Microanalytical methods

SPh boron detenuination in form of complex with Azomethine-H is the reliable microanalytical method for boronorganic compounds, carboranes, metallacarboranes, etc. Before boron determination the samples should be melted with KOH at 900°C. 

All these microanalytical methods are in the everyday use at the analytical laboratory of INEOS RAS. 

We have, in the Howard procedure and technique, a reliable microanalytical method... 

TILDEN—MEASUREMENT OF FILTH IN FOODS BY MICROANALYTICAL METHODS... 

The measurement of filth elements by microanalysis is a valuable adjunct in the enforcement of the Food, Drug, and Cosmetic Act and serves as an efficient means of evaluating conditions of cleanliness, decency, and sanitation in food-producing plants. This, of course, is in addition to the value of microanalytical methods in the determination of the fitness of foods as they reach the consumer. The techniques available, together with proficiency of manipulation, repeated references to authentic materials, and sound judgment in the interpretation of results, provide effective enforcement weapons in the constant war to prevent the production and interstate distribution of products which are unfit for the table of the American consumer. 

In most cases, the composition of the complexes is determined by standard microanalytical method, but sometimes this gives a relatively large negative error... 

Sharp, Z.D. 1990 A laser-based microanalytical method for the in situ determination of oxygen isotope ratios of silicates and oxides. Geochimica et Cosmochimica Acta 54 1353-1357. 

To discuss the development of CRMs for the emerging use of microanalytical techniques, one has to be concerned chiefly with the degree of homogeneity of the components in the material at the designated sample size. Basic indications for the homogeneity properties of a CRM for microanalytical methods and the assessment of these properties can be derived from the general requirements ... 

Certified Reference Materials for Microanalytical Methods 1135 4.3.4.3 Uncertainty Budget of INAA... 

This technique is simple in basic principle. Material is first rapidly frozen to the temperature of liquid nitrogen. It is then fractured, cryo-planed to produce a flat surface for analysis, and transferred to the cryo-stage of an SEM. It is analyzed while still frozen, and thus ion movement during tissue preparation should be minimal. A more detailed scheme of a typical procedure (45,46) is given in Subheading 3.4.2.1. This is undoubtedly the most popular microanalytical method with plant scientists at present, and as Table 1 shows it has been applied to a wide range of tissues and research topics (46-53). Recent developments include a... 

Philhps, T.M., Microanalytical methods based on affinity chromatography, in Handbook of Affinity Chromatography, 2nd edn., Hage, D.S., Ed., CRC Press, Boca Raton, FL, 2005, Chap. 28. 

High-resolution compositional measurements are possible through use of a variety of microanalytical methods. Ideally, these should be non-destructive, can be targeted on small areas of sample, and have low minimum detection limits. Electron-probe X-ray microanalysis (EPXMA) and proton-induced X-ray emission (PIXE) techniques have both been used successfully on archaeological sediment thin sections (19, 20). Both techniques yield elemental composition data for a range of elements. EPXMA has the advantage of being nondestructive, whereas PIXE when used on thin-section samples is typically destructive conversely the detection limit for PIXE is lower than EPXMA. 

Several other microanalytical methods in common use potentially have application on soil and sediments section samples. Laser-ablation inductively coupled plasma mass spectrometery (LA-ICP-MS) has been used on soil thin-sections from a controlled field experiment (21) but required special resins in the preparation. There is presently (May 2006) no reported use of this method on archaeological soil samples. Likewise, for extremely fine-resolution studies (i.e. <10 pm) with low minimum detection limits and despite difficult calibration, secondary ion microscopy (SIMS) has a potential role in examining archaeological soil thin sections. At even higher lateral resolutions ( 100 nm) Auger electron spectroscopy (AES) could also be considered for surface (<5 nm deep) analyses. At present however, the use of these methods in soil systems is limited. SIMS has been focused on biochemical applications (22), whereas AES... 

