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Method Development (method + development)
Selected AbstractsMethod Development for Assessing the Complete Process of Crumbling Cheese Using Hand EvaluationJOURNAL OF FOOD SCIENCE, Issue 4 2004S. Sandra ABSTRACT: Cheese sensory evaluation was conducted by trained panelists (n= 8) on 4 commercial cheese samples (feta, Monterey Jack, 2 brands of Queso Fresco) in duplicate. Fifteen descriptors, capturing the entire process of crumbling cheese, were tested. Degree of crumbliness was defined as the ease by which the sample breaks apart during manipulation by rolling the sample using replicated circular movements, with the thumb, forefinger, and middle finger, 5 times. Using principal component analysis, 4 components were extracted and moistness, crumbliness, color, cohesiveness, irregularity, and oiliness were the main descriptors differentiating the samples. Panelists' performances were not significantly different (P, 0.05), and each subject used the method consistently for crumbliness. [source] Catalytic Intermolecular Amination of C,H Bonds: Method Development and Mechanistic Insights.CHEMINFORM, Issue 22 2007Kristin Williams Fiori Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Dual Activation in Asymmetric Allylsilane Addition to Chiral N-Acylhydrazones: Method Development, Mechanistic Studies, and Elaboration of Homoallylic Amine Adducts.CHEMINFORM, Issue 22 2006Gregory K. Friestad Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] On-line sample stacking and short-end injection CE for the determination of fluoxetine and norfluoxetine in plasma: Method development and validation using experimental designsELECTROPHORESIS, Issue 18 2007Chia-Chia Lu Abstract A short-end injection CE method combining field-amplified sample stacking (FASS) is presented for the analysis of fluoxetine (FL) and norfluoxetine in plasma. In this study, FASS enhanced the sensitivity about 1100-fold, while short-end injection reduced the analysis time to less than 4,min. Parameters involved in the separations were investigated using a central composite design (CCD) and response surface methodology to optimize the separation conditions in a total of only 32 runs. Samples injected into the capillary for 99.9,s at a voltage of ,5,kV were stacked in a water plug (0.5,psi, 9,s). Baseline resolution of FL and its major metabolite was achieved using a BGE formulation consisting of phosphate,triethanolamine at low pH, and a separation voltage of ,10,kV. Five percent methanol was added as organic modifier to enhance selectivity and resolution. The linear range was between 10 and 500,ng/mL (r >0.9946), covering the expected plasma therapeutic ranges. The LOD in plasma were 4,ng/mL (S/N,=,3), a value comparable to that obtained using LC-MS, showing the success of the on-line stacking technique. Our method was also successfully validated in quantification and pharmacokinetic studies with three volunteer plasma samples and could be applied to pharmacogenetic studies. [source] Method development and validation for the analysis of didanosine using micellar electrokinetic capillary chromatographyELECTROPHORESIS, Issue 21 2005Swapna Mallampati Abstract A selective MEKC method was developed for the analysis of didanosine in bulk samples. Successful separation of didanosine from 13 of its potential impurities, derived from the various synthetic preparation procedures, was achieved. As CZE gave poor separation selectivity, MEKC was preferable. The use of EKC allowed achievement of the separation in a significantly shorter time than conventional HPLC. An anionic long-chain surfactant, lithium dodecyl sulfate (LiDS), was used as the pseudostationary phase and sodium tetraborate buffer as the aqueous phase. In order to obtain the optimal conditions and to test the method robustness, a central composite response surface modeling experiment was performed. The optimized electrophoretic conditions include the use of an uncoated fused-silica capillary with a total length of 40,cm and an ID of 50,,m, a BGE containing 40,mM sodium tetraborate and 110,mM LiDS at pH,8.0, an applied voltage of 18.0,kV, and the capillary temperature maintained at 15°C. The method was found to be robust. The parameters for validation such as linearity, precision, and sensitivity are also reported. Three commercial bulk samples were analyzed with this system. [source] Capillary electrochromatographic chiral separations with potential for pharmaceutical analysisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 8 2005Debby Mangelings Abstract The use of capillary electrochromatography as a chiral separation technique for pharmaceutical applications is reviewed. Publications of the past 10 years that provide a potential practical application in pharmaceutical analysis are considered. Method development or validation, separation strategies, and potential routine