Pub Date : 2000-09-01DOI: 10.1051/ANALUSIS:2000140
P. Breuil, N. Perdreau, C. Pijolat
The sensitive element that we developed is a sintered tin dioxide bar (2.5 〈 0.5 〈 0.5 mm) [3]. It is stuck on an alumina substrate (Fig. 1) with an integrated heating system (20 to 500 °C). The variations of electric conductivity are due partly to a modification of the point defects of the semiconductor in the presence of oxidizing or reducing gases. But they are also related to the catalytic reactions of surface, in particular in the presence of organic gases or vapours [2,5]. The curves conductance-temperature G = f(T) of some sensors may be characteristic of the gases present in air (Fig. 2). It is then necessary that these data be acquired in decreasing temperature in order to avoid memory effects.
{"title":"■ Quantitative gas detection with semiconductor micro-sensors and chemometrics","authors":"P. Breuil, N. Perdreau, C. Pijolat","doi":"10.1051/ANALUSIS:2000140","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000140","url":null,"abstract":"The sensitive element that we developed is a sintered tin dioxide bar (2.5 〈 0.5 〈 0.5 mm) [3]. It is stuck on an alumina substrate (Fig. 1) with an integrated heating system (20 to 500 °C). The variations of electric conductivity are due partly to a modification of the point defects of the semiconductor in the presence of oxidizing or reducing gases. But they are also related to the catalytic reactions of surface, in particular in the presence of organic gases or vapours [2,5]. The curves conductance-temperature G = f(T) of some sensors may be characteristic of the gases present in air (Fig. 2). It is then necessary that these data be acquired in decreasing temperature in order to avoid memory effects.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"25 1","pages":"633-636"},"PeriodicalIF":0.0,"publicationDate":"2000-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79612798","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 : 2000-09-01DOI: 10.1051/ANALUSIS:2000141
O. Ivanciuc, T. Ivanciuc, D. Cabrol-Bass
The in vitro or in vivo interaction between chemical compounds and their biological targets (transporters, receptors, ion channels, enzymes) can be efficiently predicted with the 3D QSAR models introduced in recent years. In this paper we describe CoRSA (comparative receptor surface analysis), a novel 3D QSAR algorithm that can be applied to compute structure-activity equations whenever the structure of the biological target is not known. Using the common steric and electrostatic features of the most active members of a series of compounds, CoRSA generates a virtual receptor model, represented as points on a surface complementary to the van der Waals surface of the set of compounds. The structural descriptors of the model are represented by the total interaction energies between each surface point of the virtual receptor and all atoms in a molecule. These descriptors are used in a partial least squares (PLS) data analysis to generate a structure-activity model. A highly significant CoRSA model was obtained for a set of compounds that act as calcium channel agonists for the guinea pig left atrium assay.
{"title":"3D quantitative structure activity relationships with CoRSA. Comparative receptor surface analysis. Application to calcium channel agonists","authors":"O. Ivanciuc, T. Ivanciuc, D. Cabrol-Bass","doi":"10.1051/ANALUSIS:2000141","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000141","url":null,"abstract":"The in vitro or in vivo interaction between chemical compounds and their biological targets (transporters, receptors, ion channels, enzymes) can be efficiently predicted with the 3D QSAR models introduced in recent years. In this paper we describe CoRSA (comparative receptor surface analysis), a novel 3D QSAR algorithm that can be applied to compute structure-activity equations whenever the structure of the biological target is not known. Using the common steric and electrostatic features of the most active members of a series of compounds, CoRSA generates a virtual receptor model, represented as points on a surface complementary to the van der Waals surface of the set of compounds. The structural descriptors of the model are represented by the total interaction energies between each surface point of the virtual receptor and all atoms in a molecule. These descriptors are used in a partial least squares (PLS) data analysis to generate a structure-activity model. A highly significant CoRSA model was obtained for a set of compounds that act as calcium channel agonists for the guinea pig left atrium assay.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"18 1","pages":"637-642"},"PeriodicalIF":0.0,"publicationDate":"2000-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82178252","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000171
C. Couteau, M. Jadaud, F. Peigne, L. Coiffard
The objective of this research was to study the effect of pH on the photodegradation kinetics of 15.8 μg.ml-1 aqueous solutions of climbazole. A high-performance liquid chromatographic method for the quantification of climbazole after irradiation of aqueous solutions was carried out, using a RP-18 column with a acetonitrile - 0.05 M sodium perchlorate mobile phase. The detector was set at a wavelength of 220 nm. Calibration curve showed linear response in the interval 5 to 25 μg.ml-1. Photodegradation appeared to follow first-order kinetics and was found pH-dependent. The degradation rate constant was calcu- lated to be 10.5 〈 10-3, 9.9 〈 10-3 and 16.5 〈 10-3 min-1, respectively at pH 5, 7 and 9.
