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Imre Molnár

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I am an analytical chemist with a German Dr.rer.nat.,have an institute for Applied Chromatography in Berlin, Germany (short: Molnar-Institute)Developed the software DryLab with Lloyd R. Snyder, John W. Dolan and Tom Jupille (LC-Resources) from 1984. Since 2006 we distribute the DryLab-licenses worldwide.

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Papers by Imre Molnár

Berührungspunkte der ungarischen und slowakischen Sozialforschung

Comparative Southeast European Studies

Prediction of experimental parameters in combined isocratic and gradient elution reversed phase high performance liquid chromatography (RP-HPLC) using acetonitrile as organic modifier

Hrc-journal of High Resolution Chromatography, Jun 1, 1981

The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.... more The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.7, with acetonitrile as the organic modifier are particularly advantageous as eluents with linear elution strength (LES). In the isocratic mode, under the experimental conditions used, fairly good linearity exists between logk' and xB (x is the volume ratio of the organic modifier, i.e. acetonitrile) with a correlation coefficient of 0.9995. The relationship between isocratic and gradient elution parameters, such as xB, x (starting composition in gradient elution), m (slope of the linear gradient), is transparent and the parameters of interest can be predicted fairly accurately using simple equations. The proposed system could be used in elaboration of a general retention index system for organic molecules in RP‐HPLC.

Peak tracking in high-performance liquid chromatography based on normalized band areas

Journal of Chromatography A, Dec 1, 1989

... 578 I. MOLNAR, R. BOYSEN, P. JEKOW 1,58 A 1,19 o,?9 ." " 0,40 36 69 133 256 495 955... more

High-performance-liquid chromatography ofThermus aquaticus 50S and 30S ribosomal proteins

Chromatographia, Jul 1, 1989

The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first ... more The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first time, been Thermus aquaticus by preventing protein-protein-interactions during separation, and by introducing computersupported techniques to ease the handling of individual peak components in the separation of complex protein mixtures.

Reactions of Disulfur Difluoride with Fluorosulfonic Acid, Oleum, Boron Trifluoride, and Arsenic Pentafluoride

Angewandte Chemie, Mar 1, 1971

The complexes (PH,),Mo(CO), and [P,H,Mo(CO),L. react with potassium in liquid ammonia, givingprod... more The complexes (PH,),Mo(CO), and [P,H,Mo(CO),L. react with potassium in liquid ammonia, givingproducts which appear to contain anions of the type [(PH2)2Mo(CO),]-2, but in the former case at least the reactions are complicated and the products are difficult to characterize. We have found, however, that phosphane complexes can be deprotonated by potassium phosphide in dimethyl ether. The complex pentacarbonylphosphanemolybdenum(O), for example, reacts quantitatively with KPH, in (CH3),0 at 0°C over a period of an hour; phosphane is evolved, and the salt K[PH,Mo(CO),] can be isolated from the resulting solutions as a yellow solid. PH3Mo(CO), + PH; + (PH~Mo(CO),]-+ PH3 The compound has been characterized by its IR andNMR spectra [J(HP) = 160.5 Hz; tpH = 10.36 in (CH,),O] and by analysis. An excess of PH,MO(CO)~ yields the binuclear anion complex p-phosphido-bis(pentacarbonylmolybdate(O))[']: PH,MO(CO)~ + [PH2Mo(CO),]-+ [(CO)5MoPH2Mo(CO)5J-+ PH,

Artificial Neural Network Modeling of pH Dependent Structural Descriptor-Mobility Relationship for Capillary Zone Electrophoresis of Tripeptides

Journal of Liquid Chromatography & Related Technologies, Aug 7, 2008

... Chemicals. Tripeptides of alanine (AAA), lysine (KKK), and tyrosine (YYY) were purchased from... more

Prediction of experimental parameters in combined isocratic and gradient elution reversed phase high performance liquid chromatography (RP‐HPLC) using acetonitrile as organic modifier

Journal of High Resolution Chromatography, 1981

The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.... more The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.7, with acetonitrile as the organic modifier are particularly advantageous as eluents with linear elution strength (LES). In the isocratic mode, under the experimental conditions used, fairly good linearity exists between logk' and xB (x is the volume ratio of the organic modifier, i.e. acetonitrile) with a correlation coefficient of 0.9995. The relationship between isocratic and gradient elution parameters, such as xB, x (starting composition in gradient elution), m (slope of the linear gradient), is transparent and the parameters of interest can be predicted fairly accurately using simple equations. The proposed system could be used in elaboration of a general retention index system for organic molecules in RP‐HPLC.

