method measures the contributions from both primary and secondary pores. The electroactive surface area measured by both methods decreases with normalised diffusion layer thickness. It follows the semi-infinite model at low normalised diffusion layer thicknesses (<0.35) and the thin-layer model at high normalised diffusion layer thickness (>0.35). The correcting factors obtained from the semi-infinite model provide quantitative information on the pore surface roughness and the secondary porosity contribution. The surface roughness of the samples produced by Lost Carbonate Sintering is 2.15. The relative contribution of secondary porosity depends on the type of porous nickel and increases with scan rate, due to reduced diffusion layer thickness. It is in the range of 0.14–0.3 for the samples produced by Lost Carbonate Sintering and loose sintering, and 0.02–0.05 for the sample produced by electrodeposition, for scan rates in the range of 0.005–0.05 V/s.

Shear Stress Affects Biofilm Structure and Consequently Current Generation of Bioanode in Microbial Electrochemical Systems (MESs).

Shear stress is an important factor that affects the formation and structure of anode biofilms, which are strongly related to the extracellular electron transfer phenomena and bioelectric performance of bioanodes. Here, we show that using nitrogen sparging to induce shear stress during anode biofilm formation increases the linear sweep voltammetry peak current density of the mature anode biofilm from 2.37 ± 0.15 to 4.05 ± 0.25 A/m2. Electrochemical impedance spectroscopy results revealed that the shear-stress-enriched anode biofilm had a low charge transfer resistance of 46.34 Ω compared to that of the unperturbed enriched anode biofilm (72.2 Ω). Confocal laser scanning microscopy observations showed that the shear-stress-enriched biofilms were entirely viable, whereas the unperturbed enriched anode biofilm consisted of a live outer layer covering a dead inner-core layer. Based on biomass and community analyses, the shear-stress-enriched biofilm had four times the biofilm density (136.0 vs. 27.50 μg DNA/cm3) and twice the relative abundance of Geobacteraceae (over 80 vs. 40%) in comparison with those of the unperturbed enriched anode biofilm. These results show that applying high shear stress during anode biofilm enrichment can result in an entirely viable and dense biofilm with a high relative abundance of exoelectrogens and, consequently, better performance.

Simultaneous Voltammetric Determination of Gallic and Protocatechuic Acids in Mango Juice Using a Reduced Graphene Oxide-Based Electrochemical Sensor

A simple and sensitive reduced graphene oxide-modified glassy carbon electrode-based electrochemical sensor was used for the concomitant determination of gallic acid (GA) and protocatechuic (PA) acid. The prepared sensor showed a significant enhancement in synergetic electro-catalytic performance towards GA and PA oxidation. A good resolution of the voltammetry peaks was obtained and a method of square wave voltammetry was developed for detection. The modified electrode was characterized by electrochemical techniques. The optimal experimental parameters were considered. GA and PA exhibited a linear increase in the peak currents with their concentrations in the range from 20 to 144 µmol·L−1 for GA and from 20 to 166 µmol·L−1 for PA, with limits of detection (S/N = 3) of 30.8 µmol·L−1 for GA and 10.2 µmol·L−1 for PA. The sensor applicability was simultaneously tested for the analytical determination of GA and PA in mango juice and exhibited a robust functionality.

Electrochemical Patterns of Phase Transforming Intercalation Materials: Diagnostic Criteria for the Case of Slow Nucleation Rate Control

In this paper we implement and test a new approach for the description of the electrochemical data (cyclic voltammetry and chronoamperometry) for phase transforming intercalation electrode materials. This approach assumes the rate-limiting step being associated with the slow nucleation of a new phase in the material particles. As a test model system, we used LiFePO4 material. It is shown that all the electrochemical data for LiFePO4 can be self-consistently described assuming a slow nucleation step with only minor influence of ionic diffusion and interfacial charge transfer kinetics on the intercalation rates. The developed formalism allows for a reliable diagnostics of the reaction rate control regime as well as for the extraction of information on the pre-exponential factor and activation energy values. The electrochemical diagnostic criteria for the slow nucleation step are formulated based on the shapes of the cyclic voltammetry peaks, current transients registered under potentiostatic conditions and specific features in the impedance spectra of phase-transforming electrodes.