analysis by the methods/applications cited are the main subjects on which we focused our attention. The indirect chiral separation method was only used once in CEC mode. In the direct chiral separations, the use of chiral stationary phases was obviously preferred over the use of chiral mobile phases with non-chiral stationary phases. Amongst the chiral stationary phases, those based on macrocyclic antibiotics and polysaccharide selectors were the most frequently used. Monolithic stationary phases also have several applications, but not so extended as those with packed capillary electrochromatography. The considered papers not only describe the applicability of the technique for relatively large sets of chiral analytes, they also showed that various types of stationary phases can be produced in-house in a simple manner. However, to survive as a mature separation technique, considerable time and effort are still needed to solve some disadvantages currently characterizing capillary electrochromatography. [source] Method development for direct detection of glycoproteins on aminophenylboronic acid functionalized self-assembled monolayers by matrix-assisted laser desorption/ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2009Kyung Kook Jang First page of article [source] Validated analysis of fluvastatin in a pharmaceutical capsule formulation and serum by capillary electrophoresisBIOMEDICAL CHROMATOGRAPHY, Issue 6 2001Dilek Do, rukol-Ak The capillary electrophoretic behavior and the determination of fluvastatin (FLU) in capsule and serum is described in this study. Method development was conducted in a fused-silica capillary (L,=,86,cm, Leff,=,58,cm and 75,µm i.d.) and a background electrolyte consisting of 10,mM borate at pH 8 was used. The separation was performed by current-controlled system applying 41,µA, detecting at 239,nm and injecting 0.5,s vacuum injection. A good electropherogram and excellent repeatability was obtained. FLU and phenobarbital sodium (internal standard) migrated (with RSD%) at 4.8 (0.3),min and 5.2 (0.6),min, respectively. Limit of detection (LOD) and limit of quantitation (LOQ) values were found to be 1,×,10,6,M and 2.89,×,10,6,M, respectively. Linearity in the range of 1.03,×,10,5 ,5.15,×,10,5 M was examined employing intra-day and inter-day studies and well-correlated calibration equations were obtained. FLU in a capsule (Lescol® 40,mg declared) was found to be 41.9,±,0.4,mg. Furthermore, FLU was determined in serum applying standard addition technique. Good repeatability and no interference were observed. The method proposed is simple, sensitive, precise and easy to use for the determination of FLU in capsule and serum. Copyright © 2001 John Wiley & Sons, Ltd. Abbreviations used: FLU fluvastatin HMG-CoA hydroxymethylglutaryl coenzyme [source] Historical review of sample preparation for chromatographic bioanalysis: pros and consDRUG DEVELOPMENT RESEARCH, Issue 3 2007Min S. Chang Abstract Sample preparation is a major task in a regulated bioanalytical laboratory. The sample preparation procedure significantly impacts assay throughput, data quality, analysis cost, and employee satisfaction. Therefore, selecting and optimizing an appropriate sample preparation method is essential for successful method development. Because of our recent expertise, this article is focused on sample preparation for high-performance liquid chromatography with mass spectrometric detection. Liquid chromatography with mass spectrometric detection (LC-MS) is the most common detection technique for small molecules used in regulated bioanalytical laboratories. The sample preparation technologies discussed are pre-extraction and post-extraction sample processing, protein precipitation (PPT), liquid,liquid extraction (LLE), offline solid-phase extraction (SPE), and online solid-phase extraction. Since all these techniques were in use for more than two decades, numerous applications and variations exist for each technique. We will not attempt to categorize each variation. Rather, the development history, a brief theoretical background, and selected references are presented. The strengths and the limitations of each method are discussed, including the throughput improvement potential. If available, illustrations from presentations at various meetings by our laboratory are used to clarify our opinion. Drug Dev Res 68:107,133, 2007. ©2007 Wiley-Liss, Inc. [source] CE-MS method development for peptides analysis, especially hepcidin, an iron metabolism markerELECTROPHORESIS, Issue 15 2009Gaëlle B. Martin Abstract A method for the resolution of a peptides mixture including hepcidin-25, an iron metabolism marker, was developed by CE-ESI-MS. Several strategies were tested to optimize peptide separation, such as the addition of cyclodextrins or organic solvents in the BGE or the use of coated capillaries. Best results in terms of resolution, symmetry and