Pub Date : 2022-01-01DOI: 10.17721/moca.2022.153-161
Choukri El Khabbaz, A. El Orche, M. Bouatia, Amine Cheikhǁ, M. E. Faouzi, Y. Cherrah, R. Boussen, H. Bouchafra
A basic bio-analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of clopidogrel in human plasma. Clopidogrel-d3 was used as an internal standard (IS). Protein precipitation with acetonitrile for extraction of clopidogrel and it IS was used. Chromatographic separation of clopidogrel and IS was performed on a Synergi reverse phase C18 column (150 mm × 2 mm, 4 μm) using an isocratic mode. The mobile phase contained a mixture of 0.1% formic acid and acetonitrile (25 : 75) applying a flow rate of 0.4 mL/min. Ionization was performed by an electrospray ionization source (ESI), in positive MRM (Multiple Reaction Monitoring) mode. This method was validated by accuracy profiles approach using tolerance intervals limits. The calibration curve ranged from 0.0156 ng/mL to 8 ng/mL. This method can be employed effectively in bioequivalence and/or pharmacokinetics. In this method we have avoided the use of methanol in all steps of bioanalysis of clopidogrel to avert the back-conversion of clopidogrel metabolite.
{"title":"Development and Validation of a Bioanalytical Method for the Quantification of Clopidogrel in Human Plasma by LC-MS/MS using the Accuracy Profiles","authors":"Choukri El Khabbaz, A. El Orche, M. Bouatia, Amine Cheikhǁ, M. E. Faouzi, Y. Cherrah, R. Boussen, H. Bouchafra","doi":"10.17721/moca.2022.153-161","DOIUrl":"https://doi.org/10.17721/moca.2022.153-161","url":null,"abstract":"A basic bio-analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of clopidogrel in human plasma. Clopidogrel-d3 was used as an internal standard (IS). Protein precipitation with acetonitrile for extraction of clopidogrel and it IS was used. Chromatographic separation of clopidogrel and IS was performed on a Synergi reverse phase C18 column (150 mm × 2 mm, 4 μm) using an isocratic mode. The mobile phase contained a mixture of 0.1% formic acid and acetonitrile (25 : 75) applying a flow rate of 0.4 mL/min. Ionization was performed by an electrospray ionization source (ESI), in positive MRM (Multiple Reaction Monitoring) mode. This method was validated by accuracy profiles approach using tolerance intervals limits. The calibration curve ranged from 0.0156 ng/mL to 8 ng/mL. This method can be employed effectively in bioequivalence and/or pharmacokinetics. In this method we have avoided the use of methanol in all steps of bioanalysis of clopidogrel to avert the back-conversion of clopidogrel metabolite.","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":"67436459","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.2022.28-33
M. Oubenali, Hayat El ouafy, Mouna Aamor, M. Mbarki, Aziz El Haimouti, T. EL Ouafy
The reactivity of Diquat ion at the carbon paste electrode (C.P.E) modified by the copper (C.P.E-Cu) has been reported. The working electrode was prepared by mixing the copper with the carbon powder. The optimal potential window has been selected in the range from -1 V to 1.5 V. The effect of parameters such as pH, scan rate, preconcentration time and concentration has been studied by cyclic voltammetry. The preconcentration time is 13 minutes. The reactivity of Diquat on the electrochemical detector has been characterized by the appearance of the cathodic peak at 0.6 V in a solution of sodium sulfate (pH 3). Catalytic influence has been examined by cyclic voltammetry and electronic impedance spectroscopy. The calculated limits of detection and quantification have been 9.48·10-6 and 3.16·10-6 mol L-1, respectively. Then relative standard deviation (RSD) at 0.8·10-4 mol L-1 of Diquat was 5.77 % for nine repetitions. The analytical application was done in the determination of Diquat in real samples of apple juice with satisfying results.