Structure and Reactivity of (μ-Oxo)dimanganese(III,III) and Mononuclear Hydroxomanganese(III) Adducts Supported by Derivatives of an Amide-Containing Pentadentate Ligand.

Mononuclear MnIII-hydroxo and dinuclear (μ-oxo)dimanganese(III,III) complexes were prepared using derivatives of the pentadentate, amide-containing dpaq ligand (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino- N-quinolin-8-yl-acetamidate). Each of these ligand derivatives (referred to as dpaq5R) contained a substituent R (where R = OMe, Cl, and NO2) at the 5-position of the quinolinyl group. Generation of the MnIII complexes was achieved by either O2 oxidation of MnII precursors (for [MnII(dpaq5OMe)]+ and [MnII(dpaq5Cl)]+ or PhIO oxidation (for [MnII(dpaq5NO2)]+). For each oxidized complex, 1H NMR experiments provided evidence of a water-dependent equilibrium between paramagnetic [MnIII(OH)(dpaq5R)]+ and an antiferromagnetically coupled [MnIIIMnIII(μ-O)(dpaq5R)2]2+ species in acetonitrile, with the addition of water favoring the MnIII-hydroxo species. This conversion could also be monitored by electronic absorption spectroscopy. Solid-state X-ray crystal structures for each [MnIIIMnIII(μ-O)(dpaq5R)2](OTf)2 complex revealed a nearly linear Mn-O-Mn core (angle of ca. 177°), with short Mn-O distances near 1.79 Å, and a Mn···Mn separation of 3.58 Å. X-ray crystallographic information was also obtained for the mononuclear [MnIII(OH)(dpaq5Cl)](OTf) complex, which has a short Mn-O(H) distance of 1.810(2) Å. The influence of the 5-substituted quinolinyl moiety on the electronic properties of the [MnIII(OH)(dpaq5R)]+ complexes was demonstrated through shifts in a number of 1H NMR resonances, as well as a steady increase in the MnIII/II cyclic voltammetry peak potential in the order [MnIII(OH)(dpaq5OMe)]+ < [MnIII(OH)(dpaq)]+ < [MnIII(OH)(dpaq5Cl)]+ < [MnIII(OH)(dpaq5NO2)]+. These changes in oxidizing power of the MnIII-hydroxo adducts translated to only modest rate enhancements for TEMPOH oxidation by the [MnIII(OH)(dpaq5R)]+ complexes, with the most reactive [MnIII(OH)(dpaq5NO2)]+ complex showing a second-order rate constant only 9-fold larger than that of the least reactive [MnIII(OH)(dpaq5OMe)]+ complex. These modest rate changes were understood on the basis of density functional theory (DFT)-computed p Ka values for the corresponding [MnII(OH2)(dpaq5R)]+ complexes. Collectively, the experimental and DFT results reveal that the 5-substituted quinolinyl groups have an inverse influence on electron and proton affinity for the MnIII-hydroxo unit.

Electroactive Au@Ag nanoparticles driven electrochemical sensor for endogenous H2S detection

In this work, a novel and facile electrochemical sensor is reported for the highly selective and sensitive detection of dissolved hydrogen sulfide (H2S), attributing to the redox reaction between Au@Ag core-shell nanoparticles (Au@Ag NPs) and H2S. Electroactive Au@Ag NPs not only possess excellent conductivity, but exhibit great electrochemical reactivity at 0.26 V due to the electrochemical oxidation from Ag° to Ag+. In the presence of H2S, the Ag shell of Au@Ag NPs can be oxidized to Ag2S, resulting in the decrease of differential pulse voltammetry (DPV) peak at 0.26 V. The electrochemical sensor exhibits a wide linear response range from 0.1 nM to 500 nM. The limit of detection (LOD) for H2S is as low as 0.04 nM. The developed sensor shows significant prospects in the study of pathological processes related to the mechanism of H2S production.

