A simple, eco-friendly, rapid, and economic spectrophotometric method for the determination of metoprolol tartrate in tablets has been developed. The procedure for metoprolol determination is based on a reaction with bromothymol blue (BTB) in acetonitrile medium. The maximum formation of the colored product was observed in acetonitrile at the absorption maximum at a wavelength of 402 nm. The stoichiometry of molecular complexes was determined by Job's method and it was found to be 1 to 1. The optimal concentration of BTB was 1.6·10-4 M. The linear relationship between absorbance at λmax and concentration of analyte ranging 16.00-24.00 μg mL-1 was found. Regression analysis of Beer’s law plot at 402 nm yielded the regression equation, y = 0.0199x + 0.0721. High values of correlations coefficient R2 = 0.9990 and small values of intercept validated the linearity of calibration curve and obedience to Beer’s law. The calculated LOD and LOQ values were 1.90 and 5.78 μg mL-1, respectively. The proposed green spectrophotometric method is simple, rapid, and suitable for routine pharmaceutical analysis.
{"title":"Development of the Spectrophotometric Method for the Determination of Metoprolol in Tablets by using Bromothymol Blue","authors":"Mariana Horyn, Marjan Piponski, Oleksandra Melnyk, Iryna Ivanchuk, Oleksandr Susla, Liliia Grytsyshyn, Dmytro Korobko, Liliya Logoyda","doi":"10.17721/moca.2023.63-69","DOIUrl":"https://doi.org/10.17721/moca.2023.63-69","url":null,"abstract":"A simple, eco-friendly, rapid, and economic spectrophotometric method for the determination of metoprolol tartrate in tablets has been developed. The procedure for metoprolol determination is based on a reaction with bromothymol blue (BTB) in acetonitrile medium. The maximum formation of the colored product was observed in acetonitrile at the absorption maximum at a wavelength of 402 nm. The stoichiometry of molecular complexes was determined by Job's method and it was found to be 1 to 1. The optimal concentration of BTB was 1.6·10-4 M. The linear relationship between absorbance at λmax and concentration of analyte ranging 16.00-24.00 μg mL-1 was found. Regression analysis of Beer’s law plot at 402 nm yielded the regression equation, y = 0.0199x + 0.0721. High values of correlations coefficient R2 = 0.9990 and small values of intercept validated the linearity of calibration curve and obedience to Beer’s law. The calculated LOD and LOQ values were 1.90 and 5.78 μg mL-1, respectively. The proposed green spectrophotometric method is simple, rapid, and suitable for routine pharmaceutical analysis.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135400866","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}
Pub Date : 2023-01-01DOI: 10.17721/moca.2023.87-91
Artur Martynov, Oksana Knysh
Nisin is the most well-known representative of subtype A1 lantibiotics. This small (< 5 kDa) peptide ribosomally produced by Gram-positive bacteria belonging to Lactococcus, Streptococcus, Staphylococcus and Blautia species. Nisin exhibits antibacterial activity against a broad range of Gram-positive bacteria and may be effective against Gram-negative pathogens. For analytical semi-preparative purposes, gradient HPLC is often used in the acetonitrile concentration range from 20 to 30 % (solvent B) and a retention time of 20 to 50 min. In this study the optimal conditions for the analysis of nisin by RP-HPLC were determined: a gradient from 23 to 28 % acetonitrile (buffer B) when used as solvents: buffer A: [4 M LiClO4 – 0.1 M HClO4 ] : H2O=1:19; and buffer B: 100 % CH3CN with a retention time up to 12 min. Differences between the chromatographic profiles of expired and non-expired nisin samples have been identified. The expired nisin sample differs from the non-expired samples by the presence of asymmetric nisin A / Z peaks with significant degradation of the nisin A peak. The results of the study indicate the possibility using RP-HPLC for checking the quality and shelf life of commercial nisin samples without the need for additional purification
