The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Zhongping Zhang - One of the best experts on this subject based on the ideXlab platform.
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ligand replacement approach to raman responded molecularly imprinted monolayer for rapid determination of Penicilloic Acid in penicillin
Analytical Chemistry, 2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)-Cu(2+)-PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods.
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Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin
2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)–Cu2+–PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods
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structure selective hot spot raman enhancement for direct identification and detection of trace Penicilloic Acid allergen in penicillin
Biosensors and Bioelectronics, 2014Co-Authors: Liying Zhang, Yang Jin, Hui Mao, Lei Zheng, Jiawei Zhao, Yan Peng, Zhongping ZhangAbstract:Trace Penicilloic Acid allergen frequently leads to various fatal immune responses to many patients, but it is still a challenge to directly discriminate and detect its residue in penicillin by a chemosensing way. Here, we report that silver-coated gold nanoparticles (Au@Ag NPs) exhibit a structure-selective hot-spot Raman enhancement capability for direct identification and detection of trace Penicilloic Acid in penicillin. It has been demonstrated that Penicilloic Acid can very easily link Au@Ag NPs together by its two carboxyl groups, locating itself spontaneously at the interparticle of Au@Ag NPs to form strong Raman hot-spot. At the critical concentration inducing the nanoparticle aggregation, Raman-enhanced effect of Penicilloic Acid is ~60,000 folds higher than that of penicillin. In particular, the selective Raman enhancement to the two carboxyl groups makes the peak of carboxyl group at C6 of Penicilloic Acid appear as a new Raman signal due to the opening of β-lactam ring of penicillin. The surface-enhanced Raman scattering (SERS) nanoparticle sensor reaches a sensitive limit lower than the prescribed 1.0‰ Penicilloic Acid residue in penicillin. The novel strategy to examine allergen is more rapid, convenient and inexpensive than the conventional separation-based assay methods.
Liying Zhang - One of the best experts on this subject based on the ideXlab platform.
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label free surface enhanced raman scattering strategy for rapid detection of Penicilloic Acid in milk products
Food Chemistry, 2016Co-Authors: Xiaoyan Huang, Liying Zhang, Yang Jin, Yan Peng, Yujie Zhou, Huijun JiangAbstract:A label-free surface-enhanced Raman scattering (SERS) strategy based on silver-coated gold nanoparticles (Au@Ag NPs) was developed for rapid detection of Penicilloic Acid (PA) in milk products. It has been demonstrated that core size and shell thickness of Au@Ag NPs are two critical variants affecting enhancement of Raman signals by coupling of two plasma resonance absorption. The Au@Ag NPs with 26-nm core and 9-nm Ag shell exhibit excellent Raman enhancement, in particular, upon the formation of hot spots through NPs aggregation induced by interaction between target molecules and Au@Ag NPs. Compared to the early studies limited to laboratory settings, our analytical approach is simple (without sample pretreatment), less time-consuming (within ∼3 min) and inexpensive. The limit of detection of PA is 3.00 ppm, 3.00 ppm and 4.00 ppm in liquid milk, yogurt and milk powder, respectively. The label-free SERS technique offers a potential for the on-site monitoring of chemical contaminants in milk products.
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ligand replacement approach to raman responded molecularly imprinted monolayer for rapid determination of Penicilloic Acid in penicillin
Analytical Chemistry, 2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)-Cu(2+)-PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods.
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Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin
2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)–Cu2+–PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods
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structure selective hot spot raman enhancement for direct identification and detection of trace Penicilloic Acid allergen in penicillin
Biosensors and Bioelectronics, 2014Co-Authors: Liying Zhang, Yang Jin, Hui Mao, Lei Zheng, Jiawei Zhao, Yan Peng, Zhongping ZhangAbstract:Trace Penicilloic Acid allergen frequently leads to various fatal immune responses to many patients, but it is still a challenge to directly discriminate and detect its residue in penicillin by a chemosensing way. Here, we report that silver-coated gold nanoparticles (Au@Ag NPs) exhibit a structure-selective hot-spot Raman enhancement capability for direct identification and detection of trace Penicilloic Acid in penicillin. It has been demonstrated that Penicilloic Acid can very easily link Au@Ag NPs together by its two carboxyl groups, locating itself spontaneously at the interparticle of Au@Ag NPs to form strong Raman hot-spot. At the critical concentration inducing the nanoparticle aggregation, Raman-enhanced effect of Penicilloic Acid is ~60,000 folds higher than that of penicillin. In particular, the selective Raman enhancement to the two carboxyl groups makes the peak of carboxyl group at C6 of Penicilloic Acid appear as a new Raman signal due to the opening of β-lactam ring of penicillin. The surface-enhanced Raman scattering (SERS) nanoparticle sensor reaches a sensitive limit lower than the prescribed 1.0‰ Penicilloic Acid residue in penicillin. The novel strategy to examine allergen is more rapid, convenient and inexpensive than the conventional separation-based assay methods.
