Samples mineralization

Because there is no natural mechanism for producing isotopically pure Th, any measurable Th in a sample for °Th/U dating implies the presence of at least some °Th when the sample (mineral or mineral assemblage) was formed. This initial °Th must then be subtracted from the total measured °Th before a valid °Th/U age can be calculated. In addition, a correction for initial U isotopes is required when the material being dated is a mechanical mixture of an isotopically homogeneous detrital material with an initially thorium-free mineral such as chemically precipitated carbonate. In these cases we are usually interested only in the time of formation of the Th-free material, and so must also subtract the detrital and before calculating the °ThAJ age. 

The story became more complicated when in 1809 the Enghsh scientist William Hyde Wollaston (1766—1828) analyzed the sample mineral and declared that columbium was really the same element as tantalum ( Ta). This error is understandable given that the level of analytical equipment available to scientists in those days was fairly primitive. Also, tantalum and niobium are very similar metals that are usually found together and thus are difficult to separate for analysis. 

KEYWORDS soil sampling mineral exploration, partial, leach, base metals, Yukon... 

Fig. 4. Typical X-ray diffractograms of 100-125 pm ground HT materials, showing purely vitreous character (P8) or vitrocrystalline character (P6, PI 6 ). For most vitrocrystalline samples, mineral phases are distributed throughout the glass matrix (e.g., P6", homogeneous vitrocrystalline), but some samples (e.g., PI6, heterogeneous vitrocrystalline) exhibit patches of concentrated crystalline phases visibly separated from the bulk vitreous matrix.

Sr is one of the most hazardous and dangerous radioactive isotopes. It is a pure beta emitter (Eimj = 546 keV) and decays to another pure beta emitter, 90Y ( max = 2283.9 keV).10 The radiochemical methods for determining 90Sr in aquatic samples (water, sediment, and biota) are based on the adsorption of radiostrontium on AMP in water samples, mineralization of sediment and biota, and sorption on Sr resin.14 16... 

TABLE 3.1 The Mineral and Chemical Composition of Bentonite Samples (%) Mineral Composition ... 

Based on assessing the quantity of an element in an extract in relation to its total quantity obtained by sample mineralization, or in relation to the overall quantity of an element in different extracts and in the mineralized post-extraction deposit... 

Solecki, J., Chibowski, S. Studies of soil sample mineralization conditions preceding the determination of Sr. J. Radioanal. Nucl. Chem. 247, 165-169 (2001)... 

Livardjani F, Heimburger R, Leroy MJF, et al. 1991a Optimization of blood sample mineralization for mercury analysis by cold vapor atomic absorption. Analysis 19(7) 205-207... 

Activation analysis is a highly sensitive nondestructive technique for qualitative and quantitative determination of atomic conqx>sition of a sample. It has been particularly useful for determination of elements in complex samples (minerals, environmental samples, biological and archeological objects, etc.), because it provides a simple alternative to much more difficult, tedious and destructive techniques. Its main limitation is the demand for a strong irradiation source. 

The distribution of elements in biological samples, mineral samples, soils, and other heterogeneous materials can be determined. Many other applications can be found in the literature. This is one of the few techniques that can provide spatial variation of composition at the micrometer scale. Other related techniques are discussed in Chapter 14. 

Sample Mineral matrix Organic substance Kerogen Bitumen... 

Thus, the objective of the proximate analysis is to determine the amount moisture, volatile matter yield, ash yield, and fixed carbon from the coal sample. Mineral matter is not directly measured but may be obtained by one of a number of empirical formula either from the yield of mineral ash or from data derived from the ultimate analysis. 

Before mineral analysis it is usually necessary to treat the sample to ensure that the sample is homogeneous and also to prepare it for the analytical procedure that follows. Various processes may be necessary, but among the most important is sample mineralization, often associated with the need to destroy organic matter present in the sample and always necessary to make the sample soluble. Moreover, the treatment of a sample may entail reduction and homogenization of its size or elimination of interferences. In any case, contamination of the sample or loss of volatile compounds may occur during these steps of the analytical process, affecting the quality of the analytical results. 