Slonek et al 1 developed a rapid and simple HPLC microanalytical method for the determination of clinically encountered plasma phenytoin levels. This method is accurate down to about 1 ug of phenytoin/ml of plasma and requires as little as 10 ul of sample. 

Despite its bad reputation as an analytical tool, XRF is potentially a traceable method according to the CCQM definition and could be a primary method although it was not selected as such, and won t be for a long time. In fact, it is the only microanalytical method which can at present be considered as a candidate for accurate microscopic elemental analysis. Proof of this statement follows from Monte Carlo calculations in which experimental XRF spectra can be accurately modelled starting from first principles [23], This is not an easy approach but with computing power now available it is feasible, though not worth the effort for bulk chemical analysis where other alternatives are available. 

Following resolution of a mixture on the paper chromatogram, the content of each spot may be quantitatively determined in various ways. Basically, however, the spot may be estimated in one of two ways directly on the paper or, after elution from the paper, by a variety of microanalytical methods. The basic methods, as applied to amino acids, have been discussed by Block and coauthors.8 Generally, the accuracy of any method, applied either in situ or after elution, rarely exceeds a precision of 5%. 

International Conference on Non-Destructive Testing. Microanalytical Methods and Environment Evaluation for Study and Conservation of Works of Art. Perugia. 1988 1/30.1 -1/30.17. 

The structure of the bioactive members of a combinatorial library prepared by split synthesis can be determined by several methods including bioactivity/deconvolution, microanalytical methods and encoding. In a generalized example of the biorecognition/ deconvolution approach, the final sublibraries are not pooled but tested as mixtures. The most active sublibrary then defines the synthon used in the last synthetic step. The synthesis is then repeated to the penultimate step these sublibraries are not mixed, but each is separately reacted with the preferred last-step synthon. These resulting sublibraries are tested the most active then defines the preferred synthon in the penultimate step, and hence the last two synthons present in the most active member of the family are defined. 

Progress in microanalytical methods continuously improves the ability of chemists to clarify the structures of new semiochemicals. In 2002, a new and revolutionary strategy in the structure determination of a biofiinc-tional and small molecule was reported by Hughson and coworkers.4 It was to determine the structure of a... 

The microanalytical methods of differential thermal analysis, differential scanning calorimetry, accelerating rate calorimetry, and thermomechanical analysis provide important information about chemical kinetics and thermodynamics but do not provide information about large-scale effects. Although a number of techniques are available for kinetics and heat-of-reaction analysis, a major advantage to heat flow calorimetry is that it better simulates the effects of real process conditions, such as degree of mixing or heat transfer coefficients. 

Microanalytical methods are used to move further down in the characterization scale. X-ray photoelectron spectroscopy (XPS or ESCA), (see Barr) Auger electron spectroscopy (AES), and secondary ion mass spectroscopy (SIMS) as presented by Leta for imaging FCC catalysts, are surface analysis techniques providing chemical analy-... 

For ternary polymer-polymer-solvent systems, the compositions of the equilibrium phases may be determined using a variety of microanalytical methods depending upon the chemical nature of the polymers (Dobry and Boyer-Kawenoki, 1947). Each of the phases is sampled, weighed, and dried to determine the solvent concentration. If the two polymers are sufficiently different chemically, microanalytical determination of carbon and hydrogen may be used. In systems containing polystyrene, the proportion of polystyrene may be determined by precipitating it with acetic acid and weighing the precipitate. Other microanalytical methods have also been used to determine phase compositions. 

To identify materials forming a criminalistic trace, it is necessary to study their morphology, determine their chemical composition (mainly qualitative) and study some physico-chemical properties. Because the sample of material forming the trace is small, microanalytical methods are applied for identification. Methods that... 

Until recently, many traces, even those perceptible to the naked eye at the scene of the incident, were not secured because sufficiently accurate methods of analysing them did not exist. It was not until the development of microanalytical methods and their introduction into practice by forensic experts that analysis of traces and their use as a valuable source of information about an incident was possible (i.e. about the course of the event and the persons taking part in it). 

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