Matrix range

The method has been validated in animal tissues and eggs at fortification levels from 0.01 to 0.1 mg kg Mean recoveries in each matrix ranged from 86 to 99% with the LOD estimated to be 0.002-0.004 mg kg The method has been validated in milk at fortification levels from 0.001 to 0.02 mg kg The mean recovery was 96% with the LOD estimated to be 0.0003-0.0005 mg kg ... 

Although PFE lacks a proven total concept for in-polymer analysis, as in the case of closed-vessel MAE (though limited to polyolefins), a framework for method development and optimisation is now available which is expected to be an excellent guide for a wide variety of applications, including non-polyolefinic matrices. Already, reported results refer to HDPE, LDPE, LLDPE, PP, PA6, PA6.6, PET, PBT, PMMA, PS, PVC, ABS, styrene-butadiene rubbers, while others may be added, such as the determination of oil in EPDM, the quantification of the water-insoluble fraction in nylon, as well as the determination of the isotacticity of polypropylene and of heptane insolubles. Thus PFE seems to cover a much broader polymer matrix range than MAE and appears to be quite suitable for R D samples. 

Another method (EPA 3545, accelerated solvent extraction) has been validated using a variety of soil matrixes, ranging from sand to clay. In the method, conventional solvents such as methylene chloride (or a hexane-acetone mixture) are heated [100°C, (212°E)] and pressurized (2000 psi), then passed through the soil sample (this technique is also suitable for application to petroleum sludge and petroleum sediment). The method has the advantage of requiring smaller solvent volumes than is required by traditional solvent extraction techniques. 

While analysis in an iron matrix ranges from the trace range to 20%, element concentrations of up to 60% are determined in oxide substances. 

No single cleanup method is able to cover the entire matrix range. The need for a cleanup procedure prior to gas chromatography analysis is largely dependent on the complexity of the matrix and the range of analytes to be analyzed. 

Typically, in clinical practice, the phase-encoding matrix ranges from 160 to 320, and the frequency-encoding between 250 and 512. These parameters allow adequate resolution, scan times and SNR. Higher resolution matrices may be used in selective cases, when the body part is small and complex, such as the paediatric wrist or ankle (Anupindi and Jaramillo 2002). 

GC/MSD instrument detection limit is typically 1 to 5 ig/mL (ppm) operated in scan mode. For a 1-g sample extracted into 10 mL, the method detection limit is about 10 /ig/g (ppm) which is sufficient for screening purposes. Table 16.1 summarizes typical recovery figures using this simplified extraction procedure. For soils fortified with 100 ppm of diesel with matrix ranging from sand to peat moss, recovery varies from 68 to 83%. To test the rapid extraction further, an actual sample contaminated with well-aged diesel was analyzed and showed a value of 54% of that obtained by more vigorous extraction (2,254 ppm versus 4,200 ppm). 

Four series of iron-titanium oxide photocatalysts have been prepared two series by impregnation of solid titanium dioxide (Tioxide CLDD 1625/2 TOx, and Degussa P25 Dg ), with aqueous iron Fe ions, and two by chemical methods from titanium and iron salts (coprecipitation CP, and spray pyrolysis SP ). The concentration of iron, expressed as percentages of the total cationic content of the TiO matrix ranged from 0.1 to 10 atom percent... 

All nitrogen determined in the ultimate analysis is assumed to have its origin in the organic coal matrix ranging from 0.5 to 2.5 wt%(waf). Consequently, the full conversion of the coal will liberate the nitrogen into the gas phase, mainly forming N2, NH3, and HCN. If the gasification process permits the survival of... 

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