Multiplexed aptasensor based on metal ions labels for simultaneous detection of multiple antibiotic residues in milk

A dual-target electrochemical aptasensor was developed for the simultaneous detection of multiple antibiotics based on metal ions as signal tracers and nanocomposites as signal amplification strategy. Metal ions such as Cd2+ and Pb2+ could generate distinct differential pulse voltammetry (DPV) peaks. When targets were present, kanamycin (KAN) and streptomycin (STR) as models, the KAN aptamer (KAP) and STR aptamer (STP) were released from their complementary strands, with more change of Cd2+ and Pb2+ corresponding to peak currents. At the same time, complementary strand of KAP (cKAP) and STP (cSTP) were linked with the poly (A) structure (cSTP-PolyA-cKAP) to increase their conformational freedom. Graphitized multi-walled carbon nanotubes (MWCNTGr) and carbon nanofibers-gold nanoparticles (CNFs-AuNPs) as a biosensor platform enhanced the surface area to capture a large amount of cSTP-PolyA-cKAP, thus amplifying the detection response. Under the optimal conditions, the aptasensor could detect KAN and STR as low as 74.50 pM and 36.45 pM respectively with the range from 0.1 to 100 nM and exhibited excellent selectively. Moreover, this aptasensor showed promising applications for the detection of other analytes by changing corresponding aptamers.

Highly Sensitive Nanostructured Electrochemical Sensor Based on Carbon Nanotubes-Pt Nanoparticles Paste Electrode for Simultaneous Determination of Levodopa and Tyramine

A multicomponent electrochemical sensor, with two nanometer-scale components in sensing matrix/electrode, was used to simultaneous determination of levodopa (LD) and tyramine (TR) in pharmaceutical and diet samples. Multiwall carbon nanotubes (MWCNTs) were used as carbonaceous materials in the electrode construction. 5-amino-3',4'-dimethoxy-biphenyl-2-ol (5ADMB) was used as electron mediator and Pt nanoparticles (nPt) as a catalyst. The 5ADMB catalyzes the oxidation of LD to the corresponding catecholamine, which is electrochemically reduced back to LD. Preparation of this electrode was very simple and modified electrode showed good properties at electrocatalytic oxidization of LD and TR. Using differential pulse voltammetry (DPV), a highly selective and simultaneous determination of LD and TR has been explored at the modified electrode. Differential pulse voltammetry peak currents of LD and TR increased linearly with their concentrations at the ranges of 0.50–100.0 μM and 0.60–100.0 μM, respectively. Also, the detection limits for LD and TR were 0.31 and 0.52 μM, respectively. The electrode exhibited an efficient catalytic response with good reproducibility and stability.

Electrochemical Detection of As (III) on a Manganese Oxide‐Ceria (Mn2O3/CeO2) Nanocube Modified Au Electrode

AbstractCeria cubes decorated with manganese oxide nanoparticles (Mn2O3/CeO2 nanocubes) were synthesized and used to modify a Au electrode for analysis of As(III) in aqueous solution. This modified electrode displayed improved sensitivity than either oxide on their own, indicating a synergistic effect due to the effect of Mn2O3 on the properties of CeO2. The improved sensitivity could be ascribed to the enhanced As (III) adsorption ability of Mn2O3/CeO2 nanocube during electrochemical pre‐concentration, combined with the well known As(III) sensing qualities of the gold substrate. The Mn2O3/CeO2 nanocube modified gold electrode behaved as a promising sensor with stable, repeatable square wave anodic stripping voltammetry (SWASV) peaks, separated from common interfering ions in natural water including Cu (II) under practical conditions. Repeatability and stability studies revealed the As (III) sensor to be robust and reliable, with a sensitivity of 0.0414 μA/ppb and a limit of detection (LoD) of 3.35 ppb under optimized conditions, indicating a possible general use of this class of heteronanostructures in electroanalytical chemistry for studies that rely upon adsorption of deposition of the analyte prior to stripping analysis.