efficiency were obtained with a BGE made of 500,mM ammonium acetate pH 4.5/ACN 70:30,v/v. Using the methodology of experimental design, BGE concentration, sheath liquid composition and MS-coupling parameters were then optimized in order to obtain the best signal intensity for hepcidin. Finally, a 225,mM BGE and a sheath liquid composed of isopropanol/water 80:20,v/v containing 0.5%,v/v formic acid were selected as it constitutes the best compromise for selectivity, peak shape and sensitivity. [source] Determination of amino acids by micellar EKC: Recent advances in method development and novel applications to different matricesELECTROPHORESIS, Issue 1 2008Paolo Iadarola Professor Abstract The extensive use of CE for the analysis of amino acids has been well documented in a series of research articles and reviews. Aim of this report is to address the attention of the reader on the recent advances of micellar electrokinetic chromatography for the separation and determination of these analytes. Enhancements in selectivity of this technique through the use of pseudostationary phases containing mixed micelles, polymers, and chiral selectors are presented. Selected applications concerning separation and quantitation of even minute amounts of amino acids in: (i) biological fluids; (ii) microdialysates; (iii) plant cells; (iv) food stuff; and (v) pharmaceutical formulations have also been covered. Advantages of MEKC over other techniques for the amino acid analysis have been underlined. [source] A generic approach to the impurity profiling of drugs using standardised and independent capillary zone electrophoresis methods coupled to electrospray ionisation mass spectrometryELECTROPHORESIS, Issue 9 2005Aurélie Vassort Abstract Three standardised, capillary zone electrophoresis-electrospray ionisation mass spectrometry (CZE-ESI-MS) methods were developed for the analysis of six drug candidates and their respective process-related impurities comprising a total of 22 analytes with a range of functional groups and lipophilicities. The selected backround electrolyte conditions were found to be: 60/40 v/v 10 mM ammonium formate pH 3.5/organic, 60/40 v/v 10 mM ammonium acetate pH 7.0/organic and 10 mM piperidine, pH 10.5, where the organic solvent is 50/50 v/v methanol/acetonitrile. The coaxial sheath flow consisted of either 0.1% v/v formic acid in 50/50 v/v methanol/water, or 10 mM ammonium acetate in 50/50 v/v methanol/water, depending on the mixture being analysed. Factor analysis and informational theory were used to quantify the orthogonality of the methods and predict their complementarities. The three selected CZE-ESI-MS methods allowed the identification of 21 out of 22 of all the drug candidates and their process-related impurities and provided orthogonality with four established high-performance liquid chromatography-mass spectrometry (HPLC-MS) methods. These methodologies therefore form the basis of a generic approach to impurity profiling of pharmaceutical drug candidates and can be applied with little or no analytical method development, thereby offering significant resource and time savings. [source] Roxarsone and transformation products in chicken manure: Determination by capillary electrophoresis-inductively coupled plasma-mass spectrometryELECTROPHORESIS, Issue 7-8 2005Charlita G. Rosal Abstract The determination of the animal feed additive roxarsone (3-nitro-4-hydroxyphenylarsonic acid) and six of its possible transformation products (arsenite, arsenate, monomethylarsonate, dimethylarsinate, 3-amino-4-hydroxyphenylarsonic acid, and 4-hydroxyphenylarsonic acid) in chicken manure was investigated using capillary electrophoresis-inductively coupled plasma-mass spectrometry (CE-ICP-MS). Initial method development was conducted using ultraviolet (UV) detection for ruggedness and time efficiency. Separation of these seven arsenic species was effected using a 20,mM phosphate buffer at pH 5.7. The CE-ICP-MS limits of detection in terms of As for each of the species was in the low µg·L,1 range, corresponding to absolute detection limits in the range 20,70,fg As (based on a 23,nL injection). Overall, the method developed in this study provides high selectivity and low limits of detection (1,3,µg·L,1 or low-ppb, based on As), uses small sample volume (low nL), and produces minimal wastes. [source] Ground Water Modeling Applications Using the Analytic Element MethodGROUND WATER, Issue 1 2006Randall J. Hunt Though powerful and easy to use, applications of the analytic element method are not as widespread as finite-difference or finite-element models due in part to their relative youth. Although reviews that focus primarily on the mathematical development of the method have appeared in the literature, a systematic review of applications of the method is not available. An overview of the general types of applications of analytic elements in ground water modeling