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Two miniature, fibreless, compact and highly integrated flow-through optoelectronic detectors dedicated for photometric and fluorimetric determination of proteins have been developed. Both detectors operating according to paired-emitter-detector-diode methodology are constructed only of light emitting diodes and therefore their total cost is extremely low. The photometric detector is dedicated for...
A simple multicommutated flow system based on optoelectronic detector, three valves and peristaltic pump only has been developed for photometric determination of alkaline phosphatase activity in human serum. A miniaturized, compact flow-through detector dedicated to selective photometric detection of product formed in the course of the enzyme assay has been constructed using two paired light emitting...
A non-extractive sequential injection spectrophotometric method for the determination of molybdenum has been developed. The method is based on the reaction between the thiocyanate complex of molybdenum and the polymethine dye (2-[2-(4-dipropylamino-phenyl)-vinyl]-1,3,3-trimethyl-3H-indolium chloride) in a hydrochloric acid medium. The calibration plot in the SIA system was linear from 0.080mgL ...
A novel lab-on-valve system has been developed for strontium determination in environmental samples. Miniaturized lab-on-valve system potentially offers facilities to allow any kind of chemical and physical processes, including fluidic and microcarrier bead control, homogenous reaction and liquid–solid interaction. A rapid, inexpensive and fully automated method for the separation and preconcentration...
A rapid, sensitive and fully automated chemiluminometric method is described for determination of five phenothiazine derivatives, namely, trifluoperazine, fluphenazine, perphenazine, thioridazine and chlorpromazine. The method is based on the chemiluminescence (CL) induced by the oxidation of drugs with Ce(IV) in nitric acid. A flow manifold based on the association of multi-commutation and multi-pumping...
Counterfeiting of documents is a common phenomenon in the modern world. A large proportion of forgeries relates to inkjet printed documents. Hence there is an evident need to develop an effective and reliable method for the differentiation and identification of inkjet inks on questioned documents. The aim of the presented study was to investigate the possibility of applying micellar electrokinetic...
Amperometric tyrosinase based biosensor for benzoic acid determination with the use of a flow-batch monosegmented sequential injection system is proposed. The functioning of the biosensor is based on the inhibition effect of benzoic acid on the biocatalytic activity of tyrosinase, polyphenol oxidase. In the biosensor, tyrosinase is entrapped in titania gel modified with multiwalled carbon nanotubes...
A highly sensitive, precise and automated method using sequential injection analysis to assay quantitatively low levels of the p-aminophenol (PAP) in paracetamol formulations has been developed. A solution containing PAP and paracetamol is injected into an acetate buffer carrier stream and merged on-line with 18-molybdodiphosphate heteropoly complex reagent to form a specific blue derivative that...
In the report of the International Union of Pure and Applied Chemistry (IUPAC) estimation of analyte recovery (RV) is recommended as one of the ways for assessment of trueness of analytical results. RV is usually estimated with the use of samples spiked with known amount of analyte. However, neither the IUPAC guidelines, nor the available literature take into consideration various effects of different...
An attempt was made to demonstrate that flow injection gradient titration should not be considered as classical titration but rather as the indirect calibration method. This was shown experimentally by exploiting indirect spectrophotometric determination of chlorite ions in the presence of iron(II) in an acid environment with measurement of absorbance for the coloured Fe(II)/o-phenanthroline complex...
An automated methodology for the kinetic study of β-galactosidase activity in sodium dodecylsulfate (SDS)/ionic liquid (IL) mixed micelles was developed. The main objective of the work was the evaluation of mixed micelles as reaction media for the industrial synthesis of glyco-oligossacharides. Enzyme activity was evaluated by means of a model reaction with the fluorescent substrate 4-methylumbelliferyl-α-d-galactopyranoside...
Heavy metals, as cadmium, attract a rising attention in environmental studies due to their increasing release by human activities and acute toxicity. In situ analytical methods are needed to minimize current uncertainties caused by the transport and conservation of samples. Here, we present the completely automatic determination of Cd in natural waters using a newly developed screen printed electrode...
A novel direct-injection detector (DID) integrated with multi-pumping flow system (MPFS) for the photometric determination of iron is proposed. Paired emitter-detector diodes have been used as a photometric detection system. The sample and reagent were injected using appropriate solenoid pulse micro-pumps directly into the detection chamber where effective mixing occured. The use of proposed stop-flow...
A new flow-injection (FI) and high performance liquid chromatography (HPLC) with chemiluminescence detection method has been proposed for the determination of α-lipoic acid (LA). The assay is based on the measurement of chemiluminescence (CL) produced during the reaction of α-lipoic acid with potassium permanganate in a sodium hexametaphosphate medium (pH 3). This reaction is accompanied by a weak...
A simple and straightforward quantification method integrated in a fully automated multi-pumping flow system (MPFS) using water-soluble mercaptopropionic acid (MPA)-capped CdTe quantum dots (QDs) was implemented for the fluorescence quantification of N-acetyl-l-cysteine (NAC) in pharmaceutical formulations. The developed approach was based on NAC ability to establish surface interactions that result...
The highly sensitive determination of lead (Pb(II)) and cadmium (Cd(II)) ions, with a limit of detection of 0.01μgL −1 for Pb(II) and Cd(II), by on-line preconcentration and anodic stripping voltammetry (ASV) controlled by a sequential injection analysis (SIA) system is reported here. The SIA system consisted of a syringe pump, an 8-port selection valve and a 6-port switching valve and was...
Bisphenol A (BPA) is a polyphenol widely used in industry as an intermediate in the production of polycarbonate plastics and epoxy resins, which are applied to produce plastic food containers, inner surface coating of food and beverage cans. Hence, BPA can migrate from these containers and cans with epoxy coating into foods. It is dangerous taking into account that BPA is considered as a potential...
Reduction of disulfide bonds is – in many cases – a critical pretreatment step for the determination of thiols in real samples. This study reports the first systematic investigation of the potentials of the on-line reduction of disulfide bonds under flow conditions in a sequential injection setup. One of the most promising reducing agents, tris-(2-carboxyethyl)phosphine (TCEP) was selected for this...
Dispersion systems like emulsions and microemulsions are able to solubilize both polar and non-polar substances due to the special arrangement of the oil and aqueous phases. The main advantages of using emulsions or microemulsions in analytical chemistry are that they do not require the previous destruction of the sample matrix or the use of organic solvents as diluents, and behave similarly to aqueous...
Simple, rapid and fully automated methods for the manual and automated spectrophotometric determination of epinephrine have been developed by using schemes of stepwise injection (SWIA) and sequential injection analysis (SIA) implemented in the same manifold. The determination is based on the formation of reduced form of 18-molybdodiphosphate heteropoly anion by its reaction with epinephrine. Using...
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