Yang Jin - One of the best experts on this subject based on the ideXlab platform.
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label free surface enhanced raman scattering strategy for rapid detection of Penicilloic Acid in milk products
Food Chemistry, 2016Co-Authors: Xiaoyan Huang, Liying Zhang, Yang Jin, Yan Peng, Yujie Zhou, Huijun JiangAbstract:A label-free surface-enhanced Raman scattering (SERS) strategy based on silver-coated gold nanoparticles (Au@Ag NPs) was developed for rapid detection of Penicilloic Acid (PA) in milk products. It has been demonstrated that core size and shell thickness of Au@Ag NPs are two critical variants affecting enhancement of Raman signals by coupling of two plasma resonance absorption. The Au@Ag NPs with 26-nm core and 9-nm Ag shell exhibit excellent Raman enhancement, in particular, upon the formation of hot spots through NPs aggregation induced by interaction between target molecules and Au@Ag NPs. Compared to the early studies limited to laboratory settings, our analytical approach is simple (without sample pretreatment), less time-consuming (within ∼3 min) and inexpensive. The limit of detection of PA is 3.00 ppm, 3.00 ppm and 4.00 ppm in liquid milk, yogurt and milk powder, respectively. The label-free SERS technique offers a potential for the on-site monitoring of chemical contaminants in milk products.
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ligand replacement approach to raman responded molecularly imprinted monolayer for rapid determination of Penicilloic Acid in penicillin
Analytical Chemistry, 2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)-Cu(2+)-PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods.
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Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin
2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)–Cu2+–PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods
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structure selective hot spot raman enhancement for direct identification and detection of trace Penicilloic Acid allergen in penicillin
Biosensors and Bioelectronics, 2014Co-Authors: Liying Zhang, Yang Jin, Hui Mao, Lei Zheng, Jiawei Zhao, Yan Peng, Zhongping ZhangAbstract:Trace Penicilloic Acid allergen frequently leads to various fatal immune responses to many patients, but it is still a challenge to directly discriminate and detect its residue in penicillin by a chemosensing way. Here, we report that silver-coated gold nanoparticles (Au@Ag NPs) exhibit a structure-selective hot-spot Raman enhancement capability for direct identification and detection of trace Penicilloic Acid in penicillin. It has been demonstrated that Penicilloic Acid can very easily link Au@Ag NPs together by its two carboxyl groups, locating itself spontaneously at the interparticle of Au@Ag NPs to form strong Raman hot-spot. At the critical concentration inducing the nanoparticle aggregation, Raman-enhanced effect of Penicilloic Acid is ~60,000 folds higher than that of penicillin. In particular, the selective Raman enhancement to the two carboxyl groups makes the peak of carboxyl group at C6 of Penicilloic Acid appear as a new Raman signal due to the opening of β-lactam ring of penicillin. The surface-enhanced Raman scattering (SERS) nanoparticle sensor reaches a sensitive limit lower than the prescribed 1.0‰ Penicilloic Acid residue in penicillin. The novel strategy to examine allergen is more rapid, convenient and inexpensive than the conventional separation-based assay methods.
Xiaoyan Huang - One of the best experts on this subject based on the ideXlab platform.
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label free surface enhanced raman scattering strategy for rapid detection of Penicilloic Acid in milk products
Food Chemistry, 2016Co-Authors: Xiaoyan Huang, Liying Zhang, Yang Jin, Yan Peng, Yujie Zhou, Huijun JiangAbstract:A label-free surface-enhanced Raman scattering (SERS) strategy based on silver-coated gold nanoparticles (Au@Ag NPs) was developed for rapid detection of Penicilloic Acid (PA) in milk products. It has been demonstrated that core size and shell thickness of Au@Ag NPs are two critical variants affecting enhancement of Raman signals by coupling of two plasma resonance absorption. The Au@Ag NPs with 26-nm core and 9-nm Ag shell exhibit excellent Raman enhancement, in particular, upon the formation of hot spots through NPs aggregation induced by interaction between target molecules and Au@Ag NPs. Compared to the early studies limited to laboratory settings, our analytical approach is simple (without sample pretreatment), less time-consuming (within ∼3 min) and inexpensive. The limit of detection of PA is 3.00 ppm, 3.00 ppm and 4.00 ppm in liquid milk, yogurt and milk powder, respectively. The label-free SERS technique offers a potential for the on-site monitoring of chemical contaminants in milk products.
