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Operational Parameters (operational + parameter)
Selected AbstractsChiral separation of N -imidazole derivatives, aromatase inhibitors, by cyclodextrin-capillary zone electrophoresis.ELECTROPHORESIS, Issue 16 2004Mechanism of enantioselective recognition Abstract Baseline separation of ten new, substituted [1-(imidazo-1-yl)-1-phenylmethyl)] benzothiazolinone and benzoxazolinone derivatives with one chiral center was achieved using cyclodextrin-capillary zone electrophoresis (CD-CZE). A method for the enantiomeric resolution of these compounds was developed using neutral CDs (native ,-, ,-, ,-CDs or ,-, ,-, ,-hydroxypropyl (HP)-CDs) as chiral selectors. Operational parameters including the nature and concentration of the chiral selectors, pH, ionic strength, organic modifiers, temperature, and applied voltage were investigated. The use of neutral CDs provides enantiomeric resolution by inclusion of compounds in the CD cavity. The HP-,-CD and HP-,-CD were found to be the most effective complexing agents and allowed efficient enantiomeric resolutions. Optimal separation of N -imidazole derivatives was obtained using 50 mM phosphate buffer at pH 2.5 containing either HP-,-CD or HP-,-CD (7.5,12.5 mM) at 25°C, with an applied field of 0.50 kV·cm,1 giving resolution factors Rs superior to 1.70 with migration times of the second enantiomer less than 13 min. The same enantiomer migration order observed for all molecules can be related to a close interaction mechanism with CDs. The influence of structural features of the solutes on Rs and tm was studied. The lipophilic character (log kw) of the solutes and the apparent and averaged association constants of inclusion complexes for four compounds with the six different CDs led us to rationalize the enantioseparation mechanisms. The conclusions were corroborated with reversed-phase high-performance liquid chromatography (HPLC) on chiral stationary phases (CSPs) based on CDs. [source] Towards waste minimisation in WWTP: activated carbon from biological sludge and its application in liquid phase adsorptionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2002Maria J Martin Abstract Surplus sludge produced during the biological treatment of wastewater requires costly disposal procedures. With increasing environmental and legislative constraints, increasing sludge production and more limited disposal options, new recycling alternatives have to be found. The possibility of obtaining activated carbons from surplus biological sludge by chemical activation with H2SO4 has been investigated. Operational parameters such as the amount of H2SO4 added, the temperature, and activation time were modified to ascertain their influence on the quality of the activated carbon obtained. The quality of the sludge-based activated carbons was evaluated by established characterisation parameters for adsorption from solution such as phenol value, iodine number, methylene blue number and tannin value and compared with commercial activated carbons. Activation at 700,°C for 30,min in the presence of 0.5,cm3 H2SO4,g,1 dry solids in the sludge led to an activated carbon with a good capacity for iodine and tannic acid. The sludge-derived activated carbon obtained is mesoporous in nature with a high presence of large macropores. Weak and moderate acidic surface functional groups were detected on the surface, which impart a hydrophilic nature to the solid. When compared with a commercial activated carbon, the sludge-derived activated carbon performed better when removing dyes with a high presence of anionic solubilising groups and heavy metals. The results indicate that COD adsorption from a biologically-treated effluent may also be an area for application. © 2002 Society of Chemical Industry [source] Effect of air flow rate on the foam fractionation of a mixture of egg white and egg yolkASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009Chris C. Stowers Abstract Foam fractionation was previously shown to be an effective tool for the separation of the two visible phases in a chicken egg: egg white and the egg yolk.1 This study is a continuation of the previous study with the objective of determining the optimal separation condition in terms of air flow rate. Our results show that air flow rate is a critical operational parameter when separating these protein-rich mixtures of egg white and egg yolk. The results show that respective concentrations of egg yolk and egg white phases change independently with respect to the air flow rate, leading to the observation that air flow rate could be exploited as a processing variable to selectively remove proteins from one section of the egg over the other section. