Pub Date : 2022-03-08DOI: 10.3390/analytica3010009
P. Banou, Konstantinos Choulis, Thanasis Karabotsos, Dimitris Tsimogiannis, L. Tsakanika, C. Tzia, A. Alexopoulou
Oil media on paper, such as oil paintings, sketches, prints, and books, occasionally present problems associated with the effect of oil medium on the paper support, raising a composite matter of condition assessment as it depends on several factors. The present work examines the effect of linseed oil on paper and, in particular, the changes caused by three types of linseed oil on the optical, morphological, mechanical, and chemical properties of pure cellulosic paper, employing mock-ups submitted to artificial ageing in controlled conditions of relative humidity and temperature in airtight vessels. The study involved colorimetry, opacity, tensile strength, pH measurements, SEM, FTIR, and VOC analysis with GC-MS. Processing of the results has so far indicated that thermal-humid ageing caused the gradual darkening of the oil-impregnated mock-ups, as well as alterations in opacity, intense fall of pH values, and severe reductions in tensile strength, while linseed oil processing during manufacture has a significant impact. FTIR spectra have indicated that chemical changes upon ageing are in accordance with those of optical and mechanical changes, while VOC emissions are mostly associated with the drying and degradation of the different types of linseed oil.
{"title":"Oil Media on Paper: Investigating the Effect of Linseed Oils on Pure Cellulosic Paper Supports. A Research Matter of Damage Assessment","authors":"P. Banou, Konstantinos Choulis, Thanasis Karabotsos, Dimitris Tsimogiannis, L. Tsakanika, C. Tzia, A. Alexopoulou","doi":"10.3390/analytica3010009","DOIUrl":"https://doi.org/10.3390/analytica3010009","url":null,"abstract":"Oil media on paper, such as oil paintings, sketches, prints, and books, occasionally present problems associated with the effect of oil medium on the paper support, raising a composite matter of condition assessment as it depends on several factors. The present work examines the effect of linseed oil on paper and, in particular, the changes caused by three types of linseed oil on the optical, morphological, mechanical, and chemical properties of pure cellulosic paper, employing mock-ups submitted to artificial ageing in controlled conditions of relative humidity and temperature in airtight vessels. The study involved colorimetry, opacity, tensile strength, pH measurements, SEM, FTIR, and VOC analysis with GC-MS. Processing of the results has so far indicated that thermal-humid ageing caused the gradual darkening of the oil-impregnated mock-ups, as well as alterations in opacity, intense fall of pH values, and severe reductions in tensile strength, while linseed oil processing during manufacture has a significant impact. FTIR spectra have indicated that chemical changes upon ageing are in accordance with those of optical and mechanical changes, while VOC emissions are mostly associated with the drying and degradation of the different types of linseed oil.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88004587","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 : 2022-02-25DOI: 10.3390/analytica3010008
Stefan Niedermayer, Markus Ellersdorfer
Aluminum Carbide (Al4C3) is a main source of corrosion problems in metal matrix composites as well as refractory products. Hydrolysis to methane happening at room temperature leads to various structural problems. As methods to quantify Al4C3 are scarce, this paper proposes a method to measure Al4C3 containing analyte powders in mg areas by combining a robust autoclave system with non-dispersive infrared (NDIR) process analytics. The method uses only water as reagent, making it easy and safe to handle. The used materials were characterized by thermogravimetric analysis coupled with fourier-transformation infrared detection (TGA-IR), LECO-C analysis, and X-ray diffraction (XRD) before and after autoclave treatment. 90–90.8% recovery of 100 mg Al4C3 with small standard deviations (<1% at n = 3) in 240, 205, and 165 min at 60, 70, and 80 °C, respectively, were achieved. XRD analysis showed the total conversion of Al4C3 to Bayerite (Al(OH)3) and Boehmite (AlO(OH)) at 70 °C. Comparison with shrinking core models showed that the reaction is neither purely reaction nor purely ash diffusion controlled. The findings indicate possibilities for further acceleration of reaction speeds by increasing temperature. The 200 mL reactor volume of the autoclave enables the analysis of bigger sample sizes at temperatures above 100 °C by separating reaction and analysis procedure. This provides an extension to gas chromatographic methods for industrial quality control of bulk materials in rougher environments.