High-performance-liquid chromatography ofThermus aquaticus 50S and 30S ribosomal proteins

Chromatographia, 1989

The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first ... more The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first time, been Thermus aquaticus by preventing protein-protein-interactions during separation, and by introducing computersupported techniques to ease the handling of individual peak components in the separation of complex protein mixtures.

Reaktionen des Dischwefeldifluorids mit Fluorsulfonsäure, Oleum, Bortrifluorid und Arsenpentafluorid

Angewandte Chemie, 1971

Modern liquid chromatography of macromolecules, vol. 25 in the series, journal of chromatography library

Analytica Chimica Acta, 1987

The authors are well-known, high-ranking experts in polymer analysis. Accordingly, the book is as... more

To a safe production - Steps in UHPLC modeling

Journal of Chromatography & Separation Techniques, Aug 8, 2017

Simultaneous optimization of mobile phase composition and pH using retention modeling and experimental design

Journal of Pharmaceutical and Biomedical Analysis, Oct 1, 2018

Chromatographic methods are progressing continuously. Increasing sample complexity and safety exp... more Chromatographic methods are progressing continuously. Increasing sample complexity and safety expectations lead to higher regulatory demands, hence challenges in liquid chromatography analysis are rising, even today, when faster and faster chromatographic systems are extensively employed and become widely accessible for successful method development. The goal of this study was to investigate the impact of mobile phase influences as important factors of selectivity tuning in method development. This would mitigate mobile phase-related robustness issues throughout the method's lifecycle. To discover and understand these effects, a new module of chromatographic modeling software Dry-Lab (ver. 4.3.4. beta) was introduced and a special experimental design (DoE) was tested, allowing the simultaneous optimization of solvent-dependent parameters, such as gradient time (t G), ternary eluent composition (t C) and pH, requiring 18 input experiments (2 × 3 × 3 = 18). Additionally, the model creation, using a UPLC system and a narrow bore column (50 × 2.1 mm), the entire experimental work could be finished in 2-3 hours. To demonstrate the applicability of this new design, amlodipine and its related pharmacopoeia impurities (A-H) were subjected to be used in a case study. Predicted vs. Experimental (or Verification) runs showed excellent agreement, average retention time deviations were typically less than 1 s. Modelled robustness testing was also performed, elucidating all important mobile phase and instrument parameters that could influence a method's lifetime performance. Furthermore, as the in silico robustness testing is the least time consuming part of the method development process, it can be used extensively to evaluate robustness even at the very early part in stage 1 of the Method Life Cycle (MLC).

Modeling UHPLC separations

Journal of Chromatography & Separation Techniques, Aug 8, 2017

In silico robustness testing of a compendial HPLC purity method by using of a multidimensional design space build by chromatography modeling—Case study pramipexole

Journal of Pharmaceutical and Biomedical Analysis, Mar 1, 2014

Purity testing of the active pharmaceutical ingredient (API) pramipexole is performed using an of... more Purity testing of the active pharmaceutical ingredient (API) pramipexole is performed using an official (compendial) and harmonized method published in the European Pharmacopeia (E.P.) and United States Pharmacopeia (USP). According to this monograph the successful chromatographic separation of the API from impurities is achieved on a C18 column with gradient elution of an ion pairing buffer of pH 3.0 (mobile phase A) and acetonitrile (mobile phase B). Although not recommended in general, compendial methods are often adapted for purity testing of generic formulations. In this paper a novel approach to evaluate method robustness of an adapted method-prior of full method validation-is described. Based on Quality-by-Design (QbD) principles, a small number of experiments are performed, which after entering them into a chromatography modeling software allow to visualize a multidimensional "Design Space", a region, in which changes in method parameters will not significantly affect the results as defined in the ICH guideline Q8(R2) leading to a more flexible method handling in routine analysis. For two different recommended C18 columns a multidimensional Design Space (Method Operating Design Region, MODR) was constructed to study the robustness of the adapted method with a newly developed Robustness Module. In a full factorial design the following six parameters were varied at three levels (low, nominal, high): gradient time, temperature, pH of the aqueous eluent (A), flow rate, start-and end concentration of the organic mobile phase component (eluent B). The resulting 3 6 = 729 experiments were performed in silico from the previously constructed models for Design Space in less than 1 min and showed that the required resolution of 2.0 could not be reached in all experiments for the two columns which were recommended by the E.P. (failure rate 25% and 16%, respectively). However, by adjusting the gradient time, we were able to fulfill the requirements with a failure rate of zero. For the aqueous eluent a separate "Eluent Design Space" study was performed, which allows the construction of ionic strength vs. ion pairing concentration models to identify the optimum combination of the concentrations for the buffer and the ion-pairing reagent.