Nisin是A1亚型抗生素中最著名的代表。这个小的(<5 kDa)肽核糖体产生的革兰氏阳性菌属于乳球菌，链球菌，葡萄球菌和蓝菌属。Nisin对多种革兰氏阳性细菌具有抗菌活性，可能对革兰氏阴性病原体有效。在半制备分析中，梯度高效液相色谱常用于乙腈浓度为20% ~ 30%(溶剂B)，保留时间为20 ~ 50 min的条件下。本研究确定了反相高效液相色谱分析nisin的最佳条件:当溶剂为23% ~ 28%乙腈(缓冲液B)时，缓冲液a: [4 M LiClO4 - 0.1 M HClO4]: H2O=1:19;缓冲液B: 100% CH3CN，保留时间长达12分钟。过期和未过期nisin样品的色谱图谱存在差异。过期的nisin样品与未过期样品的不同之处在于存在不对称的nisin A / Z峰，nisin A峰明显降解。该研究结果表明，使用反相高效液相色谱法检查商品nisin样品的质量和保质期的可能性，而无需额外的纯化
{"title":"HPLC-pharmaceutical Analysis of Lantibiotic Nisin in the Industrial Samples Including Expired Sample","authors":"Artur Martynov, Oksana Knysh","doi":"10.17721/moca.2023.87-91","DOIUrl":"https://doi.org/10.17721/moca.2023.87-91","url":null,"abstract":"Nisin is the most well-known representative of subtype A1 lantibiotics. This small (< 5 kDa) peptide ribosomally produced by Gram-positive bacteria belonging to Lactococcus, Streptococcus, Staphylococcus and Blautia species. Nisin exhibits antibacterial activity against a broad range of Gram-positive bacteria and may be effective against Gram-negative pathogens. For analytical semi-preparative purposes, gradient HPLC is often used in the acetonitrile concentration range from 20 to 30 % (solvent B) and a retention time of 20 to 50 min. In this study the optimal conditions for the analysis of nisin by RP-HPLC were determined: a gradient from 23 to 28 % acetonitrile (buffer B) when used as solvents: buffer A: [4 M LiClO4 – 0.1 M HClO4 ] : H2O=1:19; and buffer B: 100 % CH3CN with a retention time up to 12 min. Differences between the chromatographic profiles of expired and non-expired nisin samples have been identified. The expired nisin sample differs from the non-expired samples by the presence of asymmetric nisin A / Z peaks with significant degradation of the nisin A peak. The results of the study indicate the possibility using RP-HPLC for checking the quality and shelf life of commercial nisin samples without the need for additional purification","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135401776","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}
The introduction into the production of medicinal substances involves the creation of a pharmaceutical dossier, an important component of which is data on pharmaceutical development and quality control methods. The physico-chemical properties of the antiviral substance of favipiravir were investigated, and some basic sections of the analytical documentation were developed. With the help of a complex of physical, chemical, and physico-chemical methods of analysis, the "Identification" test was developed, and the structure of favipiravir was proven. Methods for the determination of related substances by the HPLC with UV detection and the assay of favipiravir by the acid-base titration method, suitable for substance quality control, have been developed. Relative retention times and correction factors for calculating their content are established for all impurities. The methods were validated on the parameters of specificity, accuracy, correctness, and linearity in the studied range of concentrations.