{"title":"Combination of Autoclave Treatment and NDIR Process Analytics for Quantification of Aluminum Carbide in Powdery Samples","authors":"Stefan Niedermayer, Markus Ellersdorfer","doi":"10.3390/analytica3010008","DOIUrl":"https://doi.org/10.3390/analytica3010008","url":null,"abstract":"Aluminum Carbide (Al4C3) is a main source of corrosion problems in metal matrix composites as well as refractory products. Hydrolysis to methane happening at room temperature leads to various structural problems. As methods to quantify Al4C3 are scarce, this paper proposes a method to measure Al4C3 containing analyte powders in mg areas by combining a robust autoclave system with non-dispersive infrared (NDIR) process analytics. The method uses only water as reagent, making it easy and safe to handle. The used materials were characterized by thermogravimetric analysis coupled with fourier-transformation infrared detection (TGA-IR), LECO-C analysis, and X-ray diffraction (XRD) before and after autoclave treatment. 90–90.8% recovery of 100 mg Al4C3 with small standard deviations (<1% at n = 3) in 240, 205, and 165 min at 60, 70, and 80 °C, respectively, were achieved. XRD analysis showed the total conversion of Al4C3 to Bayerite (Al(OH)3) and Boehmite (AlO(OH)) at 70 °C. Comparison with shrinking core models showed that the reaction is neither purely reaction nor purely ash diffusion controlled. The findings indicate possibilities for further acceleration of reaction speeds by increasing temperature. The 200 mL reactor volume of the autoclave enables the analysis of bigger sample sizes at temperatures above 100 °C by separating reaction and analysis procedure. This provides an extension to gas chromatographic methods for industrial quality control of bulk materials in rougher environments.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73094993","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 : 2022-02-23DOI: 10.3390/analytica3010007
Chanakarn Sangsum, P. Saetear
This work presents the first development of an all-steps-in-one test kit for the determination of paraquat in natural water, and vegetable and agricultural samples. A handheld photometer incorporated with a magnetic stirrer was used to complete the steps of extraction, mixing, and detection. Paraquat produces a blue free radical ion via a reduction with sodium dithionite in alkaline conditions. Sodium dithionite powder was investigated for the enhancement of reagent stability duration, which was added directly into sample solution that showed insignificant difference in sensitivity as compared with that of the solution format of sodium dithionite. The developed test kit showed good performance with the linear calibration of 0.5 to 10 mg L−1 with a high coefficient of determination (r2 = 0.9947). The lower limit of quantitation (LLOQ = 3SD of intercept per slope) carried out from the method using the handheld photometer was 0.50 mg L−1. The limit of detection (LOD) by naked eye was 0.30 mg L−1. The recovery study was acceptable in the range of 101–115%. Intraday (n = 3) and interday (n = 3) precision was less than 1%. On the basis of the significance test at the 95% confidence interval, quantitative results of the developed test kit agreed well with those from high-performance liquid chromatography (HPLC). To the best of our knowledge, this is the first report demonstrating an online extraction for vegetables incorporated into a test kit, applicable for on-site analysis. Single-point calibration based on the Beer–Lambert law also demonstrated the measurement of paraquat. In testing with a nominal standard solution of 5.00 mg L−1 paraquat, the reading concentration was 5.09 ± 0.03 mg L−1 paraquat (n = 20) with a K value of 0.0967 (close to the slope of multipoint calibration). This research is a direct benefit to agricultural products and the health of a population for the analysis of pesticides and herbicides.
