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The detection and quantitation of four ethanolamines, tris(2-hydroxyethyl)amine (triethanolamine, TEA), N,N-bis(2-hydroxyethyl)methylamine (methyldiethanolamine, MDEA), N-(2-aminoethyl)ethanolamine (AEA), and N,N-diethylethanolamine (DEA), were achieved in wastewaters from two aerobic activated sludge bioreactors located in an industrial wastewater treatment plant. The streams had salt concentrations...
In this paper, we describe DNA electrochemical detection for genetically modified organism (GMO) based on multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole (PPy). DNA hybridization is studied by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). An increase in DNA complementary target concentration results in a decrease in the faradic charge transfer resistance...
The purpose of this work was to present a chromatographic methods to analyse synthetic food dyes. The following techniques has been described: thin-layer liquid chromatography (TLC), high performance thin-layer chromatography (HPTLC), traditional column chromatography, high performance liquid chromatography (HPLC), include: ion-pair chromatography (HPLC IP), reversed phase chromatography (RP HPLC)...
Conductive composite film which contains nafion (NF) doped multi-walled carbon nanotubes (MWCNTs) along with the incorporation of poly(malachite green) (PMG) has been synthesized on glassy carbon electrode (GCE), gold and indium tin oxide (ITO) electrodes by potentiostatic methods. The presence of MWCNTs in the composite film (MWCNTs–NF–PMG) enhances surface coverage concentration (Γ) of PMG to ≈396%,...
A highly selective membrane electrodes based on a two newly synthesized nickel (II) Schiff bases, [NiL 1 ] and [NiL 2 ] where L 1 and L 2 are N,N/bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H 2 L 1 ) and N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H 2 L 2 ) were used as a neutral carrier ionophores for static...
A new, multisyringe flow injection set-up has been developed for the completely automated determination of trace thiazide compounds with diuretic action in different types of samples. The proposed instrumental set-up exploits for the first time, a low pressure on-line solid phase extraction–liquid chromatography–chemiluminescence detection method. This novel combination of sample treatments in flow...
The early clinic identification of commonly encountered Candida species became more important with the increasing human candidiasis. In this paper, a new MSPQC-PLS (multi-channel series piezoelectric quartz crystal biosensor combined with partial least square) method was proposed for early identification of the most frequent Candida species encountered in human pathology. This method was based on...
Two different derivatizing reagents were tested for the development of a fast and sensitive method for the determination of selenites (Se IV ) in human urine. The reagents were sodium tetraethylborate (NaBEt 4 ) and tetraphenylborate (NaBPh 4 ), respectively, and the procedure is based on in situ derivatization of selenites in aqueous medium. Selenite ions are converted to...
A facile solution-phase synthesis route of highly uniform Cu 2 O nanospheres (Cu 2 O NPs) with the size of 57.7±4.7nm was developed, and then the nanoparticles were applied to live cell imaging under a common dark-field microscope. Starting from copper(II) salts, the synthesis of Cu 2 O NPs was made in the presence of cetyltrimethylammonium bromide (CTAB) by reducing the copper(II)...
A series of supports functionalized with different alkyl chains and covered with magnetite were synthesized, characterized and applied in the sample pre-concentration of four non-steroidal anti-inflammatory drugs (acetaminophen, naproxen, diclofenac and ibuprofen) contained in wastewater samples. The general methodology involved magnetic solid phase dispersion followed by the analysis by high-performance...
A new approach to modelling of some binary (hydro-organic, HL/H 2 O+B) acid–base systems with organic co-solvent B fully miscible with water, is suggested and applied for the determination of acidity parameters pK for some weak acids HL. The models are designed to get the pK=pK(x) relationships (x—mole fraction of B in H 2 O+B) from results of pH titrations made in such systems and...
A new cadmium(II)-imprinted polymer based on cadmium(II) 2,2′-{ethane-1,2-diylbis[nitrilo(E)methylylidene]} diphenolate-4-vinylpyridine complex was obtained via suspension polymerization. The beads were used as a minicolumn packing for flow-injection-flame atomic absorption spectrometry (FI-FAAS) determination of cadmium(II) in water samples. Sorption effectiveness was optimal within pH range of 6...
Multidimensional analysis of instant coffee and barley beverage samples using size exclusion chromatography (SEC) combined with a dynamic surface tension detector (DSTD) and a UV–vis absorbance detector (UV) is reported. A unique finding of this study was the action of the tetrabutylammonium (TBA) cation as a modifying agent (with bromide as the counter anion) that substantially increased the surface...
Single strand DNA (ssDNA) was used to modify nanogold to obtain a nanogold-aptamer resonance scattering (RS) probe (NGssDNA) for Hg 2+ , based on the formation of stable thymine-Hg 2+ -thymine (T-Hg 2+ -T) mismatches and aggregation of the released nanogold particles. After removing the aggregated particles by filtrate membrane, the excess NGssDNA in the filtration solution...
An integrated analyzer based on the multisyringe flow injection analysis approach is proposed for the automated determination of dissolved oxygen in seawater. The entire Winkler method including precipitation of manganese(II) hydroxide, fixation of dissolved oxygen, dissolution of the oxidized manganese hydroxide precipitate, and generation of iodine and tri-iodide ion are in-line effected within...
In this study we compared the use of ordinary least squares and weighted least squares in the calibration of the method for analyzing essential and toxic metals present in human milk by ICP-OES, in order to avoid systematic errors in the measurements used. Human milk samples were provided by maternity clinic Odete Valadares and digested by means of a high-performance microwave (MW) oven. Evaluation...
In this work a single interface flow system (SIFA) with potentiometric detection was for the first time implemented and applied to the determination of nitrate in waters and plant extracts. The analytical potential of the SIFA system was exploited not only to transport the sample towards detection but also to carry out, in a reproducible and automated way, the tasks associated with sample pre-treatment,...
Despite the necessity to differentiate chemical species of mercury in clinical specimens, there are a limited number of methods for this purpose. Then, this paper describes a simple method for the determination of methylmercury and inorganic mercury in blood by using liquid chromatography with inductively coupled mass spectrometry (LC–ICP-MS) and a fast sample preparation procedure. Prior to analysis,...
Current work has evaluated uncertainty associated to quantification of several organic compounds present in particulate matter of atmospheric aerosols, setting out the stages of analytical procedure that contribute most to the global uncertainty. Several sources of uncertainty have been identified, which were clustered into five main contributions: sampling, extraction, clean-up, derivatization and...
A method has been developed based on an on-line isotope dilution technique couple with laser ablation/inductively coupled plasma mass spectrometry (LA–ICP-MS), for the determination of boron in p-type silicon wafers. The laser-ablated sample aerosol was mixed on-line with an enriched boron aerosol supplied continuously using a conventional nebulization system. Upon mixing the two aerosol streams,...
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