{"title":"Development and Validation of New Methods for Quality Control of the Antiviral Substance FAVIPIRAVIR","authors":"Yu.V. Scrypynets, G.O. Fedosenko, G.V. Maltsev, I.I. Chebotarska, D.I. Aleksandrova, S.N. Kashutskуy, A.V. Yegorova","doi":"10.17721/moca.2023.70-80","DOIUrl":"https://doi.org/10.17721/moca.2023.70-80","url":null,"abstract":"The introduction into the production of medicinal substances involves the creation of a pharmaceutical dossier, an important component of which is data on pharmaceutical development and quality control methods. The physico-chemical properties of the antiviral substance of favipiravir were investigated, and some basic sections of the analytical documentation were developed. With the help of a complex of physical, chemical, and physico-chemical methods of analysis, the \"Identification\" test was developed, and the structure of favipiravir was proven. Methods for the determination of related substances by the HPLC with UV detection and the assay of favipiravir by the acid-base titration method, suitable for substance quality control, have been developed. Relative retention times and correction factors for calculating their content are established for all impurities. The methods were validated on the parameters of specificity, accuracy, correctness, and linearity in the studied range of concentrations.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135401227","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}
Pub Date : 2023-01-01DOI: 10.17721/moca.2023.55-62
Viktoriia Klovak, Kulichenko Sergey
The spectrophotometric and fluorescent characteristics of the surfactant-modified molybdenum (VI) – bromopyrogallol red reagent system were studied. The hydrophobic modification was achieved by adding cationic, nonionic surfactants, or, accordingly, mixtures of surfactant modifiers into the metal reagent system. Modification of the metal reagent system with a nonionic surfactant leads to a decrease in the limit of detection of the hydrophobic organic cation in the molybdenum (VI) – bromopyrogallol red system by the fluorescence method and an increase in the contrast of the spectrophotometric reaction. The colloid-chemical state of molybdenum (VI) – bromopyrogallol red solutions in the presence of cationic surfactant, nonionic surfactant, and their mixture was also investigated. An increase in the turbidity of the investigated solutions is registered under the conditions of a decrease in the scattering factor, which, in turn, increases the limit of detection of the spectrophotometric determination of decamethoxine in the surfactant-modified molybdenum (VI) – bromopyrogallol red system. Based on the obtained results, the conditions for controlled modification of the metal reagent system with surfactants for the determination of hydrophobic organic cations by molecular spectroscopy methods were proposed. Fluorescence and spectrophotometric detection of decamethoxine content in medicines was carried out in optimized surfactant-modified molybdenum (VI) – bromopyrogallol red systems.
{"title":"Spectrophotometric and Fluorescent Determination of Hydrophobic Organic Cations in the Surfactant-modified System Mo(VI)– Bromopyrogallol Red","authors":"Viktoriia Klovak, Kulichenko Sergey","doi":"10.17721/moca.2023.55-62","DOIUrl":"https://doi.org/10.17721/moca.2023.55-62","url":null,"abstract":"The spectrophotometric and fluorescent characteristics of the surfactant-modified molybdenum (VI) – bromopyrogallol red reagent system were studied. The hydrophobic modification was achieved by adding cationic, nonionic surfactants, or, accordingly, mixtures of surfactant modifiers into the metal reagent system. Modification of the metal reagent system with a nonionic surfactant leads to a decrease in the limit of detection of the hydrophobic organic cation in the molybdenum (VI) – bromopyrogallol red system by the fluorescence method and an increase in the contrast of the spectrophotometric reaction. The colloid-chemical state of molybdenum (VI) – bromopyrogallol red solutions in the presence of cationic surfactant, nonionic surfactant, and their mixture was also investigated. An increase in the turbidity of the investigated solutions is registered under the conditions of a decrease in the scattering factor, which, in turn, increases the limit of detection of the spectrophotometric determination of decamethoxine in the surfactant-modified molybdenum (VI) – bromopyrogallol red system. Based on the obtained results, the conditions for controlled modification of the metal reagent system with surfactants for the determination of hydrophobic organic cations by molecular spectroscopy methods were proposed. Fluorescence and spectrophotometric detection of decamethoxine content in medicines was carried out in optimized surfactant-modified molybdenum (VI) – bromopyrogallol red systems.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135401644","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}
Pub Date : 2022-01-01DOI: 10.17721/moca.2022.125-132
О.М. Chechet, О.S. Haidei, M. Ischenko, А.V. Masluk, S. Shulyak
The new scheme of proficiency testing of laboratories for determination of main quality characteristics of oil cake was developed. In pilot round was determined such quality characteristics as moisture content (I), mass fraction of fat (II) and mass fraction of crude protein (III). The control sample was prepared from the sample of rapeseed oil cake. It was determined that control sample was sufficiently stable and homogeneous. In the round participated 22 laboratories, which used different test methods. The results were processed by the method described in ISO 13528. Based on these calculations as assigned value for characteristics I and III was chosen robust mean value and for characteristic II - mode of results. As standard deviation of proficiency testing for characteristic I was chosen robust standard deviation and for characteristics II and III was chosen value which is predicted by equation of Horwitz-Thompson. It was determined, that for characteristics I and III different test methods gives equivalent results, so some unsatisfactory results of laboratories can be attributed to laboratory bias. For characteristic II clustering of results according to measurement method in observed. It was established, that outdated standard GOST 13496.15-97 gives higher mass fraction of fat compared to other test methods.