{"title":"All-Step-in-One Test Kit for Paraquat Detection in Water and Vegetable Samples","authors":"Chanakarn Sangsum, P. Saetear","doi":"10.3390/analytica3010007","DOIUrl":"https://doi.org/10.3390/analytica3010007","url":null,"abstract":"This work presents the first development of an all-steps-in-one test kit for the determination of paraquat in natural water, and vegetable and agricultural samples. A handheld photometer incorporated with a magnetic stirrer was used to complete the steps of extraction, mixing, and detection. Paraquat produces a blue free radical ion via a reduction with sodium dithionite in alkaline conditions. Sodium dithionite powder was investigated for the enhancement of reagent stability duration, which was added directly into sample solution that showed insignificant difference in sensitivity as compared with that of the solution format of sodium dithionite. The developed test kit showed good performance with the linear calibration of 0.5 to 10 mg L−1 with a high coefficient of determination (r2 = 0.9947). The lower limit of quantitation (LLOQ = 3SD of intercept per slope) carried out from the method using the handheld photometer was 0.50 mg L−1. The limit of detection (LOD) by naked eye was 0.30 mg L−1. The recovery study was acceptable in the range of 101–115%. Intraday (n = 3) and interday (n = 3) precision was less than 1%. On the basis of the significance test at the 95% confidence interval, quantitative results of the developed test kit agreed well with those from high-performance liquid chromatography (HPLC). To the best of our knowledge, this is the first report demonstrating an online extraction for vegetables incorporated into a test kit, applicable for on-site analysis. Single-point calibration based on the Beer–Lambert law also demonstrated the measurement of paraquat. In testing with a nominal standard solution of 5.00 mg L−1 paraquat, the reading concentration was 5.09 ± 0.03 mg L−1 paraquat (n = 20) with a K value of 0.0967 (close to the slope of multipoint calibration). This research is a direct benefit to agricultural products and the health of a population for the analysis of pesticides and herbicides.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"118 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82422391","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 : 2022-02-17DOI: 10.3390/analytica3010006
Andreas Vrachas, Kostas Gkountanas, Haris Boutsikaris, Y. Dotsikas
Cetrimide (CE) is a quaternary ammonium compound and a cationic surfactant, which can be used as an antiseptic and preservative in various formulations. Antiseptic solutions of Cetrimide are available in combination with Chlorhexidine Gluconate (CHG) for external use. Chlorhexidine is a biguanide with high microbicidal activity and is widely known as a skin disinfectant. The present work displays the development and validation of an RP-HPLC isocratic method for the simultaneous determination of CE and CHG. The method consists of a Hypersil® SAS C1 (4.6 × 250 mm) 5 μm column, with a mobile phase of 85%/15% v/v MeOH-NaH2PO4·H2O, aqueous solution. In addition, 0.2% of triethylamine (Et3N) was added to the buffer for the confrontation of peak tailing, and then the pH was adjusted to 3.0 with ortho-phosphoric acid (H3PO4). The flow rate was set at 1 mL/min, and adequate detection was achieved with a diode array detector (PDA) at 205 nm. The method was successfully validated according to ICH guidelines for specificity, linearity, accuracy, precision and stability for sample and standard solutions. In addition, the robustness of the method was evaluated through statistical and graphical analysis, using a fractional factorial experimental design.