{"title":"Influence of pH on the photodegradation kinetics under UV light of climbazole solutions","authors":"C. Couteau, M. Jadaud, F. Peigne, L. Coiffard","doi":"10.1051/ANALUSIS:2000171","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000171","url":null,"abstract":"The objective of this research was to study the effect of pH on the photodegradation kinetics of 15.8 μg.ml-1 aqueous solutions of climbazole. A high-performance liquid chromatographic method for the quantification of climbazole after irradiation of aqueous solutions was carried out, using a RP-18 column with a acetonitrile - 0.05 M sodium perchlorate mobile phase. The detector was set at a wavelength of 220 nm. Calibration curve showed linear response in the interval 5 to 25 μg.ml-1. Photodegradation appeared to follow first-order kinetics and was found pH-dependent. The degradation rate constant was calcu- lated to be 10.5 〈 10-3, 9.9 〈 10-3 and 16.5 〈 10-3 min-1, respectively at pH 5, 7 and 9.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"70 1","pages":"557-560"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85627558","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000280487
J. Vasquez-Vivar, J. Joseph, H. Karoui, Hao Zhang, J. Miller, P. Martásek
15 N)- EMPO has significantly improved the sen- sitivity of superoxide detection by electron para- magnetic resonance (EPR). Unlike 5,5-dimethyl-1- pyrroline N-oxide (DMPO), a commonly used superoxide spin trap, both DEPMPO and EMPO form superoxide adducts that are persistent, which do not decay to the corresponding hydroxyl adduct. Using these new spin traps, the EPR-detection of superoxide is now straightfor- ward and more sensitive. These new superoxide traps in combination with the loop gap resonator technology have enabled us to demonstrate unequivocally the formation of superoxide from the endothelial and neuronal isoforms of nitric oxide synthase. Superoxide is formed at the oxy- genase domain of the enzyme by a calcium/ calmodulin dependent mechanism. The effect of tetrahydrobiopterin cofactor and NOS inhibitors on the release of superoxide is discussed.
{"title":"EPR spin trapping of superoxide from nitric oxide synthase","authors":"J. Vasquez-Vivar, J. Joseph, H. Karoui, Hao Zhang, J. Miller, P. Martásek","doi":"10.1051/ANALUSIS:2000280487","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000280487","url":null,"abstract":"15 N)- EMPO has significantly improved the sen- sitivity of superoxide detection by electron para- magnetic resonance (EPR). Unlike 5,5-dimethyl-1- pyrroline N-oxide (DMPO), a commonly used superoxide spin trap, both DEPMPO and EMPO form superoxide adducts that are persistent, which do not decay to the corresponding hydroxyl adduct. Using these new spin traps, the EPR-detection of superoxide is now straightfor- ward and more sensitive. These new superoxide traps in combination with the loop gap resonator technology have enabled us to demonstrate unequivocally the formation of superoxide from the endothelial and neuronal isoforms of nitric oxide synthase. Superoxide is formed at the oxy- genase domain of the enzyme by a calcium/ calmodulin dependent mechanism. The effect of tetrahydrobiopterin cofactor and NOS inhibitors on the release of superoxide is discussed.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"26 1","pages":"487-492"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86104360","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000280493
P. Manning, M. Cookson, C. Eggett, C. Tolias, S. Read, A. Hunter, M. Tsatmali, A. Thody, E. Hillhouse, P. Shaw, C. McNeil
Direct real-time electrochemical measurements have offered new insight into the importance of free radical interplay in a number of cellular models. Initially the interrelationship between O 2 - and NO generation in astrocytic, neuronal and mixed astrocytic/neuronal cell populations was examined. Results indicated a novel function for astrocytic nitric oxide synthase (cNOS) in regulating extracellular O 2 - production on rat astrocytes was assessed. Findings show that extracellular O 2 - generation initiated the production of NO by glial cells. Other findings facilitated by electrochemical measurements included the characterisation of a novel motor neuron like cell line for its ability to produce O 2 - and NO in response to extracellular glutamate and AMPA, the interaction of O 2 - with NO in an animal models of migraine headache and the modulatory effect of α-melanocyte stimulating hormone (α-MSH) on NO production by human epidermal melanocytes.
