scholarly journals Innovations in the Speciation of Organolead Compounds in Water: Towards a More Rational, Rapid, and Simple Analytical Process

2002 ◽  
Vol 2 ◽  
pp. 1332-1337
Author(s):  
J.R. Baena ◽  
M. Gallego ◽  
M. Valcarcel
Keyword(s):  
Sample Preparation ◽  
Continuous Flow ◽  
Speciation Analysis ◽  
Automated Systems ◽  
Final Solution ◽  
Analytical Process ◽  
Organolead Compounds ◽  
Simple Systems ◽  
Sodium Tetrapropylborate ◽  
Made In

Speciation analysis calls for rapid, simple systems for minimizing errors made in the most troublesome of all steps in the analytical process: sample preparation. In this context, continuous-flow systems are of great help. The evolution in the different methodologies enabled solutions to the main shortcomings occurring from the lack of selectivity of using RP–C18as sorbent material. One solution was a shift to more sensitive and selective, but only partially automated, systems employing C60fullerene and Grignard’s reagent; another was a shift to completely automated systems employing sodium tetrapropylborate; and a final solution was to employ the simplest possible configuration by removing the reagent stream. The analytical methods developed allowed the identification and quantification of different organolead species at the pg/ml levels in rainwater samples, with precision (RSD) of about 5% and recoveries ranging from 92 to 100%.

scholarly journals GOLD PROVENANCE AND CHARACTERIZATION USING MICRO X-RAY FLUORESCENCE (µXRF): PRELIMINARY RESULTS/ PROVENIÊNCIA E CARACTERIZAÇÃO DE OURO COM MICRO FLUORESCÊNCIA DE RAIOS X (μXRF): RESULTADOS PRELIMINARES

2018 ◽  
Vol 3 (3) ◽  
pp. 155-165
Author(s):  
William Murussi Canto ◽  
Hamilton Santos Gama Filho ◽  
Marcelino José dos Anjos ◽  
Armando Dias Tavares Jr. ◽  
Mauro César Geraldes
Keyword(s):  
Sample Preparation ◽  
Pure Gold ◽  
Noninvasive Technique ◽  
X Ray ◽  
Preliminary Results ◽  
Icp Ms ◽  
Para Determinar ◽  
Made In ◽  
Gold Digging

This work presents some preliminary results that allows to characterize gold samples using Micro X-Ray Fluorescence/µXRF. The first aim of this work is to apply a noninvasive technique, preserving the sample integrity, in order to identify the composition of gold samples and to recognize their possible geographical provenance. Samples have been obtained in geographically distinct gold-digging sites, in three Brazilian and one Colombian areas. These samples were processed only by fusion into a furnace at 1,200 ºC. The proportion of Au, Ag and Cu were measured in gold samples. The results of this work, allowed to characterize and to identify quite well the pure gold provenance, using µXRF instrumentation and related techniques. Further work is in progress to determine the behavior of mixed gold samples from different provenances. Besides that, measurements with different sample preparation will be made, in order to compare the results obtained in this work with those obtained by LA-ICP-MS techniques. ResumoEste trabalho apresenta resultados preliminares que permitem caracterizar amostras de ouro utilizando a Micro Fluorescência de Raios-X/ µXRF. O primeiro objetivo deste trabalho é aplicar uma técnica não invasiva, preservando a integridade da amostra, para identificar a composição de amostras de ouro e reconhecer a sua possível proveniência geográfica. As amostras foram obtidas em locais de exploração de ouro geograficamente distintos, em três áreas brasileiras e uma colombiana. Estas amostras foram sugeitas a fusão a 1.200 ºC, num forno. A proporção de Au, Ag e Cu foi medida em amostras de ouro. Os resultados deste trabalho permitiram caracterizar e claramente identificar a proveniência de ouro puro, utilizando resultados de µXRF. Estão em andamento outros trabalhos para determinar o comportamento da mistura de amostras de ouro de diferentes procedências. Além disso, serão efetuadas medições com diferentes preparações de amostras, a fim de comparar os resultados obtidos neste trabalho com os que estão sendo aquiridos com técnicas de LA-ICP-MS.

