Showing papers on "Fluorescence spectrometry published in 1978"

Passage of molecules through the wall of the gastrointestinal tract. I. A simple experimental model.

Abstract: We describe here a simple experimental model for studying how the structural integrity of the intestinal wall is related to the transmural passage of molecules into the circulation. The model is based on the deposition of fluorescently labeled dextran in the intestine and its eventual recovery in the portal blood and mesenteric lymph. The fluorescent compound can be determined with sensitivity and ease by using fluorescence spectrometry. As judged from chromatography on Sephadex G-100, the compound was not degraded or otherwise chemically altered on its route of passage. The rate of passage was inversely proportional to the molecular size. The model may prove useful for studying factors that influence the transmission of macromolecules across the intestinal wall. Such a transmission probably underlies the pathogenesis of a variety of diseases.

Serum copper and zinc measurements in patients with osteogenic sarcoma

Abstract: Serum copper level (SCL), serum zinc level (SZL), and SCL/SZL ratio were measured in 18 patients with biopsy-proven osteogenic sarcoma. Measurements were made on sequentially collected serum samples beginning prior to the institution of therapy and continuing periodically until documented relapse. All patients were treated by curative resection and adjuvant therapy consisting of high dose methotrexate (with leucovorin rescue) with or without BCG immunotherapy. The SCL, SZI, and SCL/SZL determinations were made using proton-induced x-ray fluorescence spectrometry. SCL was significantly elevated (p less than .0001) in the 18 patients with primary untreated osteogenic sarcoma )173 +/- 30 microgram/dl) compared with a sex and age-matched normal group (115 +/- 16 microgram/dl). A significantly different SZL was not found, however, so that an elevated SCL/SZL ratio in the osteogenic sarcoma patients was primarily due to the altered SCL. SCL and SCL/SZL did not change significantly following curative surgery or become more abnormal in those patients who developed recurrent disease. The SCL and SCL/SZL were noted to be markedly elevated in those patients receiving BCG therapy, raising concern regarding the specificity of these tests as markers of tumor activity. SCL, SZL, and SCL/SZL did not appear useful as markers of tumor activity in patients with osteogenic sarcoma.

X-ray fluorescence analysis of muscles in scoliosis.

Abstract: X-ray fluorescence spectrometry was used to determine calcium, copper, and zinc concentrations in paraspinal and gluteal muscles obtained during spinal surgery from patients with scoliosis. Samples of 1-3 mg were sufficient to demonstrate that calcium was higher in idiopathic than in other forms of scoliosis or in normal control muscles. It is suggested that a calcium-related neuromuscular defect could be an important factor in the genesis of idiopathic scoliosis.

Energy dispersive x-ray fluorescence spectrometric determination of trace elements in oil samples

Abstract: A method is described for the determination of trace elements in petroleum by energy dispersive x-ray fluorescence spectrometry. Minimum sample preparation is required. This is achieved by making small targets and spiking the sample with a solution of Cr and Rh in H/sub 2/SO/sub 4/ or organo-Rh in mineral oil. Use of two spiking elements with different x-ray energies facilitates the determination of x-ray absorption corrections. In the NBS fuel oil (SRM 1634), V, Fe, Ni, and Mo were detected and the results of the analyses correspond well with the NBS certified values. In the shale oil, Fe, Ni, Zn, As, and Se were detected. The one-element spiking method works well for samples of low viscosity where the sample can be spread on the supporting foil thin enough so that the absorption of measured x-rays can be ignored, whereas the two-element spike is needed for high viscosity samples (NBS fuel oil) where samples cannot be made thin enough to ignore sample absorption.

Elevation of copper and nickel levels in primaries from black and mallard ducks collected in the Sudbury district, Ontario.

Abstract: Black and mallard duck wings were collected from northern Ontario and northern Saskatchewan during the fall of 1975, and primary flight feathers were analyzed for Cu, Ni, and Zn by X-ray fluorescence spectrometry. Correlations between area sampled and mean metal concentrations in a population were investigated. Zinc concentrations did not vary with the population sampled, while mean levels of Cu and Ni were highest near Sudbury, Ontario, reflecting the known particulate fallout. Elevated Ni contents characterized the Sudbury collection site. No obvious trends in levels of the three metals were apparent with species, sex, age, or the choice of wing analyzed.