is provided in this paper. While not fully encompassing, the applications described here cover areas where the method has been historically applied (regional, two-dimensional steady-state models, analyses of ground water,surface water interaction, quick analyses and screening models, wellhead protection studies) as well as more recent applications (grid sensitivity analyses, estimating effective conductivity and dispersion in highly heterogeneous systems). The review of applications also illustrates areas where more method development is needed (three-dimensional and transient simulations). [source] MHC Class II epitope predictive algorithmsIMMUNOLOGY, Issue 3 2010Morten Nielsen Summary Major histocompatibility complex class II (MHC-II) molecules sample peptides from the extracellular space, allowing the immune system to detect the presence of foreign microbes from this compartment. To be able to predict the immune response to given pathogens, a number of methods have been developed to predict peptide,MHC binding. However, few methods other than the pioneering TEPITOPE/ProPred method have been developed for MHC-II. Despite recent progress in method development, the predictive performance for MHC-II remains significantly lower than what can be obtained for MHC-I. One reason for this is that the MHC-II molecule is open at both ends allowing binding of peptides extending out of the groove. The binding core of MHC-II-bound peptides is therefore not known a priori and the binding motif is hence not readily discernible. Recent progress has been obtained by including the flanking residues in the predictions. All attempts to make ab initio predictions based on protein structure have failed to reach predictive performances similar to those that can be obtained by data-driven methods. Thousands of different MHC-II alleles exist in humans. Recently developed pan-specific methods have been able to make reasonably accurate predictions for alleles that were not included in the training data. These methods can be used to define supertypes (clusters) of MHC-II alleles where alleles within each supertype have similar binding specificities. Furthermore, the pan-specific methods have been used to make a graphical atlas such as the MHCMotifviewer, which allows for visual comparison of specificities of different alleles. [source] The Life Trajectory Interview for Youth (LTI-Y): method development and psychometric properties of an instrument to assess life-course models and achievementINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 4 2006Ryan A. Brown Abstract This paper describes the rationale, development and psychometric properties of the Life Trajectory Interview for Youth (LTI-Y), an instrument designed to assess cognitive models of the life course and life-course achievement. This method was developed over 13 months of pilot research, and applied with a population of 350 participants from the Great Smoky Mountain Study, a longitudinal epidemiological study of mental health in western North Carolina comprising 1420 youths (among them 350 Cherokee Native Americans). The LTI-Y is designed to address gaps in our understanding of the links between large-scale structural conditions and social processes and individual outcomes such as mental health. Scale consistency (n = 350) was good to high, whereas test-retest reliability in a limited sample (n = 18) was moderate to good, depending on the domain and dimension of data considered. Overall, psychometric properties indicate fairly stable and consistent life-course strategies and priorities. Although developed and piloted with youth from Western North Carolina, the methods described could be applied to any population of interest. Copyright © 2006 John Wiley & Sons, Ltd. [source] Determination of BAPTA-AM, the acetoxymethyl tetraester of BAPTA, in rat plasma by liquid chromatography tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 12 2006Feng Zheng Abstract BAPTA-AM is the acetoxymethylester of the calcium chelator BAPTA and has demonstrated efficacy in several animal models of cerebral ischemia. This paper describes the development of a method for the determination of BAPTA-AM in rat plasma by liquid chromatography/tandem mass spectrometry. Owing to multiple ester groups in the structure of BAPTA-AM, [M + Na]+ was chosen as the analytical ion for quantification of BAPTA-AM. During the analytical method development, a high percentage of organic solvent and the addition of an amount of sodium acetate and formic acid in the mobile phase were found to favor the sensitivity and reproducibility of [M + Na]+. Poor fragmentation was usually observed in the MS/MS spectra of sodium adduct ions. However, abundant and reproducible fragment ions were observed for the BAPTA-AM sodium adduct ion, and therefore the traditional selective reaction-monitoring mode was used to further improve the sensitivity of MS