Using acrylamide as a hydrogen bonding functional monomer and (5R)-5-benzylhydantoin as a template, a molecularly imprinted polymer was prepared in a polar solvent, which exhibited good enantiomeric recognition properties. The binding selectivity of the polymer was evaluated by batch methods. Scatchard analyses showed that two classes of binding sites were produced in the imprinted polymer and their dissociation constants were estimated to be (4.6 ± 0.8) × 10–5 and (1.3 ± 0.2) × 10–4 mol L–1, respectively. This was in agreement with the prediction of the binding characteristics of the polymer by a spectrophotometric method. Study of the effect of water on the separation factor of the polymer further proved that the hydrogen bonding interactions played an important role in the recognition of acrylamide-based molecularly imprinted polymers.
{"title":"An acrylamide-based molecularly imprinted polymer for the efficient recognition of optical amino acid hydantoins","authors":"Jie Zhou, Xiwen He, Yijun Li","doi":"10.1039/A902025J","DOIUrl":"https://doi.org/10.1039/A902025J","url":null,"abstract":"Using acrylamide as a hydrogen bonding functional monomer and (5R)-5-benzylhydantoin as a template, a molecularly imprinted polymer was prepared in a polar solvent, which exhibited good enantiomeric recognition properties. The binding selectivity of the polymer was evaluated by batch methods. Scatchard analyses showed that two classes of binding sites were produced in the imprinted polymer and their dissociation constants were estimated to be (4.6 ± 0.8) × 10–5 and (1.3 ± 0.2) × 10–4 mol L–1, respectively. This was in agreement with the prediction of the binding characteristics of the polymer by a spectrophotometric method. Study of the effect of water on the separation factor of the polymer further proved that the hydrogen bonding interactions played an important role in the recognition of acrylamide-based molecularly imprinted polymers.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"23 1","pages":"243-246"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73357786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new method of depth profiling has been developed and applied to a Co-implanted Si-wafer. A square section of only some cm2 was chosen, a thin near-surface sublayer oxidized by an oxygen plasma and the oxidized sublayer precisely etched by a solution of hydrofluoric acid. The mass of Si within the sublayer was determined via differential weighing of the wafer piece and the mass of Co determined by TXRF (total reflection X-ray fluorescence) of the loaded acidic solution. These steps were repeated time and again in order to record a total depth profile showing the relative concentration of Co dependent on the depth within the wafer. The integration of this profile gave a total dose of 1.13 × 1017 ions cm–2 with high accuracy. The depth resolution of the new method might be in the order of a few nm, the detection limit about 0.01% or 5 × 1018 atoms cm–3 of Co.
{"title":"Depth profiling of a Co-implanted silicon wafer by total-reflection X-ray fluorescence analysis after repeated oxidation and HF-etching","authors":"R. Klockenkämper, A. Bohlen","doi":"10.1039/A809804B","DOIUrl":"https://doi.org/10.1039/A809804B","url":null,"abstract":"A new method of depth profiling has been developed and applied to a Co-implanted Si-wafer. A square section of only some cm2 was chosen, a thin near-surface sublayer oxidized by an oxygen plasma and the oxidized sublayer precisely etched by a solution of hydrofluoric acid. The mass of Si within the sublayer was determined via differential weighing of the wafer piece and the mass of Co determined by TXRF (total reflection X-ray fluorescence) of the loaded acidic solution. These steps were repeated time and again in order to record a total depth profile showing the relative concentration of Co dependent on the depth within the wafer. The integration of this profile gave a total dose of 1.13 × 1017 ions cm–2 with high accuracy. The depth resolution of the new method might be in the order of a few nm, the detection limit about 0.01% or 5 × 1018 atoms cm–3 of Co.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"178 1","pages":"27-29"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80012153","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}
Near-infrared (NIR) reflectance spectroscopy has been used to monitor the chemical inter-conversion of resin-bound functional groups. Measurements required no sample preparation and were made directly through the bottom of the glass reaction vessel. The time–concentration profile of the esterification of a resin-bound alcohol by acetic anhydride in a toluene medium is demonstrated.