Design and Performance of a Miniaturized High-Speed Continuous-Flow Analyzer

1974 ◽  
Vol 20 (4) ◽  
pp. 424-427 ◽  
Author(s):  
William E Neeley ◽  
Stephen C Wardlaw ◽  
Helen C Sing
Keyword(s):  
Sample Size ◽  
Continuous Flow ◽  
High Speed ◽  
Clinical Laboratory ◽  
Small Animal ◽  
Sample Volume ◽  
Small Sample ◽  
Reagent Consumption ◽  
And Performance ◽  
Made In

Abstract Design features and performance of a miniaturized high-speed continuous-flow analyzer are described. Special emphasis is made in the design towards a system that is free from the operational and mechanical complexities found in most of today’s advanced systems. Depending on the particular analyses, sample size varies from 3 to 25 µl and reagent consumption is less than 180 µl per sample. Analyses are performed under steady-state conditions at sampling rates of 150 samples per hour with a 2:1 or 3:1 sample-to-wash ratio. The marked reduction in sample size makes the system ideal for microanalyses, especially in the pediatric clinical laboratory, in small animal research, and in any other cases where small sample volume is especially important.

Confocal Laser Scanning Microscopy of Whole Mouse and Human Embryos: Apoptosis and Morphology.

1999 ◽  
Vol 5 (S2) ◽  
pp. 1084-1085
Author(s):  
Zucker Robert M. ◽  
Sulik Kathy ◽  
Owen T Price
Keyword(s):  
Sample Preparation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Human Embryos ◽  
Embryo Morphology ◽  
Optical Sectioning ◽  
Internal Structures ◽  
Opaque Surface ◽  
Made In

Two novel sample preparation procedures have been developed to visualize morphological structures in embryonic and fetal tissues. In the first, optimization of the sample preparation allows for the visualization of embryos with a thickness in excess of 500 microns. The morphology of the internal structures in these embryos is observed by optical sectioning. The general sample preparation procedures included paraformaldehyde fixation, methanol dehydration and clearing with either benzyl alcohol/benzyl benzoate or methyl salicylate. The dyes (i.e. LysoTracker Red, YoPro) are incorporated into living or fixed embryos to indicate a specific biological function or embryo morphology. Using these stained embryos, the detection of apoptosis and its subsequent quantification were made in addition to the observation of morphology.In the second technique, the confocal microscope has been adapted to produce images similar to those generated by a scanning electron microscope. For this application, the embryos are coated with a dilute solution of acridine orange resulting in opaque surface fluorescence.

scholarly journals A note on the measurement of the specific heats of gases

1930 ◽  
Vol 126 (803) ◽  
pp. 675-682
Keyword(s):  
Continuous Flow ◽  
Thermal Gradient ◽  
Unit Volume ◽  
Present Note ◽  
Constant Pressure ◽  
Gas Flows ◽  
Specific Heats ◽  
Approximate Form ◽  
Continuous Flow Method ◽  
Made In

1. In a recent paper P. M. S. Blackett, P. S. H. Henry and E. K. Rideal have described a new continuous flow method of comparing the specific heats of gases. The method, which appears to have important advantages over existing methods, is based on the simple principle that the flow of a gas through a tube modifies any thermal gradient which may by any means be maintained along the tube. The temperature is raised or lowered according as the gas flows in or opposite to the direction of decreasing temperature. The alteration of the temperature is determined by the thermal conductivity KA of the tubewalls, the rate of flow of gas ( q ) along the tube, and the specific heat σ of the gas (at constant pressure) per unit volume ; hence it may be used to determine the latter. The application of this principle as made in the new method (here referred to as the BHR method) is discussed in detail in a separate paper by P. M. S. Blackett and P. S. H. Henry. The object of the present note is to suggest a rather different application of the principle, which in some ways (though not for all purposes) seems more convenient and accurate than the BHR method. The theory of the suggested application will first be worked out in an approximate form, leaving certain detailed corrections to be discussed later (§ 13).

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