detection. Because of the lability of the ester bond, a combination of fluoride and hydrochloric acid was applied to minimize the enzymatic hydrolysis, and acetonitrile was chosen to avoid the chemical hydrolysis or solvolysis during the sample collection and preparation procedure. On the basis of these studies, a rapid, sensitive and reproducible method for the determination of BAPTA-AM in rat plasma, using LC/ESI-MS/MS and a simple protein precipitation procedure, was developed and validated. Also, the present method was successfully applied to the determination of BAPTA-AM plasma concentrations for pharmacokinetic studies in rats. Copyright © 2006 John Wiley & Sons, Ltd. [source] Determination of trace organophosphorus pesticides in water samples with TiO2 nanotubes cartridge prior to GC-flame photometric detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2010Yunrui Huang Abstract This article described a new method for the sensitive determination of organophosphorus pesticides in water samples using SPE in combination with GC-flame photometric detection. In the procedure of method development, TiO2 nanotubes were used as SPE adsorbents for the enrichment of organophosphorus pesticides from water samples. Several factors, such as eluent and its volume, sample pH, sample volume, sample flow rate, and concentration of humic acid, were optimized. Under the optimal conditions, the proposed method had good linear ranges as 0.1,40,,g/L for each of them, LOD of 0.11, 0.014, and 0.0025,,g/L, and LOQs of 0.37, 0.047, and 0.0083,,g/L for chlorpyrifos, phorate, and methyl parathion, respectively. The proposed method was validated with real environmental water samples and the spiked recoveries were over the range of 86.5,115.1%. All these results indicated that TiO2 nanotubes, as a new SPE adsorbent, would be used widespread for the preconcentraiton and determination of environmental pollutants in the future. [source] Influence of stationary phase chemistry and mobile-phase composition on retention, selectivity, and MS response in hydrophilic interaction chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2010Kenneth J. Fountain Abstract A comprehensive retention and selectivity characterization of several hydrophilic interaction chromatography (HILIC) stationary phases was performed with 28 test probes in order to study the influence of particle type, surface chemistry, and mobile-phase pH on chromatographic retention, selectivity, and MS response. Selectivity differences were compared for columns operated at both low and high pH, while ESI-MS was used to study the effects of mobile-phase pH on signal response. Additionally, acetone was explored as a potential alternative to ACN as the weak HILIC solvent. Moderate differences in selectivity were observed on the same column operated at different pH, mostly due to acidic compounds. In addition, the MS response increased when a high pH mobile phase was used, particularly for analytes that were ionized with negative ESI-MS. Even larger selectivity differences were observed for different stationary phases evaluated with the same mobile phase. Acetone was not a suitable replacement for ACN in routine HILIC separations due to differences in selectivity and MS response. Finally, the data from this study were used to establish guidelines for rapid HILIC method development of polar compounds, which is demonstrated with a mixture of histidine dipeptides and organophosphonate nerve agent metabolites. [source] Evaluation of use of a very short polar microbore column segment in high-speed gas chromatography analysisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2008Peter Quinto Tranchida Abstract Very fast GC analyses are commonly carried out by using 10 m×0.1 mm id capillaries. In order to achieve rapid elution times (1,3 min), the latter are operated under suboptimum conditions. The present research is focused on the evaluation of use of a 0.1 mm id polar column segment (2 m), operated under near-to-optimum conditions, in very fast GC analysis. The results attained are compared with those derived from using a 10 m microbore column in very fast GC experiments. Prior to method development, the effects of gas velocity, temperature program rate, and sample amounts on analytical performance were evaluated. Following these preliminary applications, a complex lipidic sample, cod liver oil, was subjected to rapid separation (,2.1 min) on the 10 m capillary through the application of a 50°C/min temperature rate and a 130 cm/s gas velocity. The same matrix was analyzed on the 2 m capillary using the same temperature program rate and range, but with a close-to-ideal linear velocity. The results observed were of interest, as the separation was achieved in less time (1.45 min) with improved peak resolution. Finally, both methods were validated in terms of retention time and peak area repeatability, LOQ, and