Polymethacrylate Matrix Research Articles

Solid-phase spectrophotometric iodometric determination of iodate in food salt using а polymethacrylate matrix

A sensitive solid-phase spectrophotometric method for the quantitative determination of iodate in iodized salt samples using a polymethacrylate matrix is proposed. The procedure is based on the reaction of iodate with excess iodide in the acidic medium (pH 1-2) with the release of free iodine in the amounts equivalent to the iodate to be determined, the extraction of the iodine formed with a polymethacrylate matrix, and the absorbance measurement of the matrix at 365 nm. The developed procedure ensures the determination of 0.2–3.6 mg/L of iodate with limits of detection of 0.03. The effect of interfering ions, that might be present in the table salt samples, on the determination of iodate is also investigated. It is shown that Ca(II), Mg(II), К + , Na + , Cl - , SO 4 2- do not interfere with the determination of iodate. However, Fe(III) causes serious interference, and the addition of fluorides is required to mask iron up to 20-fold. The proposed method has been successfully applied for the determination of iodate in salt samples. The iodate contents thus determined in the iodized salt samples by the solid-phase spectrophotometric method were compared with the total iodine determined in the salt samples by iodometric titration according to GOST 51575. The solid-phase spectrophotometric method for iodate determination in salt samples has advantages over the iodometric titration, for example the increased sensitivity, simplicity and speed of the analysis. Тhe applicability of the polymethacrylate matrix as the final analytical form for the rapid visual iodate test is shown. Keywords: iodate, iodometry, polymethacrylate matrix, solid-phase spectrophotometry, visual test determination (Russian) DOI: http://dx.doi.org/10.15826/analitika.2018.22.1.009 D.A. Fedan 1 , N . V . Saranchina 2 , N.A. Gavrilenko 1 , M.A. Proskurnin 3 1 National Research Tomsk State University, pr. Lenina, 36, 634050, Tomsk, Russian Federation 2 National Research Tomsk Polytechnic University, pr. Lenina, 30, Tomsk, 634050, Russian Federation 3 M.V. Lomonosov Moscow State University, Leninskie Gory, GSP-1 Moscow, 119991, Russian Federation

Colorimetric sensor for determination of thiocyanate in fossil and drill waters

A colorimetric sensor is proposed for determination of thiocyanate based on the destruction of mercury–diphenyl–carbazone complex immobilized in the optically transparent polymethacrylate matrix in the concentration range 0.8– 50mg dm–3 with the detection limit of 0.6mg dm–3 or visual determination with ‘naked eye’ in the concentration above 1mg dm–3. The possibility of application of such sensors for determining thiocyanate in fossil and drill waters is shown.

Colorimetric sensor for the determination of low-molecular-weight heparin

A colorimetric sensor was proposed for the visual and solid phase spectrophotometric detection of low-molecular-weight heparin in concentration ranges of 40–120 and 5–40 mg dm –3 , respectively, with a detection limit of 2.0 mg dm –3 using a color destruction reaction of toluidine blue immobilized in an optically transparent polymethacrylate matrix.

Solid-phase spectrophotometric iodometric determination of nitrite and selenium(IV) using a polymethacrylate matrix

Procedures for the iodometric solid-phase spectrophotometric determination of nitrite and selenium( IV) using a polymethacrylate matrix are proposed. The procedures are based on the reaction of nitrite and selenium(IV) with iodine in an acidic medium with the release of free iodine in amounts equivalent to those of the substances to be determined, extraction of the iodine formed with a polymethacrylate matrix, and measurement of absorbance of the matrix at 370 nm. The developed procedures ensure the determination of 0.01–0.12 mg/L of nitrite and 0.05–0.40 mg/L of selenium(IV) with limits of detection of 0.005 and 0.03 mg/L, respectively. It was shown that the proposed procedures can be applied to the determination of selenium(IV) in mineral water and nitrites in vegetables and soil.