Saccharidtrennung mittels Gradientenelution

Zeitschrift für Lebensmittel-Untersuchung und -Forschung, Nov 1, 1987

Summary The analysis of the composition of saccharide melts led to a modification of the customar... more Summary The analysis of the composition of saccharide melts led to a modification of the customary HPLC method by means of NH2 columns [1–4]. For the qualitative and quantitative determination of the saccharides (within the range from monosaccharides to oligosaccharides) a gradient system was developed that permits the separation and subsequent detection of saccharides (DP1 = 1 to DP = 6) by using a differential refractometer.

Erratum to “Computer-assisted optimization in the development of a high-performance liquid chromatographic method for the analysis of kava pyrones in Piper methysticum preparations” [J. Chromatogr. A 948 (2002) 51–63]

Journal of Chromatography A, Mar 1, 2006

ABSTRACT

Heterogeneity of corticotropin-immunoreactive compounds in human body fluids

Clinical Chemistry, Nov 1, 1981

Using reversed-phase &quot;high-performance&quot; liquid chromatography and hydrophilic i... more Using reversed-phase &quot;high-performance&quot; liquid chromatography and hydrophilic ion-pairing reagents, we studied the chromatographic profiles of corticotropin immunoreactivities in human plasma, cerebrospinal fluid, and urine. The chromatographic system we applied provides excellent separation of peptide molecules, with reproducibility (CV) of retention times better than 0.5%, and makes feasible the subsequent immunological quantitation of eluted fractions. Profiles of corticotropin immunoreactivities exhibited several chemically different compounds in each of the three body fluids studied. A considerable portion of these immunoreactive compounds is more hydrophilic and probably of lower molecular mass than the human corticotropin 1-39 molecule itself. These hydrophilic molecules are more predominant in urine and plasma than in cerebrospinal fluid.

Establishing column batch repeatability according to Quality by Design (QbD) principles using modeling software

Journal of Pharmaceutical and Biomedical Analysis, Apr 1, 2015

Column technology needs further improvement even today. To get information of batch-to-batch repe... more Column technology needs further improvement even today. To get information of batch-to-batch repeatability, intelligent modeling software was applied. Twelve columns from the same production process, but from different batches were compared in this work. In this paper, the retention parameters of these columns with real life sample solutes were studied. The following parameters were selected for measurements: gradient time, temperature and pH. Based on calculated results, batch-to-batch repeatability of BEH columns was evaluated. Two parallel measurements on two columns from the same batch were performed to obtain information about the quality of packing. Calculating the average of individual working points at the highest critical resolution (R s,crit) it was found that the robustness, calculated with a newly released robustness module, had a success rate >98% among the predicted 3 6 = 729 experiments for all 12 columns. With the help of retention modeling all substances could be separated independently from the batch and/or packing, using the same conditions, having high robustness of the experiments.

Practical Aspects of Modern High Performance Liquid Chromatography

De Gruyter eBooks, Dec 31, 1983

One day, you will discover a new adventure and knowledge by spending more money. But when? Do you... more One day, you will discover a new adventure and knowledge by spending more money. But when? Do you think that you need to obtain those all requirements when having much money? Why don't you try to get something simple at first? That's something that will lead you to know more about the world, adventure, some places, history, entertainment, and more? It is your own time to continue reading habit. One of the books you can enjoy now is practical aspects of modern high performance liquid chromatography here.