{"title":"Non-destructive real-time reaction monitoring in solid phase synthesis by near-infrared reflectance spectroscopy—esterification of a resin-bound alcohol","authors":"Jonathan Hammond, A. Moffat, R. D. Jee, B. Kellam","doi":"10.1039/A900747D","DOIUrl":"https://doi.org/10.1039/A900747D","url":null,"abstract":"Near-infrared (NIR) reflectance spectroscopy has been used to monitor the chemical inter-conversion of resin-bound functional groups. Measurements required no sample preparation and were made directly through the bottom of the glass reaction vessel. The time–concentration profile of the esterification of a resin-bound alcohol by acetic anhydride in a toluene medium is demonstrated.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"180 1","pages":"127-129"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75137808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The piezoresonators of a quartz-crystal microbalance were surface-coated with electropolymerised polypyrrole films. After potentiostatic reduction at –0.9 V, the reduced PPy-coated resonators were allowed to react with solutions containing different concentrations of CrVI. Mass changes of the polymer film, originated by ionic transfer during the oxidation reaction of PPy by hexavalent chromium, produced frequency shifts proportional to the concentration of CrVI. Also, frequency shifts were obtained by reaction of some antioxidants at oxidised PPy-coated resonators. The observed responses depend on several experimental parameters.
{"title":"A polypyrrole-coated, piezoelectric sensor for CrVI. Preliminary results","authors":"E. Desimoni, I. Bassani","doi":"10.1039/A809667H","DOIUrl":"https://doi.org/10.1039/A809667H","url":null,"abstract":"The piezoresonators of a quartz-crystal microbalance were surface-coated with electropolymerised polypyrrole films. After potentiostatic reduction at –0.9 V, the reduced PPy-coated resonators were allowed to react with solutions containing different concentrations of CrVI. Mass changes of the polymer film, originated by ionic transfer during the oxidation reaction of PPy by hexavalent chromium, produced frequency shifts proportional to the concentration of CrVI. Also, frequency shifts were obtained by reaction of some antioxidants at oxidised PPy-coated resonators. The observed responses depend on several experimental parameters.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"69 1","pages":"45-46"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73645797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Recent developments in the analysis of light isotopes by continuous flow isotope ratio mass spectrometry","authors":"A. J. Midwood","doi":"10.1039/A904908H","DOIUrl":"https://doi.org/10.1039/A904908H","url":null,"abstract":"","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"34 1","pages":"291-294"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73256504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Karyakin, L. V. Lukachova, E. E. Karyakina, A. Orlov, G. P. Karpachova
Processible polyaniline (PCPAn) modified electrodes are characterized by an advanced potentiometric pH response in comparison to those based on regular polyaniline. Glassy carbon electrodes modified with PCPAn by dip-coating exhibited a fully reversible potentiometric response of approximately 90 mV pH–1 over the range pH 3–9. Such significantly higher potentiometric responses of PCPAn modified electrodes compared to existing devices is explained on the basis of the thermodynamics of polyaniline redox reactions. The potentiometric biosensor for glucose based on processible polyaniline has been developed using a non-aqueous enzymology approach for enzyme immobilization. In the model solution, which mimics blood serum, the biosensor was useful for glucose detection over the concentration range 0.1–30 mM and the maximum response value reached was ≈80 mV. The advanced potentiometric response of PCPAn modified electrodes provides their application for sensor and biosensor development.
{"title":"The improved potentiometric pH response of electrodes modified with processible polyaniline. Application to glucose biosensor","authors":"A. Karyakin, L. V. Lukachova, E. E. Karyakina, A. Orlov, G. P. Karpachova","doi":"10.1039/A900597H","DOIUrl":"https://doi.org/10.1039/A900597H","url":null,"abstract":"Processible polyaniline (PCPAn) modified electrodes are characterized by an advanced potentiometric pH response in comparison to those based on regular polyaniline. Glassy carbon electrodes modified with PCPAn by dip-coating exhibited a fully reversible potentiometric response of approximately 90 mV pH–1 over the range pH 3–9. Such significantly higher potentiometric responses of PCPAn modified electrodes compared to existing devices is explained on the basis of the thermodynamics of polyaniline redox reactions. The potentiometric biosensor for glucose based on processible polyaniline has been developed using a non-aqueous enzymology approach for enzyme immobilization. In the model solution, which mimics blood serum, the biosensor was useful for glucose detection over the concentration range 0.1–30 mM and the maximum response value reached was ≈80 mV. The advanced potentiometric response of PCPAn modified electrodes provides their application for sensor and biosensor development.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"66 1","pages":"153-156"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89326532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sorption and elution of In(III) on a porous PTFE filter tube impregnated with bis(2-ethylhexyl) hydrogen phosphate (HDEHP) was studied. A 1 µg portion of In(III) in 1000 ml of sample solution was quantitatively complexed with HDEHP adsorbed onto a porous PTFE filter tube by passing the solution through the micropores of the filter tube. Preconcentrated In(III) was then quantitatively recovered provided that the elution, which consisted of cyclical filtering of 0.1 ml of 4 mol l–1 hydrochloric acid through the filter tube for 1 min, was repeated 3 times. The total volume of the eluent was only 0.3 ml in this case; therefore, over 3300-fold of enrichment was attained within 90 min of total preconcentration time. This method was applicable to the preconcentration of In(III) in highly saline samples. A 2.5 µg portion of In(III) could be quantitatively extracted from 500 ml of synthetic seawater and be recovered into 0.5 ml of 4 mol l–1 hydrochloric acid, with subsequent determination by flame AAS. The average recovery and the RSD of the results were 100% and of 1.4%, respectively (n = 5).