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] A Study of Nafion-Coated Bismuth-Film Electrode for the Determination of Zinc, Lead, and Cadmium in Blood SamplesELECTROANALYSIS, Issue 21 2008Benzhi Liu Abstract In this article a sensitive differential pulse stripping voltammetry technique on Nafion-coated bismuth-film electrode (NCBFE) was studied for the simultaneous determination of zinc, cadmium, and lead ions in blood samples at ultra trace levels. The measurement results were in excellent agreement with those obtained from atomic absorption spectroscopy. Various operational parameters were investigated and discussed in terms of their effect on the measurement signals. Under optimal conditions, calibration curves for the simultaneous determination of zinc, cadmium, and lead ions were achieved, based on three times the standard deviation of the baseline, the limits of detection were 0.09,,g L,1 for Cd(II), 0.13,,g L,1 for Pb(II), and 0.97,,g L,1 for Zn(II) respectively. [source] Photocatalytic degradation of organic dyes in the presence of titanium dioxide under UV and solar light: Effect of operational parametersENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2005Feryal Akbal The photocatalytic degradation of methylene blue and methyl orange have been studied in the presence of titanium dioxide powder illuminated with a 300-W UV lamp. The effect of hydrogen peroxide on the degradation process was also determined. It was found that the color removal efficiency was affected by the concentration of dye, amount of TiO2 added, and the pH of the solution. The degradation of dyes obeys first-order kinetics, with the apparent first-order rate constant increasing with decreasing dye concentration. The rate constants were evaluated as a function of the concentration of dye, amount of TiO2, and pH. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source] Performance analysis of a modified two-bed solar-adsorption air-conditioning systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2009K. Sumathy Abstract This paper presents the description and operation of a solar-powered modified two-bed adsorption air-conditioning system with activated carbon and methanol as the working pair. A simple lumped parameter model is established to investigate the performance of this continuous adsorption cycle consisting of a twin adsorber immersed in water tanks, which is measured in terms of the temperature histories, gross solar coefficient of performance and specific cooling power. In addition, the influence of some important design and operational parameters on the performance of the system has been studied. Compared with the conventional system, it is found that the modified system can operate more cycles and at a higher efficiency. The parametric study also shows that the adsorbent mass and the solar collector area have significant effect on the system performance as well as on the system size. Finally, when the system uses gas heater as an auxiliary heat source, it is found that the system can provide a stable cooling effect for a longer period of operation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Transient thermal modelling of heat recovery steam generators in combined cycle power plantsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2007Sepehr Sanaye Abstract Heat recovery steam generator (HRSG) is a major component of a combined cycle power plant (CCPP). This equipment is particularly subject to severe thermal stress especially during cold start-up period. Hence, it is important to predict the operational parameters of HRSGs such as temperature of steam, water, hot gas and tube metal of heating elements as well as pressure change in drums during transient and steady-state operation. These parameters may be used for estimating thermal and mechanical stresses which are important in HRSG design and operation. In this paper, the results of a developed thermal model for predicting the working conditions of HRSG elements during transient and steady-state operations are reported. The model is capable of analysing arbitrary number of pressure levels and any number of elements such as superheater, evaporator, economizer, deaerator, desuperheater, reheater, as well as duct burners. To assess the correct performance of the developed model two kinds of data verification were performed. In the first kind of data verification, the program output was compared with the measured data collected from a cold start-up of an HRSG at Tehran CCPP. The variations of gas, water/steam and metal temperatures at various sections of HRSG, and pressure in drums were among the studied parameters. Mean differences of about 3.8% for temperature and about 9.2% for pressure were observed in this data comparison. In the second kind of data verification, the steady-state numerical output of the model was checked with the output of the well-known commercial software. An average difference of about 1.5% was found between the two latter groups of data. Copyright © 2007 John Wiley & Sons, Ltd. [source] Evaluation of numerical simulation methods in reactive extrusionADVANCES IN POLYMER TECHNOLOGY, Issue 3 2005Linjie Zhu Abstract Reactive extrusion is a complex process, and numerical simulation is an important method in optimizing operational parameters. In the current work, two different simulation methods, one-dimensional (1D) model and three-dimensional (3D) model, were introduced to predict the polymerization of ,-caprolactone in fully filled screw elements. The predicted results of polymerization progression under different simulation conditions based on these two methods were compared. The simulation results show that the simplifications and assumptions in 1D model make it difficult to capture the complex mixing mechanism, heat generation, and heat loss in reactive extrusion. 