报道了Diquat在铜修饰的碳糊电极(cpe - e - cu)上的反应性。将铜与碳粉混合制成工作电极。在-1 V ~ 1.5 V范围内选择了最佳电位窗。采用循环伏安法研究了pH、扫描速率、预富集时间和浓度等参数对反应的影响。集中时间为13分钟。Diquat在电化学检测器上的反应性通过在pH为3的硫酸钠溶液中出现0.6 V的阴极峰来表征。通过循环伏安法和电子阻抗谱检查了催化影响。计算检测限和定量限分别为9.48·10-6和3.16·10-6 mol L-1。在0.8·10-4 mol L-1 Diquat条件下，9次重复的相对标准偏差(RSD)为5.77%。将该方法应用于实际苹果汁中Diquat的测定，结果令人满意。
{"title":"Investigation of Voltammetric Behavior of Herbicide N,N’-Ethylene- 2,2’-Bipyridinium using the Copper Modified Carbon Paste Electrode","authors":"M. Oubenali, Hayat El ouafy, Mouna Aamor, M. Mbarki, Aziz El Haimouti, T. EL Ouafy","doi":"10.17721/moca.2022.28-33","DOIUrl":"https://doi.org/10.17721/moca.2022.28-33","url":null,"abstract":"The reactivity of Diquat ion at the carbon paste electrode (C.P.E) modified by the copper (C.P.E-Cu) has been reported. The working electrode was prepared by mixing the copper with the carbon powder. The optimal potential window has been selected in the range from -1 V to 1.5 V. The effect of parameters such as pH, scan rate, preconcentration time and concentration has been studied by cyclic voltammetry. The preconcentration time is 13 minutes. The reactivity of Diquat on the electrochemical detector has been characterized by the appearance of the cathodic peak at 0.6 V in a solution of sodium sulfate (pH 3). Catalytic influence has been examined by cyclic voltammetry and electronic impedance spectroscopy. The calculated limits of detection and quantification have been 9.48·10-6 and 3.16·10-6 mol L-1, respectively. Then relative standard deviation (RSD) at 0.8·10-4 mol L-1 of Diquat was 5.77 % for nine repetitions. The analytical application was done in the determination of Diquat in real samples of apple juice with satisfying results.","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":"67436494","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.2022.10-16
O. Zhukovetska, E. Guzenko, A. Chebotarev, D. Snigur
The current work is devoted to the study of a sorbent based on organopolymeric cation exchange resin KU-2-8 modified with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium chloride for preconcentration and solidphase spectrophotometric determination of Mo(VI) microquantities. The optimal conditions for the preconcentration of Mo(VI) by the proposed sorbent were found to be: pH 5.5, a portion of the sorbent 0.5 g with a grain diameter of 0.43 ÷ 0.50 mm with shaking for 60 min (for static mode) or at a rate of 2 cm3/min with using a column with a 10 mm diameter (for dynamic mode). The calibration graph for solid-phase spectrophotometric determination of Mo(VI) after its sorption preconcentration using the modified sorbent in static mode is linear in the concentration range of 0.15-4.24 mg/dm3, and the values of the limit of detection and limit of determination are 0.05 and 0.15 mg/dm3 respectively. The proposed method was tested in the analysis of a sample of peas with a relative standard deviation no more than 4.9 %.
{"title":"Solid-phase Spectrophotometric Determination of Mo(VI) using Organopolymeric Cation Exchange Resin KU-2-8 Modified by 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium chloride","authors":"O. Zhukovetska, E. Guzenko, A. Chebotarev, D. Snigur","doi":"10.17721/moca.2022.10-16","DOIUrl":"https://doi.org/10.17721/moca.2022.10-16","url":null,"abstract":"The current work is devoted to the study of a sorbent based on organopolymeric cation exchange resin KU-2-8 modified with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium chloride for preconcentration and solidphase spectrophotometric determination of Mo(VI) microquantities. The optimal conditions for the preconcentration of Mo(VI) by the proposed sorbent were found to be: pH 5.5, a portion of the sorbent 0.5 g with a grain diameter of 0.43 ÷ 0.50 mm with shaking for 60 min (for static mode) or at a rate of 2 cm3/min with using a column with a 10 mm diameter (for dynamic mode). The calibration graph for solid-phase spectrophotometric determination of Mo(VI) after its sorption preconcentration using the modified sorbent in static mode is linear in the concentration range of 0.15-4.24 mg/dm3, and the values of the limit of detection and limit of determination are 0.05 and 0.15 mg/dm3 respectively. The proposed method was tested in the analysis of a sample of peas with a relative standard deviation no more than 4.9 %.","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":"67436534","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.2022.81-90
D.V. Yanovych, Z. Zasadna, M. Rydchuk, S. Plotytsia, S.M. Kislova, O. Pazderska, S.М. Melikyan, H. Mysko