{"title":"Development and Validation of a Novel RP-HPLC Method for the Determination of Cetrimide and Chlorhexidine Gluconate in Antiseptic Solution","authors":"Andreas Vrachas, Kostas Gkountanas, Haris Boutsikaris, Y. Dotsikas","doi":"10.3390/analytica3010006","DOIUrl":"https://doi.org/10.3390/analytica3010006","url":null,"abstract":"Cetrimide (CE) is a quaternary ammonium compound and a cationic surfactant, which can be used as an antiseptic and preservative in various formulations. Antiseptic solutions of Cetrimide are available in combination with Chlorhexidine Gluconate (CHG) for external use. Chlorhexidine is a biguanide with high microbicidal activity and is widely known as a skin disinfectant. The present work displays the development and validation of an RP-HPLC isocratic method for the simultaneous determination of CE and CHG. The method consists of a Hypersil® SAS C1 (4.6 × 250 mm) 5 μm column, with a mobile phase of 85%/15% v/v MeOH-NaH2PO4·H2O, aqueous solution. In addition, 0.2% of triethylamine (Et3N) was added to the buffer for the confrontation of peak tailing, and then the pH was adjusted to 3.0 with ortho-phosphoric acid (H3PO4). The flow rate was set at 1 mL/min, and adequate detection was achieved with a diode array detector (PDA) at 205 nm. The method was successfully validated according to ICH guidelines for specificity, linearity, accuracy, precision and stability for sample and standard solutions. In addition, the robustness of the method was evaluated through statistical and graphical analysis, using a fractional factorial experimental design.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78862624","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 : 2022-02-15DOI: 10.3390/analytica3010005
Monica Maio, Cristina Di Fiore, Alessia Iannone, Fabiana Carriera, Ivan Notardonato, P. Avino
This review would like to show the state of the art regarding the coupling of High-Performance Liquid Chromatography (HPLC) with Electrochemical Detection (ED). Since a universal detector for HPLC is not available, the electrochemical detection methods, thanks to their versatility and specificity, are competitive with respect to the detectors currently used. The papers present in literature on HPLC-ED technique are analyzed and discussed: for example, they regard the development of analytical determinations of resveratrol, rosmarinic acid, aromatic heterocyclic amines and glyphosate in food matrices such as meat, aromatic plants, vegetables, fruit and tomato juices. These papers show that electrochemical sensors used as detectors for HPLC can offer better sensitivity values than other detectors. Furthermore, the use of specific working potentials allows avoid matrix interferences to be avoided by almost exclusively determining the analytes of interest. It should be underlined that HPLC-ED methods have a selectivity that allows for limitation of the sample preparation and clean-up procedures to a minimum, making them quick and easy to apply. In addition, these methods offer advantages such as the possibility of direct analysis, that derivatization is often not necessary, the cost-effectiveness of the instrumentation and the possibility of regenerating the electrodes which allows numerous analyses in succession.
{"title":"Review of the Analytical Methods Based on HPLC-Electrochemical Detection Coupling for the Evaluation of Organic Compounds of Nutritional and Environmental Interest","authors":"Monica Maio, Cristina Di Fiore, Alessia Iannone, Fabiana Carriera, Ivan Notardonato, P. Avino","doi":"10.3390/analytica3010005","DOIUrl":"https://doi.org/10.3390/analytica3010005","url":null,"abstract":"This review would like to show the state of the art regarding the coupling of High-Performance Liquid Chromatography (HPLC) with Electrochemical Detection (ED). Since a universal detector for HPLC is not available, the electrochemical detection methods, thanks to their versatility and specificity, are competitive with respect to the detectors currently used. The papers present in literature on HPLC-ED technique are analyzed and discussed: for example, they regard the development of analytical determinations of resveratrol, rosmarinic acid, aromatic heterocyclic amines and glyphosate in food matrices such as meat, aromatic plants, vegetables, fruit and tomato juices. These papers show that electrochemical sensors used as detectors for HPLC can offer better sensitivity values than other detectors. Furthermore, the use of specific working potentials allows avoid matrix interferences to be avoided by almost exclusively determining the analytes of interest. It should be underlined that HPLC-ED methods have a selectivity that allows for limitation of the sample preparation and clean-up procedures to a minimum, making them quick and easy to apply. In addition, these methods offer advantages such as the possibility of direct analysis, that derivatization is often not necessary, the cost-effectiveness of the instrumentation and the possibility of regenerating the electrodes which allows numerous analyses in succession.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73899736","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 : 2022-02-03DOI: 10.3390/analytica3010004