linearity. [source] Pharmaceutical analysis by supercritical fluid chromatography: Optimization of the mobile phase composition on a 2-ethylpyridine columnJOURNAL OF SEPARATION SCIENCE, JSS, Issue 8 2008Claudio Brunelli Abstract The separation of neutral, acidic, and basic pharmaceuticals with diverse physicochemical properties by packed column supercritical fluid chromatography (pSFC) on a 2-ethylpyridine column (25 cm×4.6 mm id, 3 ,m particles) is presented. The optimization strategy involved separations at 100% methanol (MeOH) and at 50% MeOH/50% ACN while keeping the peak symmetry additives formic acid (FA) and isopropylamine (IPA) at constant levels of 0.25% v/v. By plotting the adjusted retention times as a function of the MeOH/ACN ratio, an optimal modifier ratio composition of 65% MeOH/35% ACN was found. The total set of 26 neutral, acidic, and basic pharmaceuticals was analyzed and the optimal composition experimentally verified. This mobile phase composition is currently used in pharmaceutical method development and open-access generic screening environments. [source] Determination of the small cell lung cancer associated biomarker pro-gastrin-releasing peptide (ProGRP) using LC-MSJOURNAL OF SEPARATION SCIENCE, JSS, Issue 2 2007Bjørn Winther Abstract Small cell lung cancer is a rapidly growing neoplasm with high mortality. A recently discovered biomarker, pro-gastrin-releasing peptide (ProGRP), is used as a specific diagnostic marker for the disease. The present methods of quantification are based on the immunoassay techniques RIA and ELISA. Our object was to develop an LC-MS method for the detection and quantification of ProGRP using specific tryptic digestion products from the recombinant peptide ProGRP (31,98), a sequence common to three isoforms of ProGRP. The conditions for enzymatic cleavage were optimized and MS compatibility was obtained. Digestion of ProGRP (31,98) yielded an array of peptide products and these were evaluated for further method development. The peptide product NLLGLIEAK proved to be the preferable candidate to monitor ProGRP due to signal intensity, column retention, and peptide specificity. The identity of this product was verified by means of LC-MS/MS and the linearity of the calibration curve evaluated. LOD was calculated to be 13.9 pg on column (O.C.). Plasma samples spiked with ProGRP (31,98) prior to digestion verified the suitability of this digest product for the determination of ProGRP. LC-MS may prove to be a valuable tool for biomarker mediated diagnosis in the future. [source] SPME , A valuable tool for investigation of flower scentJOURNAL OF SEPARATION SCIENCE, JSS, Issue 8 2003Petr Barták Abstract A novel Headspace Solid Phase Microextraction (HS-SPME) protocol is proposed for the analysis of floral scent. Volatile compounds emitted from the flower are collected on a Carboxen/PDMS fiber for 1 hour, transferred to the GC, and analyzed by GC/MS. The method completely eliminates the use of organic solvents, does not require special instrumentation, and may readily be performed in the field without access to mains electricity and other energy supplies. The method is robust, sensitive, and reduces the sampling stress on the investigated plant. Since enzymatic reactions in living flowers may cause changes in the composition of emitted fragrance, dried rosemary (Rosmarinus officinalis L.) was used as a stable standard for the method development and optimization. In addition, grape wine was also suggested as homogeneous, bio-compatible, and relatively stable standard of pronounced and typical scent for the same purpose. The optimized method was used for the comparative investigation of the fragrances emitted by two different species , Lathyrus vernus (L.) and Orchis pallens (L.). Several monoterpenes (C10 compounds) were found as the main fragrance components of lathyrus, while sesquiterpenes (C15 compounds) were typical for the orchid. [source] A PRACTICAL GUIDE FOR THE DEVELOPMENT OF A WETLAND ASSESSMENT METHOD: THE CALIFORNIA EXPERIENCE,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2006Martha A. Sutula ABSTRACT: Wetland rapid assessment methods (RAMs) can provide a cost effective, scientifically defensible estimate of wetland and riparian condition for use in ambient and project monitoring in resource management and regulatory programs. Those who have chosen to develop a RAM to assess wetland and riparian condition are faced with a range of issues and important choices that they must make throughout the development process. This paper is intended as a practical guide to RAM development. Six basic stages in the RAM development process are discussed: (1) organize RAM development by identifying the intended applications, assessment endpoints, and geographic scope of the RAM and forming appropriate teams to advise and review the development process and its products; (2) build a scientific foundation for