{"title":"Pilot Round of Proficiency Testing Scheme for Determination of Main Quality Characteristics of Oil Cake","authors":"О.М. Chechet, О.S. Haidei, M. Ischenko, А.V. Masluk, S. Shulyak","doi":"10.17721/moca.2022.125-132","DOIUrl":"https://doi.org/10.17721/moca.2022.125-132","url":null,"abstract":"The new scheme of proficiency testing of laboratories for determination of main quality characteristics of oil cake was developed. In pilot round was determined such quality characteristics as moisture content (I), mass fraction of fat (II) and mass fraction of crude protein (III). The control sample was prepared from the sample of rapeseed oil cake. It was determined that control sample was sufficiently stable and homogeneous. In the round participated 22 laboratories, which used different test methods. The results were processed by the method described in ISO 13528. Based on these calculations as assigned value for characteristics I and III was chosen robust mean value and for characteristic II - mode of results. As standard deviation of proficiency testing for characteristic I was chosen robust standard deviation and for characteristics II and III was chosen value which is predicted by equation of Horwitz-Thompson. It was determined, that for characteristics I and III different test methods gives equivalent results, so some unsatisfactory results of laboratories can be attributed to laboratory bias. For characteristic II clustering of results according to measurement method in observed. It was established, that outdated standard GOST 13496.15-97 gives higher mass fraction of fat compared to other test methods.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436661","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}
Pub Date : 2022-01-01DOI: 10.17721/moca.2022.133-140
M. V. Milyukin, М.V. Gorban
The results of the dispersed-phase distribution of major classes of organic ecotoxicants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the water of various river systems have been discussed in the current research. The main parameters of water quality in these river systems differ significantly. Despite this, the following constancy has been established for all studied river systems: the higher the hydrophobicity coefficient log (Ko/w) of the organic ecotoxicant, the smaller its water-soluble fraction. Relevant dependences have been established and their statistical processing has been carried out. The correlations determined are significant and reliable for most aquatic systems, with R ranging from 0.67 to 0.98 (P > 95%). It follows that the hydrophobicity coefficient of a compound is an essential parameter by which its disperse-phase distribution can be estimated. The results were almost identical for the Dnieper and Elbe rivers due to the similar physicochemical characteristics of these water systems.
{"title":"Patterns of the Disperse-phase Distribution of Organic Ecotoxicants in the Water of the World River Systems","authors":"M. V. Milyukin, М.V. Gorban","doi":"10.17721/moca.2022.133-140","DOIUrl":"https://doi.org/10.17721/moca.2022.133-140","url":null,"abstract":"The results of the dispersed-phase distribution of major classes of organic ecotoxicants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the water of various river systems have been discussed in the current research. The main parameters of water quality in these river systems differ significantly. Despite this, the following constancy has been established for all studied river systems: the higher the hydrophobicity coefficient log (Ko/w) of the organic ecotoxicant, the smaller its water-soluble fraction. Relevant dependences have been established and their statistical processing has been carried out. The correlations determined are significant and reliable for most aquatic systems, with R ranging from 0.67 to 0.98 (P > 95%). It follows that the hydrophobicity coefficient of a compound is an essential parameter by which its disperse-phase distribution can be estimated. The results were almost identical for the Dnieper and Elbe rivers due to the similar physicochemical characteristics of these water systems.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436802","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 stability-indicating RP-HPLC method for the simultaneous determination of Serdexmethylphenidate (SER) and Dexmethylphenidate (DEX) has been developed and validated in bulk and tablet dosage forms. SER and DEX are central nervous system stimulants. This combination is used to treat attention deficit hyperactive disorder. The chromatographic analysis was carried out on a Waters C18 Column with 250mm x 4.6 and a particle size of 5 μm, using an isocratic mobile phase of Phosphate Buffer pH 4.8: Methanol (70:30, v/v) at a flow rate of 0.8 mL/min, and the eluents were monitored at an isosbestic point of 215 nm. Specificity, precision, accuracy, linearity, and robustness of the proposed method were all validated according to ICH standards. Forced degradation studies confirmed the method's stability indicating nature. SER and DEX had retention times of 2.390 and 4.602 min, respectively. The developed technique was found to be specific and accurate. SER linearity was achieved between 90-270 μg/mL, while DEX linearity was obtained between 17.50-52.50 μg/mL. SER had LOD and LOQ of 6.35 and 21.17 μg/mL, whereas DEX had LOD and LOQ of 1.18 and 3.93 μg/mL, respectively. As a result, the suggested HPLC method for the quantification of Serdexmethylphenidate (SER) and Dexmethylphenidate (DEX) was reliable, repeatable, accurate, and sensitive.