A. A. Chudin, E. Kudryashova
Reversed micelles are helpful to solubilize otherwise insoluble membranotropic or membrane-bound enzymes in their functional form, thus enabling activity assay and inhibition analysis. However, in the case of redox enzymes, this task is further complicated by the necessity to select an appropriate electron-acceptor (EA) which, ideally, should be compatible with spectrophotometric measurements in reversed micelles. Here, we have identified such an EA and successfully used it in a reversed micellar environment to assay the activity of two homologous enzymes from mitochondria: l-galactone-1,4-lactone dehydrogenase (EC 1.3.2.3) from Arabidopsis thaliana (AtGALDH) and galactonolactone oxidase (EC 1.3.3.12) from Trypanosoma cruzi (TcGAL), differing in their membranotropic properties, with TcGAL being almost insoluble in water and particularly difficult to assay. Furthermore, we have demonstrated the possibility to use this assay for inhibition analysis, with an elucidation of the mechanism and inhibition parameters, which otherwise could not be possible. In order to perform inhibition analysis, we improved the approach for the determination of activity of such membrane enzymes based on a reversed micellar system as membrane matrix, necessary for the functioning of membrane enzymes. A number of electron acceptors (EA) were tested for AtGALDH and optimal conditions of activity determination for AtGALDH were found. The suggested method was successfully applied to the study of the inhibition of AtGALDH by lycorine, and the mixed competitive mechanism of inhibition of AtGALDH by lycorine was determined. The developed approach to inhibitor analysis was applied for TcGAL, insoluble in water membrane, and the method provides new opportunities for searching effective inhibitors that may be potential drugs. Indeed, galactonolactone oxidase from Trypanosoma cruzi (TcGAL) and AtGALDH are homologues, and the inhibition of TcGAL stops the vital biosynthesis of vitamin C in parasite Trypanosoma cruzi from causing Chagas disease. The approach proposed can be applied for the screening of inhibitors of AtGALDH and TcGAL, as well as to study properties of other membrane enzymes including determination of the mechanisms of inhibition, structure and catalytic properties, the impact of membrane components (for example lipids), and so on.
{"title":"Improved Enzymatic Assay and Inhibition Analysis of Redox Membranotropic Enzymes, AtGALDH and TcGAL, Using a Reversed Micellar System","authors":"A. A. Chudin, E. Kudryashova","doi":"10.3390/analytica3010004","DOIUrl":"https://doi.org/10.3390/analytica3010004","url":null,"abstract":"Reversed micelles are helpful to solubilize otherwise insoluble membranotropic or membrane-bound enzymes in their functional form, thus enabling activity assay and inhibition analysis. However, in the case of redox enzymes, this task is further complicated by the necessity to select an appropriate electron-acceptor (EA) which, ideally, should be compatible with spectrophotometric measurements in reversed micelles. Here, we have identified such an EA and successfully used it in a reversed micellar environment to assay the activity of two homologous enzymes from mitochondria: l-galactone-1,4-lactone dehydrogenase (EC 1.3.2.3) from Arabidopsis thaliana (AtGALDH) and galactonolactone oxidase (EC 1.3.3.12) from Trypanosoma cruzi (TcGAL), differing in their membranotropic properties, with TcGAL being almost insoluble in water and particularly difficult to assay. Furthermore, we have demonstrated the possibility to use this assay for inhibition analysis, with an elucidation of the mechanism and inhibition parameters, which otherwise could not be possible. In order to perform inhibition analysis, we improved the approach for the determination of activity of such membrane enzymes based on a reversed micellar system as membrane matrix, necessary for the functioning of membrane enzymes. A number of electron acceptors (EA) were tested for AtGALDH and optimal conditions of activity determination for AtGALDH were found. The suggested method was successfully applied to the study of the inhibition of AtGALDH by lycorine, and the mixed competitive mechanism of inhibition of AtGALDH by lycorine was determined. The developed approach to inhibitor analysis was applied for TcGAL, insoluble in water membrane, and the method provides new opportunities for searching effective inhibitors that may be potential drugs. Indeed, galactonolactone oxidase from Trypanosoma cruzi (TcGAL) and AtGALDH are homologues, and the inhibition of TcGAL stops the vital biosynthesis of vitamin C in parasite Trypanosoma cruzi from causing Chagas disease. The approach proposed can be applied for the screening of inhibitors of AtGALDH and TcGAL, as well as to study properties of other membrane enzymes including determination of the mechanisms of inhibition, structure and catalytic properties, the impact of membrane components (for example lipids), and so on.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"442 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75809440","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: 10.3390/analytica3010002