1D model is feasible only under particular conditions, such as low screw rotating speed, small heat from reaction, and small screw diameter, whereas 3D model is a more powerful simulation tool for much wider processing conditions. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24: 183,193, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20041 [source] Photocatalytic degradation of methyl tert -butyl ether (MTBE) in contaminated water by ZnO nanoparticlesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2008Akbar Eslami Abstract BACKGROUND: Over the past several decades methyl tert -butyl ether (MTBE) as additive to gasoline, intended to either boost ratings of fuel or to reduce air pollution, has been accepted worldwide. Since MTBE has high water solubility, the occurrence of fuel spills or leaks from underground storage tanks or transferring pipeline has led to the contamination of natural waters. In this study the degradation of aqueous MTBE at relatively high concentrations was investigated by a UV-visible/ZnO/H2O2 photocatalytic process. The effects of important operational parameters such as pH, amount of H2O2, catalyst loading and irradiation time were also investigated. Concentration of MTBE and intermediates such as tert -butyl formate and tert -butyl alcohol were measured. RESULTS: Time required for complete degradation increased from 20 to 150 min when the initial concentration was increased from 10 to 500 mg L,1. The first-order rate constants for degradation of MTBE were estimated to be 0.183,0.022 min,1 as the concentration increased from 10 to 500 mg L,1. Study of the overall mineralization monitored by total organic carbon analysis showed that at an initial concentration of 100 mg L,1 MTBE complete mineralization was obtained after 100 min under UV-visible/ZnO/H2O2 photocatalysis. CONCLUSION: The data presented in this paper clearly indicated that UV-visible/ZnO/O2 as an advanced oxidation process provides an efficient treatment alternative for the remediation of MTBE-contaminated waters. Copyright © 2008 Society of Chemical Industry [source] A systematic evaluation of the benefits and hazards of variable selection in latent variable regression.JOURNAL OF CHEMOMETRICS, Issue 7 2002Part I. Search algorithm, simulations, theory Abstract Variable selection is an extensively studied problem in chemometrics and in the area of quantitative structure,activity relationships (QSARs). Many search algorithms have been compared so far. Less well studied is the influence of different objective functions on the prediction quality of the selected models. This paper investigates the performance of different cross-validation techniques as objective function for variable selection in latent variable regression. The results are compared in terms of predictive ability, model size (number of variables) and model complexity (number of latent variables). It will be shown that leave-multiple-out cross-validation with a large percentage of data left out performs best. Since leave-multiple-out cross-validation is computationally expensive, a very efficient tabu search algorithm is introduced to lower the computational burden. The tabu search algorithm needs no user-defined operational parameters and optimizes the variable subset and the number of latent variables simultaneously. Copyright © 2002 John Wiley & Sons, Ltd. [source] EFFECTS OF CO-IMMOBILIZATION OF PECTINASE AND AMYLASE ON ULTRAFILTRATION OF APPLE JUICE SIMULATEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2001MARÍA E. CARRÍN ABSTRACT In view of its possible application in apple juice clarification, the potential of co-immobilized pectinase/amylase by physical adsorption on a polysulfone ultrafiltration hollow fiber was examined. Solutions containing different concentrations of pectin and starch were used. The effect of various operational parameters on the production of reducing compounds, mainly galacturonic acid and maltose, was investigated. Results indicated that relative permeate flux, during ultrafiltration of starch-pectin solutions, was up to 35% higher when commercial pectinase and amylase were co-immobilized on a hollow fiber membrane. Although the concentration of reaction products increased up to 50% with the pectin concentration, the same was not verified when the starch content changed from 3.85 to 5.00 mg/mL. However, the reference permeate flux was improved when starch was added to substrate, independently