研究了浸渍磷酸氢二(2-乙基己基)(HDEHP)的多孔PTFE滤管对In(III)的吸附和洗脱。将1µg In(III)加入1000ml的样品溶液中，通过过滤管的微孔，将溶液与吸附在多孔PTFE过滤管上的HDEHP定量络合。预先浓缩的In(III)定量回收，条件是通过滤管循环过滤0.1 ml 4 mol l-1盐酸1分钟，重复3次。本实验中洗脱液的总体积仅为0.3 ml;因此，在90分钟的总富集时间内，富集量达到3300倍以上。该方法适用于高盐样品中In(III)的预富集。从500 ml合成海水中定量提取2.5µg部分In(III)，回收到0.5 ml 4 mol l-1盐酸中，火焰原子吸收法测定。结果的平均回收率为100%，RSD为1.4% (n = 5)。
{"title":"Novel sorbent extraction technique using a chelating agent impregnated porous PTFE filter tube : Preconcentration of In(III) with a bis(2-ethylhexyl) hydrogen phosphate (HDEHP) loaded porous PTFE filter tube","authors":"M. Murakami, T. Takada","doi":"10.1039/A902146I","DOIUrl":"https://doi.org/10.1039/A902146I","url":null,"abstract":"The sorption and elution of In(III) on a porous PTFE filter tube impregnated with bis(2-ethylhexyl) hydrogen phosphate (HDEHP) was studied. A 1 µg portion of In(III) in 1000 ml of sample solution was quantitatively complexed with HDEHP adsorbed onto a porous PTFE filter tube by passing the solution through the micropores of the filter tube. Preconcentrated In(III) was then quantitatively recovered provided that the elution, which consisted of cyclical filtering of 0.1 ml of 4 mol l–1 hydrochloric acid through the filter tube for 1 min, was repeated 3 times. The total volume of the eluent was only 0.3 ml in this case; therefore, over 3300-fold of enrichment was attained within 90 min of total preconcentration time. This method was applicable to the preconcentration of In(III) in highly saline samples. A 2.5 µg portion of In(III) could be quantitatively extracted from 500 ml of synthetic seawater and be recovered into 0.5 ml of 4 mol l–1 hydrochloric acid, with subsequent determination by flame AAS. The average recovery and the RSD of the results were 100% and of 1.4%, respectively (n = 5).","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"44 1","pages":"185-188"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90663705","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}
Sol–gel processes were used to fabricate amperometric biosensors that are active for hypoxanthine (Hx) determination. Xanthine oxidase was immobilized in the bulk of the silica–graphite matrix (SGM) to produce electrodes where new surfaces can be generated on demand by mechanical polishing. The immobilized enzyme electrodes can be used in unmediated hydrogen peroxide oxidation mode, or in unmediated and mediated oxygen reduction mode, to result in three different types of Hx biosensors with detection limits of 1.3 × 10–6, 5.6 × 10–6 and 3.8 × 10–7M, respectively. Benzyl viologen was used as the charge transfer mediator to enhance the response in the hydrogen peroxide production mode. The sensors show good linear response over a wide range of concentrations of about 1 × 10–6–1 × 10–3M. The use of bulk immobilization and the possibility of renewable surfaces have enabled the easy operation of these sensors with high stability. The experimental results from a carp sample stored under different conditions demonstrate the practicality of these sensors as simple, rapid and cost effective measurement of fish meat freshness.
