scholarly journals The influence of nature of active components and modifiers on electroanalytic properties of planar cefalexine-selective sensors

2021 ◽  
Vol 21 (2) ◽  
pp. 134-144
Author(s):  
Elena G. Kulapina ◽  
◽  
Olga I. Kulapina ◽  
Vlada D. Ankina ◽  
◽  
...  
Keyword(s):  
Response Time ◽  
Aqueous Solutions ◽  
Oral Fluid ◽  
Cupric Oxide ◽  
Active Material ◽  
Complex Compounds ◽  
Active Components ◽  
Kinetic Spectrophotometry ◽  
Biological Environment

The 1st generation cefalexine-cephalosporine antibiotic is used in the treatment of various infectious diseases. Spectrophotometry, kinetic spectrophotometry, spectrofluorimetry are proposed to determination of cefalexine in medicine and biological environment. Planar screenprinted sensors allow analyzing the micro-volumes of samples, which is important for the analysis of biological objects without preliminary samplepreparation. Depending on the active material and modifiers, you can create planar sensors for the determination of different organic compounds. In this work we have studied the influence of the nature of electroactive compounds and modifiers on the electroanalytic properties of planar cefalexine-selective sensors. Associates of tetradecylammonium and dimethyldistearylammonium with complex compounds silver (1) – cefalexine (Ceas = 1–3%), polyaniline modifiers and cupric oxide nanoparticles have been used as active components, the ratio EAS: modifier is 1:1. The main electroanalytic and operational characteristics of cefalexine-selective sensors in aqueous solutions and on the background of oral fluid are determined. Advantage of tetradecylammonium in active components of cefalexine-selective sensors is shown. For cefalexine- sensors, the optimal is: linearity interval 1·10-2 – 1·10-4, response time 20–25 seconds, for unmodified: 10–15 sec, for modified in 1·10-2 M solutions of cefalexine, service life – 1 month. Modifiers approximate angular coefficients of electrode functions to theoretical values for single-charge ions, reduce response time and drift of potential, reduce the detection limit of cefalexine. Sensors are used for the determination of cephalexine in model aqueous solutions and oral fluid with added antibiotic additives, in expired cephalexine preparations.

Arrays of solid contact potentiometric sensors for separate determination of some cephalosporin antibiotics

2021 ◽  
Vol 87 (5) ◽  
pp. 5-13
Author(s):  
E. G. Kulapina ◽  
A. E. Dubasova ◽  
O. I. Kulapina ◽  
V. D. Ankina
Keyword(s):  
Response Time ◽  
Reference Model ◽  
Complex Compounds ◽  
Potentiometric Sensors ◽  
Separate Determination ◽  
Solid Contact ◽  
Active Components ◽  
Membrane Surfaces ◽  
Cephalosporin Antibiotics

Arrays of potentiometric sensors including developed solid-contact unmodified and modified sensors based on tetradecylammonium associates with complex compounds of silver (1) and some β-lactam antibiotics (cefazoline, cefuroxime, cefotaxime (n = 3 – 6)) are proposed; polyaniline and copper oxide being modifiers. The main electroanalytic properties of the sensors are determined (the range of the determined concentrations in antibiotic solutions 1 × 10–4 – 0.1 M, 46.3 < S < 48, Cmin = n × 10–5 М, response time 4 – 10 sec, potential drift 4 – 6 mV/day, service life — 2 months). It is shown that modification of the membrane surfaces brings the steepness of the electrode functions to Nernst-values for single-charged ions of the antibiotics under study; reduces the response time and the detection limits, the linearity intervals of the electrode functions being the same. The potentiometric selectivity coefficients of unmodified and modified sensors based on different electrode active components (EAC) to the studied cephalosporins in the presence of interfering antibiotics are close to unity; cross sensitivity parameters for the considered sensors (the average slope of the electrode function of the sensor Sav, the unselectivity factor F, and the reproducibility factor K) are 46.3 < S (mV/pC) < 48; 0.85 < F < 0.90; 144 < K < 170, respectively. Application of sensors in the multisensory analysis of model mixtures of cephalosporin antibiotics is shown. Method of artificial neural networks (ANN) is used for processing of analytical signals. The correctness of the determination is carried out using «spike tests» on the reference model mixtures (the relative error of the determination does not exceed 12 %).

scholarly journals A novel optode sensor for the determination of palladium(II) in water and a hydrogenation catalyst

