{"title":"Voltammetric bienzymatic sensor for sucrose determination in honey","authors":"Anastasiia Kornii, Anna Borets, O. Tananaiko","doi":"10.17721/moca.2021.61-70","DOIUrl":"https://doi.org/10.17721/moca.2021.61-70","url":null,"abstract":"An electrochemical sensor based on nanostructured planar carbon electrodes (nanoSPCE) modified with a SiO2 biocomposite film containing MnO2 particles and enzymes glucose oxidase and invertase was developed. MnO2 particles obtained by electrochemical deposition possessed electrocatalytic activity toward hydrogen peroxide. Glucose oxidase (GOx) and invertase (Inv) were encapsulated into SiO2 film by method of electroassisted deposition. The electrode modified with biocomposite film nanoSPCE/MnO2/GoX/Inv/SiO2 was electroactive toward sucrose. The indicator reaction was oxidation of H2O2 – the product of bienzymatic reaction which was catalyzed by MnO2 on the electrode surface. The linearity range of the calibration graph for the voltametric determination of sucrose using developed modified electrode is 0.017-0.342 mg/ml, the detection limit is 0.006 mg/ml. The obtained nanoSPCE/MnO2/GoX/Inv/SiO2 electrode demonstrated satisfactory stability of the analytical signal during one month of operation. The developed method was used for sucrose determination in the honey samples. The 50-fold molar excess of glucose and fructose does not interfere the determination of sucrose.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Matching Effects in the Interaction of Ionic Surfactants with Fluorescent Reagents in Micellar Solutions of Triton X-100","authors":"V. Klovak, S. Kulichenko, S. Lelyushok","doi":"10.17721/moca.2021.117-126","DOIUrl":"https://doi.org/10.17721/moca.2021.117-126","url":null,"abstract":"The influence of cationic and anionic surfactant solutions on the character of the fluorescence spectra of reagents of different charge and hydrophobicity in aqueous solutions of nonionic surfactant Triton X-100 has been studied. An increase in the fluorescence intensity and a shift in the position of the fluorescence maximum with increasing hydrophobicity of reagents and ionic surfactants have been shown. The analytical signal of the surfactant is further amplified in the proximity of the charge values of the reagent and the counterion of the surfactant. The non-monotonic nature of the hydrophobicity effect of cationic surfactants on their analytical signal in the system has been shown. The observed effects are explained by the realization of charge and hydrophobic matching in the interaction of surfactants with the fluorescent reagents. The obtained effects are significant in the design of fluorescent systems for the determination and study of surfactant micelles. Conditions for detecting the content of cetylpyridinium chloride by reaction with eosin Y and sodium tetradecyl sulfate by reaction with rhodamine 6G in the presence of Triton X-100 were proposed. The methods have been tested in detecting the content of the ionic surfactants in pharmaceuticals.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hayat El ouafy, T. EL Ouafy, M. Oubenali, Aziz El Haimouti, A. Gamouh, M. Mbarki
{"title":"Electrochemical Evaluation of Catalytic Effect of Aluminum in Oxidation the Paracetamol in Human Blood","authors":"Hayat El ouafy, T. EL Ouafy, M. Oubenali, Aziz El Haimouti, A. Gamouh, M. Mbarki","doi":"10.17721/moca.2021.162-168","DOIUrl":"https://doi.org/10.17721/moca.2021.162-168","url":null,"abstract":"The reactivity of paracetamol (Pa) using the carbon paste electrode (CPE) modified by the aluminum (CPE-Al) was reported. The working electrode was prepared by mixing the aluminum with the carbon powder. The optimal potential window was selected from -1.7 V to 1.7 V. The effect of parameters such as pH, scan rate, accumulation time and concentration were affected by cyclic voltammetry (CV) and square wave voltammetry (SWV). The optimal preconcentration time is 8 minutes. The reactivity of Pa on the electroanalysis detector was characterized by the appearance of the anodic peak at 0.25 V in a solution of sodium sulfate (0.1 M, pH 7). The calculated limits of detection and quantification have been 8.28·10-9 and 2.74·10-8 mol L-1, respectively. Then relative standard deviation (RSD) at 2.0·10-5 mol L-1 Pa concentration was 4.08 % for nine repetitions. The analytical application was carried out in the detection of Pa in human blood with satisfying results.