Applicability of an HPLC System in the Analysis of Biodegraded Crude Oil Components

Abstract

High performance liquid chromatography has been used for the separation of biodegraded crude blend into fractions using back flushing procedure. The stationary phase was Energy analysis (3.9mm × 30cm) NH₂ column and the detection mode was UV absorptiometry. The method was compared with the liquid chromatography method.     

Determination of radioactive and stable cobalt in marine biological materials (author's transl)]

Studies were made to develop the method for rapid determination of radioactive and stable cobalt in a single specimen of marine biological materials. The sample was dried, ashed, and dissolved in acid. The cobalt was extracted with 1-nitroso-2-naphthol benzene and determined by absorptiometry on the benzene phase. Then, the organic solution was evaporated to dryness, and the residue was treated with nitric-perchloric acid mixture to decompose any organic matter, and taken up with hydrochloric acid. The cobolt was extracted from the solution with TIO A-toluene, and the radioactive cobalt was determined by liquid scintillation counting on the toluene phase. Examinations were made on the chemical yield and on the decontamination factor of the fission product nuclides. Analysis were made on the marine biological samples of Urazoko Bay, Fukui prefecture. Agreement of the radioactive cobalt data between that by the present method and that by Ge(Li) gamma ray spectometry was good. Also, the stable cobalt value by the present method agreed well with that by neutron activation analysis method.     

Clinical usefulness of a dual photon absorptiometry system using X-ray for peripheral bone--comparison with a single photon absorptiometric system

A newly developed dual photon absorptiometry system (DCS-600, ALOKA Co., LTD.) using two monochromatic X-rays for the determination of bone mineral in the peripheral bone was fundamentally studied, in comparison to single photon absorptiometry system (SPA). The accuracy and precision in DCS-600 were equal to or better than SPA system. Furthermore, in DCS-600 the forearm could be imaged, and the manipulation was easy. Thus DCS-600 was found to be a good instrument as a quantifying system of bone mass.     

Evaluation of the possibility of detecting benzenic pollutants by direct spectrophotometry on PDMS solid sorbent

Solid-phase extraction has become one of the most commonly used techniques for preconcentration of analytes from environmental samples. In the standard use of solid sorbent phases the extracted pollutants are subsequently eluted with a suitable organic solvent before chromatographic analysis. An alternative to this procedure is analysis of the adsorbed and concentrated pollutants by direct application of a spectroscopic method (fluorimetry or absorptiometry) to the phase. Although this method cannot be expected to give results as precise as those given by chromatographic methods, it might have valuable applications, particularly for "on site" pollution monitoring. This paper reports an evaluation of the capability of the method for the spectrophotometric detection of BTX (benzene, toluene, xylenes) in aqueous media and in contaminated atmospheres, with polydimethylsiloxane (PDMS) as sorbent. The tests performed, with the estimated detection limits, indicate that the method is relatively simple and easy to operate and sensitive enough for application to the monitoring of pollution both in water and in air in an industrial ambient atmosphere.     

Determination of neodymium by ion-exchanger absorptiometry with the f-f electron transition band

Summary Ion-exchanger absorptiometry, based on the direct measurement of light absorption by neodymium in the cation-exchange phase, has been developed for metal determination. In the presence of ethylenediaminetetraacetic acid (EDTA) about 99% of the neodymium in a 200-ml sample solution (pH 2.2 to 2.5) was concentrated in 0.50 g Muromac 50W-X12 cation exchanger within 15 min. EDTA does not interfere with the sorption of neodymium ions on the resin but suppresses spectrophotometric interference by ferric ions and ion-exchange saturation by ferric and thorium cations. The resin-phase attenuations at 740.5 nm and of the resin background at 620 nm were used for measurements with a 5-mm cell. Neodymium in the range 0.1 – 10 mg could be simply and rapidly determined without interference from other rare earths and the proposed method was used to analyse the rare-earth minerals and alloys.

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Bestimmung von Neodym durch Ionenaustauscherharz-Absorptiometrie mit Hilfe der f-f-Elektronenübergangsbande

     

应用绕丹宁衍生物测定贱金属研究的国内现状

绕丹宁衍生物是光度法测定贵金属的一类传统显色剂,这类试剂容易合成,近年来涌现出一批新型绕丹宁衍生物,除测定贵金属外,已拓展到一些贱金属的分析测定.分析手段已由传统的吸光光度法向荧光光度法和催化动力学荧光分析法转移,使测定的灵敏度和选择性大大提高.根据文献检索,将国内在这一领域的研究应用现状进行介绍.     

The Study of Polarography Analysis of Molybdenum,Sulfur and Phosphorus in Additives for Oil Saving

Because of the importance in industry, organic Molybdenum compounds have been advanced rapidly in synthesis research and application. The additive foroilsaving is one of organic Molybdenum compounds it is necessary to determine the contents of Molybdenum(Mo), Sulfur(S) and Phosphorus(P) for study of the properties of additives because of antioxygenation of S and recorrodibility and regrindibity of P. Many methods for determination of Mo in additives, such as absorptiometry or differential spetrophometry, have been reported in recent years.     

