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Analytical Parameters (analytical + parameter)
Selected AbstractsA 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] Determination of tryptamine derivatives in illicit synthetic drugs by capillary electrophoresis and ultraviolet laser-induced fluorescence detectionELECTROPHORESIS, Issue 12 2005Carolin Huhn Abstract A method based on separation by capillary electrophoresis combined with UV-laser-induced fluorescence detection (,ex,=,266,nm) was developed for the determination of nine tryptamine derivatives of forensic interest and potential matrix constituents. The composition of the separation electrolyte was optimized with respect to the resolution of solutes of interest and to the sensitivity of fluorescence detection. Native ,-cyclodextrin was employed as a complex forming modifier of the electrophoretic separation and fluorescence-enhancing agent. With the help of a stacking procedure, limits of detection of 0.1,6,µg/L for all analytes were obtained. The repeatability for the peak area (at a concentration of the analyte about 100 times the LOD) was less than 2.3%,RSD. A second HPLC method was developed, and its analytical parameters were evaluated for an estimation of the accuracy of the CE-LIF method and for method comparison. The results of the determination of tryptamine derivatives in the samples of forensic interest obtained with the two independent methods are in good agreement. [source] When Thailand was an island , the phylogeny and biogeography of mite harvestmen (Opiliones, Cyphophthalmi, Stylocellidae) in Southeast AsiaJOURNAL OF BIOGEOGRAPHY, Issue 6 2010Ronald M. Clouse Abstract Aim, To develop a comprehensive explanation for the biological diversity of Southeast Asia, especially in the Wallacea and Sundaland regions. This study focuses on a group of arachnids, mite harvestmen, which are thought to be an extremely old group of endemic animals that have been present in the region since most of its land supposedly formed part of the northern rim of the supercontinent Gondwana. Location, Eastern Himalayas, Thai-Malay Peninsula, Sumatra, Borneo, Java, Sulawesi, and New Guinea. Methods Approximately 5.6 kb of sequence data were obtained from 110 South-east Asian Cyphophthalmi specimens. Phylogenetic analyses were conducted under a variety of methods and analytical parameters, and the optimal tree was dated using calibration points derived from fossil data. Event based and paralogy-free subtree biogeographical analyses were conducted. Results, The Southeast Asian family Stylocellidae was recovered as monophyletic, arising on what is now the Thai-Malay Peninsula and diversifying into three main clades. One clade (Meghalaya, here formally placed in Stylocellidae) expanded north as far as the eastern Himalayas, a second clade entered Borneo and later expanded back across the Sundaland Peninsula to Sumatra, and a third clade expanded out of Borneo into the entire lower part of Sundaland. Molecular dating suggested that Stylocellidae separated from other Cyphophthalmi 295 Ma and began diversifying 258 Ma, and the lineage that inhabits mostly Borneo today began diversifying between 175 and 150 Ma. Main conclusions, The topology and molecular dating of our phylogenetic hypothesis suggest that Stylocellidae originated on Gondwana, arrived in Southeast Asia via the Cimmerian palaeocontinent, and subsequently diversified north, then south. Their present distribution in the Indo-Malay Archipelago is explained largely by a diversification over the Sundaland Peninsula before western Sulawesi departed and the peninsula was extensively inundated. [source] Comparison of immunoradiometric assays for determination of thyroglobulin: a validation studyJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 3 2007L.A. Tortajada-Genaro Abstract In this study we compared and validated commercial immunoradiometric assays (IRMA) to determine thyroglobulin (Tg) levels in serum. From a set of 440 samples, 68 were selected to calculate the validation parameters and the clinical performance of the assays. The commercial kits evaluated were the Tg-CTK (DiaSorin), IRMAZenco Tg (ZenTech), and SELco-Tg (Medipan). We found that 21% of the collected samples were in the critical range of concentration. Detection limits were calculated as being below 3,µg/L. Intra- and inter-reproducibility were lower than 3.1% and 9.2%, respectively. Dilution and recovery studies provided quantitative determinations. Correlation regression coefficients from the results of the methods were obtained. The determined concentrations were compared with the clinical evidence of disease. Variation in the 125-iodine-labeled antibody concentration and control charts showed the robustness of the methods. Analysis time and