Photochemical and Photocatalytic Degradation of 1-Propanol Using UV/H2O2: Identification of Malonate as Byproduct
Fotocatálise mediada por TiO2 no estado nanoparticulado: revisão da reatividade pelo conceito de traps e algumas aplicações em química analítica

Photochemical Oxidation of Alcohols: Simple Derivatization Strategy for their Analysis by Capillary Electrophoresis

Gold Leaf: From Gilding to the Fabrication of Disposable, Wearable and Low-cost Electrodes

Chemical Analysis of Household Oxygen-Based Powdered Bleach: An Engaging Approach to Teaching Sampling of Heterogeneous Materials and Address Statistics

DNA adduct formation in the lungs and brain of rats exposed to low concentrations of [13C2]-acetaldehyde

Analysis of Methanol in the Presence of Ethanol Using a Hybrid Capillary Electrophoresis Device with Electrochemical Derivatization and Conductivity Detection

Online monitoring of electrocatalytic reactions of alcohols at platinum and gold electrodes in acidic, neutral and alkaline media by capillary electrophoresis with contactless conductivity detection (EC-CE-C4D)

Determination of neutral diols and carboxylic acids formed during glycerol electrooxidation process by capillary electrophoresis with dual C4D

Fotoeletrocatálise em Semicondutores: Dos Princípios Básicos até sua Conformação à Nanoescala
Oxygen Bleach under the Microscope: Microchemical Investigation and Gas-Volumetric Analysis of a Powdered Household Product

Fast production of microfluidic devices by CO2 laser engraving of wax-coated glass slides

Exhaled Breath Analysis in Heart Failures

Quick cold preparation of TiO2 nanolayers on gold from P25 suspensions–film structure, voltammetric behavior and photocatalytic performance for the oxidation of EDTA under UVA-LED irradiation

Impact of Exhaled Breath Acetone in the prognosis of patients with heart failure. One year of Clinical Follow-up

Use of poly(methyl methacrylate)/polyethyleneimine flow microreactors for enzyme immobilization

Unveiling the structure of polytetraruthenated nickel porphyrin by Raman spectroelectrochemistry

Electrochemical Derivatization-Capillary Electrophoresis-Contactless Conductivity Detection: A versatile strategy for simultaneous determination of cationic, anionic and neutral analytes

Novel photoelectrocatalytic approach aiming at the digestion of water samples, estimation of organic matter content and stripping analysis of metals in a special UV-LED irradiated cell with a TiO2-modified gold electrode

Exhaled acetone as a new biomarker of heart failure severity

From Sample Processing to Quantification: A Full Electrochemical Approach for
Neutral Analyte Derivatization, Capillary Electrophoresis Separation and Contactless Conductivity Detection

Interview – main subjects: Personal Contributions and Views of the Development of Analytical Chemistry in Brazil

Interview – main subject: Analytical Instrumentation in Brazil

Automated two-dimensional separation flow system with electrochemically controlled preconcentration, stripping, capillary electrophoresis and contactless conductivity detection for trace metal ion analysis

Automation of an analysis system with microvolume porous membrane sampling, capillary electrophoresis separation and contactless conductivity detection for near-real-time monitoring of traces of low-molecular-weight carboxylic acids in air

Capillary Electrophoresis Assisted Flow System for In Situ Analysis of Products of Heterogeneous Electrocatalytic and Catalytic Processes: Application to the Oxidation of Glycerol

Unraveling the Role of Sulfur Compounds in Acid Rain Formation: Experiments on a Wetted Glass pH Electrode

Flow injection analysis of ethyl xanthate by gas diffusion and UV detection as CS2 for process monitoring of sulfide ore flotation

Fully electrochemical hyphenated flow system for preconcentration, cleanup, stripping, capillary electrophoresis with stacking and contactless conductivity detection of trace heavy metals

Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air

A efervescente reação entre dois oxidantes de uso doméstico e a sua análise química por medição de espuma

Bioluminescent sensor for naphthalene in air: cell immobilization and evaluation with a dynamic standard atmosphere generator

Environmental formaldehyde analysis by active diffusive sampling with a bundle of polypropylene porous capillary filaments followed by capillary zone electrophoretic separation and contactless conductivity detection

