Showing papers on "Fluorescence spectrometry published in 1982"

Human central nervous system distribution of cis-diamminedichloroplatinum and use as a radiosensitizer in malignant brain tumors

Abstract: The human central nervous system pharmacology of cis -diamminedichloroplatinum (CDDP) was studied, and trials were initiated of CDDP as a radiosensitizer in the treatment of malignant primary brain tumors. Samples were assayed for platinum using X-ray-dispersive fluorescence spectrometry. Platinum was barely detectable in cerebrospinal fluid from two patients and was not detectable ( Fifteen patients with malignant brain tumors received CDDP, 40 mg/sq m/week i.v., during cranial irradiation, and some received 105 to 120 mg/sq m every 3 weeks after cranial irradiation. Close follow-up was necessary, and some weekly treatments needed to be omitted in individual patients. During the weekly CDDP, gastrointestinal, scalp, and renal toxicities and hypomagnesemia were noted but were tolerable. Only one patient developed myelosuppression. Ototoxicity may have been enhanced. Postirradiation CDDP, 105 to 120 mg/sq m every 3 weeks, caused substantially more gastrointestinal toxicity and may have caused central nervous system toxicity in four patients, although other factors probably contributed. It is too early to evaluate effect on survival.

Human tissue distribution of platinum after cis-diamminedichloroplatinum.

Abstract: Using X-ray fluorescence spectrometry, platinum concentrations were determined in autopsy tissue samples from 12 patients who had received cis-diamminedichloroplatinum (DDP) 20-120 mg/m2 up to 6 months antemortem. Tissue platinum concentrations were highest in liver (0.5-3.7 micrograms/g wet weight), prostate (1.6-3.6 micrograms/g), and kidney (0.4-2.9 micrograms/g), somewhat lower in bladder, muscle, testicle, pancreas, and spleen, and lowest in bowel, adrenal, heart, lung, cerebrum, and cerebellum, Platinum concentrations in tumors were generally somewhat lower than the concentration in the organ in which the tumor was located, with the exception of intracerebral tumors. Different metastatic sites in the same patient had substantially different platinum concentrations and hepatic metastases had the highest concentrations. Intra-arterial administration of drug may augment tissue concentrations of platinum. In a patient undergoing therapeutic abortion 4 days after treatment, the platinum concentration was 0.5 micrograms/g in the placenta and 0.3 micrograms/g in the fetus. The data suggest that for in vitro sensitivity testing, DDP concentrations of less than or equal to 7 micrograms/ml should be used.

Seasonal and vertical variations in the chemical composition of suspended particulate matter in an oxygen-deficient fjord

Abstract: Chemical analysis of suspended particulate matter in marine waters gives insight into important geochemical processes. Additionally, fjords offer suitable locations to study these processes. The Bunnefjord in south-east Norway was selected for a 1-year study of the vertical and seasonal variations in the particulate matter chemistry. Analysis of particulate Al, Si, P, Fe and Mn on Nuclepore membrane filters by X-ray fluorescence spectrometry elucidates the distribution of various particulate matter phases in the water column. While particulate Al, Si and P are abundant above the halocline due to the influence of river water (Al), diatoms (Si) and organic matter (P), particulate Fe and Mn phases preferentially occur in the lowoxygenated bottom water. The latter is a result of redox reactions at or near the sediment-water interface. The mobility of Mn is particularly well demonstrated, showing a rapid loss of Mn from the sediments when the oxygen concentration in the bottom water dropped below 1 ml l−1. The flux of Mn from the sediments to the water and the conversion of dissolved Mn to a particulate phase was estimated to a minimum of 0·7 μg cm−2 day−1.

Dibenzylammonium and sodium dibenzyldithiocarbamates as precipitants for preconcentration of trace elements in water for analysis by energy dispersive x-ray fluorescence

Abstract: Precipitation with combined dibenzylammonium dibenzyldithiocarbamate and sodium dibenzyldithiocarbamate at pH 5.0 can be used to separate 22 trace elements from water. Membrane filtration of the precipitate yielded a thin sample, suitable for analysis by energy dispersive X-ray fluorescence spectrometry. Alkalis, alkaline earths, lanthanides, and halides were not precipitated, permitting a clean separation of trace elements from the macro constituents of drinking water and drinking water supplies. Methods are given for preparation of reagents of higher purity than previously described.