of its concentration. Considering the size of an average starch granule, this increase in permeate flux was attributed to the removal of pectin gel by dragging. Permeate fluxes were comparable for both batch and permeate recycling operations. [source] Critical flux determination by flux-steppingAICHE JOURNAL, Issue 7 2010Søren Prip Beier Abstract In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step length, step height, and flux start level. Filtrating 8 kg/m3 yeast cell suspensions by a vibrating 0.45 × 10,6 m pore size microfiltration hollow fiber module, critical fluxes from 5.6 × 10,6 to 1.2 × 10,5 m/s have been measured using various step lengths from 300 to 1200 seconds. Thus, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes can predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start guesses, in our case, in constant flux verification experiments for 5 and 1/2 hours, a sustainable flux was identifiable. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Granular mixing and segregation in a horizontal rotating drum: A simulation study on the impact of rotational speed and fill levelAICHE JOURNAL, Issue 12 2008M. M. H. D. Arntz Abstract The rich phase behavior of granular beds of bidisperse hard spherical particles in a rotating horizontal drum is studied by Discrete Element Method (DEM) simulations. Several flow regimes and various forms of radial segregation, as well as mixing, are observed by systematically varying the operational parameters of the drum, i.e. fill level and angular velocity, over a wide range. Steady states after several dozen revolutions are summarized in two bed behavior diagrams, showing strong correlations between flow regime and segregation pattern. An entropy method quantifies the overall degree of mixing, while density and velocity plots are used to analyze the local properties of the granular bed. The percolation mechanism may provide a qualitative explanation for the distinct segregation processes, and for the transient mixing in nonradially segregated beds. Initially blockwise segregated beds are found to mix before radial segregation sets in. High fill fractions (>65%) show the most intense segregation. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] Designing man-portable power generation systems for varying power demandAICHE JOURNAL, Issue 5 2008Mehmet Yunt Abstract Portable electronic devices operate at varying power demand levels. This variability of power demand must be considered explicitly in the design of man-portable power generation systems for acceptable performance and portability. In this regard, a mathematical programming based design method is proposed. The method transcribes optimal operation of the system at a given power demand into a mathematical program. The power demand specific programs are incorporated into another upper level mathematical program encoding design requirements to form a final two-stage formulation. The design and operational parameters of the power generation system comprise a solution of the formulation. Unlike designs, based on a nominal power demand, the design guarantees that each power demand and all operational requirements can be satisfied. A detailed study of a microfabricated fuel-cell based system is performed. The proposed method produces smaller designs with significantly better performances than nominal power demand based approaches. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] In vitro femtosecond laser subsurface micro-disruption inside human cornea and pre-cleared scleraLASER PHYSICS LETTERS, Issue 6 2010A.A. Alekhin Abstract Micro-incisions were fabricated inside human cornea and sclera in vitro using single femtosecond laser pulses. In these experiments sclera was for the first time pre-cleared by means of a biocompatible and clinically safe (non-toxic) natural agent (refractive-index matching 40%-glucose solution in water), partially replacing water in the tissue comparing to its severe dehydration by previously used agents. Basic operational parameters of the corresponding microsurgical procedures are reported. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] A simple and fast detection technique for arsenic speciation based on high-efficiency photooxidation and gas-phase chemiluminescence detectionLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 5 2009Junhai Xue Abstract High-efficiency photooxidation (HEPO) and gas phase chemiluminescence detection (CL) combined with high-performance liquid chromatography (HPLC) and hydride generation were developed for speciation of As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). After chromatography separation, the arsenic species were passed through HEPO which performed efficient photooxidation and converted MMA and DMA to As(V) in several seconds. Then the reaction of ozone and arsine upon hydride generation produced a CL signal as the analytical parameter. The total analytical process was completed within 10 min. The effects of operational parameters such