the simplicity of the methods were also evaluated. Reliable Tg determination is important for monitoring patients with differentiated thyroid cancer (DTC), controlling other thyroid diseases, and assessing the quality of imaging techniques. A strategy for verification and comparison based on analytical parameters and clinical performance is proposed. J. Clin. Lab. Anal. 21:147,153, 2007. © 2007 Wiley-Liss, Inc. [source] A new FT-IR method combined with multivariate analysis for the classification of vinegars from different raw materials and production processesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2010Enrique Durán Guerrero Abstract BACKGROUND: Due to the diversity of vinegars on the market and the increase in demand, it is considered necessary to investigate and establish criteria for classifying them in order to obtain more information concerning their real origin. New spectroscopic techniques such us mid-infrared spectroscopy with Fourier transform (FT-IR) are capable of providing information in relation to these aspects. FT-IR combined with multivariate analysis has been used to classify vinegars according to the raw materials and production processes (with or without ageing in wood). Principal component analysis (PCA), partial least-squares discriminant analysis regression (PLS-DA) and stepwise linear discriminant analysis (SLDA) were used. RESULTS: The results obtained have been compared to those achieved using different analytical parameters (polyphenolic content, organic acids and volatile compounds). SLDA and PLS-DA results show the ability of mid-FT-IR spectra to discriminate among vinegars from different raw materials and with or without ageing in wood, with correct classification percentages similar to those obtained using different analytical parameters. CONCLUSION: The discriminative ability combined with other advantages (e.g. rapid and non-destructive analysis, low cost) makes this new FT-IR method a promising tool for the classification and/or differentiation of vinegars. Copyright © 2010 Society of Chemical Industry [source] Determination of Copper and Zinc Ions by Flame-AAS After Preconcentraction Using Sodium Dodecyl Sulfate Coated Alumina Modified with 3-((1H -Indol-3-yl)-3,4,5-trimethyl)-1H -indoleCHINESE JOURNAL OF CHEMISTRY, Issue 10 2009Mehrorang Ghaedi Abstract A sensitive and simple method for the simultaneous preconcentration of trace amount Cu2+ and Zn2+ ions in some real samples has been established, which is based on the sorption of Cu2+ and Zn2+ on 3-((1H -indol-3-yl)-3,4,5-trimethyl)-1H -indole (ITMI) loaded on sodium dodecyl sulfate (SDS) coated alumina. The metal absorbed on the complexes was eluted using 3 mol/L nitric acid. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a low RSD. The method has been successfully applied to content evaluation of these metals in real samples. [source] Higher-level phylogenetics of linyphiid spiders (Araneae, Linyphiidae) based on morphological and molecular evidenceCLADISTICS, Issue 3 2009Miquel A. Arnedo This study infers the higher-level cladistic relationships of linyphiid spiders from five genes (mitochondrial CO1, 16S; nuclear 28S, 18S, histone H3) and morphological data. In total, the character matrix includes 47 taxa: 35 linyphiids representing the currently used subfamilies of Linyphiidae (Stemonyphantinae, Mynogleninae, Erigoninae, and Linyphiinae (Micronetini plus Linyphiini)) and 12 outgroup species representing nine araneoid families (Pimoidae, Theridiidae, Nesticidae, Synotaxidae, Cyatholipidae, Mysmenidae, Theridiosomatidae, Tetragnathidae, and Araneidae). The morphological characters include those used in recent studies of linyphiid phylogenetics, covering both genitalic and somatic morphology. Different sequence alignments and analytical methods produce different cladistic hypotheses. Lack of congruence among different analyses is, in part, due to the shifting placement of Labulla, Pityohyphantes, Notholepthyphantes, and Pocobletus. Almost all combined analyses agree on the monophyly of linyphioids, Pimoidae, Linyphiidae, Erigoninae, Mynogleninae, as well as Stemonyphantes as a basal lineage within Linyphiidae. Our results suggest independent origins of the desmitracheate tracheal system in micronetines and erigonines, and that erigonines were primitively haplotracheate. Cephalothoracic glandular specializations of erigonines and mynoglenines apparently evolved independently. Subocular sulci of mynoglenines and lateral sulci (e.g. Bathyphantes) evolved independently but glandular pores in the prosoma proliferated once. The contribution of different character partitions and their sensitivity to changes in traditional analytical parameters is explored and quantified. ,© The Willi Hennig Society 2009. [source] | |||||||||||||