Sample preparation methods fusion

Quantitative analysis usually requires the use of standards and/or certified reference materials (CRMs), the selection of an appropriate elemental optical emission line, and, in most cases, the selection of a normalization line, used as an IS. Calibration curves are then constructed using the normalized peak area versus concentration, as previously described for calibration using an IS. When there is a dominant matrix component for which the concentration will remain approximately constant across the calibration set, it is best to use an emission line from that matrix element for normalization. This approach helps minimize effects due to changes in plasma conditions caused by shot-to-shot fluctuations in laser intensity. Alternatively, chemometric correlation analysis of the entire observed spectrum with the concentration of the analyte can be used to construct calibration curves automatically. In general, RSDs of 5%-10% are readily achievable. To improve quantitation, sample preparation methods such as pressing pellets may improve results for soils and sediments and fusion with salts to convert the sample into a glass bead can eliminate matrix effects. Fusion was discussed in Chapter 1 and is used extensively in XRF analysis (Chapter 8). 

The determination of ionic substances, or substances that can be converted into ionic form from solid samples, is an important field of application of ion chromatography. This includes the analysis of sods, sediments, dusts, geological materials, various industrial products, as well as biological samples and all types of foodstuffs. The sample preparation methods for solid substances can be classified according to whether treatment with a liquid, fusion, ashing, or combustion of the dry sample is necessary. 

Laser ablation ICP-MS (LA-ICP-MS) was established in the early 1990s as a potential routine tool for the measurement of trace and ultra-trace elements in silicate systems for geology. Early studies (Perkins et al. 1993) used sample preparation techniques identical to that used to prepare rock samples for WDXRF, i.e., either a pressed powder disk or a glass bead fusion method (see Appendix VIII). Such studies concluded that LA-ICP-MS had the potential to surpass XRF in terms of the limits of detection achieved and INAA in terms of the speed of analysis (Perkins et al. 1993 481). It has long been recognized that the main limit on the quantitative performance of LA-ICP-MS is the homogeneity at the trace and ultra-trace level of the solid calibration standards available. Subsequent work (e.g., Hollecher and Ruiz 1995, Norman et al. 1996) has demonstrated that some of the international... 

With the PGSS process, micronized drugs and drug/PEG 4000 samples were prepared in a new way, which has some advantages over conventional methods for the micronization of pure drugs and for drug/carrier solid dispersion preparation, namely fusion methods and solvent processes. 

Basically, the literature provides two dissolution methods sample preparation with sample weights of 0.2—1 g and large dilutions, or smaller sample weights with less dilution (III.B). The relatively large dilution, in general after a fusion [51], for the determination of main and lesser components, as for example in silicate analysis [2], the determination of Al, Ca, Mg, Mn and Si in slags [4], Si [55], Pb and Mn [143], and also Cd, Ca, Cu, Pb, Mg and Si in ores or iron sinter [97, 147] and Cr, Mg in refractories [93] is presently used in routine analysis. 

The book begins with a discussion of the basic physico-chemical aspects of reactions utilised in qualitative inorganic analysis. A description of laboratory equipment follows, and operations which include semimicro and micro techniques, and simple electrochemical, spectroscopic and chromatographic methods. The reactions of the most important cations and anions are described, followed by a treatment of systematic qualitative analysis. Sample preparation, dissolution and fusion of insoluble materials are treated in detail. A separate chapter deals with the reactions of less common ions, with guidelines to their separation and identification in the course of systematic analysis. Finally, a simplified course of qualitative analysis is given this chapter will be particularly useful where the time allocated to qualitative analysis is limited. 

The optical microscope is a valuable tool in the laboratory and has numerous applications in most industries. Depending on the type of data that is required to solve a particular problem, optical microscopy can provide information on particle size, particle morphology, color, appearance, birefringence, etc. There are many accessories and techniques for optical microscopy that may be employed for the characterization of the physical properties of materials and the identification of unknowns, etc. Utilization of a hot-stage accessory on the microscope for the characterization of materials, including pharmaceutical solids (drug substances, excipients, formulations, etc.), can be extremely valuable. As with any instrument, there are many experimental conditions and techniques for the hot-stage microscope that may be used to collect different types of data. Often, various microscope objectives, optical filters, ramp rates, immersion media, sample preparation techniques, microchemical tests, fusion methods, etc., can be utilized. 

Standard Practice for Sample Preparation for X-Ray Emission Spectrometric Analysis of Uranium in Ores Using the Glass Fusion or Pressed Powder Method... 

The Benefits of the X Series 2 ICP-MS for the Analysis of Geological Samples Prepared Using the Lithium Metaborate Fusion Method, Thermo Scientific Application Note—40790, 2007, http //www.thermo.com/eThermo/CMA/PDFs/Articles/articles-File 2375.pdf. 

The importance of ignoring surface contamination, appropriate sample form and preparation method is illustrated by the analysis of a lead sample (c = 1 g/g) for oxygen by reducing fusion ... 

For the synthesis of materials, the reactants are placed in the copper crucible. An arc is struck by allowing the cathode to touch the anode. The current is raised slowly while the cathode is simultaneously withdrawn so as to maintain the arc. The arc is then positioned so that it bathes the sample in the crucible. The current is increased until the reactants melt When the arc is turned off, the product solidifies in the form of a button. Because of the enormous temperature gradient between the melt and the water-cooled crucible, a thin solid layer of the sample usually separates the melt from the copper hearth in this sense, the sample forms its own crucible and hence contamination with copper does not take place. Contamination of the sample by tungsten vaporizing from the cathode can be avoided by using water-cooled cathodes. The arc method has been successfully used for the synthesis of various oxides of Ti, V and Nb. A number of lower-valence rare-earth oxides, LnO, 5 have been prepared by arc fusion of LnjOj... 

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