method development by conducting a literature review, choosing a wetland classification system, building conceptual models, and identifying the major assumptions underlying the model; (3) assemble the method as a system of attributes and metrics that describe a full range of conditions; (4) verify the ability of the method to distinguish between wetlands along a continuum of conditions; (5) calibrate and validate the method against sets of quantitative data representing more intensive measures of wetland condition; and (6) implement the method through outreach and training of the intended users. Important considerations within each of these stages lead to choices in accuracy, precision, robustness, ease of use, and cost. These are identified and the tradeoffs of the various options discussed. Experience with the ongoing development and implementation of the California Rapid Assessment Method (CRAM) is used to illustrate these stages and associated choices in RAM development. [source] Technical advance in fungal biotechnology: development of a miniaturized culture method and an automated high-throughput screeningLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2009F. Alberto Abstract Aims:, The goal of the study was to develop a reliable, reproducible and rapid method of culture in order to screen a large number of fungal transformants. Methods and Results:, The method is based upon miniaturized cell cultures and automated expression screening in microwell plates. For the method development, 50 recombinant Aspergillus vadensis clones producing feruloyl esterase B (FaeB) from Aspergillus niger were screened in 6 days. Then a panel of clones showing various behaviours was checked in flasks in order to demonstrate the reproducibility of the method. Using this method, a transformant of A. vadensis producing 1·2 g l,1 of FaeB was selected (12-fold more than the A. niger overproducing strain). Conclusions:, This miniaturized culture method allows to obtain reliable and reproducible results. The procedure has the advantages of being efficient, time-saving and more efficient than conventional in-flask culture screening as it can screen 800 clones per day after a culture of 3 days. Significance and Impact of the Study:, This method could be applied to any other fungal strain culture, enzyme activity or biodiversity screening. [source] Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update covering the period 2001,2002MASS SPECTROMETRY REVIEWS, Issue 2 2008David J. Harvey Abstract This review is the second update of the original review on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates that was published in 1999. It covers fundamental aspects of the technique as applied to carbohydrates, fragmentation of carbohydrates, studies of specific carbohydrate types such as those from plant cell walls and those attached to proteins and lipids, studies of glycosyl-transferases and glycosidases, and studies where MALDI has been used to monitor products of chemical synthesis. Use of the technique shows a steady annual increase at the expense of older techniques such as FAB. There is an increasing emphasis on its use for examination of biological systems rather than on studies of fundamental aspects and method development and this is reflected by much of the work on applications appearing in tabular form. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 27:125,201, 2008 [source] Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update covering the period 1999,2000MASS SPECTROMETRY REVIEWS, Issue 4 2006David J. Harvey Abstract This review describes the use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates and continues coverage of the field from the previous review published in 1999 (D. J. Harvey, Matrix-assisted laser desorption/ionization mass spectrometry of carbohydrates, 1999, Mass Spectrom Rev, 18:349,451) for the period 1999,2000. As MALDI mass spectrometry is acquiring the status of a mature technique in this field, there has been a greater emphasis on applications rather than to method development as opposed to the previous review. The present review covers applications to plant-derived carbohydrates, N- and O- linked glycans from glycoproteins, glycated proteins, mucins, glycosaminoglycans, bacterial glycolipids, glycosphingolipids, glycoglycerolipids and related compounds, and glycosides. Applications of MALDI mass spectrometry to the study of enzymes acting on carbohydrates (glycosyltransferases and glycosidases) and to the synthesis of carbohydrates, are also covered. © 2006 Wiley Periodicals, Inc., Mass Spec Rev 25:595,662, 2006 [source] Neue Methoden zur Beurteilung der Betriebsfestigkeit im Fahrzeugauslegungs- und -absicherungsprozessMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 10 2008M. Brune Fatigue strength; design and validation process; method development; load data simulation; lightweight design; short fibre