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Nowadays,a nalytical methods with portable characteristics for on-site and in-situ measurements continue to attract significant attention. In this context,t he use of miniaturizede lectrochemical systems has been proposed because they have severalo ft he requirements of portable methods [1,2].H owever, in manyc ases,m iniaturized systems are characterized by low robustness and reduced range of applications for each system or device. In 1991, Wang and Taha [3] introduced at echnique named batch injection analysis (BIA). In BIA systems with electrochemical detection, as ample plug is injected from am icropipette tip directly on the electrodes urface that is immersed in al arge-volume blank electrolyte solution. Ther esults obtained with aB IA system are conceptionally similar to FIA or SIA, however, withoutu sing additional components such as pumping systems,i njection valves,a nd tubes (possibility of problemsw ith air bubbles and leaks) [4].I nB IA systems, all of these components were replaced by ab attery powered electronic micropipette and, therefore,t he set consisting by BIA cell, electronic micropipette,m ini-potentiostat, and tablet or laptop computerc an be used as ap ortable electrochemical system.R ecently,o ur research group has developed BIA cells specially designed to work with screen-printed electrodes (SPEs) [5,6].S imilar to BIA systems, SPEs also presented some desirable features useful in portable analytical systems,s uch as low cost (large-scale production), disposability,r apid responses,s implicity and robustness (working, countera nd pseudo-reference electrodes are printed on achemically inert substrate).Considering the characteristics of BIA cells and SPEs, one can conclude that the system that combinesb oth de-vices has great potential to be used as ap ortable electrochemical system. Recently,w ei ntroduced ac ompact system composed by aB IA cell specially designed for SPEs( BIASPE cell).F igure 1s howsi mages of the detailed schematic design of the cell (Fig. 1A), photographs of the complete BIASPE cell ( Fig. 1B) and the innovative open-close system (no screws needed) for easy SPE replacement (Fig.1C).When the BIASPE cell is combinedw ith battery-powered accessories( electronic micropipette,p otentiostat and at ablet or al aptop computer), the generateds et can be considered as ar obust portable electrochemical system (Fig.1D). Further details on the proposed BIASPE cell can be found in multiplei mages availablei n supporting information. In addition, specific details on the operation of the BIASPE system (cella ssembly,p ositioning of the SPE in the cell, electronic micropipette operation,a mperometric and voltammetric experiments and visualization of the phenomena that occur on the working electrode surface during injection procedures) can be ac-Abstract:H erein, ac ompact batch injection analysisc ell for screen printed electrodes (BIASPE cell) is reported. Thep roposed system shows several requirements of ap ortable system that include easy-to-operate ("userfriendly"),h igh-speed qu...

In this work, the performance of two methods for simultaneous determination of propyphenazone (PRO), paracetamol (PAR), and caffeine (CAF) were compared. One is based on the use of a conventional electrochemical cell (steady‐state condition) and the other on the use of a batch injection analysis (BIA) cell; both systems were associated with square‐wave voltammetric detection (SWV). Three well separated (▵E ≥ 0.25 V) oxidation peaks were obtained for PRO, PAR, and CAF using 0.1 mol L−1 H2SO4 as electrolyte and a boron‐doped diamond (BDD) as working electrode. In addition, the electrochemical oxidation mechanism of PRO is being proposed for the first time. The average relative standard deviations of CB and BIA methods were 4.1 % and 3.1 %, respectively. The conventional system presented better limits of detection and the BIA system a significantly greater throughput (four times faster). Statistical comparison between the results obtained with both proposed methods and those obtained by chromatography was carried out and no significant differences were observed (95 % confidence level).

This work presents a portable electrochemical system for the continuous monitoring of corrosion inhibitors in a wide range of matrices including ethanol, seawater and mineral oil following simple dilution of the samples. Proof-of-concept is demonstrated for the sensing of 2,5-dimercapto-1,3,5-thiadiazole (DMCT), an important corrosion inhibitor. Disposable screen-printed graphitic electrodes (SPGEs) associated with a portable batch-injection cell are proposed for the amperometric determination of DMCT following sample dilution with electrolyte (95% v/v ethanol + 5% v/v 0.1molL HSO solution). This electrolyte was compatible with all samples and the organic-resistant SPGE could be used continuously for more than 200 injections (100µL injected at 193µLs) free from effects of adsorption of DMCT, which have a great affinity for metallic surfaces, and dissolution of the other reported SPGE inks which has hampered prior research efforts. Fast (180h) and precise responses (RSD < 3% n = 10) with a detection limit of 0.3µmolL was obtained. The accuracy of the proposed method was attested through recovery tests (93-106%) and the reasonable agreement of results of DMCT concentrations in samples analyzed by both proposed and spectrophotometric (comparative) methods.

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Recebido em 11/09/2019; aceito em 12/12/2019; publicado na web em 09/03/2020 This work presents a simple electrochemical method for 2-naphthylamine (2NAP) determination in perfume by differential-pulse voltammetry (DPV) employing a boron-doped diamond (BDD) electrode cathodically treated. Simple dilution of sample in supporting electrolyte was performed before electrochemical analysis. A borate buffer solution of pH 10.0 containing 20% (v/v) ethanol provided stable responses of 2NAP without electrode fouling. Modulation time, step potential and modulation amplitude were optimized at 20 ms, 6 mV and 70 mV, which achieved a limit of detection (LOD) of 0.0046 μmol L −1 with a linear range between 0.5 and 90 μmol L −1 , and RSD < 2.9%, respectively. Recovery values for spiked samples with 2NAP were between 102 and 104%. The proposed method is feasible to be applied for 2NAP detection and quantification on perfume samples with simple sample preparation.

Tibolone (TIB) is a synthetic steroid banned by the World Anti‐Doping Agency (WADA) due to its similar properties to estrogen and progesterone. In this work, a simple and low‐cost electrochemical method for the determination of TIB and its metabolites (3‐α hydroxytibolone and 3‐β hydroxytibolone) in authentic human saliva is reported. Square‐wave voltammetry (SWV) with an unmodified boron‐doped diamond (BDD) electrode and phosphate buffer 0.1 mol L−1 were selected as the electrochemical technique, working electrode, and supporting electrolyte, respectively. Analytical characteristics of the proposed method include good repeatability (RSD <2.4 %), wide linear range (1 to 110 μmol L−1; r=0.999) and low detection limit (0.3 μmol L−1). Average recovery values (104±3 % for TIB and 98±5 % for the metabolites) for direct analysis of spiked saliva samples (only diluted in supporting electrolyte) indicate that no significant matrix interference was observed. The proposed method was also efficient for the determination of TIB in pharmaceutical samples (statistically similar results to those obtained by HPLC).