as the concentrations of hydrochloric acid and NaBH4 solution, carrier gas flow and air gas flow for ozone generation were investigated. Detection limits were 3.7, 10.3, 10.2 and 10.0 µg/L for As(III), As(V), MMA and DMA, respectively. The recoveries of the four arsenic species in human urine sample ranged from 87 to 94%. Copyright © 2009 John Wiley & Sons, Ltd. [source] Improved imaging resolution in desorption electrospray ionization mass spectrometry,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2008Vilmos Kertesz The imaging resolution of desorption electrospray ionization mass spectrometry (DESI-MS) was investigated using printed patterns on paper and thin-layer chromatography (TLC) plate surfaces. Resolution approaching 40,µm was achieved with a typical DESI-MS setup, which is approximately 5 times better than the best resolution reported previously. This improvement was accomplished with careful control of operational parameters (particularly spray tip-to-surface distance, solvent flow rate, and spacing of lane scans). In addition, an appropriately strong analyte/surface interaction and uniform surface texture on the size scale no larger than the desired imaging resolution were required to achieve this resolution. Overall, conditions providing the smallest possible effective desorption/ionization area in the DESI impact plume region and minimizing the analyte redistribution on the surface during analysis led to improved DESI-MS imaging resolution. Published in 2008 by John Wiley & Sons, Ltd. [source] Modification of a commercial electrospray nebulizer for operation in a liquid chromatography/mass spectrometry system at flow rates in the low,µL/min rangeRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2001Alain Carrier A simple and inexpensive approach to convert the electrospray nebulizer of a commercial liquid chromatography/mass spectrometry (LC/MS) system (HP 1100) to accommodate lower flow rates has been proposed and evaluated. This modification consists of simply replacing the nebulizer needle by a commercially available stainless steel needle with a smaller internal diameter. Experiments were conducted in order to optimize operational parameters. Using two different internal diameter needle sizes, flow rates ranging from 1 to 250,µL/min could be accommodated. The modification presented allows an extension of the range of compatible flow rates without major modification of the standard design of the interface. Copyright © 2001 John Wiley & Sons, Ltd. [source] Simultaneous algorithm for trajectory planningASIAN JOURNAL OF CONTROL, Issue 4 2010Francisco J. Rubio Abstract This paper addresses the solution of smooth trajectory planning for industrial robots in environments with obstacles using a direct method, creating the trajectory gradually as the robot moves. The presented method deals with the uncertainties associated with the lack of knowledge of kinematic properties of intermediate via-points since they are generated as the algorithm evolves looking for the solution. Several cost functions are also proposed, which use the time that has been calculated to guide the robot motion. The method has been applied successfully to a PUMA 560 robot and four operational parameters (execution time, computational time, distance travelled and number of configurations) have been computed to study the properties and influence of each cost function on the trajectory obtained. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Re-entrainment of wall deposits from a laboratory-scale spray dryerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2007M. J. Hanus Abstract This work has determined the magnitude of re-entrainment and established the operational parameters that may be manipulated to influence re-entrainment of salt particles for a small-scale spray dryer (Buchi B-290). The wetness of the spray dryer wall deposits was found to significantly influence the magnitude of re-entrainment. It was shown both experimentally and numerically that wet deposits form at low nozzle air-to-liquid ratios (<2000), which form large droplets that dry slowly, while the initial droplet velocity did not have a large influence on wet deposition. Wet deposits form strong liquid and solid bridges, and thus deposits formed from wet particles were difficult to re-entrain. Less than 2% of deposits formed at nozzle air-to-liquid ratios less than 2000 were re-entrained, while 15.4 to 21.2% of dry deposited particles (formed at nozzle air-to-liquid ratios ranging from 2308 to 3409) were re-entrained. The threshold re-entrainment velocity of sodium chloride particles in the Buchi B-290 spray dryer was found to be between 4 and 7.7 ms,1, which is consistent with the lower-end threshold velocities presented in the literature. No significant trend relating relative humidity to the magnitude of re-entrainment was found in the 0.2,7.4% average relative humidity range, suggesting that the adhesive forces in spray dryer wall deposits are fairly constant across this relative humidity range. Decreasing wall deposit wetness through use of high (>2000) nozzle air-to-liquid ratios and use of high main gas velocities increased the re-entrainment of wall deposits in this spray dryer. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Performance of Dual-Media Expanded Bed BioreactorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5-6 2005R. Abdul-Rahman Abstract Adsorption and biological treatment are two possible approaches to remove chloro-organic and organic compounds. Granular activated carbon (GAC) biofilm reactors combine these two features, the adsorptive capacity and irregular shape of GAC particles providing niches for bacterial colonisation protected from high fluid forces, while the variety of functional groups on the surface enhance the attachment of microorganisms. The biofilm process is compact and offers reactions in both aerobic and anoxic states. Studies on removal of nitrogen constituents by a biofilm process were carried out using a dual-media expanded bed bioreactor, with GAC and plastic media as support media. The plastic media also acts as a filter for the effluent. Experiments were carried out at F:M of about 0.45 and hydraulic residence times (HRT) of 48, 24 and 12 hours. Bed expansion was maintained at 20,30% by recirculation flow. Aerobic condition was maintained at dissolved oxygen (DO) of about 2 mg/l throughout the bed. Chemical oxygen in demand (COD) in feed was 1000 mg/L while the total-N was 100 mg/L. Analysis showed that the process is able to maintain very stable conditions, achieving substantial COD removal of about 85% and total-N removal of about 80%. Biofilm biomass measurements showed an increase from 400 mg/l at HRT of 48 hours to 10,100 mg/l at HRT 12 hours, showing that much higher biomass concentrations may be contained in a biofilm process as compared to a conventional suspended biomass process. Bioreactors contain their own ecosystems, the nature of the community and the state of microorganisms define the kinetics and determine reactor performance. Growth kinetic parameters obtained are YH = 0.3421 mg/mg, m,H = 0.2252 day,1, KH = 319.364 mg/l and bH = 0.046 day,1. The denitrification kinetic parameters obtained are YHD = 0.9409 mg/mg, m,HD = 0.1612 day,1, KHD = 24.6253 mg/l and bHD = 0.0248 day,1. These parameters enable prediction of required reactor sizes and operational parameters. The plastic media has greatly improved effluent clarification by 98% as compared to single-media (GAC) only reactor. [source] Hydrothermal carbonization of biomass: A summary and discussion of chemical mechanisms for process engineeringBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2010Axel Funke Abstract Hydrothermal carbonization can be defined as combined dehydration and decarboxy lation of a fuel to raise its carbon content with the aim of achieving a higher calorific value. It is realized by applying elevated temperatures (180,220°C) to biomass in a suspension with water under saturated pressure for several hours. With this conversion process, a lignite-like, easy to handle fuel with well-defined properties can be created from biomass residues, even with high moisture content. Thus it may contribute to a wider application of biomass for energetic purposes. Although hydrothermal carbonization has been known for nearly a century, it has received little attention in current biomass conversion research. This review summarizes knowledge about the chemical nature of this process from a process design point of view. Reaction mechanisms of hydrolysis, dehydration, decarboxylation, aromatization, and condensation polymerization are discussed and evaluated to describe important operational parameters qualitatively. The results are used to derive fundamental process design improvements. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Use of capillary electrophoresis in drug quality assessment of synthetic porcine secretinBIOMEDICAL CHROMATOGRAPHY, Issue 1 2005Baile A. Moumakwa Abstract The purity pro,le for porcine secretin attributable to contamination by equilibrium products such as aspartoyl3 secretin has been shown to be dependent on the pH of the analytical system. Capillary zone electrophoresis (CZE) methods have been developed for the ef,cient separation of synthetic porcine secretin, its equilibrium products and other impurities in aqueous solutions at both acidic and alkaline pH. These conditions are more representative of those used for the reconstitution and administration of porcine secretin, and good results cannot be achieved using HPLC due to poor peak shape above pH 5.8. The in,uence of various CZE operational parameters was systematically examined. The methods were validated for accuracy, precision, linearity, LOD and LOQ. A comparative evaluation of the stability of test solutions was determined using CZE and HPLC over a range of pH values. HPLC and CZE methods produced similar results at low pH. 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