{"title":"■ Real-time measurement of free radical production using specific electrochemical sensors: new insight into the consequences of O 2 - and NO flux","authors":"P. Manning, M. Cookson, C. Eggett, C. Tolias, S. Read, A. Hunter, M. Tsatmali, A. Thody, E. Hillhouse, P. Shaw, C. McNeil","doi":"10.1051/ANALUSIS:2000280493","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000280493","url":null,"abstract":"Direct real-time electrochemical measurements have offered new insight into the importance of free radical interplay in a number of cellular models. Initially the interrelationship between O 2 - and NO generation in astrocytic, neuronal and mixed astrocytic/neuronal cell populations was examined. Results indicated a novel function for astrocytic nitric oxide synthase (cNOS) in regulating extracellular O 2 - production on rat astrocytes was assessed. Findings show that extracellular O 2 - generation initiated the production of NO by glial cells. Other findings facilitated by electrochemical measurements included the characterisation of a novel motor neuron like cell line for its ability to produce O 2 - and NO in response to extracellular glutamate and AMPA, the interaction of O 2 - with NO in an animal models of migraine headache and the modulatory effect of α-melanocyte stimulating hormone (α-MSH) on NO production by human epidermal melanocytes.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"186 1","pages":"493-505"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88471405","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000169
F. L. Coupannec, D. Morin, O. Sire, J. Peron
The leachates from municipal landfills are characterised by the complex chemical distribution and wide molecular weights range of their constituents. We have designed a high performance size exclusion chromatography method to take into account these two aspects. By using eluents of low ionic strength, electrostatic interactions between the eluted molecules and the negative sites of the stationary phase are enhanced. Thus, the compounds are eluted mostly according to their physico-chemical properties. Contrarily, using eluents of high ionic strength allows eliminating most of these electrostatic interactions which, in turn, permits to estimate the molecular weights, since steric exclusion is then the dominating mechanism of separation. A spec- troscopic fingerprint may also be determined through multidetection (UV absorption, fluorescence and evaporative light scatter- ing detection) coupled on line which allows to sort out the compounds into a few number of families.
{"title":"Influence of secondary interactions on high performance size exclusion chromatography. Application to the fractionation of landfill leachates","authors":"F. L. Coupannec, D. Morin, O. Sire, J. Peron","doi":"10.1051/ANALUSIS:2000169","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000169","url":null,"abstract":"The leachates from municipal landfills are characterised by the complex chemical distribution and wide molecular weights range of their constituents. We have designed a high performance size exclusion chromatography method to take into account these two aspects. By using eluents of low ionic strength, electrostatic interactions between the eluted molecules and the negative sites of the stationary phase are enhanced. Thus, the compounds are eluted mostly according to their physico-chemical properties. Contrarily, using eluents of high ionic strength allows eliminating most of these electrostatic interactions which, in turn, permits to estimate the molecular weights, since steric exclusion is then the dominating mechanism of separation. A spec- troscopic fingerprint may also be determined through multidetection (UV absorption, fluorescence and evaporative light scatter- ing detection) coupled on line which allows to sort out the compounds into a few number of families.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"36 1","pages":"543-549"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87003135","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000280465
M. Pontie, F. Bedioui
We report in this paper a global and exhaustive overview of the various attempts reported in the literature to develop electrochemical microsensors for the direct determination of nitric oxide (NO) in biological systems. In this compilation, we address the physico-chemical characteristics and the performances (in term of sensitivity) of the numerous chemically modified microelectrodes that were specially designed for the determination of NO, without judging what the biological applications might be.