A formed filter paper medium for microdroplet analyses of liquid samples by X-ray fluorescence spectrometry

Abstract: A new type of a formed filter paper is proposed as a sample medium for a microdroplet analysis by x-ray fluorescence spectrometry. It has a circular center part, separated by a narrow circular groove from its edge, and four, paraffined, supporting bridges. It can thus keep a spot area constant when a liquid sample drops at the center part. After dropping the liquid sample, the paper is dried and used for the x-ray measurement. It can be stored for years without any chemical change. This formed filter paper is effective in improving the linearity range of a calibration curve and the precision of a fluorescent x-ray measurement as compared with a non-formed filter paper. The sample volume required is only 20 to 100 μ1 and therefore microscale analysis of the liquid sample is allowable.

Two dimensional TLC determination of PAH in diluted automobile exhaust gases

Abstract: A method is described for the determination of polycyclic aromatic hydrocarbons (PAH) in the diluted exhaust gas of diesel vehicles. Sampling is done by drawing off proportional streams from the dilution tunnel. The particulates deposited on filters are sublimed, and the sublimate is purified and prefractionated on silica gel. Further separation and quantitative determination of the PAH is performed by two dimensional TLC in conjunction with In situ fluorescence spectrometry. Results of theoretical considerations and experimental data on the distribution of the emitted PAH between particulate matter and the corresponding gas phase in diluted exhaust are presented. A modified Langmuir adsorption model is used to explain the effects of dilution ratio and sample temperature in the dilution tunnel. Comparison of the emission values for PAH obtained from diluted and undiluted exhaust shows good agreement. Furthermore, the PAH contents of the exhaust gas of several diesel-engined cars are also compared for various driving cycles.

A Spectrometric Study of the Fluorescence Detection of Fecal Urobilinoids

Abstract: Fluorescence spectra of extracts of fecal material, in the presence of zinc ion, display the well-known green fluorescence used in the Schlesinger test for the urobilinoids, together with several other fluorescences. All of these can be demonstrated in a single spectrum by the synchronous fluorescence technique, which, with new extraction conditions, enables the urobilinoid fluorescence to be detected in quantities of human fecal material down to about 50 ng in mass. This represents a reduction on the order of a thousandfold in the detection limit of the original visual technique; selectivity too is greatly increased. The effects caused by a variety of reagents on the fluorescences have been examined. It is shown that in Edelman's version of the test the presence of mercuric ion largely quenches the fluorescence. The synchronous spectra vary considerably between different samples of human feces and between different mammals according to their diet. The specificity of the recommended technique is discussed with reference to the spectra given by other body materials.

Determination of polycyclic aromatic hydrocarbons in diluted and undiluted exhaust gas of diesel engines

Abstract: Presentation et discussion des resultats d'analyse des hydrocarbures aromatiques polycycliques adsorbes sur les particules solides, a l'aide de la chromatographie en phase gazeuse capillaire et de la chromatographie sur couche mince couplee a la spectrometrie de fluorescence in situ

REE distribution patterns of granites in South China

Abstract: REE determinations were conducted for their respective contents on granitoid rocks in South China, which differ in age, composition and origin, by means of chemical-X-ray fluorescence spectrometry and instrumental neutron activation analysis.

Determination of trace amounts of iron, nickel, and tin in zircaloys by X-ray fluorescence spectrometry after coprecipitation with hexamethyleneammonium hexamethylenedithiocarbamate.