The article presents the results of development of feed samples preparation method for further testing on salinomycin residues by ELISA using Salinomycin ELISA test kit, manufactured by Beijing Kwinbon Biotechnology (China) for another target matrix: tissues and eggs. Comparative study by means of different extractants and conditions of analyte extraction from feed was carried out, and recoveries’ percentages were established. Optimal conditions for two-stage extraction with methanol saline solution followed by ethyl acetate extraction from alkaline medium were experimentally selected; with further analyte concentration by evaporation and dry residue reconstitution. Application of this technique makes it possible to determine salinomycin residues in feed samples at the level of 0.35 - 0.70 mg/kg with absolute recovery of ~ 70 %. Suitability of the method was confirmed by comparative study of actually contaminated feed samples, performed by two screening methods: ELISA and TLC, and confirmatory method UHPLC-MS/MS. Developed technique has main advantages: it is simple, rapid and cost effective. Elaborated ELISA method is recommended for salinomycin residues determination at the level of cross-contamination on feed production and can be utilized in routine laboratory tests to prevent economic losses, caused by mortality of poultry and non-target animals, and to prevent salinomycine residues accumulation in food.
{"title":"Comparative Studies of Feed Samples on Salinomycin Contamination using Screening and Confirmatory Methods","authors":"D.V. Yanovych, Z. Zasadna, M. Rydchuk, S. Plotytsia, S.M. Kislova, O. Pazderska, S.М. Melikyan, H. Mysko","doi":"10.17721/moca.2022.81-90","DOIUrl":"https://doi.org/10.17721/moca.2022.81-90","url":null,"abstract":"The article presents the results of development of feed samples preparation method for further testing on salinomycin residues by ELISA using Salinomycin ELISA test kit, manufactured by Beijing Kwinbon Biotechnology (China) for another target matrix: tissues and eggs. Comparative study by means of different extractants and conditions of analyte extraction from feed was carried out, and recoveries’ percentages were established. Optimal conditions for two-stage extraction with methanol saline solution followed by ethyl acetate extraction from alkaline medium were experimentally selected; with further analyte concentration by evaporation and dry residue reconstitution. Application of this technique makes it possible to determine salinomycin residues in feed samples at the level of 0.35 - 0.70 mg/kg with absolute recovery of ~ 70 %. Suitability of the method was confirmed by comparative study of actually contaminated feed samples, performed by two screening methods: ELISA and TLC, and confirmatory method UHPLC-MS/MS. Developed technique has main advantages: it is simple, rapid and cost effective. Elaborated ELISA method is recommended for salinomycin residues determination at the level of cross-contamination on feed production and can be utilized in routine laboratory tests to prevent economic losses, caused by mortality of poultry and non-target animals, and to prevent salinomycine residues accumulation in food.","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":"67436398","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.2022.111-117
N. Shulyak, S. Protsyk, T. Kuche, L. Kryskiw, O. Poliak, L. Mosula, L. Logoyda
A simple, rapid, and inexpensive spectrophotometric method for the determination of atorvastatin calcium in tablets has been developed. It requires only one reagent (BPB) and suitable for routine pharmaceutical analysis with less sophisticated equipment. The procedure for atorvastatin determination is based on its interaction with bromophenol blue (BPB) in medium of organic solvent. As a result of the reaction, the intensity of the band of the doubly ionized form of the BPB with a maximum at 595 nm increases. The maximum analytical signal is observed in a solution of methanol, chloroform, or acetonitrile, while ethanol and ethyl acetate turned out to be unsuitable. The optimal concentration of BPB is 4.12·10-4 M. To study the stability, the absorbance of the obtained solution was measured under optimal conditions for 45 min. The stoichiometric ratio of components in the resulting associate, determined by the method of continuous variations, is 1:1. The calibration graph is linear in the range from 4.1 to 33 μmol/L. The calculated LOD and LOQ values were 1.36 μmol/L and 4.13 μmol/L, respectively. The systematic error of the method is statistically insignificant in the whole range of calibration graph. The developed method was successfully applied for the determination of atorvastatin in tablets.