Flow Voltammetry

Microfluidic cell with a TiO2-modified gold electrode irradiated by an UV-LED for in situ photocatalytic decomposition of organic matter and its potentiality for voltammetric analysis of metal ions

Flow injection analysis of ethyl xanthate by in-line dialysis and UV spectrophotometric detection

Trace analysis of acids and bases by conductometric titration with multiparametric non-linear regression

Wet deposition and related atmospheric chemistry in the São Paulo Metropolis, Brazil: Part 3 – Trends in precipitation chemistry during 1983 – 2003

Electronic micropipettor: A versatile fluid propulsion and injection device for micro-flow analysis

In memoriam: Eduardo Neves, nosso eterno mestre

FIA-potentiometry in the sub-Nernstian response region for rapid and direct chloride assays in milk and in coconut water
Spectroelectrochemical determination of chlorpromazine hydrochloride by flow-injection analysis
Simultaneous determination of three surfactants and water in shampoo and liquid soap by ATR-FTIR
Fast Mapping of Gunshot Residues by Batch Injection Analysis with Anodic Stripping Voltammetry of Lead at the Hanging Mercury Drop Electrode
Extending the lifetime of the running electrolyte in capillary electrophoresis by using additional compartments for external electrolysis Disposable twin gold electrodes for amperometric detection in capillary electrophoresis
Wet deposition and related atmospheric chemistry in the São Paulo Metropolis, Brazil: Part 1 – Major inorganic ions in rainwater as evaluated by capillary electrophoresis with contactless conductivity detection
Wet deposition and related atmospheric chemistry in the São Paulo Metropolis, Brazil: Part 2 – Contribution of formic and acetic acids
A tribute to Professor Eduardo Neves for outstanding contributions to the development of Electroanalytical Chemistry in Brazil
Ultra-simple adaptor to convert batch cells with mercury drop electrodes in voltammetric detectors for flow analysis
Quick production of gold electrode sets or arrays and of microfluidic flow cells based on heat transfer of laser printed toner masks onto compact discs
Flow injection spectroelectroanalytical method for the determination of promethazine hydrochloride in pharmaceutical preparations
O uso de radiação ultravioleta para o pré-tratamento de amostra em análise inorgânica
Effect of scavengers on the photocatalytic digestion of organic matter in water samples assisted by TiO₂ in suspension for the voltammetric analysis of heavy metals
Determination of low concentrations of the flotation reagent ethyl xanthate by sampled DC polarography and flow injection with amperometric detection
Long-optical-path thin-layer spectroelectrochemical flow cell with inexpensive gold electrodes
Injetor multicanal com válvulas de estrangulamento para análise em fluxo
Propulsor pneumático versátil e isento de pulsação para sistemas de análise em fluxo
In-line TiO ₂-assisted photodigestion of organic matter in aqueous solution for voltammetric flow analysis of heavy metals in water samples
Determination of traces of uranium in environmental  samples using a flow injection system with amperometric catalytic detection
A Batch Injection Analysis System for Ascorbic Acid Determination Using Amperometric Detection on a Sessile Mercury Drop Electrode
Overcoming oxygen quenching in fluorescence spectrometry with a highly efficient in-line degassing device interfaced with a flow cell
Determination of the surface charge density of a mercury electrode by extrusion: a new method for correction of the Faradaic component
Critical Comparison of Four Simple Adaptors for Flow Amperometric and Stripping Voltammetry with Mercury Drop Electrodes in Batch Cells
Analysis and Speciation of Traces of Arsenic in Environmental, Food and Industrial Samples by Voltammetry: a Review
Eletrodos modificados com DNA: uma nova alternativa em eletroanálise
Voltammetric Behaviour of Metronidazole at Mercury Electrodes
Mechanism of interaction of in situ produced nitroimidazole reduction derivatives with DNA using electrochemical DNA biosensor Selective determination of traces of copper by adsorptive accumulation of copper(I) benzotriazolate, transient amalgamation and anodic stripping voltammetry
Flow-injection determination of catechol with a new tyrosinase/DNA biosensor
Comparison of the voltammetric behavior of metronidazole at a DNA-modified glassy carbon electrode, a mercury thin film electrode and a glassy carbon electrode

BRETT, A.M.O.; SERRANO, S.H.P.; GUTZ, I.G.R.; LA-SCALEA, M.A.
Electroanalysis, 1997, 9 (2), 110-114.
https://doi.org/10.1002/elan.1140090204.