2009 ◽  
Vol 74 (3) ◽  
pp. 311-315 ◽  
Author(s):  
Hossein Tavallali ◽  
Pisheh Jahromi
Keyword(s):  
Response Time ◽  
Aqueous Solutions ◽  
Optical Sensor ◽  
Color Change ◽  
Limit Of Detection ◽  
Linear Range ◽  
Hydrogenation Catalyst ◽  
Catalyst Sample ◽  
Dynamic Linear Range

A novel optical sensor was established to determine palladium(II) based on the immobilization of 1-(2-pyridylazo)-2-naphthol (PAN) on a triacetylcellulose membrane. Palladium ions react with the immobilized PAN and cause a decrease in the absorbance of the membrane at 469 nm. The response time of the optode was 8-10 min depending on the concentration of Pd(II) ions. This sensing phase had a dynamic linear range of 0.10-12.0 ?g ml-1 palladium ions with a limit of detection of 65 ng ml-1. The sensor can readily be regenerated using an ethylenediamine solution. The sensor could be fully regenerated, and the color change was fully reversible. The method was successfully applied for the determination of Pd(II) in synthetic aqueous solutions and in a hydrogenation catalyst sample.

scholarly journals “Electronic tongue” multi-systems for the separate determination of cefotaxime and cefazoline

2021 ◽  
Vol 21 (1) ◽  
pp. 4-11
Author(s):  
Elena G. Kulapina ◽  
◽  
Anastasia E. Dubasova ◽  
Olga I. Kulapina ◽  
Vlada D. Ankina ◽  
...  
Keyword(s):  
Electronic Tongue ◽  
Complex Compounds ◽  
Cuo Nanoparticles ◽  
Potentiometric Sensors ◽  
Separate Determination ◽  
Solid Contact ◽  
Active Components ◽  
Potentiometric Selectivity ◽  
Two Component

Electroanalytical properties of unmodified and modified by polyaniline and by CuO nanoparticles solid-contact potentiometric sensors which are based on associates of tetradecylammonium with complex compounds of silver (I) with cephuroxime, cephotaxime and cephazoline Ag(β-lac)2TDA in solutions of corresponding antibiotics were studied. It was revealed that Ag(β-lac)2TDA –based sensors had no specificity to the basic ion but showed sensitivity to other cephalosporins. Taking into account the potentiometric selectivity coefficients and cross-sensitivity parameters of sensors based on different electrode-active components, their use for creating «electronic tongue» multi-sensor systems was shown. Arrays of low-selective potentiometric sensors were created for separate determination of cephazoline and cephotaxime in two-component model mixtures at concentration intervals of 2,5·10-4 – 0,01 М. The method of artificial neural networks was used for processing analytical signals (the relative error of determination not exceeding 13%).

INFLUENCE OF OFFICE BLEACHING SYSTEMS ON THE RESISTANCE OF HARD TOOTH TISSUES

2020 ◽  
pp. 119-125
Author(s):  
Magsumova O.A. ◽  
Postnikov M.A. ◽  
Ryskina E.A. ◽  
Tkach T.M. ◽  
Polkanova V.A.
Keyword(s):  
Informed Consent ◽  
Oral Fluid ◽  
Personal Data ◽  
Acid Resistance ◽  
Non Invasive ◽  
Hard Tissues ◽  
Voluntary Informed Consent

One of the non-invasive methods for treating discoloration of hard tooth tissues is teeth whitening. The aim of this work is to assess the dynamics of changes in the acid resistance of enamel and hard tissues of teeth and the rate of its remineralization after the procedure of office teeth whitening. The study involved 123 patients aged 18 to 35 years with discoloration of various origins, with the color of hard tooth tissues on the Vita Classic A2 scale and darker. Before performing the office, teeth whitening procedure, all patients gave their written voluntary informed consent to participate in this study, as well as consent to the processing of personal data. Depending on the chosen method of office teeth whitening, patients were divided into 3 groups. The resistance of hard tooth tissues was judged based on the determination of TOER and CASRE tests. These indicators were determined at various times (5 days before the office teeth whitening procedure, 5 days after it, after 14, 30 days and 6 months). Regardless of the chosen whitening system, the office teeth whitening procedure is accompanied by a decrease in the enamel's resistance to acids and a decrease in the rate of its remineralization. The remineralizing function of oral fluid promotes the positive dynamics of the studied parameters after 14 days and after 30 days values increased due to the appointment of remineralizing therapy to all patients in 2 weeks after the teeth whitening procedure. After 6 months, all patients had high enamel resistance and the rate of its remineralization.