They confirmed the excesses in Cr/ Cr and Cr/ Cr for bulk carbonaceous chondrites, which may affect the use of the Mn-Cr chronometer in carbonaceous chondrites, reported by Shukolyukov and Lugmair (2004,2006). Bulk chondrites have small s Cr (1 e unit is 1 part in 10 ) excesses (up to 0.3) relative to the Earth, most likely reflecting the subchondritic Mn/Cr ratio of the Earth. The e Cr variations in chondrites probably correlate with Mn/Cr and yield an initial solar system Mn/ Mn value of 5.4( 2.4) x 10 , corresponding to an absolute age of4,566.4 ( 2.2) Ma. Interactions of cosmic rays result in excesses of s Cr and a Cr with 4 1 ratio in phases with high Fe/Cr. These are most dramatically verified in the iron meteorite Carbo. Hence, the Mn-Cr chronometer should be used with caution in samples/minerals with high Fe/Cr and long cosmic-ray exposure ages. 

Wet digestion is certainly a good procedure for zinc sample mineralization no significant differences have been found between Parr bomb-, microwave-, and hot plate-based systems [67-69]. 

A method for preconcentration and separation of ultra-trace amounts of uranium from aqueous samples (mineral water, rivers, wells, springs, and seawater) based on combining SPE with liquid-liquid microextraction was described (Dadfarnia et al. 2013). The water samples were filtered (0.45 pm) and acidified fo pH 2 wifh... 

Ion chromatography. Ion chromatography is a powerful technique for analysis of both anions and cations. Detection limits usually range from low parts-per-billion to low parts-per-million. For application in plastic materials analysis, the method provides two type of information (a) free ionic content and (2) total content of some of the inorganic elements (for example, chloride, sulfur, etc.) after suitable sample mineralization. 

Most of the methods (except for direct dissolution in organic solvents) used to convert the analytes of interest in the plastics to solution involve sample mineralization which results in oxidation of its organic constituents to carbon dioxide and water. The oxidation process can be accomplished as sample combustion (dry ashing) whereby the sample is oxidized in a stream of oxygen or air, or alternatively, strong liquid oxidizers (mineral acids, peroxides, etc.) can be used for the same purpose (wet ashing). 

I-19.3 (imol/L ammonium molybdate flow rate 0.8 mUmin detection UV/Vis at 352 nm after postcolumn reaction with 027mol/L Kl PCR flow rate 02 mU/min PCR temperature ambient injection volume lOOOpL sample mineral water spiked with 0.5 pg/L bromate (1). 

The minimum and maximum ages of materials that can be dated depend on the decay constant/half-life of the parent isotope (Table 9.1) and the relative enrichment of parent over daughter isotope, apart from the precision of the isotope ratio measurements. The materials most suitable for dating purposes are those that only incorporate the parent isotope at the time of formation, as a single sample (mineral) suffices to obtain an age, whereas at least two, but preferably three or more, samples are necessary to obtain an age by the isochron method. 

The WHO (1984) maximal value guideline for chloride concentration in drinking water is 250 mg/dm. The maximal value of chloride concentration for water used in irrigation is 100 mg/dm. Industrial applications (e.g., boiler feeding) often require water with much less chloride content. However, seawater, mixed water samples, mineral waters, and sewage contain chlorides in much higher concentration. 

Figure 16. Chromatogram obtained from the moving chain detector. Sample mineral oil and surfactant, solvent n-heptane, ethyl alcohol, column 2 x 300 mm, column packing silica gel, flow rate 0.7 ml/min, chart speed 24 cm/min, evaporator temperature 150°C, N2 flow rate 30 ml/min, H2 flow rate 25 ml/min, O2 flow rate 30 ml/min.

The first step in the search for a mineral poison is the sample mineralization. Organic matters must indeed be destroyed since they may dissimulate the ion with respect to their reagents. After minCTalization, the element is converted into an ion. Numerous methods have been proposed to carry out mineralizations. We ll only mention the mineralization with Cbtg), which is insufficient since it does not destroy... 

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