Procedure For Quantitative Analysis Research Articles

Gas chromatography-mass spectrometry of fatty aldehydes and their oxime derivatives

Gas chromatography-mass spectrometry (GC-MS) investigation of long chain several aldehydes and their O-methyl and O- t-butyldimethylsilyl oximes has established that chemical ionization of the unmodified aldehydes is the most satisfactory procedure for both qualitative and quantitative analysis of these compounds.

On quantifying images of element distributions obtained with an ion microprobe

In SIMS analysis sputtered ion intensities are used to produce images of the distribution of elements in the surface of solid samples. Due to changes in the sputtered ion yield for different points of the sample (topography, matrix effects) the resulting pictures may lead to incorrect interpretation. Therefore, a computer-supported routine was developed which allows the collecting of data for all ions sputtered from the sample on a raster of specific points. Correction procedures for quantitative analysis can then be applied to these data, which could subsequently be displayed as graphs of element concentrations rather than sputtered ion yields. These proved to be much more reliable.

Modifications to an electron microprobe to aid in the determination of low atomic number elements

AbstractThe design and installation of a cold trap system is described specifically with reference to its use in ameliorating analysis for low atomic number elements. This trap has been mounted aon an A.R.L. EMX instrument and its use in the analysis of carbon has been investigated. This paper also discusses the metallurgical and metallographic preparation of standards for carbon analysis along with matrix correction procedures for quantitative analysis.

The use of preparative electrophoresis as a fractionation procedure for quantitative mammalian DNA analysis

The use of preparative electrophoresis as a fractionation procedure for quantitative mammalian DNA analysis

QUANTITATIVE CHEMICAL ANALYSIS OF CHRYSOTILE FIBRILS IN RAT LUNG TISSUE BY ANALYTICAL ELECTRON MICROSCOPY

A procedure of quantitative chemical analysis on a crysotile fiber under electron microscopy was developed, and was successfully adopted to a study on its changing chemical composition in situ during its long lasting residence in the rat lung.Lungs were obtained from the rats, which were sacrificed at 4 and 28 months after an intratracheal insuffiation of 10 mg of the crysotile. Routine paraffin sec-tions from those lungs were treated by means of carbon extraction technique and were submitted to analytical electron microscopy. Every single fiber identified under transmission EM was determined for the chemical composition by an simultaneous application of the X-ray microanalysis of energy dispersing type.It was found that magnesium ion leached far faster than silica out of crysotile fibril during their residence in the lung tissue. It was also suggested that, in calculating the ratio of magnesium content to silica in the single fiber, rough estimation may also be possible on its past retention period in the lung tissue.Preliminary determinations on the experimentally degradated crysotile in the test tube were also described. Results obtained from the X-ray Fluorescence Spec-trometry and the X-ray microanalysis of energy dispersive type were compared and discussed on possible application of the latter method to the crysotile fiber in vivo.

A computerized quantitative image analysis procedure for investigating features and an adapted image process*

A computerized quantitative image analysis procedure for investigating features and an adapted image process*

An automated procedure for qualitative and quantitative analysis of mixtures by means of carbon magnetic resonance spectroscopy: Applications to carbohydrate analysis

A generalized, automated c.m.r. procedure is described for the rapid qualitative and quantitative analysis of mixtures of related compounds. This technique has been applied to the analysis of carbohydrates extracted from various tissues of Pinus radiata, giving results comparable to those obtained by other techniques, but with many advantages - in particular, the availability of structural information on unknown components in the extract.

Abstract: Cross sections for ionization of inner-shell electrons by electron impact

Auger electron spectroscopy (AES) has been used extensively for qualitative surface analyses in recent years. There have, however, been relatively few attempts at quantitative surface analyses on account of lack of knowledge of key parameters (such as electron attenuation lengths, inner‐shell ionization cross sections, and backscattering factors) as a function, where appropriate, of material, incident electron energy, Auger electron energy, and instrumental characteristics. A review of experimental electron attenuation length data in the energy range relevant to AES and to x‐ray photoelectron spectroscopy (XPS) was given in a previous paper1 together with a method to predict attenuation lengths in other materials. We give a summary here of an analysis2 of available data concerning cross sections for ionization of inner‐shell electrons by electron impact. Cross‐section data of this type is also required in correction procedures for quantitative analysis by electron probe microanalysis.3 necessity the analy...

Diagnostic différentiel des troubles salivaires par scintigraphie quantitative

The scintigraphy of salivary glands with technetium-99m pertechnetate is predisposed to be an excellent test for evaluating salivary gland function. But the absence of a sufficiently precise and simple quantitative analysis procedure of the technetium uptake has reduced its clinical use. For this reason, the authors propose a new and quick method: the quantitative salivary gland scintigraphy. With an uptake index (ratio of technetium uptake between the glandular tissue and a cervical reference) they get precise quantitative information on functional activity. Among other applications, the test allows to make within a few minutes, in a case of xerostomia, the differential diagnosis between Sjäogren syndrome and sialosis.