{"title":"Analytical Validation and Stability Indicating Studies for Simultaneous Estimation of Serdexmethylphenidate and Dexmethylphenidate by RP-HPLC in Bulk and Capsules","authors":"Hathibelagal Mundarinti Sudheer Kumar, Kothapalli Bannoth Chandrasekhar","doi":"10.17721/moca.2022.99-105","DOIUrl":"https://doi.org/10.17721/moca.2022.99-105","url":null,"abstract":"A stability-indicating RP-HPLC method for the simultaneous determination of Serdexmethylphenidate (SER) and Dexmethylphenidate (DEX) has been developed and validated in bulk and tablet dosage forms. SER and DEX are central nervous system stimulants. This combination is used to treat attention deficit hyperactive disorder. The chromatographic analysis was carried out on a Waters C18 Column with 250mm x 4.6 and a particle size of 5 μm, using an isocratic mobile phase of Phosphate Buffer pH 4.8: Methanol (70:30, v/v) at a flow rate of 0.8 mL/min, and the eluents were monitored at an isosbestic point of 215 nm. Specificity, precision, accuracy, linearity, and robustness of the proposed method were all validated according to ICH standards. Forced degradation studies confirmed the method's stability indicating nature. SER and DEX had retention times of 2.390 and 4.602 min, respectively. The developed technique was found to be specific and accurate. SER linearity was achieved between 90-270 μg/mL, while DEX linearity was obtained between 17.50-52.50 μg/mL. SER had LOD and LOQ of 6.35 and 21.17 μg/mL, whereas DEX had LOD and LOQ of 1.18 and 3.93 μg/mL, respectively. As a result, the suggested HPLC method for the quantification of Serdexmethylphenidate (SER) and Dexmethylphenidate (DEX) was reliable, repeatable, accurate, and sensitive.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67437017","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}
Pub Date : 2022-01-01DOI: 10.17721/moca.2022.59-69
L. Angelova, N. Genova, G. Pencheva, Yasena Statkova, Violeta Yotova, A. Surleva
This paper presents a study on the molybdenum blue reaction (MB) as a finishing detection step in soil analysis for quantification of plant available phosphorus. An ammonium acetate/calcium lactate reagent (pH = 4.2) was used for soil phosphorus extraction. The molybdenum blue color reaction using premixed Murphy-Riley reagent and ascorbic acid as a reductant was reinvestigated. UV-Vis characteristics of MB, optimal wavelength, reaction time and concentration of reductant were studied. The effect of ascorbic acid concentration and the reaction time on linearity, bias and uncertainty was discussed. The molybdenum blue reaction was found to obey Beer’s law in the targeted concentration range of 0.04 – 1.0 mg L-1 PO43- - P. The linearity was proved by “lack-of-fit” test. The uncertainty budget was made and the uncertainty was estimated by modelling approach, as well as single laboratory and quality control approach. The recovery and the expanded uncertainty were found to be, respectively, (95.7 ± 8.7) % (P = 95 %, n = 3) and 9.2 mg PO43- - P/kg dry soil (k = 2). The results showed that the soil sample inhomogeneity and the repeatability of extraction process were the main factors which contribute to the uncertainty of measurement in soil analysis.