Visible color changes estimation in colorimetric determination of chromium (VI) using polymeric sensors

<p class="Abstract"><span lang="EN-US">The paper describes an application of a kind of optical analytical method, digital color analysis (DCA), using colorimetric polymethacrylate sensors (optodes) in order to determine Cr (VI). The optodes are made of optically transparent polymethacrylate matrix (PMM) with 1.5-diphenylcarbazide immobilized. The developed optode can be used in determination of the analytes using solid phase spectrophotometry and calculating color coordinates as functions of absorbance spectra. Also color coordinates can be represented as basic color (e.g. RGB) data after the optode image digitizing. Then one can determine the content of an analyte in a sample by an appropriate color difference calculated for these coordinates. Experimental results of Cr (VI) determination in tap water show that the DCA relative standard deviation is 8-17 % and recovery is < 12 % at the range of determined concentrations 0.05-1.0 </span><span lang="EN-US">mg·L<sup>–1</sup></span><span lang="EN-US">. The characteristics are comparable with those of the solid phase spectrophotometry.</span></p>

Polymethacrylate Matrix with Immobilized Acid–Base Indicators as pH Sensor

The paper demonstrates possibility of using a polymethacrylate matrix(PMM) to the immobilization conventional volumetric pH indicators .Acid–base properties of the indicators immobilized into PMM were studied. It was found that immobilization of pH indicators into PMM led to changes in the absorption maximum of both basic and acidic forms of pH indicators. The pKa values of pH indicator immobilized into the PMM also changed in comparison with the solution. The immobilization of pH indicators into PMM enabled to extend its a pH indicating range compared with solution. The possibility of using a pH indicator immobilized into the PMM as pH sensors was shown.

Твердофазно-спектрофотометрическое определение меди(II)

This paper presents a solid-phase spectrophotometric method for the determination of copper(II) with neocuproine immobilized in a transparent polymethacrylate matrix. The proposed method is based on the reduction of Cu(II) to Cu(I) in a sample solution and the formation of the colored complex of Cu(I) with neocuproine in polymethacrylate matrix with the absorption maximum at 450 nm. The optimal determination conditions of Cu(II) with neocuproine immobilized in polymethacrylate matrix, and interference from the foreign ions were studied. The copper determination was carried out by measuring the absorbance at 450 nm of polymethacrylate matrix with immobilized neocuproine after its contact with the sample solution for 15 mins at pH 4-7. The analytical performance characteristics of the developed method were estimated. Under these experimental conditions the range of determined concentrations are 0.05-0.30 mg/L with 3 s limit of detection of 0.018 mg/L. The proposed method was used to perform drinking water analysis for the Cu(II) contents by solid-phase spectrophotometry method without pre-sample preparation, and the applicability of polymethacrylate matrix with immobilized neocuproine as the final analytical form for rapid visual Cu(II) test was shown. Keywords: copper(II), neocuproine, polymethacrylate matrix, immobilized reagents, solid-phase spectrophotometry, visual test determination DOI: http://dx.doi.org/10.15826/analitika.2016.20.4.001 N.A. Gavrilenko 1 , N . V . Saranchina 2 , M.A. Gavrilenko 2 1 National Research Tomsk State University, pr. Lenina, 36, Tomsk, 634050, Russian Federation 2 National Research Tomsk Polytechnic University,pr. Lenina, 30, Tomsk, Russian Federation

Novel Colorimetric Sensor for Cupric Reducing Antioxidant Capacity (CUPRAC) Measurement

A novel optic sensor was developed for screening the total antioxidant capacity based on the use of cupric – neocuproine (Cu(II)−Nc) immobilized into a polymethacrylate matrix (PMM) with spectrophotometric measurement. The absorption change associated with the formation of the colored Cu(I)−Nc chelate in the PMM as a result of reaction with antioxidants was measured at 450nm. The colorimetric CUPRAC sensor can be used for quantitative assessment of total antioxidant capacity of complex matrices such as food extracts. The sensor is small and cheap, suitable to fit in a portable instrument for in situ antioxidant analysis.

A colorimetric sensor based on a polymethacrylate matrix with immobilized 1-(2-pyridylazo)-2-naphthol for the determination of cobalt

A colorimetric sensor is proposed for the determination of cobalt. It is prepared by immobilizing 1-(2-pyridylazo)-2-naphthol (PAN) in an optically transparent polymethacrylate matrix. The conditions for determining cobalt by the proposed colorimetric sensor are found in the study of the complexation of cobalt with a PAN-modified polymethacrylate matrix. The determination is based on the interaction of the sensor with a cobalt solution at pH 4 for 5 min, followed by the measurement of absorbance at 620 nm. The sensor ensures the determination of 0.05–0.50 mg/L of cobalt with the detection limit 0.03 mg/L. It is demonstrated that the sensor can be used for the determination of cobalt in the Cyanocobalamin medical preparation and potable water.