Quantitative gas chromatographic analysis in case of overlapping peaks

Three procedures of quantitative gas chromatographic analysis in case of overlapping peaks are discussed. Basing on the behaviour of a chromatographic system the experimental data are evaluated mathematically by the first procedure. The second method needs more than one column to be used. In both procedures the analysis is carried out by the linear relationship method and none of the components of the analysed mixtures has to be available as pure substance. The third procedure requires that every overlapping component is available as pure substance.

Quantitative Electron Microprobe Analysis of Silicates Using Energy-Dispersive X-Ray Spectrometry

The advantages of using a lithium-drifted silicon X-ray detector instead of conventional Bragg spectrometers in microprobe analysis include simplicity and speed of operation. Also electron beam damage to minerals can be almost eliminated, owing to the low probe current required. A procedure for quantitative analysis is outlined here, and its scope and limitations are discussed, with special reference to silicate analysis. Analyses of 34 silicates independently analysed by chemical methods and conventional probe analysis are given. Above about 0·2 wt. per cent (element) systematic differences between energy-dispersive and conventional probe results are hardly significant. There are some discrepancies between probe and chemical data, probably mostly due to errors in the latter (e.g. high Al2O3 and low FeO). Concentrations below 0·2 per cent but above the theoretical limit of detection are sometimes not recorded. This is presumed to be due to slight over-correction for background, which could be rectified by a more complicated background correction procedure.

Mono- and diacylglycerols in human adipose tissue

A method is described to separate and determine monoacylglycerols, diacylglycerols, triacylglycerols and free fatty acids in one and the same lipid extract of human adipose tissue. Lipids were extracted by the Dole procedure. By column chromatography with silica gel most of the triacylglycerols were removed from free fatty acids, monoacylglycerols, and diaceylglycerols, which were then separated by thin-layer chromatography. Free fatty acids were measured by titration, and the partial glycerides were determined by measuring the glycerol content after hydrolysis. The applicability of the procedure for quantitative analysis of partial acylglycerols was demonstrated on lipid extracts from human subcutaneous adipose tissue from four different subjects. The concentrations, expressed as μmoles per g of neutral lipid were 1.48–1.74 for diacylglycerols 0.10–0.55 for monoacylglycerols and 0.65–1.35 for free fatty acids. When lipolysis was stimulated in vitro, no increase in the concentration of monoacylglycerols occurred, but the concentration of diacylglycerols increased significantly by about 50% in the experiments in which the stimulation of lipolysis was most pronounced. Evidence for the existence of a monoacylglycerol pathway was obtained by in vitro studies with labelled palmitic acid.

Simple Procedure for Quantitative Analysis of Turfgrass Color1

AbstractAssessments of turfgrass responses to environment, management, and culture are most often subjective, visual estimates. A simple procedure, based on methanol extraction of chlorophyll from dried turfgrass clippings, was developed to provide an objective quantitative measure of turf color. Extracted chlorophyll (chlorophyll index, CI) ranged from about 4 to 10 mg/g for ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) containing from 3 to 5.2% N. The procedure was validated by linear correlation (r3 = 0.77 to 0.90) of CI and % N values. The procedure adapts easily to routine use because it uses common laboratory instruments and is not time‐consuming. The resulting values are not confounded by turf density, cover, or thatch.

A new procedure for quantitative X-ray analysis with electron excitation

A method of quantitative x-ray analysis with electron excitation which eliminates the need to correct for absorption, fluorescence, and electron backscatter has been developed. This method consists of 1) analyzing an element using two or more different electron beam energies, 2) extrapolating the observed intensity ratios as a function of energy to an intensity ratio at the critical excitation potential, and 3) multiplying the result by an easily calculated factor to account for electron retardation effects. This method makes possible quantitative analyses of a single element in a multi-element assemblage without knowledge of the other elements. The procedure has been tested with a number of mineral and alloy specimens, and its accuracy is found to be at least as great as that obtained by conventional correction methods.

Accelerated ion-exchange chromatography of some biogenic amines

There has been increasing evidence of the importance of biogenic amines, some of which function as transmitting agents for impulses in the central nervous system. This paper attempts to provide procedures for separation and subsequent quantitative analysis of these compounds in physiological fluids. Detection sensitivity and resolving power are sufficient to allow samples of these fluids to be analysed directly after removal of particulate matter and adjustment of acid concentration, thereby avoiding degradation of labile compounds by exposure to aerial oxygen or extremes of heat or pH. Those amines which have primary amino groups may be determined at concentrations of io −3 to io −6 M on a standard amino acid analyser with columns of a specific ion-exchange resin and buffers which are completely compatible with reproducible ninhydrin colorimetry. Some of the other biologically important amines which do not have primary amine functions, e.g., catecholamines and indole derivatives, were monitored to even lower concentrations by continuous flow fluorimetry.