Anion-exchange high-performance liquid chromatography with conductivity detection for the analysis of phytic acid in food

A sensitive method for the accurate determination of phytic acid in food samples is described. The proposed procedure involves the anion-exchange liquid chromatography with conductivity detection. Initially, two methods of determination of phytic acid were compared: absorptiometry and high-performance ion chromatography (HPIC) with chemically suppressed conductivity detector. Unlike most conventional methods involving precipitation by FeCl3, the simpler and more reliable HPIC assay avoids the numerous assumptions inherent in the iron precipitation and the accuracy is independent of the phytate content. The protocol was also applied to a survey of phytic acid concentration in some cereal, oil and legume seeds.     

原子吸收,原子荧光和火焰光谱分析

本文根据1988～1990年国内主要分析刊物所发表的文章,以及第三届北京分析测试学术报告会及展览会(BCEIA)、中国化学会第三届原子光谱会的主要论文,对我国原子吸收、原子荧光和火焰光谱分析的进展进行了评述,对于国外有关的重要文章也简单地加以介绍。     

Simultaneous determination of trace metals by solid phase absorptiometry: application to flow analysis of some rare earths

Solid phase absorptiometry was applied to the simultaneous flow analysis of trace metals in combination with a micro black flow-through cell packed with ion exchanger beads and a multi-channel photodetector connected with optical fibers. A 4.0 cm³ sample solution containing five rare earth metal ions (Dy, Ho, Tm, Er and Nd) was introduced into a flow system and these metal ions were concentrated on a cation exchanger (Muromac 50W-X4) in a flow-through cell. The absorbance increases originating from the f-f or d-f transition bands of these metal ions were directly and continuously measured at 910 nm for Dy, at 530 nm for Ho, at 683 nm for Tm, 522 nm for Er and at 790 nm for Nd, respectively. A multi-variable analysis method was combined with the flow analysis because the absorption spectra of the five rare earth metal ions partly overlapped one another. Although no coloring reagents were used, the proposed method was about ¶200 times more sensitive than the corresponding solution method. The reproducibility of this method was less than ± 5%. The detection limits were 0.03, 0.40, 0.30, 0.35 and 0.23 mg dm^–3 for Dy, Ho, Tm, Er and Nd, respectively. Five rare earth metal ions could be precisely determined in practical samples such as yttrium concentrate.     

Under‐reporting of food intake is frequent among Brazilian free‐living older persons: a doubly labelled water study

The assessment of food intake is essential for the development of dietetic interventions. Accuracy is low when intake is assessed by questionnaires, the under‐reporting of food intake being frequent. Most such studies, however, were performed in developed countries and there is little data about the older population of developing nations. This study aimed to verify the total energy expenditure (TEE) of independent older Brazilians living in an urban area, through the doubly labelled water (DLW) method and to compare it with the reported energy intake obtained through the application of a food frequency questionnaire (FFQ). Initially, 100 volunteers aged from 60 to 75 years had their body composition determined by dual‐energy X‐ray absorptiometry (DEXA). Five volunteers of each quartile of body fat percentage had their energy expenditure determined by DLW. The mean age of the subjects included in this phase of the study was 66.4 ± 3.5 years, and ten of the subjects were men. The mean TEE was 2565 ± 614 and 2154 ± 339 kcal.day^?1 for men and women, respectively. The Physical Activity Level (PAL) was 1.58 ± 0.31 and 1.52 ± 0.22, respectively. Under‐reporting of food intake was highly prevalent, with a mean percentage of reported intake in relation to measured TEE of ?17.7%. Thus, under‐reporting of food intake is highly prevalent among Brazilian independent older persons. The DLW method is an important tool in nutritional studies and its use is to be recommended in developing countries. Copyright © 2010 John Wiley & Sons, Ltd.     

Advances in accelerator based analysis techniques

Various ion beam techniques (E≥1 MeV/amu) are compared from the standpoint of their analytical capabilities: Charged Particle Activation Analysis (CPAA), Particle Induced X-Ray Emission (PIXE), Ion Induced γ-Ray Emission for bulk analysis, Prompt Reaction Analysis (PRA), Rutherford Backscattering Spectrometry for surface layer characterization and ion absorptiometry for microscopic analysis. With CPAA and PIXE≥70 elements can be detected with sub-ppm sensitivity. The scope of CPAA is being extended with heavy ion beams for radioactivation of H, He, Li, Be, B, C isotopes. In surface layer characterization recent developments in PRA and RBS also involve heavy ion beams. In RBS they can significantly enhance mass resolution for M>50 in comparison with α scattering. For example,⁶³Cu and⁶⁵Cu can be quantitatively identified in surface films using a 1 MeV/amu⁴⁰Ar beam. In microscopic analysis, the nuclear microprobe can provide atom-specific signals from quantities ≥10⁻¹² g on spots of a diameter ≥2 μm. Ion absorptiometry techniques can sense density variations as low as ±0.5% in 1 μm³ or less of sample volume.     