The electroanalytical performance at three electrodes: DNA‐modified galssy carbon electrode, mercury thin film electrode and glassy carbon electrode, for the study of the electrochemical reduction of metronidazole is compared. All three electrodes showed a similar trend in the reduction mechanism for metronidazole, depenent on pH in the acid and neutral region and independent in alkaline media, although there was a shift in the peak potentials to more negative values when a bare glassy carbon electrode was used compared to the other two. Besides the advantage of using a solid electrode for the reduction of metronidazole, the DNA‐modified galssy carbon electrode enables a lower detection limit of 1.0 μM owing to the preconecentration of the drug on the electrode surface, which is not the case for the mercury thin film or bare glassy carbon electrodes.
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ROCHA, R. T., GUTZ, I.G.R., LAGO, C. L.
J. Chem. Educ., 1997, 74(5), 572-574.
https://doi.org/10.1021/ed074p572

A two-electrode conductivimeter is described, which keep good performance in spite of its low cost. It is composed of a triangular wave generator, a current-to-voltage converter, and a precision half-wave rectifier. All these functions were implemented with only one integrated circuit TL084. A 3 1/2-digits multimeter is used as the display. Four scales allow measurements over a wide range of conductance (0.01 µS to 19.99 mS). To ensure the low cost and robustness, a stainless steel electrode was developed. The low amplitude and high frequency of the oscillator allow good measurements with this kind of electrode, giving, in some cases, even better results than commercial ones. Anyway, platinum electrode is the better choice for very oxidant media. Electronic diagrams and complete list of components as well as examples of applications are shown.

Electrochemical Reduction of metronidazole at a DNA-modified glassy carbon electrode

BRETT, A.M.O.; SERRANO, S.H.P.; GUTZ, I.G.R.; LA-SCALEA, M.A.
Bioelectrochem. Bioenerg., 1997, 42(2), 175-178.
https://doi.org/10.1016/S0302-4598(96)05122-7

The electrochemical reduction of metronidazole was investigated using, for the first time, the newly developed DNA-modified glassy carbon electrode. The results are compared with reduction at bare glassy carbon electrodes. The potentials for reduction were less negative when using the DNA-modified glassy carbon electode although the mechanism was the same. A potential-pH dependence of one electron per proton was observed in acid media whereas for neutral and alkaline solution no dependence was found. The DNA-modified glassy carbon electrode enables preconcentration of the sample for chosen times on the electrode surface which is convenient for analytical applications. The limit of detection using the DNA-modified glassy carbon electrode at pH 4.5 with 2 min preconcentration is 1.67 μM, and without preconcentration it is three times higher, 3.25 μM. At a bare glassy carbon electrode, where preconcentration is not possible, the limit of detection for the same pH is 3.44 μM.

A flow-through cell based on an array of gold microelectrodes obtained from modified integrated circuit chips

AUGELLI, M.A.; NASCIMENTO, V.B.; PEDROTTI, J.J; GUTZ, I.G.R; ANGNES, L.A.
The Analyst, 1997, 122, 843-847.
https://doi.org/10.1039/A701519D