ТВЕРДОФАЗНО-СПЕКТРОФОТОМЕТРИЧЕСКОЕ ОПРЕДЕЛЕНИЕ НИТРИТОВ В ВОДЕ С ИСПОЛЬЗОВАНИЕМ РЕАКТИВА ГРИССА И САФРАНИНА, ИММОБИЛИЗОВАННЫХ В ПОЛИМЕТАКРИЛАТНОЙ МАТРИЦЕ

This paper presents a solid phase spectrophotometric method for the nitrite determination with safranin and Griess reagent immobilized in a transparent polymethacrylate matrix. The proposed method is based on the interaction between the nitrites in water with reagents immobilized into the matrix and the formation of azocompound in the solid phase. The use of the Griess reagent leads to the formation of the azocolored compound with an absorption maximum at 490 nm. In the case of using safranin the decrease in absorbance at 530 nm is observed. The optimal conditions for the nitrite determination and interference from foreign ions were studied and the analytical performance characteristics of the developed method were estimated. The optimized conditions gave the response time of 15 min and pH = 1 for when using the Griess reagent. Nitrite interacts with safranin in polymethacrylate matrix in strongly acidic media (pH ~ 0) for 5 min. Under these experimental conditions the ranges of determined concentrations are 1.0-3.0 mg/L with 3 s detection limit of 0.9 mg/L and 1.0-5.0 mg/L with the limit of detection of 0.5 mg/L when using immobilized in matrix Griess reagent and safranin respectively. The proposed methods were successfully applied to the determination of nitrites in drinking and mineral water. These methods are simple, inexpensive, non-toxic, and fast and use only the conventional instrumentation. Keywords: nitrite, polymethacrylate matrix, immobilized reagents, solid-phase spectrophotometry. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2015.19.3.004 N.A. Gavrilenko 1 , N.V. Saranchina 2 , A.V. Sukhanov 1 1 Federal State Autonomous Educational Institution of Higher Education «National Research Tomsk Polytechnic University», Tomsk, Russian Federation 2 Federal State Autonomous Educational Institution of Higher Education «National Research Tomsk State University », Tomsk, Russian Federation

Effect of Polyethylene Glycol Immobilized into a Polymethacrylate Matrix on the Sorption of Rhodamine

Combined matrix PMMA and PEG, having a polymethacrylate backbone and hydrophilic PEG chains, has been synthesized and applied for the design of transparent colour sensors. Introduction of the hydrophilic PEG chains in the PMMA bulk overcomes the limitations caused by the hydrophobicity of PMMA, and exhibits good wettability, stable and specific adsorption. We suppose that the adsorption of rhodamine on such networks depends on the chemical composition of the system and describes the interaction of the xanthene dye with the polymers.

Colorimetric Sensor Based on Silver Nanoparticle – Embedded Polymethacrylate Matrix

Silver nanoparticles synthesized by a reagent less method involving only thermal treatment have been used in colorimetric assay for the detection of hydrogen peroxide. The silver nanoparticles were directly synthesized in polymethacrylate matrix (PMM) by method based on the reduction of the inorganic precursor AgNO3, which was pre-adsorbed by PMM from solution, through thermal treatment. These silver nanoparticles were characterized using absorption spectroscopy. It was shown that the silver nanoparticles in PMM (Ag – PMM) had ability for reduction of hydrogen peroxide with silver oxidation. As a result, the yellow color of Ag – PMM samples was gradually changed to transparent color depending on the hydrogen peroxide concentrations. Hence, the silver nanoparticles in PMM could be used as colorimetric sensor for hydrogen peroxide in aqueous medium.

Sorption of Rhodamine into Polymer Block Matrix

A method for the trace analysis of rhodamine with colorimetric measurements based on solid-phase extraction by transparent polymethacrylate matrix is described. The quantity of sorbed РММ reagent is proportional to intensity of its painting and it depends on conditions of modification: рН, concentration of the reagent in solution and durations of processing. The interactions between PMM and rhodamine were studied by solid-phase spectrophotometry under batch conditions. The kinetic profiles of sorption at different temperatures are similar. This suggests that the sorption mechanism is mainly due to the formation of an inclusion complex through host–guest interactions.

Trace Determination of Rhodamine and Eosine in Oil-Water Reservoir Using Solid-Phase Extraction

A method for the trace analysis of rhodamine and eosine with colorimetric measurements based on solid-phase extraction (SPE) by transparent polymethacrylate matrix (PMM) is described. Solid-phase extraction on PMM allowed a 380-fold enrichment of the dyes if 10 mL sample volume is used with extraction efficiencies 98%. The method enables the determination of rhodamine to 0.06 mg/L and eosine to 1.2 mg/L combined with a fast and easy sample-preparation (pH-adjusting prior to SPE). Simultaneous extraction and determination of rhodamine and eosine in reservoir samples with high salinity confirmed the applicability and reproducibility of the method. Batch adsorption results indicated that Langmuir isotherm described the adsorption isotherms better.