Electrochemical impedance sensor for herbicide alachlor based on imprinted polymer receptor

Alachlor (ALA), a carcinogenic herbicide is detected in surface and groundwater, as well as in milk, eggs, and meat. So, the sensitive detection of ALA is essential for humans. To respond, we report a molecularly imprinted polymer (MIP) receptor for simple electrochemical sensing of ALA. The MIP film was immobilized onto glassy carbon electrode by electrodeposition of o‑phenylenediamine (o‑PD) in the presence of ALA as a template, followed by the ALA leaching out to create specific recognition cavities to ALA. The stepwise fabrication of the sensor was characterized by recording cyclic, square wave voltammetry peak currents and the electron transfer resistance (Ret) where the [Fe(CN)6]3−/4− was used as an electro-active probe. The mole ratio of ALA to o‑PD as well as the controlled release of the alachlor from the MIP‑o‑PD network was optimized to create a maximum number of free imprinted sites that affected the sensor sensitivity and its linear range. The increment in the Ret of the redox probe [Fe(CN)6]3−/4− upon selective recognition of ALA to the free cavities of MIP film is employed as the sensor response. At the optimal experimental conditions, the relative change in Ret is linearly correlated to the ALA concentrations in a range of 1 nM to 1 μM ALA. This sensor shows the high sensitivity of ALA with a limit of detection of 0.78 nM ALA. The affinity of MIP to ALA is proved by calculating the dissociation constant (Kd) in nM range. The high selectivity of the MIP sensor against the interferences propachlor and metalaxyl has been confirmed. Finally, the reliability of MIP-GCE for ALA detection is proved in tap water samples spiked by ALA. These findings indicate that such a sensor can be used for in-field measurements of other herbicides as a simple detection platform.

Charged additives modify drug release rates from lipidic cubic phase carriers by modulating electrostatic interactions

Functionalized lipidic cubic phases (LCPs) have gained considerable interest as drug delivery systems (DDS) in recent years. Among their advantages, one of the most intriguing features that make them interesting as DDS is the possibility of controlling the release of drugs based on electrostatic interactions. Here modulation of the release of a positively charged drug, doxorubicin (DOX) is obtained by incorporation of small amounts of designed charged derivatives of the monoolein host lipid as additives to the otherwise non-charged LCP. By design, the charged hydrophilic head group of the additive is exposed to the aqueous channels, whereas the hydrophobic tail is incorporated in the lipid bilayer and forms an integral part thereof. Our results show that in vitro DOX release profiles can be modulated by the electrostatic interactions between the drug molecule and the charged LCP used. We demonstrate that monitoring shifts of the voltammetry peak potentials gives a unique opportunity of following even subtle changes of pH inside the aqueous channels of the cubic mesophase, while measurement of the peak current allows establishing the release profile of the drug from the dopant-modified mesophase. Small angle X-ray scattering (SAXS) data confirm that the behavior of DOX in the mesophase was not dependent on the LCP symmetry, as it remains unchanged, but rather on the charges delineating the water channel compartment.