reinforced polymers; material porosity; die casted aluminium Abstract Der moderne Auslegungs- und Absicherungsprozess in der Automobilindustrie beinhaltet experimentelle, messtechnische und auch rechnerische Methoden. Dieser Beitrag erläutert anhand von Beispielen neue Entwicklungen in der Betriebsfestigkeitsauslegung, insbesondere auf dem Gebiet der virtuellen Methoden. Dies bezieht sich zum einen auf die virtuelle Lastdatenermittlung, zum anderen auf die Verbesserung der rechnerischen Lebensdauerabschätzung. Hier werden zwei aktuelle Beispiele der Methodenentwicklung erläutert. Das erste Beispiel behandelt die Berücksichtigung von Werkstoffinhomogenitäten bei der Berechnung von Aluminium-Gussbauteilen, das zweite Beispiel beschreibt die Vorgehensweise der Auslegung von Bauteilen aus kurzfaserverstärkten Kunststoffen mittels eines neuen Berechnungsverfahrens. Advanced durability evaluation in vehicle design and validation process The modern process of evaluation and validation conducted in the automotive industry uses experimental, metrological, and calculation-based methods. Offering various examples, the present paper describes new developments in the determination and evaluation of operating strength, particularly in terms of virtual methods and their application in practice. The first point considered is the virtual determination of load data, the second is the improvement of calculated fatigue life. Two current examples in the development of methods are presented in this context: The first example examines the inhomogeneity of materials in calculating aluminium castings. The second example describes the approach taken in the configuration of components made of short-fibre-reinforced polymers, applying a new method of calculation. [source] High-throughput quantification of selenium in individual serum proteins from a healthy human population using HPLC on-line with isotope dilution inductively coupled plasma-MSPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 19 2010Sophia Letsiou Abstract In this study, a method, based on dual column affinity chromatography hyphenated to isotope dilution inductively coupled plasma,quadrupole MS, was developed for selenium determination in selenoprotein P, glutathione peroxidase, and selenoalbumin in human serum samples from a group of healthy volunteers (n=399). Method improvement was achieved using methanol-enhanced isotope dilution which resulted in improved sensitivity and removal of isobaric interferences. Although no human serum reference materials are currently certified for their selenium species levels, method development was conducted using human serum reference material BCR 637 and 639 as their Se species content has been reported in the previous studies, and thus comparisons were possible. The mean selenium concentrations determined for the 399 healthy volunteer serum samples were 23±10,ng Se mL,1 for glutathione peroxidase, 49±15,ng Se mL,1 for selenoprotein P and 11±4,ng Se mL,1 for selenoalbumin. These values are found to be in close agreement with published values for a limited number of healthy volunteer samples, and to establish baseline Se levels in serum proteins for an apparently healthy group of individuals, thus allowing for subsequent comparisons with respective values determined for groups of individuals with selenium related health issues, as well as assist in the discovery of potential selenium biomarkers. Also, the relationship between Se serum protein levels and some anthropometric characteristics of the volunteer population were investigated. Additionally, further development of the analytical method used in this study was achieved by adding a size exclusion chromatography column after the two affinity columns via a switching valve. This allowed for the separation of small selenium-containing molecules from glutathione peroxidase and thus enhanced the overall confidence in its identification. [source] Mass spectrometry in clinical proteomics , from the present to the futurePROTEOMICS - CLINICAL APPLICATIONS, Issue 1 2009Magnus Palmblad Abstract MS is an important analytical tool in clinical proteomics, primarily in the disease-specific discovery, identification and characterisation of proteomic biomarkers and patterns. MS-based proteomics is increasingly used in clinical validation and diagnostic method development. The latter departs from the typical application of MS-based proteomics by exchanging some of the high performance of analysis for the throughput, robustness and simplicity required for clinical diagnostics. Although conventional MS-based proteomics has become an important field in clinical applications, some of the most recent MS technologies have not yet been extensively applied in clinical proteomics. In this review, we will describe the current state of MS in clinical proteomics and look to the future of this field. [source] | |||||||||||||||||||||||||||||||