{"title":"Development of the Spectrophotometric Method for the Determination of Atorvastatin Calcium in Tablets by using Bromophenol Blue","authors":"N. Shulyak, S. Protsyk, T. Kuche, L. Kryskiw, O. Poliak, L. Mosula, L. Logoyda","doi":"10.17721/moca.2022.111-117","DOIUrl":"https://doi.org/10.17721/moca.2022.111-117","url":null,"abstract":"A simple, rapid, and inexpensive spectrophotometric method for the determination of atorvastatin calcium in tablets has been developed. It requires only one reagent (BPB) and suitable for routine pharmaceutical analysis with less sophisticated equipment. The procedure for atorvastatin determination is based on its interaction with bromophenol blue (BPB) in medium of organic solvent. As a result of the reaction, the intensity of the band of the doubly ionized form of the BPB with a maximum at 595 nm increases. The maximum analytical signal is observed in a solution of methanol, chloroform, or acetonitrile, while ethanol and ethyl acetate turned out to be unsuitable. The optimal concentration of BPB is 4.12·10-4 M. To study the stability, the absorbance of the obtained solution was measured under optimal conditions for 45 min. The stoichiometric ratio of components in the resulting associate, determined by the method of continuous variations, is 1:1. The calibration graph is linear in the range from 4.1 to 33 μmol/L. The calculated LOD and LOQ values were 1.36 μmol/L and 4.13 μmol/L, respectively. The systematic error of the method is statistically insignificant in the whole range of calibration graph. The developed method was successfully applied for the determination of atorvastatin in tablets.","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":"67436546","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.2022.118-124
Azhar S. Hamody, F. Zankanah, S. Ali, N. Alassaf, S. B. Dikran
A Novel artificial neural network (ANN) model was constructed for calibration of a multivariate model for simultaneously quantitative analysis of the quaternary mixture composed of carbamazepine, carvedilol, diazepam, and furosemide. An eighty-four mixing formula where prepared and analyzed spectrophotometrically. Each analyte was formulated in six samples at different concentrations thus twentyfour samples for the four analytes were tested. A neural network of 10 hidden neurons was capable to fit data 100%. The suggested model can be applied for the quantitative chemical analysis for the proposed quaternary mixture.
{"title":"Spectrophotometric Analysis of Quaternary Drug Mixtures using Artificial Neural network model","authors":"Azhar S. Hamody, F. Zankanah, S. Ali, N. Alassaf, S. B. Dikran","doi":"10.17721/moca.2022.118-124","DOIUrl":"https://doi.org/10.17721/moca.2022.118-124","url":null,"abstract":"A Novel artificial neural network (ANN) model was constructed for calibration of a multivariate model for simultaneously quantitative analysis of the quaternary mixture composed of carbamazepine, carvedilol, diazepam, and furosemide. An eighty-four mixing formula where prepared and analyzed spectrophotometrically. Each analyte was formulated in six samples at different concentrations thus twentyfour samples for the four analytes were tested. A neural network of 10 hidden neurons was capable to fit data 100%. The suggested model can be applied for the quantitative chemical analysis for the proposed quaternary mixture.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"52 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67436588","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.2022.34-42
L. Oleksenko, N. Maksymovych, I. Matushko, G. Fedorenko, O. Ripko, L. Lutsenko
A semiconductor sensor with a gas sensitive layer based on SnO2 and Sb2O5 with Pd additive synthesized by co-precipitation was studied as a chromatographic detector. It was found that the subject detector, using air as a carrier gas, can selectively detect each of the reducing gases (H2, CO, CH4, C2H2, C2H4, C2H6) which can leak into transformer oil if defects emerge during high-voltage transformers operation. It was established that for the fabricated detector the dependences of the signals on concentrations of the analyzed gases are linear in the range of 0–50 ppm for H2, CO, CH4 and 0–100 ppm for C2H2, C2H4, C2H6. The detector can be on-stream as combined with a chromatograph instrumentality which is rational for a wide practical application. The usage of the semiconductor detector based on the adsorption-semiconductor sensor is promising to significantly reduce the detection cost of the gases and to simplify diagnostics of the high-voltage transformer conditions.