{"title":"Contribution to the Molybdenum Blue Reaction and its Application in Soil Analysi","authors":"L. Angelova, N. Genova, G. Pencheva, Yasena Statkova, Violeta Yotova, A. Surleva","doi":"10.17721/moca.2022.59-69","DOIUrl":"https://doi.org/10.17721/moca.2022.59-69","url":null,"abstract":"This paper presents a study on the molybdenum blue reaction (MB) as a finishing detection step in soil analysis for quantification of plant available phosphorus. An ammonium acetate/calcium lactate reagent (pH = 4.2) was used for soil phosphorus extraction. The molybdenum blue color reaction using premixed Murphy-Riley reagent and ascorbic acid as a reductant was reinvestigated. UV-Vis characteristics of MB, optimal wavelength, reaction time and concentration of reductant were studied. The effect of ascorbic acid concentration and the reaction time on linearity, bias and uncertainty was discussed. The molybdenum blue reaction was found to obey Beer’s law in the targeted concentration range of 0.04 – 1.0 mg L-1 PO43- - P. The linearity was proved by “lack-of-fit” test. The uncertainty budget was made and the uncertainty was estimated by modelling approach, as well as single laboratory and quality control approach. The recovery and the expanded uncertainty were found to be, respectively, (95.7 ± 8.7) % (P = 95 %, n = 3) and 9.2 mg PO43- - P/kg dry soil (k = 2). The results showed that the soil sample inhomogeneity and the repeatability of extraction process were the main factors which contribute to the uncertainty of measurement in soil analysis.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436788","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}
Pub Date : 2022-01-01DOI: 10.17721/moca.2022.91-98
A. Yegorova, Yu. V. Skrypynets, I. Leonenko, D. Aleksandrova, T. Kirichenko, S. S. Basok, C. Kulygina
Copper is widely used and therefore it is a pollutant metal. It is important to develop probes that can selectively determine copper with high sensitivity. The benzoaza-15-crown-5 derivatives are used as fluorescence sensing systems and excellent spectroscopic properties are demonstrated. The “N”, “O” atoms of the heterocyclic unit act as binding sites for recognizing copper ions. A new, simple, sensitive fluorescence method for the determination of Cu2+ ions was developed and analytical characteristics of the proposed probe were estimated. The Cu2+ ions can significantly quench the fluorescence intensity of N-(2-carboxymethyl)benzoaza-15-crown-5 (Cr) in ethanol/H2O (4:6, v/v) solvent mix containing urotropine buffer (pH 7.5) at λex = 274 nm and λem = 308 nm. The probe has high photostability. Under optimal conditions, the quenching of fluorescence intensity depends on the concentration of Cu2+ ions in the range of 1.70 × 10-6 - 2.38 × 10-4 М, detection limit was 0.56 μМ. This method was applied for the determination of Cu2+ ions in drinking water. The quenching effect in the presence of copper (II) can be explained by the termination of intramolecular charge transfer from the chelate center to the aromatic part of the molecule due to chelation.
