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Other Analytical Methods (other + analytical_methods)
Selected AbstractsIEF in microfluidic devicesELECTROPHORESIS, Issue 5 2009Greg J. Sommer Abstract IEF is one of the most powerful and prevalent techniques used in separation sciences. The power of IEF comes from the fact that it not only separates analytes based on their pI but also focuses them into highly resolved bands. In line with the miniaturization trend spurring the analytical community, the past decade has yielded a wealth of research focused on implementing IEF in microfluidic chip-based formats (,IEF). Scaling down the separation technique provides several advantages such as reduced sample sizes, assay automation, and significant improvements in assay speed without sacrificing separation performance. Besides presenting microscale adaptations of standard schemes, researchers have also developed improved detection techniques, demonstrated novel ,IEF assays, and incorporated ,IEF with other analytical methods for achieving on-chip multidimensional separations. This review provides a brief historical outline of IEF's beginnings, theoretical incentives driving miniaturization of the methodology, a thorough synopsis of ,IEF publications to date, and an outlook to the future. [source] Investigation of interaction between human hemoglobin A0 and platinum anticancer drugs by capillary isoelectric focusing with whole column imaging detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2008Tibebe Lemma Abstract CIEF with whole column imaging detection (WCID) was used to investigate the interaction of platinum-based anticancer drugs, cis -platinum(II) diamine dichloride (cisplatin) and [SP-4-2-{1R-trans)]-(1,2-cyclohexanediamine- N,N,)[ethanedioata(2,)- O,O,]platinum (oxaliplatin), with human hemoglobin A0 (Hb). This technique facilitates the investigation and characterization of the formation of adducts between drugs and proteins. Cisplatin and oxaliplatin were mixed with the target protein at different concentrations (0:1, 1:1, 1:10, 1:50, and 1:100), and the reaction mixtures were incubated for 0, 0.5, 1, 12, 24, 48, and 72 h at 37°C in a water-bath. The focused Hb,drug adduct profiles were imaged by WCID. At higher drug to protein molar ratios (for both oxaliplatin and cisplatin), the results exhibit significant changes in the peak shapes and heights, which may indicate the destabilization of the protein. However, the conformational change was less evident at lower molar ratios. In addition, a major pI shift was observed for the oxaliplatin reaction mixtures (for 1:10, 1:50, and 1:100 ratios). In comparison with previously reported findings obtained by other analytical methods, conclusions were drawn about the validity of CIEF as a simple and convenient method for the investigation of protein,drug interactions. These results may provide useful information for further understanding the activity and toxicity of these chemotherapeutic drugs and improving their clinical performance. [source] How Did Mississippians Prepare Maize?ARCHAEOMETRY, Issue 1 2004The Application of Compound-Specific Carbon Isotope Analysis to Absorbed Pottery Residues From Several Mississippi Valley Sites A newly developed compound-specific stable carbon isotope technique allows the detection of maize in absorbed organic pottery residues. This method was applied to absorbed organic residues from a variety of Mississippi Valley potsherds, and successfully identified maize components. Maize was cooked in sampled vessels less often than expected, but otherwise fitted expected patterns of maize use derived from stable carbon isotope analysis of human bone from the region. Absorbed organic pottery residue analysis is useful in determining pottery use, particularly in concert with other analytical methods. [source] Interpretation of the Thermogravimetric Curves of Ancient Pozzolanic ConcretesARCHAEOMETRY, Issue 4 2001F. Branda Pozzolanic concretes submitted to thermogravimetric (TG) analysis show a continuous weight loss starting from about 400 °C. In order to reconcile these observations with those from other analytical methods, it is necessary to attribute this weight loss to CO2 removal. It has been proposed, in the literature, that silicates and CaCO3 react at lower temperatures, producing calcium silicates and CO2. In this paper, the FTIR spectra collected on samples submitted to TG analysis, stopped at conveniently selected temperatures, provide direct evidence that the continuous weight loss recorded with thermogravimetric analysis of the pozzolanic concrete in the temperature range 400,900 °C is to be attributed to the reaction between the silicates and calcite, with the formation of CO2 and of a silicate that is richer in CaO. Therefore it is justifiable that the whole weight loss, in the temperature range 400,900 °C, should be taken into account in the calculation of the CaCO3 content of the concrete. Moreover, the described procedure,of recovering small samples (2 mg) from the sample-holder of the TG apparatus at various steps of the heating rate and comparing the FTIR spectra,can help in identifying the pozzolanic nature of a concrete that, in general, is not easily recognizable from the trend of the thermoanalytical curve. [source] Product and contaminant measurement in bioprocess development by SELDI-MSBIOTECHNOLOGY PROGRESS, Issue 3 2010Alex Berrill Abstract Bioprocesses for therapeutic protein production typically require significant resources to be invested in their development. Underlying these efforts are analytical methods, which must be fit for the purpose of monitoring product and contaminants in the process. It is highly desirable, especially in early-phase development when material and established analytical methods are limiting, to be able to determine what happens to the product and impurities at each process step with small sample volumes in a rapid and readily performed manner. This study evaluates the utility of surface-enhanced laser desorption ionization mass spectroscopy (SELDI-MS), known for its rapid analysis and minimal sample volumes, as an analytical process development tool. In-process samples from an E. coli process for apolipoprotein A-IM (ApoA-IM) manufacture were used along with traditional analytical methods such as HPLC to check the SELDI-MS results. ApoA-IM is a naturally occurring variant of ApoA-I that appears to confer protection against cardiovascular disease to those that carry the mutated gene. The results show that, unlike many other analytical methods, SELDI-MS can handle early process samples that contain complex mixtures of biological molecules with limited sample pretreatment and thereby provide meaningful process-relevant information. At present, this technique seems most suited to early-phase development particularly when methods for traditional analytical approaches are still being established. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | ||||||||||