{"title":"Chromatographic Detector Based on Adsorption-Semiconductor Sensor for Detection of Reducing Gases in Air","authors":"L. Oleksenko, N. Maksymovych, I. Matushko, G. Fedorenko, O. Ripko, L. Lutsenko","doi":"10.17721/moca.2022.34-42","DOIUrl":"https://doi.org/10.17721/moca.2022.34-42","url":null,"abstract":"A semiconductor sensor with a gas sensitive layer based on SnO2 and Sb2O5 with Pd additive synthesized by co-precipitation was studied as a chromatographic detector. It was found that the subject detector, using air as a carrier gas, can selectively detect each of the reducing gases (H2, CO, CH4, C2H2, C2H4, C2H6) which can leak into transformer oil if defects emerge during high-voltage transformers operation. It was established that for the fabricated detector the dependences of the signals on concentrations of the analyzed gases are linear in the range of 0–50 ppm for H2, CO, CH4 and 0–100 ppm for C2H2, C2H4, C2H6. The detector can be on-stream as combined with a chromatograph instrumentality which is rational for a wide practical application. The usage of the semiconductor detector based on the adsorption-semiconductor sensor is promising to significantly reduce the detection cost of the gases and to simplify diagnostics of the high-voltage transformer conditions.","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":"67436642","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.2022.141-152
Y. Omelchun, A. Kobish, N. Klochkova, L. Shevchenko
In this paper we present the results of evaluating the suitability of the developed method for the simultaneous determination of 200 pesticide residues in bee honey using ultraperformance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS). The main stages of extraction of pesticides from the matrix using QuEChERS (Quick Easy Cheap Effective Rugged Safe) sample preparation are described. Appropriate mobile phase composition was used to better identify analytes, internal standards were not applied. The studied list of pesticides is relevant for use in modern agriculture. The limit of quantification of the method (LOQ) for each of the analytes is 0.001 mg/kg, the relative standard deviation in the conditions of repeatability and reproducibility < 20.0 %, the expanded measurement uncertainty is less than the limit of regulatory requirements < 50.0 %. The calibration graph for each of the analytes had a coefficient R2 > 0.99. The use of QuEChERS sample preparation methods allows to reduce labor intensity, time and reagents, increase the accuracy and precision of research in comparison with classical methods of sample preparation. The described method makes it possible to detect a wide range of pesticides and has a fairly high sensitivity
{"title":"Validation of the Multiresidue Method Analysis for Pesticides in Bee Honey by UPLC-MS/MS using the Method of Samples Preparation QuEChERS","authors":"Y. Omelchun, A. Kobish, N. Klochkova, L. Shevchenko","doi":"10.17721/moca.2022.141-152","DOIUrl":"https://doi.org/10.17721/moca.2022.141-152","url":null,"abstract":"In this paper we present the results of evaluating the suitability of the developed method for the simultaneous determination of 200 pesticide residues in bee honey using ultraperformance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS). The main stages of extraction of pesticides from the matrix using QuEChERS (Quick Easy Cheap Effective Rugged Safe) sample preparation are described. Appropriate mobile phase composition was used to better identify analytes, internal standards were not applied. The studied list of pesticides is relevant for use in modern agriculture. The limit of quantification of the method (LOQ) for each of the analytes is 0.001 mg/kg, the relative standard deviation in the conditions of repeatability and reproducibility < 20.0 %, the expanded measurement uncertainty is less than the limit of regulatory requirements < 50.0 %. The calibration graph for each of the analytes had a coefficient R2 > 0.99. The use of QuEChERS sample preparation methods allows to reduce labor intensity, time and reagents, increase the accuracy and precision of research in comparison with classical methods of sample preparation. The described method makes it possible to detect a wide range of pesticides and has a fairly high sensitivity","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":"67436364","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.2022.70-80
V. Doroshchuk, B. Oliinyk, S. Alekseev
This article demonstrates a new approach of multiple additions direct potentiometric determination of nitrate ion in natural and potable freshwater. The main feature of this approach is no need to pre-calibrate the electrode and to use the slope in the calculations. The experimental procedure is very similar to one of classic potentiometric titration. To test and illustrate the approach, ion-selective electrodes with tridodecylmethylammonium nitrate as ion-exchanger in plasticized membrane were produced. The application of the proposed mathematical algorithm for processing of data obtained by the method of multiple standard additions simplifies and speeds up the analysis by reducing the number of required manipulations, while maintaining high accuracy of analysis. The work of the method and calculation algorithm were tested on real samples of natural river water taken from the rivers Saone and Rhone (Lyon, France); possibility of nitrate determination in low mineralized natural waters at the level of 10 mg L-1 corresponding to 1/5 of maximum allowable concentration was shown.