3D hierarchical bayberry-like Ni@carbon hollow nanosphere/rGO hybrid as a new interesting electrode material for simultaneous detection of small biomolecules

Metal-organic framework derived hierarchical bayberry-like Ni@carbon hollow nanosphere/reduced graphene oxide (Ni@CHS/rGO) hybrid was synthesized by combining a simple solvothermal reaction with a further annealing treatment. 3D hierarchical bayberry-like Ni@CHS/rGO hybrid not only offered a continuous highly conductive Ni metal and graphene matrix to facilitate the charge transfer, but also allowed uptaking and releasing of electrolytes and enchanted adsorbing of targets due to a hollow structure and introduction of graphene. Consequently, such a charming architecture displays preeminent electrocatalytic activity towards the electro-oxidation on ternary mixtures of ascorbic acid (AA), uric acid (UA) and dopamine (DA). For simultaneous detection of three small molecules, the fabricated sensor exhibited good application prospects toward analytes of DA, UA and AA. Furthermore, three well-separated voltammetry peaks were obtained using Ni@CHS/rGO electrode in differential pulse voltammetry (DPV) measurements. The calibration curves for UA, DA and AA were obtained: 0.25–126µM, 0.25–126µM and 2–4000µM, respectively, the detection limits were 0.05µM, 0.05µM, 0.37µM, respectively. This sensor exhibited excellent sensitivity, good stability, outstanding anti-interference ability and acceptable reproducibility. Moreover, the intriguing sensor was triumphantly applied for the quantitative analysis of UA, DA and AA in human urine and vitamin C tablets samples with satisfactory recovery, which manifests its viability application for practical analysis.

Formation of Ba bismuthate nanobelts and sensitive electrochemical determination of tartaric acid

A facile hydrothermal route without additives was used to prepare novel Ba bismuthate nanobelts. The Ba bismuthate nanobelts were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM and electrochemical method. The obtained nanobelts are composed of single crystalline monoclinic BaBiO2.5 phase with the thickness, width and length of about 50 nm, 1 µm and several dozens of micrometers, respectively. The formation of the Ba bismuthate nanobelts is dependent on the temperature and reaction time. Electrochemical measurements display that the Ba bismuthate nanobelts modified glassy carbon electrode has good electrochemical activity toward tartaric acid. A pair of semi-reversible cyclic voltammetry (CV) peaks are observed at −0.49 V and +0.01 V, respectively. The peak current is linearly relative to the scan rate and tartaric acid concentration. The limit of detection (LOD) is 0.12 µM with the linear range of 0.001–2 mM. The work provides new electrode modified materials for the sensor to detect tartaric acid.

Effective properties of undoped and Indium3+-doped tin manganese telluride (Sn1 − xMnxTe) nanoparticles via using a chemical bath deposition route

Tin manganese telluride nanoparticles (Sn1−xMnxTe NPs) were first synthesized on a niobium pentoxide (Nb2O5) film using a chemical bath deposition (CBD) route. An individual particle size before and after indium (In3+) doping of ∼70–150 nm was investigated with stoichiometric formation of the SnMnTe phase. Furthermore, a cubic or rocksalt structure of the Sn0.938Mn0.062Te phase was also kept incorporated in the structure. The plotted energy band gaps for undoped and In3+-doped samples were 2.17 and 1.83 eV, respectively. The reduction of photoluminescence (PL) spectra after In3+ doping, while the indium dopant acted as a trap state incorporated in Sn1−xMnxTe NPs, showed enhanced charge separation and reduced charge recombination, which resulted in a higher charge density trapped in the conduction band of Nb2O5 and was also confirmed by the result of anodic peaks in the cyclic voltammetry. These results suggest new possibilities in optoelectronic and electrochemical devices.

Peptide aptamer-based biosensor for the detection of human chorionic gonadotropin by converting silver nanoparticles-based colorimetric assay into sensitive electrochemical analysis