STUDY ON NEW COMPLEX COMPOUNDS OF Ti(IV) AND Zr(IV) IN AQUEOUS SOLUTIONS: SYNTHESIS, STABILITY AND APPLICATION IN CLEANER TECHNOLOGIES OF NATURAL LEATHER

2008 ◽  
Vol 7 (3) ◽  
pp. 241-248 ◽  
Author(s):  
Doina Sibiescu ◽  
Ioan Rosca ◽  
Daniel Sutiman ◽  
Marian Crudu ◽  
Adrian Cailean ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Complex Compounds ◽  
Cleaner Technologies

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

New Coordination Compounds of Fe(III) with Organic Ligands

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Mihaela Flondor ◽  
Ioan Rosca ◽  
Doina Sibiescu ◽  
Mihaela-Aurelia Vizitiu ◽  
Daniel-Mircea Sutiman ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Complex Compounds ◽  
Organic Ligands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Chemical Analysis ◽  
Structural Formulae ◽  
Paramagnetic Properties

In this paper the synthesis and the study of some complex compounds of Fe(III) with ligands derived from: 2-(4-chloro-phenylsulfanyl)-1-(2-hydroxy-3,5-diiodo-phenyl)-ethanone (HL1), 1-(3,5-dibromo-2-hydroxy-phenyl)-2-phenylsulfanyl-ethanone(HL2), and 2-(4-chloro-phenylsulfanyl)-1-(3,5-dibromo-2-hydroxy-phenyl)-ethanone (HL3) is presented. The characterization of these complexes is based on method as: the elemental chemical analysis, IR and ESR spectroscopy, M�ssbauer, the thermogravimetric analysis and X-ray diffraction. Study of the IR and chemical analysis has evidenced that the precipitates form are a complexes and the combination ratio of M:L is 1:2. The central atoms of Fe(III) presented paramagnetic properties and a octaedric hybridization. Starting from this precipitation reactions, a method for the gravimetric determination of Fe(III) with this organic ligands has been possible. Based on the experimental data on literature indications, the structural formulae of the complex compounds are assigned.

Simultaneous Determination of Six Components in Jingzhiguanxin Tablet by High-Performance Liquid Chromatography

2019 ◽  
Vol 15 (2) ◽  
pp. 130-137
Author(s):  
Hui Jiang ◽  
Lianhao Fu ◽  
Yu Wang ◽  
Shaozhi Wang ◽  
Xiaoxu Zhang ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Gradient Elution ◽  
Tanshinone Iia ◽  
Array Detector ◽  
Control Analysis ◽  
Active Components ◽  
Quality Control Analysis

Background: Jingzhiguanxin (JZGX) tablet, a traditional Chinese prescription, is commonly used for treating coronary heart disease and angina pectoris in the clinic. There are six active components (Danshensu (DSS), Protocatechuic aldehyde (PD), Paeoniflorin (PF), Ferulic acid (FA), Salvianolic acid B (Sal B) and Tanshinone IIA (TA)) in JZGX tablet. </P><P> Objective: In this paper, a simple and reliable method was used for simultaneous determining the six active components by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). Methods: These six active components were separated on an Agilent Zorbax Eclipse XDB-C18 column (150 mmx4.6 mm, 5 µm) at 30 °C. Acetonitrile (A), methanol (B) and 0.5% H3PO4 aqueous solution (C) were used as mobile phase for gradient elution. The flow rate was 1 mL/min and the detection wavelengths were set at 280 nm for DSS, PD and Sal B, 230 nm for PF, 320 nm for FA and 270 nm for TA, respectively. Results: All of the six components showed good linearity regressions (r2≥0.9997) in the detected concentration range. The recovery rates and coefficient of variation (CV) for all analytes were 98.66%- 100.18% and 0.75%-1.89%, respectively. This method was successfully applied to simultaneously determine the six components in JZGX tablet from different batches and manufacturers. Conclusion: The validated method can be used in routine quality control analysis of JZGX tablet without any interference.

Sorption of Lead by the Selective Ion Exchanger Ostsorb DETA

1992 ◽  
Vol 57 (7) ◽  
pp. 1393-1404 ◽  
Author(s):  
Ladislav Svoboda ◽  
Jan Uhlíř ◽  
Zdeněk Uhlíř
Keyword(s):  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Ion Exchanger ◽  
Preconcentration Procedure ◽  
Bead Cellulose

The properties of Ostsorb DETA, a selective ion exchanger based on modified bead cellulose with chemically bonded diethylenetriamine functional groups, were studied, and its applicability to the preconcentration of trace amounts of lead from aqueous solutions was verified. The conditions of the preconcentration procedure in the column and batch modes were optimized for this purpose. The results obtained were applied to the determination of lead in phosphoric acid.

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