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Indirect Determination of Phosphate-ions in Waters with the Reagent Sulfonitrazo DAF","authors":"S. Kel’ina, O. G. Nevinsky","doi":"10.17721/moca.2021.147-152","DOIUrl":"https://doi.org/10.17721/moca.2021.147-152","url":null,"abstract":"An indirect method for the determination of phosphate ions in natural and treated wastewater is proposed, which is based on the formation of molybdophosphate complex (MFC), separating it from excess unbound molybdate by isoamyl acetate extraction, extraction of MFC into weakly alkaline aqueous phase, destruction of MFC and photometric determination of the equivalent amount of molybdate ions with the sulfonitrazo DAF reagent. The technique allows to determine from 0.02 to 0.43 mg dm-3 of phosphate ion (in terms of phosphorus).","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"151 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"In-Vessel Headspace Liquid Phase Microextraction Coupled to Spectrophotometry for Iodate Determination","authors":"Aimad-Eddine Tamen, A. Vishnikin","doi":"10.17721/moca.2021.137-146","DOIUrl":"https://doi.org/10.17721/moca.2021.137-146","url":null,"abstract":"A new, highly sensitive and selective method for the spectrophotometric determination of iodate is developed based on the in-vessel mode of headspace liquid phase microextraction (IV-HS-LPME). The approach involves converting iodate to vapor iodine with excess of iodide and extracting it into a 50 μL of 1 % potassium iodide, which exposed to the headspace in a specially designed vessel. The extraction proceeds from 8 mL of aqueous solution containing 0.24 mmol L-1 of iodide and 0.5 mol L-1 of Na2SO4 after injection of 2 mL of 25 % H2SO4. The complete equilibrium is established after the aqueous solution stirred at 1200 rpm for 20 minutes. After that, the triiodide complex formed in the acceptor phase is withdrawn with a microsyringe and transferred to a 50 μL quartz micro cell with a 10 mm path length, where the absorbance is measured at 288 or 350 nm. The calibration graph is linear (r2 = 0.9998) in the range of 4 to 180 μg L-1 (as IO3-) with a detection limit of 1.5 μg L-1. The developed method has a high precision of 0.5 – 1.4 %. It was successfully applied to the determination of iodate in table salt, sea, and mineral water samples.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Pourhossein, O. Heravizadeh, F. Omidi, M. Khadem, S. Shahtaheri
{"title":"Ultrasound-Assisted Emulsified Microextraction Based on Deep Eutectic Solvent for Trace Residue Analysis of Metribuzin in Urine Samples","authors":"M. Pourhossein, O. Heravizadeh, F. Omidi, M. Khadem, S. Shahtaheri","doi":"10.17721/moca.2021.153-161","DOIUrl":"https://doi.org/10.17721/moca.2021.153-161","url":null,"abstract":"Deep eutectic solvent was used as extraction solvent to develop and optimize a new sample preparation method for the determination of metribuzin in urine samples. In order to determine the optimal values of the effective factors in the deep eutectic solvent-based ultrasound assisted emulsification microextraction method, six effective parameters were selected. The design of experiments was performed using the onevariable- at-a-time method. Totally, 96 experimental runs were performed, and the samples were analyzed using high-performance liquid chromatography with a UV detector. Under the optimum conditions, the calibration curve for metribuzin was linear in the concentration range of 5 to 500 μg L-1 for urine samples. The accuracy and reproducibility of the introduced method were determined using the relative recovery (RR %) and relative standard deviation (RSD %) tests on the fortified urine samples. RR % and RSD % were found to be 96.3 – 101.7 % and 3.2 – 7.6 %, respectively. The limit of quantification and the limit of detection were obtained 5 and 0.8 μg L-1, respectively.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Alberti, Sofia Callegari, Ilaria Concardi, Lorenzo Ronca, Maria Teresa Sbardi
{"title":"From Colour Catcher® to colorimetric sensors: disposable and cheap devices for inorganic ions determination","authors":"G. Alberti, Sofia Callegari, Ilaria Concardi, Lorenzo Ronca, Maria Teresa Sbardi","doi":"10.17721/moca.2021.93-102","DOIUrl":"https://doi.org/10.17721/moca.2021.93-102","url":null,"abstract":"We describe disposable and cheap colorimetric devices obtained by fixing classical dyes on the commercial paper sheet known as \"Colour Catcher®\" (here named under the acronym CC), the product used to prevent color runs in washing machines cycles. These devices can be used as colorimetric sensors for different analytes of environmental and biological interest since the indicator dye, fixed on the solid material, changes its spectral properties (color and hence UV-vis spectrum) upon contact with the analyte. The relationship between the analyte content and the UV-vis spectrum (or RGB values) change of each sensor is provided using a chemometric tool: the Partial Least Squares regression (PLS). Promising results were obtained when applying these sensors to actual samples, so because of their simple preparation with low-cost reagents, they can be effective for application in environmental and food analysis.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
К.К. Tsymbaliuk, O. Snurnikova, K. Melnyk, E.M. Fadeev, V. Antonovich