{"title":"■ Design of electrochemical microsensors to monitor nitric oxide production in biological systems: a global compilation","authors":"M. Pontie, F. Bedioui","doi":"10.1051/ANALUSIS:2000280465","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000280465","url":null,"abstract":"We report in this paper a global and exhaustive overview of the various attempts reported in the literature to develop electrochemical microsensors for the direct determination of nitric oxide (NO) in biological systems. In this compilation, we address the physico-chemical characteristics and the performances (in term of sensitivity) of the numerous chemically modified microelectrodes that were specially designed for the determination of NO, without judging what the biological applications might be.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"17 1","pages":"465-469"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74921044","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000280469
A. Brunet, C. Privat, O. Stepien, M. David‐Dufilho, J. Devynck, M. Devynck
Electrochemical monitoring with a porphyrinic microsensor of in situ nitric oxide production from cultured cells offers numerous advantages but requires cautious analysis, repeated calibration and accurate localisation of the electrode. It also had some limitations. We describe here some characteristics of this method, the stability of the electrode response during experiments and its application to nitric oxide production by constitutive and inducible nitric oxide synthases. Real-time measurements of NO concentration allow the study of the kinetics of NO production. This is illustrated by the time-course of NO release from cultured human endothelial cells. How NO production by inducible nitric oxide synthase in cultured smooth muscle cells obtained from human internal mammary artery can be evaluated by Nafion- and Ni-porphyrin-coated electrode is also described. The results thus obtained are compared to the cumulated NO 2 - production evaluated by the Griess method.
{"title":"■ Advantages and limits of the electrochemical method using Nafion and Ni-porphyrin-coated microelectrode to monitor NO release from cultured vascular cells","authors":"A. Brunet, C. Privat, O. Stepien, M. David‐Dufilho, J. Devynck, M. Devynck","doi":"10.1051/ANALUSIS:2000280469","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000280469","url":null,"abstract":"Electrochemical monitoring with a porphyrinic microsensor of in situ nitric oxide production from cultured cells offers numerous advantages but requires cautious analysis, repeated calibration and accurate localisation of the electrode. It also had some limitations. We describe here some characteristics of this method, the stability of the electrode response during experiments and its application to nitric oxide production by constitutive and inducible nitric oxide synthases. Real-time measurements of NO concentration allow the study of the kinetics of NO production. This is illustrated by the time-course of NO release from cultured human endothelial cells. How NO production by inducible nitric oxide synthase in cultured smooth muscle cells obtained from human internal mammary artery can be evaluated by Nafion- and Ni-porphyrin-coated electrode is also described. The results thus obtained are compared to the cumulated NO 2 - production evaluated by the Griess method.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"55 1","pages":"469-474"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80741093","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000280479
J. Iliou, N. Villeneuve, M. Fournet-Bourguignon, F. Robin, C. Jacquemin, V. Lestriez, C. Petit, A. Pillon, J. Vilaine
Regulation of vascular redox homeostasis plays a central role in the control of vascular tone (e.g.: redox modulation of endothelial NO synthase and soluble guanylate cyclase activities). Superoxide anion is one of the main reactive oxygen species involved in the modulation of the redox status of the vessel. It is crucial to know if pathological situations or drug treatments are able to modify NAD(P)H oxidase-dependent production of O 2 - . As a steady-state approach is the only way for a valid assessment of these parameters, a mathematical treatment allowing visualisation of the linear portion of the initial velocity of O 2 - production was developed. Using two vascular preparations (rat aortic rings and mouse thoracic aortae), the chemiluminescence (CL) in the presence of lucigenin was recorded every second in the 15-30 minute period after successive injections of NADPH and superoxide dismutase (SOD). Because, both O 2 - and photons are labile and evanescent products, visualisation of the steady-state requires calculation of their cumulative production by integral calculus using a first order integral equation. The cumulative production of CL and/or O 2 - was plotted as a function of the NADPH concentrations, were determined from the linear portion of these plots. For a precise molar quantification of O 2 - production, a calibration curve of initial velocities using xanthine oxidase + xanthine as a source of O 2 - was plotted by comparing CL and cytochrome C reduction. The NADPH-dependent CL production exihibited Michaelian behavior and SOD acted as a noncompetitive inhibitor. For example, the values for NADPH oxidase in rat aorta were: Km = 237 ± 2μM; Vmax = 500-600 pmol O 2 - /min/ring.