Aerial mineral survey method and apparatus using pulsed laser beam to vaporize surface material

Abstract: A high-energy laser (22) carried in an aircraft (10) directs a laser beam (16) downward to a point (18) on the earth's surface beneath the aircraft (10). The intensity of the laser beam (16) is such that the material at the point (18) of contact is vaporized and thereby caused to emit atomic emission spectra characteristic of the material. A spectrometer (28) carried in the aircraft (10) collects the resulting spectra which is analyzed to determine the type and quantity of chemical elements present in the vaporzied sample. The laser beam (16) is directed at the point (18) on the surface with sufficient energy and for a period of time so as to penetrate the surface layer and vaporize the underlying material more representative of the overall mineral composition present in the region of the sample. A second laser beam from laser (29) is directed to the point (18) of contact to generate radiation for Raman and fluorescence spectrometry.

Routine performance of a matrix‐correction free X‐ray fluorescence spectrometric method for rock analysis

Abstract: In modern geochemical laboratoriesX-tay fluorescence spectrometry (XRFS) is a highly favoured analytical technique particularly when the need for geochemical data is relatively important. The analytical procedures currently employed involve XRFS analysis of lithium borate fused glass disc of rock samples, followed by computer generated mathematical corrections for the usual matrix effects. A significantly different procedure, free from mathematical matrix effect corrections, is presented here. After the lithium borate fusion step, the ground fusion product is dissolved by thorough mixing with an aqueous suspension, of a strong acid cation exchange resin in H+ form. During the caution exchange dissolution, the cautions originally present in the sample are transfered quantitatively and uniformly to the resin pahse. The oven-dried resin heads coated as a thin film on a strip of adhesive paper are analysed. The routine performance of the procedure is illustrated with the data accumulated on six major elements (Al, Fe, Ca, Mg, K and Ti) in five international rock reference samples during a period of one academic year. The main feature of this analytical method is the production of high quality geochemical data without any need for mathematical corrections.

Improved high‐intensity microwave discharge lamp for atomic resonance absorption and fluorescence spectrometry

Abstract: An unusually good combination of high intensity and narrow line has been achieved in a microwave discharge lamp by placing the optical window in the center of the microwave cavity. Construction details and performance characteristics are described.

High Performance Liquid Chromatographic Analysis for Free Valine in Plasma

Abstract: A precolumn derivatization method is presented with the use of a fluorescent derivative, 1-dimethylaminonaphhalene-5-sulfonyl-chloride, dansyl chloride, for the detection of free valine in plasma. Dansylated amino acids were determined in deproteinized samples by reverse-phase liquid chromatography. The level of detection is 100 femtoraoles (10−15). Sample preparation required precipitation of proteins with trichoroacetic acid and removing the excess acid with water saturated ether. The deproteinized sample was adjusted to pH 9.0 and reacted with dansyl chloride. The dansylated products were detected by ultraviolet and fluorescence spectrometry. Elution time for valine subsequent to injection is 25 minutes, while the total assay requires less than 50 minutes.

Development of EDXRF techniques for the quantitative multielement analysis of urban dust samples

Abstract: The investigation and monitoring of suspended particulate matter in air require accurate and sensitive multielement analysis of large numbers of samples. In the work described, airborne particles and settled urban dusts were examined by energy dispersive X-ray fluorescence spectrometry with secondary-target excitation. The practical requirements of trace-element determinations in dusts are reasonably satisfied by two techniques. Deposition of fine particles (under 3.5μm) on Nucleopore membrane filters provides thin-film samples, for which absorption and particle-size effects are usually negligible. Calibration is achieved by sputtering of certified NBS standard glasses onto membrane filters. In the destructive “fusion and direct solidification” technique, sample inhomogeneities and particle-size effects are eliminated by fusing the sample with lithium borate in a Pt/Au alloy crucible. La2O3 or WO3, added as heavy absorbers, can reduce the interelement-effects of the thick specimens to a certain extent. A newly developed computer program, based on a modified mathematical expression for the intensity, compensates for absorption and secondary fluorescence effects. It is demonstrated that for some trace elements the background can be easily predicted as a linear function of the incomplete charge-collection of the Si(Li) detector. An intermethod comparison with atomic-absorption results is presented; the results are verified with the NBS Fly Ash standard reference material.