Polymethacrylate Colorimetric Sensor for Evaluation of Total Antioxidant Capacity

A new colorimetric sensor using an immobilized chromogenic redox reagent was devised for measuring the total antioxidant level in a liquid sample without requiring sample pretreatment. The reagent, Fe(III) – 1,10-phenanthroline (Fe(III)-phen), was immobilized into a polymethacrylate matrix (PMM), and the absorbance changes associated with the formation of the highly colored Fe(II)-phen chelate as a result of reaction with antioxidants was measured at 510nm. The developed optical sensor was used to screen total antioxidant capacity of some black and green teas, red and white wines.

Solid phase spectrophotometric determination of selenium(IV) using dithisone immobilized in a polymethacrylate matrix

Solid phase spectrophotometric determination of selenium(IV) using dithisone immobilized in a polymethacrylate matrix

Определение хрома(VI) с использованием 1.5-дифенилкарбазида, иммобилизованного в полиметакрилатную матрицу

The interaction of chromium(VI) with 1.5-diphenylcarbazide immobilized in transparent polymethacrylate matrix was studied. The optimal conditions were found for interaction metal with reagent in solid phase. The solid-phase spectrophotometric procedure was proposed for determination of chromium(VI) with the range of determinated concentrations 0.05…1.0 mg/L and the detection limit 0.014 mg/L. The possibility of using thermal lens spectrometry as a more sensitive method of molecular absorption spectroscopy for lowering the limit of detection of chromium(VI) was studied. The thermal lens spectrometer with the modulated excitation beam at 514.5 nm was used for measurement thermal lens signal. Changes in the preparation of transparent polymethacrylate matrix and analytical procedures for photothermal measurements compared with spectrophotometry not required. The using of thermal lens spectrometry allowed decreasing of the detection limit to the value 0.002 mg /L. The range of determinated concentrations was 0.005…0.05 mg/L. Keywords : chromium(VI), polymethacrylate matrix, immobilized reagent, solid-phase spectrophotometry, solid-phase thermal lens spectrometry. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2014.18.1.012 1 N . V . Saranchina , 2 I . V . Mikheev , 1 N . A . Gavrilenko , 2 M . A . Proskurnin , 3 M . A . Gavrilenko 1 Tomsk Polytechnic University , Tomsk, Russian Federation 2 M.V. Lomonosov Moscow State University, Moscow, Russian Federation 3 Tomsk State University , Tomsk, Russian Federation

Colorimetric Polymethacrylate Sensor

The paper describes a new colorimetric sensor. The colorimetric sensors were made of optically transparent polymethacrylate matrix with physically immobilized analytical reagent which is responsible for the extraction of the analyte into the sensing material and changing its color. The developed colorimetric sensor can be used in determination of various analytes using both solid-phase spectrophotometer and naked eye.

Polymethacrylate optodes: A potential for chemical digital color analysis

The paper describes results of implementing a new kind of optical analytical method, digital color analysis (DCA), in which colorimetric polymethacrylate sensors (optodes) are used. The optodes are made of optically transparent polymethacrylate matrix with physically immobilized analytical reagent which is responsible for the extraction of the analyte into the sensing material and changing its color. The developed optodes can be used in determination of various analytes using both solid-phase spectrophotometer and naked eye. In order to improve accuracy and sensitivity of the naked-eye determination, it is possible to measure visible color changes using digital imaging of the polymethacrylate optode. The digital images then can be represented as basic color (e.g. RGB) data. The DCA determinations of Cu (II), Ag (I) and Co (II) have indicated that the developed optodes are linear in concentration ranges 0.02–0.30; 0.02–0.20 and 0.05–0.25mgL−1 appropriately with corresponding practical detection limits of 0.01; 0.02 and 0.07mgL−1.

Potentials of thermal lens spectroscopy for polymethacrylate optical sensors

The sensitivity of the earlier proposed procedures for the determination of iron(II, III) with 1,10-phenanthroline, silver(I) with dithizone, mercury with copper(II) dithizonate, copper(II) with lead diethyldithiocarbamate, and ascorbic acid with 2,6-dichlorophenolindophenol using polymethacrylate optical sensitive elements for solid phase spectrophotometry is enhanced through the use of thermal lens spectrometry as the most sensitive method of molecular absorption spectroscopy. The limits of detection for all photometric reactions in the polymethacrylate matrix are reduced by an order of magnitude (to 10 nM) without substantial changes in the experimental conditions.