Modern liquid chromatography of Macromolecules. B. G. Belenkii and L. Z. Vilenchik, Elsevier, 432 pp

Hrc-journal of High Resolution Chromatography, Jul 1, 1985

The authors are well-known, high-ranking experts in polymer analysis. Accordingly, the book is as... more

Berührungspunkte der ungarischen und slowakischen Sozialforschung

Comparative Southeast European Studies

Prediction of experimental parameters in combined isocratic and gradient elution reversed phase high performance liquid chromatography (RP-HPLC) using acetonitrile as organic modifier

Hrc-journal of High Resolution Chromatography, Jun 1, 1981

The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.... more The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.7, with acetonitrile as the organic modifier are particularly advantageous as eluents with linear elution strength (LES). In the isocratic mode, under the experimental conditions used, fairly good linearity exists between logk' and xB (x is the volume ratio of the organic modifier, i.e. acetonitrile) with a correlation coefficient of 0.9995. The relationship between isocratic and gradient elution parameters, such as xB, x (starting composition in gradient elution), m (slope of the linear gradient), is transparent and the parameters of interest can be predicted fairly accurately using simple equations. The proposed system could be used in elaboration of a general retention index system for organic molecules in RP‐HPLC.

Peak tracking in high-performance liquid chromatography based on normalized band areas

Journal of Chromatography A, Dec 1, 1989

... 578 I. MOLNAR, R. BOYSEN, P. JEKOW 1,58 A 1,19 o,?9 ." " 0,40 36 69 133 256 495 955... more

High-performance-liquid chromatography ofThermus aquaticus 50S and 30S ribosomal proteins

Chromatographia, Jul 1, 1989

The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first ... more The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first time, been Thermus aquaticus by preventing protein-protein-interactions during separation, and by introducing computersupported techniques to ease the handling of individual peak components in the separation of complex protein mixtures.

Reactions of Disulfur Difluoride with Fluorosulfonic Acid, Oleum, Boron Trifluoride, and Arsenic Pentafluoride

Angewandte Chemie, Mar 1, 1971

The complexes (PH,),Mo(CO), and [P,H,Mo(CO),L. react with potassium in liquid ammonia, givingprod... more The complexes (PH,),Mo(CO), and [P,H,Mo(CO),L. react with potassium in liquid ammonia, givingproducts which appear to contain anions of the type [(PH2)2Mo(CO),]-2, but in the former case at least the reactions are complicated and the products are difficult to characterize. We have found, however, that phosphane complexes can be deprotonated by potassium phosphide in dimethyl ether. The complex pentacarbonylphosphanemolybdenum(O), for example, reacts quantitatively with KPH, in (CH3),0 at 0°C over a period of an hour; phosphane is evolved, and the salt K[PH,Mo(CO),] can be isolated from the resulting solutions as a yellow solid. PH3Mo(CO), + PH; + (PH~Mo(CO),]-+ PH3 The compound has been characterized by its IR andNMR spectra [J(HP) = 160.5 Hz; tpH = 10.36 in (CH,),O] and by analysis. An excess of PH,MO(CO)~ yields the binuclear anion complex p-phosphido-bis(pentacarbonylmolybdate(O))[']: PH,MO(CO)~ + [PH2Mo(CO),]-+ [(CO)5MoPH2Mo(CO)5J-+ PH,

Artificial Neural Network Modeling of pH Dependent Structural Descriptor-Mobility Relationship for Capillary Zone Electrophoresis of Tripeptides

Journal of Liquid Chromatography & Related Technologies, Aug 7, 2008

... Chemicals. Tripeptides of alanine (AAA), lysine (KKK), and tyrosine (YYY) were purchased from... more

Prediction of experimental parameters in combined isocratic and gradient elution reversed phase high performance liquid chromatography (RP‐HPLC) using acetonitrile as organic modifier

Journal of High Resolution Chromatography, 1981

The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.... more The use of gradient elution in RP‐HPLC is increasing. Aqueous buffers, such as phosphate at pH 1.7, with acetonitrile as the organic modifier are particularly advantageous as eluents with linear elution strength (LES). In the isocratic mode, under the experimental conditions used, fairly good linearity exists between logk' and xB (x is the volume ratio of the organic modifier, i.e. acetonitrile) with a correlation coefficient of 0.9995. The relationship between isocratic and gradient elution parameters, such as xB, x (starting composition in gradient elution), m (slope of the linear gradient), is transparent and the parameters of interest can be predicted fairly accurately using simple equations. The proposed system could be used in elaboration of a general retention index system for organic molecules in RP‐HPLC.

