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Analytical Steps (analytical + step)
Selected AbstractsRapid screening and confirmation of drugs and toxic compounds in biological specimens using liquid chromatography/ion trap tandem mass spectrometry and automated library searchRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2010Hsiu-Chuan Liu Recent advances in liquid chromatography/tandem mass spectrometry (LC/MS/MS) technology have provided an opportunity for the development of more specific approaches to achieve the ,screen' and ,confirmation' goals in a single analytical step. For this purpose, this study adapts the electrospray ionization ion trap LC/MS/MS instrumentation (LC/ESI-MS/MS) for the screening and confirmation of over 800 drugs and toxic compounds in biological specimens. Liquid-liquid and solid-phase extraction protocols were coupled to LC/ESI-MS/MS using a 1.8-µm particle size analytical column operated at 50°C. Gradient elution of the analytes was conducted using a solvent system composed of methanol and water containing 0.1% formic acid. Positive-ion ESI-MS/MS spectra and retention times for each of the 800 drugs and toxic compounds were first established using 1,10,µg/mL standard solutions. This spectra and retention time information was then transferred to the library and searched by the identification algorithm for the confirmation of compounds found in test specimens , based on retention time matches and scores of fit, reverse fit, and purity resulting from the searching process. The established method was found highly effective when applied to the analyses of postmortem specimens (blood, urine, and hair) and external proficiency test samples provided by the College of American Pathology (CAP). The development of this approach has significantly improved the efficiency of our routine laboratory operation that was based on a two-step (immunoassay and GC/MS) approach in the past. Copyright © 2009 John Wiley & Sons, Ltd. [source] Scientific workflow management and the Kepler systemCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 10 2006Bertram Ludäscher Abstract Many scientific disciplines are now data and information driven, and new scientific knowledge is often gained by scientists putting together data analysis and knowledge discovery ,pipelines'. A related trend is that more and more scientific communities realize the benefits of sharing their data and computational services, and are thus contributing to a distributed data and computational community infrastructure (a.k.a. ,the Grid'). However, this infrastructure is only a means to an end and ideally scientists should not be too concerned with its existence. The goal is for scientists to focus on development and use of what we call scientific workflows. These are networks of analytical steps that may involve, e.g., database access and querying steps, data analysis and mining steps, and many other steps including computationally intensive jobs on high-performance cluster computers. In this paper we describe characteristics of and requirements for scientific workflows as identified in a number of our application projects. We then elaborate on Kepler, a particular scientific workflow system, currently under development across a number of scientific data management projects. We describe some key features of Kepler and its underlying Ptolemy II system, planned extensions, and areas of future research. Kepler is a community-driven, open source project, and we always welcome related projects and new contributors to join. Copyright © 2005 John Wiley & Sons, Ltd. [source] New approach for rapid detection of known hemoglobin variants using LC-MS/MS combined with a peptide database,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2007F. Basilico Abstract The identification of hemoglobin (Hb) variants is usually performed by means of different analytical steps and methodologies. Phenotypic methods, such as gel electrophoresis and high performance liquid chromatography, are used to detect the different electrophoretic or chromatographic behaviors of hemoglobin variants in comparison to HbA0 used as a control. These data often need to be combined with mass spectrometry analyses of intact globins and their tryptic peptide mixtures. As an alternative to a ,step-by-step' procedure, we have developed a ,single step' approach for the identification of Hb variants present in biological samples. This is based on the µHPLC-ESI-MS/MS analysis of the peptide mixture generated by a tryptic digestion of diluted Hb samples and an in-house new database containing solely the variant tryptic peptide of known human Hb variants. The experimental results (full MS and MS/MS spectra) are correlated with theoretical mass spectra generated from our in-house-built variant peptide database (Hbp) using the SEQUEST algorithm. Simple preparation of samples and an automated identification of the variant peptide are the main characteristics of this approach, making it an attractive method for the detection of Hb variants at the routine clinical level. We have analyzed 16 different samples, each containing a different known variant of hemoglobin. Copyright © 2006 John Wiley & Sons, Ltd. [source] Characterisation of proteinaceous binders in artistic paintings by chromatographic techniquesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2004Maria Perla Colombini Abstract This review discusses the application of chromatographic techniques (GC, HPLC and Py-GC) for the characterisation of proteinaceous materials in artistic paintings. The focus is on the various analytical steps that are needed to determine these natural materials in paint samples, from sampling and sample pre-treatment, including various methods of hydrolysis and derivatisation for GC and HPLC, to approaches for data evaluation. [source] | ||||||||||