André M. Segurado, S. M. Ahmad, N. Neng, Margarida M. Maniés-Sequeira, H. Gaspar, J. Nogueira
Synthetic cathinones are analogue compounds of the plant based stimulant cathinone. Its use, abuse, and related consumption complications have steadily increased in the last years. For this reason, there is a need for innovative analytical approaches that enable its rapid screening in biological matrices (e.g., oral fluids). The present work proposes a new analytical methodology by combining bar adsorptive microextraction followed by microliquid desorption and gas chromatography coupled to mass spectrometry (BAµE-µLD/GC-MS) for screening three synthetic cathinones (α-PVP, α-PVT, and MDPV) in oral fluids. The optimization of the BAµE-µLD/GC-MS methodology was successfully applied for the analysis of the target compounds in oral fluids. The results show average recoveries between 43.1 and 52.3% for the three synthetic cathinones. Good selectivity was also noticed. The developed methodology presents itself as an alternative tool to screen these compounds in oral fluids. To the best of our knowledge, this is the first work that combines a microextraction sorption-based technique followed by GC-MS analysis for the screening of synthetic cathinones in oral fluids.
{"title":"Simple Analytical Strategy for Screening Three Synthetic Cathinones (α-PVT, α-PVP, and MDPV) in Oral Fluids","authors":"André M. Segurado, S. M. Ahmad, N. Neng, Margarida M. Maniés-Sequeira, H. Gaspar, J. Nogueira","doi":"10.3390/analytica3010002","DOIUrl":"https://doi.org/10.3390/analytica3010002","url":null,"abstract":"Synthetic cathinones are analogue compounds of the plant based stimulant cathinone. Its use, abuse, and related consumption complications have steadily increased in the last years. For this reason, there is a need for innovative analytical approaches that enable its rapid screening in biological matrices (e.g., oral fluids). The present work proposes a new analytical methodology by combining bar adsorptive microextraction followed by microliquid desorption and gas chromatography coupled to mass spectrometry (BAµE-µLD/GC-MS) for screening three synthetic cathinones (α-PVP, α-PVT, and MDPV) in oral fluids. The optimization of the BAµE-µLD/GC-MS methodology was successfully applied for the analysis of the target compounds in oral fluids. The results show average recoveries between 43.1 and 52.3% for the three synthetic cathinones. Good selectivity was also noticed. The developed methodology presents itself as an alternative tool to screen these compounds in oral fluids. To the best of our knowledge, this is the first work that combines a microextraction sorption-based technique followed by GC-MS analysis for the screening of synthetic cathinones in oral fluids.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74700795","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 : 2021-12-29DOI: 10.3390/analytica3010001
S. J. Davis, W. Wise, S. Recchia, A. Spinazzè, Maurizio Masi
The topic of hexavalent chromium (Cr(VI)) in leather has been debated throughout the whole supply chain for years. However, its significance has recently increased due to proposed changes in European legislation concerned with skin-sensitising substances suggesting that acceptable Cr(VI) concentrations in leather goods should be lowered from 3 mg kg−1 to 1 mg kg−1. The proposition of a stricter limit and current analytical difficulties created the need for a review of current standard test methods. The research presented in this paper investigates both the colorimetric (Part 1) and chromatographic (Part 2) methods under BS EN ISO 17075. The focus of the study was to identify possible sources of interference leading to large statistical variance in results and to define the limit of quantification with respect to the proposed new compliance limit. This study into the colorimetric method has shown that the presence of Cr(III), dyes, and proteins can be significant interferences, becoming critical at low Cr(VI) concentrations. Dilution factors worsen the problem of detecting low concentrations: a reliable quantitative detection of 0.01 mg kg−1 and 0.003 mg kg−1 Cr(VI) in solution are required at the 3 mg kg−1 and 1 mg kg−1 compliance limits in leather, respectively. BS EN ISO 17075 part 1 was shown to be incapable of reliably resolving to 3 mg kg−1 or below in leather. Part 2 shows a marked improvement in detection limits and reliability; however, data suggest that 1 mg kg−1 Cr(VI) is not reliably detectable in leather. Suggested improvements to the established test methods and a possible alternative are discussed.