High-performance-liquid chromatography ofThermus aquaticus 50S and 30S ribosomal proteins

Chromatographia, 1989

The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first ... more The ribosomal 50S and 30S subunit proteins (r-proteins) of Thermus aquaticus have, for the first time, been Thermus aquaticus by preventing protein-protein-interactions during separation, and by introducing computersupported techniques to ease the handling of individual peak components in the separation of complex protein mixtures.

Reaktionen des Dischwefeldifluorids mit Fluorsulfonsäure, Oleum, Bortrifluorid und Arsenpentafluorid

Angewandte Chemie, 1971

Modern liquid chromatography of macromolecules, vol. 25 in the series, journal of chromatography library

Analytica Chimica Acta, 1987

The authors are well-known, high-ranking experts in polymer analysis. Accordingly, the book is as... more

To a safe production - Steps in UHPLC modeling

Journal of Chromatography & Separation Techniques, Aug 8, 2017

Simultaneous optimization of mobile phase composition and pH using retention modeling and experimental design

Journal of Pharmaceutical and Biomedical Analysis, Oct 1, 2018

Chromatographic methods are progressing continuously. Increasing sample complexity and safety exp... more Chromatographic methods are progressing continuously. Increasing sample complexity and safety expectations lead to higher regulatory demands, hence challenges in liquid chromatography analysis are rising, even today, when faster and faster chromatographic systems are extensively employed and become widely accessible for successful method development. The goal of this study was to investigate the impact of mobile phase influences as important factors of selectivity tuning in method development. This would mitigate mobile phase-related robustness issues throughout the method's lifecycle. To discover and understand these effects, a new module of chromatographic modeling software Dry-Lab (ver. 4.3.4. beta) was introduced and a special experimental design (DoE) was tested, allowing the simultaneous optimization of solvent-dependent parameters, such as gradient time (t G), ternary eluent composition (t C) and pH, requiring 18 input experiments (2 × 3 × 3 = 18). Additionally, the model creation, using a UPLC system and a narrow bore column (50 × 2.1 mm), the entire experimental work could be finished in 2-3 hours. To demonstrate the applicability of this new design, amlodipine and its related pharmacopoeia impurities (A-H) were subjected to be used in a case study. Predicted vs. Experimental (or Verification) runs showed excellent agreement, average retention time deviations were typically less than 1 s. Modelled robustness testing was also performed, elucidating all important mobile phase and instrument parameters that could influence a method's lifetime performance. Furthermore, as the in silico robustness testing is the least time consuming part of the method development process, it can be used extensively to evaluate robustness even at the very early part in stage 1 of the Method Life Cycle (MLC).

Modeling UHPLC separations

Journal of Chromatography & Separation Techniques, Aug 8, 2017

In silico robustness testing of a compendial HPLC purity method by using of a multidimensional design space build by chromatography modeling—Case study pramipexole

Journal of Pharmaceutical and Biomedical Analysis, Mar 1, 2014

Purity testing of the active pharmaceutical ingredient (API) pramipexole is performed using an of... more Purity testing of the active pharmaceutical ingredient (API) pramipexole is performed using an official (compendial) and harmonized method published in the European Pharmacopeia (E.P.) and United States Pharmacopeia (USP). According to this monograph the successful chromatographic separation of the API from impurities is achieved on a C18 column with gradient elution of an ion pairing buffer of pH 3.0 (mobile phase A) and acetonitrile (mobile phase B). Although not recommended in general, compendial methods are often adapted for purity testing of generic formulations. In this paper a novel approach to evaluate method robustness of an adapted method-prior of full method validation-is described. Based on Quality-by-Design (QbD) principles, a small number of experiments are performed, which after entering them into a chromatography modeling software allow to visualize a multidimensional "Design Space", a region, in which changes in method parameters will not significantly affect the results as defined in the ICH guideline Q8(R2) leading to a more flexible method handling in routine analysis. For two different recommended C18 columns a multidimensional Design Space (Method Operating Design Region, MODR) was constructed to study the robustness of the adapted method with a newly developed Robustness Module. In a full factorial design the following six parameters were varied at three levels (low, nominal, high): gradient time, temperature, pH of the aqueous eluent (A), flow rate, start-and end concentration of the organic mobile phase component (eluent B). The resulting 3 6 = 729 experiments were performed in silico from the previously constructed models for Design Space in less than 1 min and showed that the required resolution of 2.0 could not be reached in all experiments for the two columns which were recommended by the E.P. (failure rate 25% and 16%, respectively). However, by adjusting the gradient time, we were able to fulfill the requirements with a failure rate of zero. For the aqueous eluent a separate "Eluent Design Space" study was performed, which allows the construction of ionic strength vs. ion pairing concentration models to identify the optimum combination of the concentrations for the buffer and the ion-pairing reagent.