Abstract: A rapid and precise X-ray fluorescence spectrometry is proposed for the determination of the trace amounts of iron, nickel, and tin in zircaloys. A zircaloy sample was dissolved in a mixture of tetrafluoroboric acid and hydrochloric acid, diluted to a definite volume with water. After the addition of 3 cm3 of 1% (R,R)-tartaric acid solution as an auxiliary chelating agent and 50 μg of cobalt as an internal standard to an aliquot (less than 200 μg of tin) of the solution, the pH was adjusted to 2 with ammonia solution and 3 cm3 of 1% hexamethyleneammonium hexamethylenedithiocarbamate (HMA–HMDC) was added. The resulting HMA–HMDC complexes were collected on a membrane filter and dried. The contents of iron, nickel, and tin in zircaloys were calculated by the calibration curves with the ratios of Kα intensities for each element to that for cobalt. The coefficients of variation (5 results for each metal) were 2.16, 0.63, and 1.52% for 10, 10, and 200 μg of iron, nickel, and tin, respectively. The analytical re...

Practical Determination of Flame Species via Laser Saturation Fluorescence Spectroscopy

Abstract: The observation of molecular fluorescence caused by high-power pulsed laser excitation has been found to be an accurate technique for the determination of relative OH radical concentrations on a spatially resolved basis in a circular air-acetylene flame. It was found that the high power of radiational excitation used allowed fluorescence saturation to be approached. Theory then predicts fluorescence intensities to be independent of temperature and collisional quenching effects. However accurate estimates of relative concentrations can not be obtained unless corrections are made for incomplete saturation and postfilter effects. Procedures for conveniently applying such corrections are reported.

A modified background-ratio method for x-ray fluorescence analysis of soil and plant materials

Abstract: The isolated atom model of x-ray scatter has been used to develop a new analytical strategy for internal standardization in x-ray fluorescence spectrometry. The method defines quantitatively by how much and within what limitations various background-ratio calibration techniques can improve results for particular elements in specific materials. The analytical strategy is based on a modified peak to background ratio equation, where the background intensity is raised by an exponent T. The variable T combines as special cases all existing analytical strategies which use scattered x-rays, together with the basic linear calibration where T=0. Variation in T was evaluated using extensive computer processing of matrix data for typical soil and plant materials. It was found that T varied with analyte, scatter wavelength and the matrix component contributing to the mass absorption error. Most existing methods using a background-ratio technique are shown to be improved by using a value of T other than the previously assumed unity or zero.

Two new iron meteorites from western australia

Abstract: Two new iron meteorites from Western Australia are described: Cosmo Newberry — a 2.156 kg meteorite of unusual spiky shape, and Gnowangerup — a 33.6 kg pear-shaped meteorite. X-ray fluorescence spectrometry shows that Cosmo Newberry can be classified in Group IIA, whilst Gnowangerup is a member of Group IIIAB. Neither iron can be associated with any other Western Australian meteorite.

DNA interaction with 57Co-bleomycin.

Abstract: Tumor-diagnostic 57Co-bleomycin is a mixture of two isomers: types I and II. Interaction between these and DNA was studied by fluorescence spectrometry and thermal denaturation. The fluorescence study indicated that cobalt chelation resulted in a remarkable increase in the apparent DNA-bleomycin association constant and a slight increase in bleomy-cin-DNA binding; a remarkable difference was observed between the two isomers. In the thermal denaturation study, the difference of DNA binding behavior was also observed. The tumor affinity of these isomers was slightly different, and type I isomer showed higher tumor affinity than type II. These results indicate that cobalt chelation to bleomycin enhances DNA-bleomycin binding and its DNA binding stability, and these mechanisms, although not fully understood, appear to underly the difference in tumor affinity of cobalt-bleomycin isomers.

Speciation of iron, copper and zinc in the Hawkesbury River

Abstract: A combination of membrane filtration, ion exchange, coprecipitation and thin-film X-ray fluorescence spectrometry was used to obtain data on the chemical speciation of iron, copper and zinc in surface waters, ranging in salinity from 0 to 30Ym, of the Hawkesbury River, N.S.W. Iron, the principal trace metal, was found mainly (>90%) in the particulate form. The dissolved (filterable) iron fraction was largely non-ion- exchangeable (colloidal) in the freshwater region and ion-exchangeable in saline waters (as hydrated ions or metal complexes that dissociate on the chelating resin column). Copper and zinc, by contrast, were almost entirely filterable over the whole salinity range, copper being 50-100% in the non-ion-exchangeable fraction, and zinc, 70-100% ion-exchangeable.

