Analyser, optical

A 5 ml sample is adequate to analyse optical density, glucose/sucrose concentration and ethanol concentration. For sugar analysis you may dilute 1 ml of sample and 9 ml of distilled water to have a suitable concentration range for DNS analysis. 

Gibberellin Ax was the first gibberellin to be isolated from a higher plant (10, 12), It was readily identified by infrared spectrum, elementary analyses, optical rotation, and conversion to the methyl ester. Our highest yields have been 2 mg. per kg. fresh weight of seed. 

NIR radiation can be transmitted down readily available, relatively cheap optical fibers thus allowing spectrometers to be located remotely from the process streams they are monitoring, away from potentially hazardous areas. Optical fibers also provide a convenient means of multiplexing a single spectrometer to several streams, thus reducing the overall cost of the analyses. Optical fibers, optical switching and sample probes have been crucial to the development of NIR spectroscopy for process analytical applications [8, 9]. 

Following the increase in biological research using nanowire arrays, for which there is a market for low-cost, disposable substrates for tissue culture that can be analysed optically from the bottom, Sikorski and... 

The composite before trials investigated with the help of roentgen - structural and roentgen - spectral of the analyses, optical and raster electronic microscopy on standard techniques. 

Iron oxides and hydroxides are the most important iron-bearing constituents of soils, sediments and clays. To characterize the samples, i.e. the identification of the different minerals present and the determination of their morphology and chemical composition, a variety of standard techniques are commonly used such as X-ray and electron diffraction, chemical analyses, optical and electron microscopy, infrared spectroscopy and thermal analysis (DTA, DTC,...). Most of these techniques are further applied in conjunction with selective dissolution or other separation methods in order to obtain more specific information about particular components in the complex soil system. In addition to all those characterization methods, MS has proven to be a valuable complementary technique for the study of these kinds of materials and in particular for the characterization of iron oxides and hydroxides which are usually poorly crystallized. 

Figure C3.5.3. Schematic diagram of apparatus used for (a) IR pump-probe or vibrational echo spectroscopy by Payer and co-workers [50] and (b) IR-Raman spectroscopy by Dlott and co-workers [39]. Key OPA = optical parametric amplifier PEL = free-electron laser MOD = high speed optical modulator PMT = photomultiplier OMA = optical multichannel analyser.

Por IR-Raman experiments, a mid-IR pump pulse from an OPA and a visible Raman probe pulse are used. The Raman probe is generated either by frequency doubling a solid-state laser which pumps the OPA [16], or by a two-colour OPA [39]. Transient anti-Stokes emission is detected with a monocliromator and photomultiplier [39], or a spectrograph and optical multichannel analyser [40]. 

Physical testing appHcations and methods for fibrous materials are reviewed in the Hterature (101—103) and are generally appHcable to polyester fibers. Microscopic analyses by optical or scanning electron microscopy are useful for evaluating fiber parameters including size, shape, uniformity, and surface characteristics. Computerized image analysis is often used to quantify and evaluate these parameters for quaUty control. 

National Institute of Standards and Technology (NIST). The NIST is the source of many of the standards used in chemical and physical analyses in the United States and throughout the world. The standards prepared and distributed by the NIST are used to caUbrate measurement systems and to provide a central basis for uniformity and accuracy of measurement. At present, over 1200 Standard Reference Materials (SRMs) are available and are described by the NIST (15). Included are many steels, nonferrous alloys, high purity metals, primary standards for use in volumetric analysis, microchemical standards, clinical laboratory standards, biological material certified for trace elements, environmental standards, trace element standards, ion-activity standards (for pH and ion-selective electrodes), freezing and melting point standards, colorimetry standards, optical standards, radioactivity standards, particle-size standards, and density standards. Certificates are issued with the standard reference materials showing values for the parameters that have been determined. 

Analyses of alloys or ores for hafnium by plasma emission atomic absorption spectroscopy, optical emission spectroscopy (qv), mass spectrometry (qv), x-ray spectroscopy (see X-ray technology), and neutron activation are possible without prior separation of hafnium (19). Alternatively, the combined hafnium and zirconium content can be separated from the sample by fusing the sample with sodium hydroxide, separating silica if present, and precipitating with mandelic acid from a dilute hydrochloric acid solution (20). The precipitate is ignited to oxide which is analy2ed by x-ray or emission spectroscopy to determine the relative proportion of each oxide. 

Spectroscopic methods for the deterrnination of impurities in niobium include the older arc and spark emission procedures (53) along with newer inductively coupled plasma source optical emission methods (54). Some work has been done using inductively coupled mass spectroscopy to determine impurities in niobium (55,56). X-ray fluorescence analysis, a widely used method for niobium analysis, is used for routine work by niobium concentrates producers (57,58). Paying careful attention to matrix effects, precision and accuracy of x-ray fluorescence analyses are at least equal to those of the gravimetric and ion-exchange methods. 

Several instmmental methods are available for quantitative estimation of from moderate to trace amounts of cerium in other materials. X-ray fluorescence is widely available, versatile, and suitable for deterrninations of Ce, and any other Ln, at percent levels and lower in minerals and purer materials. The uv-excited visible luminescence of cerium is characteristic and can be used to estimate Ce content, at ppm levels, in a nonluminescing host. X-ray excited optical luminescence (15), a technique especially appropriate for Ln elements including cerium, rehes on emissions in the visible, and also measures ppm values. Atomic emission spectrometry is appHcable to most lanthanides, including Ce (16). The precise lines used for quantitative measurement must be chosen with care, but once set-up the technique is suitable for routine analyses. 

Smectites are stmcturaUy similar to pyrophylUte [12269-78-2] or talc [14807-96-6], but differ by substitutions mainly in the octahedral layers. Some substitution may occur for Si in the tetrahedral layer, and by F for OH in the stmcture. Deficit charges in smectite are compensated by cations (usually Na, Ca, K) sorbed between the three-layer (two tetrahedral and one octahedral, hence 2 1) clay mineral sandwiches. These are held relatively loosely, although stoichiometricaUy, and give rise to the significant cation exchange properties of the smectite. Representative analyses of smectite minerals are given in Table 3. The deterrnination of a complete set of optical constants of the smectite group is usually not possible because the individual crystals are too small. Representative optical measurements may, however, be found in the Uterature (42,107). 

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