{"title":"■ Mathematical treatment of chemiluminescence data allowing an optimised kinetic analysis of vascular NAD(P)H-dependent superoxide anion production","authors":"J. Iliou, N. Villeneuve, M. Fournet-Bourguignon, F. Robin, C. Jacquemin, V. Lestriez, C. Petit, A. Pillon, J. Vilaine","doi":"10.1051/ANALUSIS:2000280479","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000280479","url":null,"abstract":"Regulation of vascular redox homeostasis plays a central role in the control of vascular tone (e.g.: redox modulation of endothelial NO synthase and soluble guanylate cyclase activities). Superoxide anion is one of the main reactive oxygen species involved in the modulation of the redox status of the vessel. It is crucial to know if pathological situations or drug treatments are able to modify NAD(P)H oxidase-dependent production of O 2 - . As a steady-state approach is the only way for a valid assessment of these parameters, a mathematical treatment allowing visualisation of the linear portion of the initial velocity of O 2 - production was developed. Using two vascular preparations (rat aortic rings and mouse thoracic aortae), the chemiluminescence (CL) in the presence of lucigenin was recorded every second in the 15-30 minute period after successive injections of NADPH and superoxide dismutase (SOD). Because, both O 2 - and photons are labile and evanescent products, visualisation of the steady-state requires calculation of their cumulative production by integral calculus using a first order integral equation. The cumulative production of CL and/or O 2 - was plotted as a function of the NADPH concentrations, were determined from the linear portion of these plots. For a precise molar quantification of O 2 - production, a calibration curve of initial velocities using xanthine oxidase + xanthine as a source of O 2 - was plotted by comparing CL and cytochrome C reduction. The NADPH-dependent CL production exihibited Michaelian behavior and SOD acted as a noncompetitive inhibitor. For example, the values for NADPH oxidase in rat aorta were: Km = 237 ± 2μM; Vmax = 500-600 pmol O 2 - /min/ring.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"6 1","pages":"479-486"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88837343","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 : 2000-07-01DOI: 10.1051/ANALUSIS:2000168
S. P. Rodrigues, L. Coppée, J. Toullec, G. Moutiers
Experimental conditions have been designed which allowed the use of a chloride ion selective electrode for the mon- itoring of reactions that proceed with a moderately fast departure of Cl - ion, i.e. t1/2 ∪ 40 seconds, in aqueous solution. The pro- cedure has been applied in particular to the hydrolysis of yperite (HD) analogues (CEES, CEMS, CEPS) in aqueous solution in presence of HEPES buffer and oximate nucleophiles. Kinetic parameters were obtained in these conditions and the S N1 mecha- nism for the hydrolysis was confirmed.
{"title":"Use of a chloride ion selective electrode as a tool for monitoring relatively fast kinetic processes. Application to the hydrolysis of yperite analogues in presence of oximate nucleophiles","authors":"S. P. Rodrigues, L. Coppée, J. Toullec, G. Moutiers","doi":"10.1051/ANALUSIS:2000168","DOIUrl":"https://doi.org/10.1051/ANALUSIS:2000168","url":null,"abstract":"Experimental conditions have been designed which allowed the use of a chloride ion selective electrode for the mon- itoring of reactions that proceed with a moderately fast departure of Cl - ion, i.e. t1/2 ∪ 40 seconds, in aqueous solution. The pro- cedure has been applied in particular to the hydrolysis of yperite (HD) analogues (CEES, CEMS, CEPS) in aqueous solution in presence of HEPES buffer and oximate nucleophiles. Kinetic parameters were obtained in these conditions and the S N1 mecha- nism for the hydrolysis was confirmed.","PeriodicalId":8221,"journal":{"name":"Analusis","volume":"74 1","pages":"529-534"},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85546111","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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