Standard Reference Material of Fluorite FM

Abstract: Standard reference material of fluorite FM, consisting chiefly of fluorite, quartz and baryte, was prepared by the Institute of Mineral Raw Materials in Kutna Hora (Czechoslovakia). The homogeneity of the pulverised SRM was checked by X-ray fluorescence spectrometry from counts corresponding to the amounts of iron, copper, barium, strontium and titanium. The SRM was considered homogeneous if the “between bottles” variance was not significantly greater than the “within bottles” variance and further, if the error caused by heterogeneity of the SRM was less than one third of the error of an analytical determination carried out in a routine manner. Analytical results from 26 laboratories were processed following the recommended procedure of CMEA-countries which includes: Testing the normality of results, eliminating out-lying results and computing the arithmetic means, estimates of standard deviations and the confidence intervals of the means. Attested values for 17 components and non-attested values for 30 components and/or elements are reported.

pitfalls in Using Filter Paper Disks as Standard Supports In X-Ray Fluorescence Spectrometry

Abstract: Standard solutions of dimethylarsinic acid in water and methanol are deposited on Whatman No. 1 and No. 114 filter papers. The arsenic content is measured by X-ray fluorescence spectrometry. The observed specific count depends on the nature of solvents, the volume of spotting solutions, the method of spotting and the type of filter papers.

REE Distribution Patterns of Granites in South China

Abstract: REE determinations were conducted for their respective contents on granitoid rocks in South China,which differ in age,composition and origin,by means of chemical-X-ray fluorescence spectrometry and instrumental neutron activation analysis. Granites under consideration can be divided into three major categories in terms of chon- drite normalized REE distribution patterns and δEu values. 1.REE distribution pattern is approximately expressed by a smooth curve,with unre- markable negative Eu anomaly and δEu value greater than 0.5. 2.REE distribution pattern exhibits a moderately remarkable negative Eu anomaly with δEu value in the range of 0.3—0.4. 3.REE distribution pattern gives a greatly remarkable negative Eu anomaly,with δEu value being less than 0.2. The granites belonging to the first category are mostly older in age and closely con- nected with granitization in origin,those to the second category show a number of evidences for magmatic origin and those to the third category are especially distinguishable for their characterisitic features of later magmatic differentiation and replacement.

A comparison of two equations used as calibration curves for ternary samples in x-ray fluorescence spectrometry

Abstract: It is well known that calibration curves in x-ray fluorescence spectrometry offer to the analyst different alternatives to fit measured data. We have set out to compare two well-known algorithms, those of Rasberry and Heinrich (R–H) and Lachance and Traill modified by Claisse and Quintin (LTCQ), with computer generated data using the fundamental parameter method. It is seen that both work reasonable well for binary samples, but in ternary samples deviations from reference points are larger for R–H than for LTCQ. We conclude from this study that ternary effects in R–H are not accounted for adequately, since only binary coefficients are needed to determine a calibration curve for any ternary as well as any multicomponent sample. In LTCQ, inclusion of an additional coefficient determined from a ternary standard suffices to improve considerably the degree of fitting to reference.

Model Experiments for Wastewater Treatment on the System Zeolite/Heavy Metal Ions

Abstract: X-ray diffraction and ion exchange studies were conducted on several rhyolitic tuffs of Hungarian origin (Tokaj region). Clinoptilolite shows nearly linear relationship between zeolite content and ion exchange capacity of the rock, whereas the exchange capacity does not follow the increase of the zeolite content with mordenitic rocks over 30% content, as determined by X-ray fluorescence spectrometry. The latter finding is attributed to diffusion problems derived from morphological pecularities. The ion exchange sequence found on both untreated clinoptilolite and mordenite is: Rb + , Ag + , Hg + , Pb ++ , Cu ++ , Zn ++ , Ni ++ .