We presented an antibody-free electrochemical technique for the determination of human chorionic gonadotropin (hCG) using silver nanoparticles (AgNPs) as the redox reporters and a hCG-specific binding peptide as the receptor. Peptide-induced AgNPs assembly was achieved on the electrode surface that was modified with the same sequence of peptide (recognition element) used in the AgNPs aggregation. As a result, a well-defined linear-sweep voltammetry (LSV) peak was observed. The attachment of hCG on the electrode surface made the peptide probe lose its ability to trigger the in situ formation of the AgNPs-based network architecture on the electrode surface, thus leading to a much attenuated LSV current. The current decreased with the increase of hCG concentration ranging from 1mIU/mL to 0.2IU/mL. Consequently, a detection limit of 0.4mIU/mL was achieved. To demonstrate the amenability of our method, the contents of hCG in human serum/urine samples were determined. The results were consistent with those obtained by the enzyme linked immunosorbent assay (ELISA). Based on the well-defined and amplified electrochemical signal of the AgNPs-based network architecture, our work would also be valuable for the design of novel electrochemical sensors by marrying specific receptors.

Single‐Particle Performances and Properties of LiFePO4 Nanocrystals for Li‐Ion Batteries

It has been recently reported that the solution diffusion, efficiency porosity, and electrode thickness can dominate the high rate performance in the 3D‐printed and traditional LiMn0.21Fe0.79PO4 electrodes for Li‐ions batteries. Here, the intrinsic properties and performances of the single‐particle (SP) of LiFePO4 are investigated by developing the SP electrode and creating the SP‐model, which will share deep insight on how to further improve the performance of the electrode and related materials. The SP electrode is generated by fully scattering and distributing LiFePO4 nanoparticles to contact with the conductive network of carbon nanotube or conductive carbon to demonstrate the sharpest cyclic voltammetry peak and related SP‐model is developed, by which it is found that the interfacial rate constant in aqueous electrolyte is one order of magnitude higher, accounting for the excellent rate performance in aqueous electrolyte for LiFePO4. For the first time it has been proposed that the insight of pre‐exponential factor of interface kinetic Arrhenius equation is related to desolvation/solvation process. Thus, this much higher interfacial rate constant in aqueous electrolyte shall be attributed to the much larger pre‐exponential factor of interface kinetic Arrhenius equation, because the desolvation process is much easier for Li‐ions jumping from aqueous electrolyte to the Janus solid–liquid interface of LiFePO4.

Electrochemical Reduction of Atrazine at Carbon and Silver Cathodes

Since its introduction in the 1950s, atrazine (6-chloro-N2-ethyl-N4-(1-methylethyl)-1,3,5-triazine-2,4-diamine) has become one of the mostly widely used pesticides in the world. Although atrazine has been banned in the European Union since 2004, it is still applied extensively in the US, and can be detected in water sources, soil, and even air.1 Environmental persistence of atrazine and its metabolites has caused contamination to spread away from regions of herbicide application, and some studies have shown evidence of endocrine disruption in amphibians exposed to these chemicals.1 For these reasons, the degradation of atrazine to less environmentally harmful compounds is of great concern. In this study, we have employed electrochemical reduction for the degradation of atrazine at different cathode materials. Previous electrochemical studies of atrazine have been performed at mercury cathodes, and were successful in both the detection of atrazine by means of square-wave voltammetry and its degradation through controlled-potential (bulk) electrolyses.2-4 At mercury cathodes, long electrolyses resulted in both the breaking of the carbon–halogen bond and reduction of the triazine ring.4 To avoid the use of mercury, we have explored the use of carbon and silver cathodes; glassy carbon provides a simple, environmentally friendly alternative, whereas silver has been shown to be catalytic for the cleavage of carbon–halogen bonds. Reduction of atrazine at carbon and silver cathodes, respectively, in dimethylformamide (DMF) containing 0.050 M tetramethylammonium tetrafluoroborate (TMABF4), results in a single cyclic voltammetry peak at –1.77 or –1.62 V vs. a Cd(Hg) reference electrode. Investigations of the products arising from controlled-potential electrolysis by means of gas chromatography–mass spectrometry indicate the presence of dechlorinated atrazine (N2-ethyl-N4-(1-methylethyl)-1,3,5-triazine-2,4-diamine) after electrolyses at both carbon and silver cathodes.