{"title":"Renewable-surface graphite–ceramic enzyme sensors for the determination of hypoxanthine in fish meat","authors":"J. Niu, J. Lee","doi":"10.1039/A900896I","DOIUrl":"https://doi.org/10.1039/A900896I","url":null,"abstract":"Sol–gel processes were used to fabricate amperometric biosensors that are active for hypoxanthine (Hx) determination. Xanthine oxidase was immobilized in the bulk of the silica–graphite matrix (SGM) to produce electrodes where new surfaces can be generated on demand by mechanical polishing. The immobilized enzyme electrodes can be used in unmediated hydrogen peroxide oxidation mode, or in unmediated and mediated oxygen reduction mode, to result in three different types of Hx biosensors with detection limits of 1.3 × 10–6, 5.6 × 10–6 and 3.8 × 10–7M, respectively. Benzyl viologen was used as the charge transfer mediator to enhance the response in the hydrogen peroxide production mode. The sensors show good linear response over a wide range of concentrations of about 1 × 10–6–1 × 10–3M. The use of bulk immobilization and the possibility of renewable surfaces have enabled the easy operation of these sensors with high stability. The experimental results from a carp sample stored under different conditions demonstrate the practicality of these sensors as simple, rapid and cost effective measurement of fish meat freshness.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"11 1","pages":"81-83"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80791740","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}
C. Baggiani, G. Giraudi, C. Giovannoli, A. Vanni, F. Trotta
Polymers able to bind the pesticide bentazone were prepared by utilising the technique of the non-covalent molecular imprinting polymerisation and using different molar ratios of methacrylic acid and 4-vinylpyridine as interacting monomers. Polymers obtained were packed in HPLC columns and the imprinting effect was studied using chloroform and acetonitrile as mobile phase. The polymer obtained from equimolar amounts of methacrylic acid and 4-vinylpyridine was found to recognise bentazone better than other polymers, both in chloroform and acetonitrile. The bentazone capacity for this stationary phase was studied considering aqueous buffers with different pH values and ionic strengths. A preliminary procedure of solid phase extraction was tested on aqueous samples containing a fixed amount of bentazone. Good recoveries (91–96%) and concentration factors of 3.2–15.2 were found.
{"title":"A molecularly imprinted polymer for the pesticide bentazone","authors":"C. Baggiani, G. Giraudi, C. Giovannoli, A. Vanni, F. Trotta","doi":"10.1039/A902968K","DOIUrl":"https://doi.org/10.1039/A902968K","url":null,"abstract":"Polymers able to bind the pesticide bentazone were prepared by utilising the technique of the non-covalent molecular imprinting polymerisation and using different molar ratios of methacrylic acid and 4-vinylpyridine as interacting monomers. Polymers obtained were packed in HPLC columns and the imprinting effect was studied using chloroform and acetonitrile as mobile phase. The polymer obtained from equimolar amounts of methacrylic acid and 4-vinylpyridine was found to recognise bentazone better than other polymers, both in chloroform and acetonitrile. The bentazone capacity for this stationary phase was studied considering aqueous buffers with different pH values and ionic strengths. A preliminary procedure of solid phase extraction was tested on aqueous samples containing a fixed amount of bentazone. Good recoveries (91–96%) and concentration factors of 3.2–15.2 were found.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"29 1","pages":"263-266"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85232743","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}
K. Skudar, O. Brüggemann, A. Wittelsberger, O. Ramström
Molecularly imprinted polymers (MIPs) to penicillin V or oxacillin were prepared, and their recognition properties were investigated, both in organic and aqueous phases. The resulting MIPs proved to be efficient in distinguishing between different penicillins (penicillin V, penicillin G and oxacillin), but could also be prepared to recognise the penicillins as a group. The results indicate that MIPs can be used to prepare either selective or general recognition matrices for penicillins, which can be of potential use in separation and detection applications.
{"title":"Selective recognition and separation of β-lactam antibiotics using molecularly imprinted polymers","authors":"K. Skudar, O. Brüggemann, A. Wittelsberger, O. Ramström","doi":"10.1039/A905151A","DOIUrl":"https://doi.org/10.1039/A905151A","url":null,"abstract":"Molecularly imprinted polymers (MIPs) to penicillin V or oxacillin were prepared, and their recognition properties were investigated, both in organic and aqueous phases. The resulting MIPs proved to be efficient in distinguishing between different penicillins (penicillin V, penicillin G and oxacillin), but could also be prepared to recognise the penicillins as a group. The results indicate that MIPs can be used to prepare either selective or general recognition matrices for penicillins, which can be of potential use in separation and detection applications.","PeriodicalId":7814,"journal":{"name":"Analytical Communications","volume":"23 1","pages":"327-331"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81504379","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：