皮革中六价铬(Cr(VI))的话题已经在整个供应链中讨论了多年。然而，它的重要性最近有所增加，因为欧洲有关皮肤致敏物质的立法拟议的变化表明，皮革制品中可接受的Cr(VI)浓度应从3 mg kg - 1降至1 mg kg - 1。更严格限制的提议和当前的分析困难产生了对当前标准测试方法进行审查的需要。本文研究了BS EN ISO 17075的比色法(第一部分)和色谱法(第二部分)方法。该研究的重点是确定可能导致结果出现较大统计差异的干扰源，并确定拟议的新遵守限度的量化限度。比色法的研究表明，Cr(III)、染料和蛋白质的存在可能是显著的干扰，在低Cr(VI)浓度下变得至关重要。稀释因素加剧了检测低浓度Cr(VI)的问题:在皮革的3 mg kg - 1和1 mg kg - 1合规限值下，溶液中Cr(VI)的可靠定量检测分别为0.01 mg kg - 1和0.003 mg kg - 1。BS EN ISO 17075第1部分被证明不能可靠地分辨皮革中3 mg kg - 1或以下的含量。第2部分显示了检测限和可靠性的显著改进;然而，数据表明，在皮革中不能可靠地检测到1 mg kg - 1 Cr(VI)。讨论了对现有测试方法的改进建议和一种可能的替代方法。
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Pub Date : 2021-12-20DOI: 10.3390/analytica2040018
Ngabo Yves Musafili, H. Samsodien, M. Aucamp
Tuberculosis (TB) remains a life-threatening infection, and it is well-known that effective TB treatment is associated with multiple drugs administered to infected patients on a daily basis. Terizidone (TZD) is an anti-TB drug used in the treatment of multi-drug resistant and extensively drug-resistant TB but presents with polyneuropathic adverse effects in some patients. To counteract these adverse effects, TZD is typically prescribed with pyridoxine (PDX), well known as Vitamin B6. As part of a pre-formulation study investigating the potential to co-formulate these two compounds, it became necessary to have a simple and reliable reversed-phase high-performance liquid chromatography (RP-HPLC) method. Optimal, simultaneous separation and detection of TZD and PDX were obtained using an isocratic mobile phase setup, consisting of ultrapure water and acetonitrile (30:70% v/v), with 1 mL glacial acetic acid added to the mobile phase mixture. A Discovery® C18, 150 × 4.6 mm, 5 μm column maintained at ambient temperature was utilized, with a detection wavelength of 260 nm. The method was validated in terms of linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), specificity, robustness, and solution stability. Validation proved this method to be acceptable and reliable for the simultaneous accurate detection and quantification of TZD and PDX.