{"title":"Modified Gran’s Plot Method for Calibrationless Potentiometric Nitrate Determination","authors":"V. Doroshchuk, B. Oliinyk, S. Alekseev","doi":"10.17721/moca.2022.70-80","DOIUrl":"https://doi.org/10.17721/moca.2022.70-80","url":null,"abstract":"This article demonstrates a new approach of multiple additions direct potentiometric determination of nitrate ion in natural and potable freshwater. The main feature of this approach is no need to pre-calibrate the electrode and to use the slope in the calculations. The experimental procedure is very similar to one of classic potentiometric titration. To test and illustrate the approach, ion-selective electrodes with tridodecylmethylammonium nitrate as ion-exchanger in plasticized membrane were produced. The application of the proposed mathematical algorithm for processing of data obtained by the method of multiple standard additions simplifies and speeds up the analysis by reducing the number of required manipulations, while maintaining high accuracy of analysis. The work of the method and calculation algorithm were tested on real samples of natural river water taken from the rivers Saone and Rhone (Lyon, France); possibility of nitrate determination in low mineralized natural waters at the level of 10 mg L-1 corresponding to 1/5 of maximum allowable concentration was shown.","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":"67436849","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 : 2021-01-01DOI: 10.17721/moca.2021.88-92
S. Kovalev, A. Golovach, V. Kovalev
Amino acids in the extract of Erigeron annuus herb were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and UV Vis detection. This objective is reached with automatic derivatization using o-phthalaldehyde (OPA) for primary amino acids and 9-Fluorenylmethyl chloroformate (FMOC) for secondary amino acids. Then derivatization integrates into high performance liquid chromatography (HPLC). The applied procedure is fast with easily reproduced results. The insufficient knowledge about amino acids composition of herb of Erigeron annuus is the basis for study. This work reports on content of 16 free and bound amino acids (391.41 μg/mg) in the plant raw material and influence’s evaluation of different extraction types on the amino acid profile. The total content of free amino acids was 4.66 μg/mg; proline prevailed (2.498 μg/mg). The total content of bound amino acids was 386.7 μg/mg; proline (146.8 μg/mg), arginine (67.8 μg/mg), phenylalanine (25.8 μg/mg), asparagine (24.3 μg/mg), histidine (20.4 μg/mg), alanine (18.2 μg/mg), serine (16.6 μg/mg), valine (16.0 μg/mg) were the dominant amino acids. Nine amino acids were classified as essential.
{"title":"An Identification and Study of Amino Acids of Erigeron annuus Herb","authors":"S. Kovalev, A. Golovach, V. Kovalev","doi":"10.17721/moca.2021.88-92","DOIUrl":"https://doi.org/10.17721/moca.2021.88-92","url":null,"abstract":"Amino acids in the extract of Erigeron annuus herb were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and UV Vis detection. This objective is reached with automatic derivatization using o-phthalaldehyde (OPA) for primary amino acids and 9-Fluorenylmethyl chloroformate (FMOC) for secondary amino acids. Then derivatization integrates into high performance liquid chromatography (HPLC). The applied procedure is fast with easily reproduced results. The insufficient knowledge about amino acids composition of herb of Erigeron annuus is the basis for study. This work reports on content of 16 free and bound amino acids (391.41 μg/mg) in the plant raw material and influence’s evaluation of different extraction types on the amino acid profile. The total content of free amino acids was 4.66 μg/mg; proline prevailed (2.498 μg/mg). The total content of bound amino acids was 386.7 μg/mg; proline (146.8 μg/mg), arginine (67.8 μg/mg), phenylalanine (25.8 μg/mg), asparagine (24.3 μg/mg), histidine (20.4 μg/mg), alanine (18.2 μg/mg), serine (16.6 μg/mg), valine (16.0 μg/mg) were the dominant amino acids. Nine amino acids were classified as essential.","PeriodicalId":18626,"journal":{"name":"Methods and Objects of Chemical Analysis","volume":"10 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67435930","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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