Educational Web site: Radioisotopic methods of determining body composition

We have designed a Web site intended to inform the general public aboutexisting nuclear technologies based on the measurement of radioisotopes inthe human body. The presentation is focused on the concept of radioisotopemeasurements for determination of body composition (bone, muscle, water, fat),and the risks, benefits, and clinical applications of these techniques. Procedurescovered are ⁴⁰K whole body counting, delayed-gamma neutron activation,prompt-gamma neutron activation, and dual-energy X-ray absorptiometry. Theinformation presented is tailored for the nonscientific public, in order topromote familiarity with and understanding of the basic concepts of radioisotopemeasurements in the human body. Further development of the site will includegreater scientific detail, suitable for student instruction or for continuingeducation requirements of various certification programs.     

Simultaneous determination of trace metals by solid phase absorptiometry: application to flow analysis of some rare earths

Solid phase absorptiometry was applied to the simultaneous flow analysis of trace metals in combination with a micro black flow-through cell packed with ion exchanger beads and a multi-channel photodetector connected with optical fibers. A 4.0 cm³ sample solution containing five rare earth metal ions (Dy, Ho, Tm, Er and Nd) was introduced into a flow system and these metal ions were concentrated on a cation exchanger (Muromac 50W-X4) in a flow-through cell. The absorbance increases originating from the f-f or d-f transition bands of these metal ions were directly and continuously measured at 910 nm for Dy, at 530 nm for Ho, at 683 nm for Tm, 522 nm for Er and at 790 nm for Nd, respectively. A multi-variable analysis method was combined with the flow analysis because the absorption spectra of the five rare earth metal ions partly overlapped one another. Although no coloring reagents were used, the proposed method was about ?200 times more sensitive than the corresponding solution method. The reproducibility of this method was less than ± 5%. The detection limits were 0.03, 0.40, 0.30, 0.35 and 0.23 mg dm^–3 for Dy, Ho, Tm, Er and Nd, respectively. Five rare earth metal ions could be precisely determined in practical samples such as yttrium concentrate. Received: 14 March 2000 / Revised: 24 May 2000 / Accepted: 28 May 2000     

Skeletal calcium/phosphorus ratio measuring techniques by neutron activation and X-ray absorptiometry

Summary An approach to the problem of bone disorders is the measurement of the skeletons’ static and dynamic strength, an estimate of the bone mineral density. A decrease in the bone density may be due to the decrease in either Ca or P content, or to dissimilar decreases in both. Consequently, the determination of the Ca/P ratio may provide a sensitive measure of bone mineral changes and may add to our understanding of the changes occurring in bone diseases. This paper reviews the instrumental neutron activation analysis (INAA) and X-ray absorptiometry techniques, which have been developed for the in vitro or in vivo assessment of the Ca, P content and the Ca/P ratio in bones, respectively. Their main aspects and results are presented, regarding the referred values.     

Reduced Bone Mineral Density and Bone Metabolism in Aquaporin-1 Knockout Mice

An overt phenotype of aquaporin-1 knockout(AQP1 ko) mice is growth retardation, suggesting possible defects in bone development and metabolism. In the present study, we analyzed the bone mineral density(BMD), bone calcium and phosphorus contents, and bone metabolism in an AQP1 ko mouse model. The BMD of femurs in AQP1 ko mice was significantly lower than that of litter-matched wildtype mice as measured by dual energy X-ray absorptiometry. Consistently, the contents of bone total calcium and phosphorus were also significantly lower in AQP1 ko mice. The reduced BMD caused by AQP1 deficiency mainly affect male mice. Bone metabolic activity, as indicated by 99mTc-MDP absorption measurements, was remarkably reduced in AQP1 ko mice. These results provide the first evidence that AQP1 play an important role in bone structure and metabolism.     

Determination of bone mineral density in selected residents by DEXA

Bone mineral density (BMD) determination has been performed in 210 selected Shanghai residents of both sexes of age range 15–50 using Hologic QDR-2000 dual energy X-ray absorptiometry (DEXA). The results showed that in female groups the peak value of L1-L4 BMD was 1.023 g/cm² at the age of 31–35, but in the male groups it was 0.971 g/cm² aged 26–30 and the peak period lasted till the group aged 46–50. The similar conclusion has also obtained by further statistics.     

On gauging and control of grainy materials by gamma-ray absorptiometry in hydraulic transport of solids in pipes

Grain-size effects on γ-ray absorptiometry in non-destructive assay of rainy solid materials with uniform grain radii are widely investigated. In many applications the grain radii are not uniform, but follow more or less a distribution function. The present work offers a Monte Carlo model for γ-ray attenuation in materials with grain-size distributions. Suitable correction functions for grain-size effects have been derived. A comparison between the Monte Carlo results and those from analytical calculations shows a good agreement when the grain sizes are uniform, but a disagreement appears when grain sizes are statistically distributed. This disagreement between the two results may be due to the several approximations introduced in the analytical calculations.