Synthesis of 3-deoxy-D-galacto-octulosonic acid

3-Deoxy-D-galacto-octulosonic acid was prepared by oxidation of 3-deoxy-D-glycero-L-manno-octonic acid, and 3-deoxy-D-glycero-L-gluco-octonic acid made by the action of sodium cyanide on 2-deoxy-D-galacto-heptose. Gas–liquid chromatographic procedures for the detection and quantitative analysis of the 3-deoxy-D-galacto-octulosonic acid are described.

Analysis of nucleic acid derivatives at the subnanomole level: III. A tritium labeling procedure for quantitative analysis of ribose derivatives

Mixtures of ribonucleosides are quantitatively analyzed by a procedure involving the following steps: 1. (1) Oxidation with sodium metaperiodate. 2. (2) Reduction with tritiated sodium borohydride. 3. (3) Thin-layer chromatography on cellulose. 4. (4) Elution of labeled nucleoside trialcohol derivatives and quantitative evaluation by liquid scintillation counting. The method is over 1000-fold more sensitive than the conventional optical techniques. Ribopolynucleotides are analyzed by the labeling technique after appropriate enzymic digestion. In the course of this investigation the molar absorptivity ( ε 260) of guanosine, measured in 0.02 M Tris-hydrochloride buffer, pH 7.4, was determined to be 12.5 × 10 3 M −1 cm −1.

The determination of the crystalline content of glass-ceramics

The determination of the crystalline content of glass-ceramic materials is complicated by small crystal size (0.1 to 20μm) as well as by variable crystal composition and morphology. Electron microscope, X-ray diffraction, and chemical separation techniques for quantitative crystallinity determinations can give equally valid results. Electron microscopy, however, is more universal in its application, since identification and synthesis or insolubility of the crystals are not important factors in quantitative results. Replica and transmission electron microscopy are used to determine the crystalline content of complex polycrystalline glass-ceramics. These techniques involve preparation of replicas of selectively etched surfaces as well as thin sections less than 0.1μm thick. The X-ray diffraction peak-intensity procedure for quantitative crystallinity analysis is demonstrated in glass-ceramics exhibiting extensive crystal solid solution. Chemical separation techniques for quantitatively distinguishing between glass and crystalline phases corroborate electron microscope and X-ray diffraction results.

Sex Pheromones of Noctuid Moths. IX. Isolation Techniques and Quantitative Analysis for the Pheromones, with Special Reference to that of Trichoplusia ni (Lepidoptera: Noctuidae)12

General extraction and purification steps for sex pheromones of noctuid moths are outlined as derived from the specific case of Trichoplusia ni (Hubner). These include an ether extraction, a falling-film distillation, preparative thin-layer chromatography, and preparative gas-liquid chromatography. Operating parameters are given for these procedures. Collecting only abdomen tips gave a 4-fold purification over extracting whole moths. In the case of T. ni the distillation was carried out at 100°C (0.5 mm) and 140° (0.1 mm) and resulted in a 10-fold purification. Thin-layer chromatography of the pheromones of T. ni , Autographa californica (Speyer), and Heliothis virescens (F.) all resulted in R t 's of 0.30 to 0.50 on silica gel, using benzene as the developing solvent. The retention time for the pheromone of T. ni was determined for 4 different gas-liquid chromatography columns. The time of biological activity was correlated with the electrical response of a hydrogen flame detector. Criteria for the purity of a gas chromatogram are given. A procedure for quantitative analysis for the pheromone of T. ni is given. This analysis made use of an internal standard. Apparatus and procedures are given for the collection of sub-milligram amounts from a gas chromatograph.

Quantitative colorimetric method and extraction procedure for determination of chlorpromazine in animal tissues

A procedure for quantitative analysis of chlorpromazine from biologic tissues based on oxidation of CPZ by ferric ion in the presence of concentrated sulfuric acid, and on its extraction into alkaline ether, is described. Cherry-red chromophore is read spectrophotometrically. Eighty to ninety percent recoveries of chlorpromazine, after its incubation with brain homogenates, could be obtained by means of this method. The procedure was specific for chlorpromazine and other 2-chlorophenothiazines possessing a side chain on the ring nitrogen; color was not present, or a different color was obtained, with changes in the phenothiazine nucleus and with substitutions for chlorine in position 2.