The construction of a flow-through cell incorporating an array of gold microelectrodes is described and its application to flow injection analysis with amperometric detection is presented. Simple modification of almost any conventional integrated circuit chip, used as an inexpensive source of pre-assembled gold micro-wires, leads to the rapid and successful preparation of arrays of 8–48 elements. The polymeric encapsulation material from the top face of the chip is removed by abrasion until the gold micro-wires (used to interconnect the silicon circuit to the external contact pins of the chip) are disrupted and their transversal (elliptical) sections become exposed. Once polished, the flat and smooth top surface of the gold microelectrode-array chip (MEAC) is provided with a spacer and fitted under pressure against an acrylic block with the reference and auxiliary electrodes, to form the electrochemical (thin-layer) flow cell, while the contact pins are plugged into a standard IC socket. This design ensures autonomous electric contact with each electrode and allows fast dismantling for polishing or substitution. The performance of flow cells with MEACs was investigated utilizing the technique of reverse pulse amperometry without oxygen removal. A method was established for the determination of the copper concentration in sugar cane spirit, regulated by law for beverages. Samples from industrial producers and small-scale (alembic) brewers were compared. With a 24 MEAC, a detection limit of 30 µg l-1 of copper (4.7 × 10-7 mol l-1 of CuII for 100 µl injections) was calculated. Routine operation was established at a frequency of 60–90 determinations per hour. Intercomparison with atomic absorption spectrometric determinations resulted in excellent agreement.

Arrays of gold microelectrodes made from split integrated circuit chips

NASCIMENTO, V.B.; AUGELLI, M.A.; PEDROTTI, J.J; GUTZ, I.G.R; ANGNES, L.A.
Electroanalysis, 1997, 9(4), 335-339.
https://doi.org/10.1002/elan.1140090415

A simple and inexpensive way to fabricate arrays of gold microelectrodes is proposed. Integrated circuit chips are sawed through their middle, normal to the longest axis, leading to destruction of the silicon circuit and rupture of the gold wires that interconnect it with the external terminals. Polishing the resulting rough surface converts the tips of the wires embedded in the chip halves into arrays of gold microdisks of about 25 m diameter. The number of active microelectrodes (MEs), of an array depends on the number of pins in the chip, n, being typically (n/2)-4. These MEs can be used individually or externally interconnected in any combination. X-ray images of the chips and micrographs of the resulting surface of the polished arrays have revealed variable distances between neighbor MEs, which are however, larger than 10 times the radius of the disks. This feature of the MEs prevents diffusional cross-talk between electrodes. The use of these microdisk electrodes for analytical purposes exhibits sigmoidal voltammograms, and chronoamperometric experiments confirm the nonlinear i vs. t1/2 plots, typical for processes where radial diffusion prevails, Satisfactory uniformity was observed for the response of each electrode of an array, indicating similarity of geometry and disk areas. The potentialities of these MEs were demonstrated by the determination of cadmium at ppb levels using square wave voltammetry with preconcentration. Due to the relative ease with which these MEs can be manufactured and their good performance in (chemical) analysis, wide applications in electrochemistry and electroanalysis is envisioned.

Voltammetric behavior of nitroimidazoles at a DNA-biosensor

BRETT, A.M.O.; SERRANO, S.H.P.; GUTZ, I.G.R.; LA-SCALEA, M.A.; CRUZ, M.L.
Electroanalysis, 1997, 9 (14), 1132-1137.
https://doi.org/10.1002/elan.1140091419

The newly developed DNA-biosensor is a very promising tool for the investigation and study of the action of drugs specifically designed to interact with DNA. In this work the electrochemical reduction of nitroimidazole drugs was studied in the presence of DNA immobilized onto the surface of a glassy carbon electrode. This enabled preconcentration of the drug onto the electrode surface, which was then electrochemically reduced to the corresponding hydroxylamine which followed by reoxidation give the nitroso compound and subsequently an azoxycompound. Moreover, as the target of the nitroimidazole action was the DNA, the damage caused to DNA on the electrode surface by areduction product of this drug could be detected in situ.

Miniaturized reference electrodes with microporous polymer junctions 

PEDROTTI, J.; ANGNES, L.; GUTZ, I.G.R.
Electroanalysis, 1996, 8(7), 673-675.
https://doi.org/10.1002/elan.1140080713

The construction and evaluation of a simple and effective mini-reference electrode is presented. Major innovations are the use of high density microporous polyethylene for the restricted flow junction between the internal and external electrolyte and a polypropylene disposable pipette tip as the electrode body. Low electrolyte bleeding, reduced size, relatively low electrical resistance and simplified procedure of construction are some of the advantages of the presented design. These characteristics make this electrode particularly suitable for use with small-volume cells and flow cells, as well as applications where chloride contamination should be avoided. Other applications for the microporous membrane in electroanalysis are introduced.