{"title":"A New Fluorescent Probe Based on N-(2-carboxymethyl)benzoaza-15-crown-5 for Sensitive and Selective Determination of Cu2+","authors":"A. Yegorova, Yu. V. Skrypynets, I. Leonenko, D. Aleksandrova, T. Kirichenko, S. S. Basok, C. Kulygina","doi":"10.17721/moca.2022.91-98","DOIUrl":"https://doi.org/10.17721/moca.2022.91-98","url":null,"abstract":"Copper is widely used and therefore it is a pollutant metal. It is important to develop probes that can selectively determine copper with high sensitivity. The benzoaza-15-crown-5 derivatives are used as fluorescence sensing systems and excellent spectroscopic properties are demonstrated. The “N”, “O” atoms of the heterocyclic unit act as binding sites for recognizing copper ions. A new, simple, sensitive fluorescence method for the determination of Cu2+ ions was developed and analytical characteristics of the proposed probe were estimated. The Cu2+ ions can significantly quench the fluorescence intensity of N-(2-carboxymethyl)benzoaza-15-crown-5 (Cr) in ethanol/H2O (4:6, v/v) solvent mix containing urotropine buffer (pH 7.5) at λex = 274 nm and λem = 308 nm. The probe has high photostability. Under optimal conditions, the quenching of fluorescence intensity depends on the concentration of Cu2+ ions in the range of 1.70 × 10-6 - 2.38 × 10-4 М, detection limit was 0.56 μМ. This method was applied for the determination of Cu2+ ions in drinking water. The quenching effect in the presence of copper (II) can be explained by the termination of intramolecular charge transfer from the chelate center to the aromatic part of the molecule due to chelation.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436964","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}
Pub Date : 2022-01-01DOI: 10.17721/moca.2022.43-53
V. D. Kurochkin, M. Kolomytsev, O. Romanenko
The peculiarities of the glow discharge mass-spectrometry (GDMS) analysis of the main components and elements of microalloying of high-entropy AlCrFeCoNiCu alloy are considered in the paper. Molecular interferences of ArxAy+i, ArxG+i, AxBy+i types (where A, B are the components of the sample, G are single and 2-3 atomic gases; x, y = 1, 2, i - charge of ion, i = 1, 2), which are formed during cathode sputtering of this alloy in glow discharge plasma were calculated and experimentally tested. It is shown for spectrometers at resolution R0.5 ≥ 7000, the greatest influence of molecular ions of Me2+ and ArMe+ types exist in the range of isotope masses from 85Rb to about 107Ag. A careful selection of isotopes is required in this mass range to meet detection limit conditions. In other areas of the mass spectrum, the sensitivity of the analysis is limited by the background current and the sensitivity of the detectors and is at the usual ppb-level for this method.
本文考虑了高熵AlCrFeCoNiCu合金微合金化主要成分和元素的辉光放电质谱分析的特殊性。ArxAy+i、ArxG+i、AxBy+i型分子干扰(其中A、B为样品组分，G为单原子气体和2-3原子气体;计算了该合金在辉光放电等离子体阴极溅射过程中形成的X, y = 1,2, I -离子电荷，I = 1,2)，并进行了实验测试。结果表明，在分辨率为R0.5≥7000的光谱仪上，Me2+和ArMe+类型的分子离子在同位素质量85Rb到107Ag范围内的影响最大。在这个质量范围内，需要仔细选择同位素以满足检测极限条件。在质谱的其他领域，分析的灵敏度受到背景电流和探测器灵敏度的限制，并且在通常的ppb水平上使用这种方法。
{"title":"Investigation of Molecular Interferences at GDMS Analysis of Main Elements and Microalloing of High-Entropy Alloy AlCrFeCoNiCu","authors":"V. D. Kurochkin, M. Kolomytsev, O. Romanenko","doi":"10.17721/moca.2022.43-53","DOIUrl":"https://doi.org/10.17721/moca.2022.43-53","url":null,"abstract":"The peculiarities of the glow discharge mass-spectrometry (GDMS) analysis of the main components and elements of microalloying of high-entropy AlCrFeCoNiCu alloy are considered in the paper. Molecular interferences of ArxAy+i, ArxG+i, AxBy+i types (where A, B are the components of the sample, G are single and 2-3 atomic gases; x, y = 1, 2, i - charge of ion, i = 1, 2), which are formed during cathode sputtering of this alloy in glow discharge plasma were calculated and experimentally tested. It is shown for spectrometers at resolution R0.5 ≥ 7000, the greatest influence of molecular ions of Me2+ and ArMe+ types exist in the range of isotope masses from 85Rb to about 107Ag. A careful selection of isotopes is required in this mass range to meet detection limit conditions. In other areas of the mass spectrum, the sensitivity of the analysis is limited by the background current and the sensitivity of the detectors and is at the usual ppb-level for this method.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436768","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}
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