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ligand replacement approach to raman responded molecularly imprinted monolayer for rapid determination of Penicilloic Acid in penicillin
Analytical Chemistry, 2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)-Cu(2+)-PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods.
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Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin
2015Co-Authors: Liying Zhang, Yang Jin, Xiaoyan Huang, Yujie Zhou, Zhongping ZhangAbstract:Penicilloic Acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)–Cu2+–PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods
Jens Nielsen - One of the best experts on this subject based on the ideXlab platform.
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On-line monitoring of glucose and penicillin by sequential injection analysis
Analytica Chimica Acta, 1996Co-Authors: Rong Wei Min, Jens Nielsen, John VilladsenAbstract:A sequential injection analysis (SIA) system has been developed for on-line monitoring of glucose and penicillin during cultivations of the filamentous fungus Penicillium chrysogenum. The SIA system consists of a peristaltic pump, an injection valve, two piston pumps, two multi-position valves and a detector. The glucose analyzer is based on an enzymatic reaction using glucose oxidase, which converts glucose to glucono-lactone with formation of hydrogen peroxide and subsequent detection of H2O2 by a chemiluminescence reaction involving luminol. The penicillin analysis is based on formation of Penicilloic Acid by penicillinase. Penicilloic Acid is detected either by a chemiluminescence method or by a decolorization method. In the chemiluminescence method the Penicilloic Acid is quantified by its quenching effect on the chemiluminescence signal obtained when luminol reacts with iodine. In the decolorization method the Penicilloic Acid is detected spectrophotometrically by the decrease in the absorbance of an iodine-starch complex.
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on line monitoring of penicillin v during penicillin fermentations a comparison of two different methods based on flow injection analysis
Analytica Chimica Acta, 1993Co-Authors: Morten Carlsen, Rong Wei Min, Jens Nielsen, Claus Lindvald Johansen, Helmut Meier, Francois LantreibecqAbstract:Abstract Two different flow-injection analysis (FIA) methods used for on-line monitoring of penicillin V during fed-batch penicillin fermentations are compared. The fermentations are carried out using a high yielding strain of Penicillium chrysogenum and both analyzers are used continuously for on-line monitoring during 200 h. Both methods are based on a reaction catalyzed by β-lactamase, which converts penicillin V to Penicilloic Acid. In analyzer 1 the sample is injected into a buffer stream and carried to a stirred measurement cell containing an enzyme electrode. The enzyme electrode consists of β-lactamase immobilized onto a sensitive pH glass electrode with a very low response time. No predilution of the sample is required in this analyzer. In analyzer 2 the sample is injected into an enzyme reactor containing immobilized β-lactamase. The formed Penicilloic Acid is detected by decolorization of an iodine-starch complex. By means of a second injection valve it is possible to have the sample by-pass the enzyme reactor and instead pass a dummy reactor in which no β-lactamase is immobilized. Thereby both the concentration of penicillin and Penicilloic Acid can be measured. On-line dilution of the sample is ensured by a gradient technique. Experimental results from on-line monitoring of penicillin V using the two methods are presented. The large amount of precise measurements enables a very good resolution of the penicillin production; something of extreme value for verification of mathematical models describing the fermentation kinetics.
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flow injection analysis for the measurement of penicillin v in fermentation media
Analytica Chimica Acta, 1993Co-Authors: Morten Carlsen, Lars H Christensen, Jens NielsenAbstract:Abstract Three different flow-injection analysis systems for measuring penicillins in complex fermentation media were tested: a molybdenum blue, an iodimetric and a potentiometric method. All the methods are based on enzymatic hydrolysis of the penicillin to the corresponding Penicilloic Acid using β-lactamase, followed by detection of Penicilloic Acid. The β-lactamase is immobilized in a packed-bed reactor in which there is 100% conversion of penicillin to Penicilloic Acid, and all the methods therefore measure the sum of Penicilloic Acid and penicillin in the sample. The iodimetric method was found to be the best method for measurement in fermentation media. By replacing the enzyme reactor with an enzyme-free dummy reactor, it is possible to measure the concentration of Penicilloic Acid alone, and thence the penicillin concentration can be determined by subtraction of the Penicilloic Acid concentration from the total response in the analyser with the enzyme reactor inserted. The application of the analyser was tested by monitoring a fed-batch penicillin fermentation and the correlation between measurements by the FIA system and a liquid chromatographic method was very good.