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Analytical Capabilities (analytical + capability)
Selected AbstractsAccelerator mass spectrometry offers new opportunities for microdosing of peptide and protein pharmaceuticalsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 10 2010Mehran Salehpour Accelerator Mass Spectrometry (AMS) is an ultra-sensitive analytical method which has been instrumental in developing microdosing as a strategic tool in early drug development. Considerable data is available for AMS microdosing using typical pharmaceutical drugs with a molecular weight of a few hundred Daltons. The so-called biopharmaceuticals such as proteins offer interesting possibilities as drug candidates; however, experimental data for protein microdosing and AMS is scarce. The analysis of proteins in conjunction with early drug development and microdosing is overviewed and three case studies are presented on the topic. In the first case study AMS experimental data is presented, for the measured concentration of orally administered recombinant insulin in the blood stream of laboratory rabbits. Case study 2 concerns minimum sample size requirements. AMS samples normally require about 1,mg of carbon (10,µL of blood) which makes AMS analysis unsuitable in some applications due to the limited availability of samples such as human biopsies or DNA from specific cells. Experimental results are presented where the sample size requirements have been reduced by about two orders of magnitude. The third case study concerns low concentration studies. It is generally accepted that protein pharmaceuticals may be potentially more hazardous than smaller molecules because of immunological reactions. Therefore, future first-in-man microdosing studies might require even lower exposure concentrations than is feasible today, in order to increase the safety margin. This issue is discussed based on the current available analytical capabilities. Copyright © 2010 John Wiley & Sons, Ltd. [source] Comprehensive plasma-screening for known and unknown substances in doping controlsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2010Andreas Thomas Occasionally, doping analysis has been recognized as a competitive challenge between cheating sportsmen and the analytical capabilities of testing laboratories. Both have made immense progress during the last decades, but obviously the athletes have the questionable benefit of frequently being able to switch to new, unknown and untested compounds to enhance their performance. Thus, as analytical counteraction and for effective drug testing, a complementary approach to classical targeted methods is required in order to implement a comprehensive screening procedure for known and unknown xenobiotics. The present study provides a new analytical strategy to circumvent the targeted character of classical doping controls without losing the required sensitivity and specificity. Using 50,µL of plasma only, the method potentially identifies illicit drugs in low ng/mL concentrations. Plasma provides the biological fluid with the circulating, unmodified xenobiotics; thus the identification of unknown compounds is facilitated. After a simple protein precipitation, liquid chromatographic separation and subsequent detection by means of high resolution/high accuracy orbitrap mass spectrometry, the procedure enables the determination of numerous compounds from different classes prohibited by the World Anti-Doping Agency (WADA). A new hyphenated mass spectrometry technology was employed without precursor ion selection for higher collision energy dissociation (HCD) fragmentation experiments. Thus the mass spectra contained all the desired information to identify unknown substances retrospectively. The method was validated for 32 selected model compounds for qualitative purposes considering the parameters specificity, selectivity, limit of detection (<0.1,10,ng/mL), precision (9,28%), robustness, linearity, ion suppression and recovery (80,112%). In addition to the identification of unknown compounds, the plasma samples were simultaneously screened for known prohibited targets. Copyright © 2010 John Wiley & Sons, Ltd. [source] Assessing Ceramic Compositional Data: A Comparison of Total Reflection X-ray Fluorescence and Instrumental Neutron Activation Analysis On Late Iron Age Spanish Celtiberian CeramicsARCHAEOMETRY, Issue 3 2001M. García-Heras A solid-phase, non-chemical processing protocol was recently developed as a means of chemically characterizing archaeological ceramics by total reflection X-ray fluorescence (TXRF). Following this methodology, TXRF can provide semi-quantitative determinations for 18 elements with comparable levels of precision and accuracy for the majority of them in comparison with a clay reference material analysed by instrumental neutron activation (INAA). In order critically to assess the analytical capabilities of TXRF, a large sample set of Late Iron Age Spanish Celtiberian ceramics and modern clays was analysed both by TXRF and INAA. Semi-quantitative chemical data provided by TXRF and quantitative data provided by INAA were subjected to commonly used multivariate statistical methods as a way of evaluating the ability of the new technique to discriminate among different compositional groups. The comparison of the two data sets shows no significant discrepancies, thereby allowing support for the same archaeological interpretation. These results suggest that TXRF has potential applicability for compositional characterization of archaeological ceramics, providing data that are useful for provenance studies. [source] PTR-TOF-MS and data-mining methods for rapid characterisation of agro-industrial samples: influence of milk storage conditions on the volatile compounds profile of Trentingrana cheese,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2010Alessandra Fabris Abstract Proton transfer reaction-mass spectrometry (PTR-MS), a direct injection mass spectrometric technique based on an efficient implementation of chemical ionisation, allows for fast and high-sensitivity monitoring of volatile organic compounds (VOCs). The first implementations of PTR-MS, based on quadrupole mass analyzers (PTR-Quad-MS), provided only the nominal mass of the ions measured and thus little chemical information. To partially overcome these limitations and improve the analytical capability of this technique, the coupling of proton transfer reaction ionisation with a time-of-flight mass analyser has been recently realised and commercialised (PTR-TOF-MS). Here we discuss the very first application of this new instrument to agro-industrial problems and dairy science in particular. As a case study, we show here that the rapid PTR-TOF-MS fingerprinting coupled with data-mining methods can quickly verify whether the storage condition of the milk affects the final quality of cheese and we provide relevant examples of better compound identification in comparison with the previous PTR-MS implementations. In particular, ,Trentingrana' cheese produced by four different procedures for milk storage are compared both in the case of winter and summer production. It is indeed possible to set classification models with low prediction errors and to identify the chemical formula of the ion peaks used for classification, providing evidence of the role that this novel spectrometric technique can play for fundamental and applied agro-industrial themes. Copyright © 2010 John Wiley & Sons, Ltd. [source] Fourier-transform Raman spectroscopy of archaeological resinsJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2008Howell G. M. Edwards Abstract The adoption of Raman spectroscopy as a first-pass screening technique for the presence of organic compounds on diverse substrates is now being advocated for the non-destructive examination of potential sites for limited sampling for other analytical techniques. In this paper, examples of the analytical capability of Raman spectroscopy using long wavelength excitation in the near infrared for the characterisation of archaeological resins from Egyptian Dynastic and pre-Dynastic periods and artefacts are used to illustrate the advantages and limitations of the technique. The resin specimens and artefacts span a period of about 7000 years. Raman spectra have been obtained of resin specimens from archaeological sites and of resins on several artefacts; from the latter it is possible to assess the influence of diverse substrates upon the spectral information that can be derived from the resins themselves. Key molecular spectral features are proposed for each resin studied and the presence of degradation assessed. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||