Saccharidtrennung mittels Gradientenelution

Zeitschrift für Lebensmittel-Untersuchung und -Forschung, Nov 1, 1987

Summary The analysis of the composition of saccharide melts led to a modification of the customar... more Summary The analysis of the composition of saccharide melts led to a modification of the customary HPLC method by means of NH2 columns [1–4]. For the qualitative and quantitative determination of the saccharides (within the range from monosaccharides to oligosaccharides) a gradient system was developed that permits the separation and subsequent detection of saccharides (DP1 = 1 to DP = 6) by using a differential refractometer.

Erratum to “Computer-assisted optimization in the development of a high-performance liquid chromatographic method for the analysis of kava pyrones in Piper methysticum preparations” [J. Chromatogr. A 948 (2002) 51–63]

Journal of Chromatography A, Mar 1, 2006

ABSTRACT

Heterogeneity of corticotropin-immunoreactive compounds in human body fluids

Clinical Chemistry, Nov 1, 1981

Using reversed-phase &quot;high-performance&quot; liquid chromatography and hydrophilic i... more Using reversed-phase &quot;high-performance&quot; liquid chromatography and hydrophilic ion-pairing reagents, we studied the chromatographic profiles of corticotropin immunoreactivities in human plasma, cerebrospinal fluid, and urine. The chromatographic system we applied provides excellent separation of peptide molecules, with reproducibility (CV) of retention times better than 0.5%, and makes feasible the subsequent immunological quantitation of eluted fractions. Profiles of corticotropin immunoreactivities exhibited several chemically different compounds in each of the three body fluids studied. A considerable portion of these immunoreactive compounds is more hydrophilic and probably of lower molecular mass than the human corticotropin 1-39 molecule itself. These hydrophilic molecules are more predominant in urine and plasma than in cerebrospinal fluid.

Establishing column batch repeatability according to Quality by Design (QbD) principles using modeling software

Journal of Pharmaceutical and Biomedical Analysis, Apr 1, 2015

Column technology needs further improvement even today. To get information of batch-to-batch repe... more Column technology needs further improvement even today. To get information of batch-to-batch repeatability, intelligent modeling software was applied. Twelve columns from the same production process, but from different batches were compared in this work. In this paper, the retention parameters of these columns with real life sample solutes were studied. The following parameters were selected for measurements: gradient time, temperature and pH. Based on calculated results, batch-to-batch repeatability of BEH columns was evaluated. Two parallel measurements on two columns from the same batch were performed to obtain information about the quality of packing. Calculating the average of individual working points at the highest critical resolution (R s,crit) it was found that the robustness, calculated with a newly released robustness module, had a success rate >98% among the predicted 3 6 = 729 experiments for all 12 columns. With the help of retention modeling all substances could be separated independently from the batch and/or packing, using the same conditions, having high robustness of the experiments.

Practical Aspects of Modern High Performance Liquid Chromatography

De Gruyter eBooks, Dec 31, 1983

One day, you will discover a new adventure and knowledge by spending more money. But when? Do you... more One day, you will discover a new adventure and knowledge by spending more money. But when? Do you think that you need to obtain those all requirements when having much money? Why don't you try to get something simple at first? That's something that will lead you to know more about the world, adventure, some places, history, entertainment, and more? It is your own time to continue reading habit. One of the books you can enjoy now is practical aspects of modern high performance liquid chromatography here.

Modern liquid chromatography of Macromolecules. B. G. Belenkii and L. Z. Vilenchik, Elsevier, 432 pp

Hrc-journal of High Resolution Chromatography, Jul 1, 1985

The authors are well-known, high-ranking experts in polymer analysis. Accordingly, the book is as... more