{"title":"Determination of Polycyclic Aromatic Hydrocarbons in Agricultural Products","authors":"К.К. Tsymbaliuk, O. Snurnikova, K. Melnyk, E.M. Fadeev, V. Antonovich","doi":"10.17721/moca.2021.127-136","DOIUrl":"https://doi.org/10.17721/moca.2021.127-136","url":null,"abstract":"The procedure for the determination of polycyclic aromatic hydrocarbons (PAH) in agricultural products on the example of five crops (rapeseed, sunflower, flax, corn, soybeans) by gas chromatography mass spectrometry (GC-MS) was developed. It was showed the advantage of using binary mixtures of organic solvents \"hexanedichloromethane\" for PAH extraction. The time of Soxhlet extraction is from 6 to 8 hours at optimized conditions. The fractionation and purification of extracts by column chromatography on deactivated alumina was optimized. The article presents the optimization of sample injection in the programmed temperature vaporization (PTV) mode, parameters of gas chromatographic separation and mass spectrometric detection in determining 16 priority PAH in agricultural products. The recoveries, correctness and accuracy of the proposed method were checked by “spikes” with concentrations 0.5, 1.0, 2.5, 5.0 μg kg-1. The linearity of the method was determined by calibration curves obtained for three measurements of calibration solutions with concentrations of 0.5-100 ng mL-1. The effectiveness of the proposed combination of sample preparation and analysis by PTV-GC-MS was studied for linearity, accuracy, matrix effects and reproducibility. The method was validated by linearity, accuracy, matrix effect and reproducibility.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"409 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Yegorova, Yu. V. Skrypynets, I. Leonenko, G. Maltsev, S. Kashutskуy, O. Voitiuk
{"title":"Development and Validation of HPLC-MS Method of Determination of Memantine Hydrochloride for Study of Dissolution Profiles","authors":"A. Yegorova, Yu. V. Skrypynets, I. Leonenko, G. Maltsev, S. Kashutskуy, O. Voitiuk","doi":"10.17721/moca.2021.71-80","DOIUrl":"https://doi.org/10.17721/moca.2021.71-80","url":null,"abstract":"A method for quantitative determination of memantine hydrochloride by HPLC with mass spectrometric detection (HPLC-MS), suitable for the study of dissolution profiles of tablets \"Mematon IС\" was developed. Chromatographic determination was performed using a mobile phase of methanol - 0.1% (v/v) aqueous solution of formic acid (55:45) on a column of Zorbax Eclipse Plus C18 size 10 cm Ч 4.6 mm (3.5 μm) at a flow rate of 1 ml/min. The linearity interval in the appropriate dissolution media is 35 - 150 % of the normalized content of memantine hydrochloride in the tablet. The method is validated on the parameters of specificity, accuracy, correctness, linearity in the studied range of concentrations, robustness. The stability of the tested solutions and reference solutions in the case of their storage at room temperature for 24 hours was confirmed. It is established that in the case of the study of solutions prepared in a dissolution medium of 0.1 M hydrochloric acid solution pH 1.2, there is a need to preneutralize hydrochloric acid before analysis, because it, as stronger than formic acid, almost completely ionizes all dissolved molecules, which leads to a significant deviation of the linear dependence of the analytical signal on the concentration of the analyte. Neutralization is performed with 0.1 M sodium hydroxide solution, which is added to the sample of the test solution. The release of more than 85 % of memantine hydrochloride in 15 min in all dissolution media indicates the similarity of the dissolution profiles and does not require the calculation of the similarity factor f2.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Voltammetric Determination of Paracetamol in Pharmaceutical Formulations at Iodine-Coated Polycrystalline Platinum Electrode","authors":"Mohammad Amayreh, W. Hourani, M. Hourani","doi":"10.17721/moca.2021.103-111","DOIUrl":"https://doi.org/10.17721/moca.2021.103-111","url":null,"abstract":"In this work the modified iodine-coated polycrystalline platinum electrode was used to develope a voltammetric sensor for paracetamol determination in pharmaceutical formulations. The optimized experimental parameters for the determination of paracetamol were using 0.5 M H2SO4 as a supporting electrolyte with a scan rate of 50 mV/s. The anodic peak related to paracetamol oxidation was centered at about +0.60 V. The extended calibration graph was constructed between 1 ppm and 500 ppm. The anodic current showed excellent linearity with R2 = 0.9985. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.046 and 0.139 ppm, respectively, which attests to the sensitivity of the method. The investigation for the effect of potential interferences from the content of tablet matrices indicated a specific selectivity toward paracetamol and the absence of any electrochemical response toward these components. The developed method was successfully applied to analysis paracetamol in three brands of pharmaceutical formulations and the obtained results were in good agreement with the labeled values, besides that, the statistical tests indicated no significant difference at p = 0.05 with a 95 % confidence level.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}