结核病仍然是一种危及生命的感染，众所周知，有效的结核病治疗与每天向感染患者施用多种药物有关。特立齐酮(TZD)是一种用于治疗多重耐药和广泛耐药结核病的抗结核药物，但在一些患者中出现多神经病变不良反应。为了抵消这些副作用，TZD通常与吡哆醇(PDX)一起开处方，也就是众所周知的维生素B6。作为研究这两种化合物共配制可能性的制剂前研究的一部分，有必要建立一种简单可靠的反相高效液相色谱(RP-HPLC)方法。以超纯水和乙腈(30:70 v/v)为流动相，在流动相混合物中加入1 mL冰醋酸，采用等温流动相设置，获得了同时分离和检测TZD和PDX的最佳方法。采用Discovery®C18色谱柱，150 × 4.6 mm, 5 μm，常温保存，检测波长260 nm。从线性、准确度、精密度、检出限(LOD)、定量限(LOQ)、特异性、鲁棒性和溶液稳定性等方面对方法进行了验证。验证结果表明，该方法可用于同时准确检测和定量TZD和PDX。
{"title":"A Validated RP-HPLC Method for the Simultaneous Detection and Quantification of Pyridoxine and Terizidone in Pharmaceutical Formulations","authors":"Ngabo Yves Musafili, H. Samsodien, M. Aucamp","doi":"10.3390/analytica2040018","DOIUrl":"https://doi.org/10.3390/analytica2040018","url":null,"abstract":"Tuberculosis (TB) remains a life-threatening infection, and it is well-known that effective TB treatment is associated with multiple drugs administered to infected patients on a daily basis. Terizidone (TZD) is an anti-TB drug used in the treatment of multi-drug resistant and extensively drug-resistant TB but presents with polyneuropathic adverse effects in some patients. To counteract these adverse effects, TZD is typically prescribed with pyridoxine (PDX), well known as Vitamin B6. As part of a pre-formulation study investigating the potential to co-formulate these two compounds, it became necessary to have a simple and reliable reversed-phase high-performance liquid chromatography (RP-HPLC) method. Optimal, simultaneous separation and detection of TZD and PDX were obtained using an isocratic mobile phase setup, consisting of ultrapure water and acetonitrile (30:70% v/v), with 1 mL glacial acetic acid added to the mobile phase mixture. A Discovery® C18, 150 × 4.6 mm, 5 μm column maintained at ambient temperature was utilized, with a detection wavelength of 260 nm. The method was validated in terms of linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), specificity, robustness, and solution stability. Validation proved this method to be acceptable and reliable for the simultaneous accurate detection and quantification of TZD and PDX.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87884364","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 : 2021-12-13DOI: 10.3390/analytica2040017
Merve Yence, Leyla Karadurmus, G. Ozcelikay, Nurgul K. Bakirhan, S. Ozkan
In this study, the electrochemical determination of Ivabradine hydrochloride (IH) was studied in detail using a glassy carbon electrode (GCE) modified with mesoporous carbon solution (MCS) and carboxylated group linked single-walled carbon nanotube (SWCNT-COOH). The developed nanosensor showed a significant effect by remarkably increasing the IH signal compared with the bare GCE. Cyclic (CV) and differential pulse voltammetric (DPV) methods were applied to perform electrochemical analysis of IH in pH 3.0 BRB solutions. The calibration plot for IH with a detection limit of 1.47 × 10−7 M was obtained using the DPV technique in the range of 1–10 µM under optimum experimental conditions. The proposed method has been validated and applied for the detection of the IH tablet. The produced nanosensor was also performed for the determination of IH in serum and urine. Excellent recoveries of 98.4%, 98.0%, and 100.2% were achieved for tablet, serum, and urine analysis, respectively.
{"title":"Achievements of Mesoporous Carbon Solution and Single-Walled Carbon Nanotube Composite on the Sensitive Electrochemical Assay of Ivabradine","authors":"Merve Yence, Leyla Karadurmus, G. Ozcelikay, Nurgul K. Bakirhan, S. Ozkan","doi":"10.3390/analytica2040017","DOIUrl":"https://doi.org/10.3390/analytica2040017","url":null,"abstract":"In this study, the electrochemical determination of Ivabradine hydrochloride (IH) was studied in detail using a glassy carbon electrode (GCE) modified with mesoporous carbon solution (MCS) and carboxylated group linked single-walled carbon nanotube (SWCNT-COOH). The developed nanosensor showed a significant effect by remarkably increasing the IH signal compared with the bare GCE. Cyclic (CV) and differential pulse voltammetric (DPV) methods were applied to perform electrochemical analysis of IH in pH 3.0 BRB solutions. The calibration plot for IH with a detection limit of 1.47 × 10−7 M was obtained using the DPV technique in the range of 1–10 µM under optimum experimental conditions. The proposed method has been validated and applied for the detection of the IH tablet. The produced nanosensor was also performed for the determination of IH in serum and urine. Excellent recoveries of 98.4%, 98.0%, and 100.2% were achieved for tablet, serum, and urine analysis, respectively.","PeriodicalId":7829,"journal":{"name":"Analytica","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77845152","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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