Röntgenfluoreszenzspektrometrische Bestimmung von Spurenelementen in verdünnten wäßrigen Lösungen nach Anreicherung auf Cellulose-Ionenaustauschern

Abstract: Determination of trace elements in dilute aqueous solutions by X-ray fluorescence spectrometry after preconcentration on cellulose ion exchangers Different methods dealing with the X-ray fluorescence analysis of solutions are reviewed. Cellulose ion exchangers were found to be a medium for the preconcentration of traces of elements in aqueous solutions. The enrichment is carried out by filtering 11 water containing μg-amounts of different ions through a column. After drying, the cellulose ion exchangers are pressed into pellets and analysed by X-ray fluorescence. For the collection step strong acid SE- (sulfoethyl-) cellulose and strong basic DEAE-(diethylaminoethyl-) cellulose are used having an exchange capacity of 0,2 meq./gram and 0.85 meq./gram, respectively. The accuray of the method is about ± 10%. Detection limits (theoretical values) are in the range of 1–5 μg. Variations of the method referring to preparation of pellets, sensitivity and column dimensions are discussed.

Mineral characterization of fluidized-bed combustion aerosol ash--Montana Rosebud sub-bituminous coal

Abstract: Bulk and aerosol flyash samples from the MERC 18'' atmospheric fluidized bed combustor have been characterized by three analytical techniques: X-ray fluorescence spectrometry (XRF) for elemental analysis, x-ray powder diffraction (XRD) for mineral identification and scanning electron microscopy/x-ray emission (SEM) for regional and surface analysis. The combustion tests were carried out on Montana Rosebud sub-bituminous coal with limestone added as a sulfur sorbent. Bulk samples were removed from the bed and particle collecting devices. Aerosol sampling from the effluent stream was conducted by the Lovelace Inhalation Toxicology Research Institute. The results of these analyses indicate that (1) the fluidized-bed flyash is not composed of spherical, homogeneous particles, but irregularly shaped particles; (2) particle size distributions of the aerosols may exhibit multimodal behavior; (3) excess calcium from the bed may react with the aluminosilicate flyash to form crystalline calcium aluminosilicates; and (4) calcium sulfate predominates in the small particles.

硫黄のスズ(ii)-強リン酸を利用した気化分離-けい光x線分析法による定量

Abstract: The method is divided into three operations, the nrst being the evolution of hydrogen sulfide, the second being its fixing to a silver nitrate test paper, and the third is measurement of sulfur in the test paper by X-ray fluorescence spectrometry. Hydrogen sulfide was made by heating the sample with tin(II)-strong phosphoric acid reagent (500 g of reagent grade phosphoric acid was concentrated and heated to 270°C. To this 40 g stanous chloride dihydrate was added and the mixture was heated again to 290°C). The method was applied to the determination of sulfur in iron and steels. Procedure Place a sample containing up to 25μg of sulfur into the reaction tube. Add 10 ml of tin(II)strung phosphoric acid reagent and connect the capture part to which a test paper has been attached. Heat the contents for. 15 minutes in a stream of nitrogen (45 ml/min) on a furnace whose temperature has been regulated at 400°C. Transfer the test paper to a sample holder and measure the intensity of SKα line. The intensity was proportional to the sulfur amount (1 to 25 μg). The coefficient of variation was 3.5% (with 10 μg of sulfur) in five runs.

X-ray spectrometric determination of glass content of melts incorporating radioactive waste: a feasibility study

Abstract: X-ray fluorescence spectrometry was evaluated for the determination of glass content and homogeneity of glass incorporating high-level radioactive waste. Accuracy and precision were determined for analyses of Al/sub 2/O/sub 3/, SiO/sub 2/, CaO, TiO/sub 2/, MnO, Fe/sub 2/O/sub 3/, and NiO in specimens of known composition. These specimens were prepared by fusing powdered glass with nonradioactive synthetic waste. Matrix effects of sodium on these analyses were specifically evaluated. X-ray fluorescence spectrometry was shown to be applicable to the proposed determinations by comparing the known glass contents of 14 glass waste compositions with those calculated from experimentally determined concentrations of SiO or TiO/sub 2/.