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Sample types preservation

Sample Type Container Preservative Storage Time (Days)... [Pg.156]

Numerous CE separations have been published for synthetic colours, sweeteners and preservatives (Frazier et al., 2000a Sadecka and Polonsky, 2000 Frazier et al., 2000b). A rapid CZE separation with diode array detection for six common synthetic food dyes in beverages, jellies and symps was described by Perez-Urquiza and Beltran (2000). Kuo et al. (1998) separated eight colours within 10 minutes using a pH 9.5 borax-NaOH buffer containing 5 mM /3-cyclodextrin. This latter method was suitable for separation of synthetic food colours in ice-cream bars and fmit soda drinks with very limited sample preparation. However the procedure was not validated for quantitative analysis. A review of natural colours and pigments analysis was made by Watanabe and Terabe (2000). Da Costa et al. (2000) reviewed the analysis of anthocyanin colours by CE and HPLC but concluded that the latter technique is more robust and applicable to complex sample types. Caramel type IV in soft drinks was identified and quantified by CE (Royle et al., 1998). [Pg.124]

Foods. The determination of antioxidants and food preservatives is a very active part of the gas chromatography field. Adaptations and sample types are almost limitless for example, analysis of fruit juices, wines, beers, syrups, cheeses, beverages, food aromas, oils, dairy products, decomposition products, contaminants, and adulterants. A detailed discussion of this field may be found in Chapter 9. [Pg.17]

The use of techniques that focus on a subset of resonances make it possible to do productive NMR experiments on systems that do not have the narrowest possible linewidths, and thus to investigate more challenging proteins or to optimize sample conditions for a particular functional state rather than for the narrowest resonances. However, since the information content of the NMR experiment depends on the number of resolvable resonances, which depends on their linewidths, it is critical to seek conditions that minimize the linewidths while preserving functionality. The membrane protein system of interest will dictate which sample types are possible and which conditions preserve functionality Table 1 documents membrane protein linewidths that have been observed in a variety of sample types including nanocrystals, 2D crystals, detergent micelles, proteoliposomes and nanodisks. [Pg.142]

Unlike vanadium, REE/Fe ratios recorded in even the most recent metalliferous sediments are much higher than those in suspended hydrothermal plume particles (German et al., 1990, 1997 Sherrell et al., 1999). Further, hydrothermal sediments REE/Fe ratios increase systematically with distance away from the paleo-ridge crest (Ruhlin and Owen, 1986 Olivarez and Owen, 1989). This indicates that the REE may continue to be taken up from seawater, at and near the sediment-water interface, long after the particles settle from the plume to the seabed. Because increased uptake of dissolved REE from seawater should also be accompanied by continuing fractionation across the REE series (e.g., Rudnicki and Elderfield, 1993) reconstruction of deep-water REE patterns from preserved metalliferous sediment records remain problematic. Much more tractable, however, is the exploitation of these same sample types for isotopic reconstructions. [Pg.3066]

The sample type, type of containers and their preparation, possible forms of contamination, and preservation methods must be considered to maintain the integrity of the sample. Risk assessors are encouraged to seek the advice of their analytical laboratory during the sampling design stage. [Pg.141]

Preservative or technique used Effect on sample Type of samples for which the method is employed... [Pg.289]

Sample type Collection Storage container Preservation... [Pg.79]

Urine is the most common bioassay sample type because it is nonintrusive and readily available, and provides some insight into radionuclide intake, retention, and excretion, but is not ideal for all radionuclides. A preservative can be added to urine samples immediately after collection. Bioassay samples are refrigerated for prompt analysis and kept frozen for extended storage. [Pg.91]

One type of reality check is comparing a radionuclide measurement with values for similar samples collected at the same time or previously, either in the same program or reported by others. It is usually invoked when the result under consideration appears to be unusually low or high. As indicated in Chapter 12, the best response is reanalysis. If the questioned value is confirmed, an unexpected situation has been found. If the second result does not confirm the questioned value, the source of error should be sought in the analysis, radiation detection, sample identification, preservation, or possible contamination. [Pg.214]

Careful understauding of the effects of each preanalytical variable on the biomarker data is complex and necessitates a staged approach conceptually similar to the fit-for-purpose analytical validation of a biomarker assay (see Chapter 41). In the early exploratory phase of biomarker investigation, standardization of procedures with a defined protocol for sample collection and handling will permit comparative interpretation and analysis of the data within study and/or between studies. Minimally, variables that should be experimentally evaluated to optimize sample collection for a specific biomarker will include matrix type, preservation... [Pg.477]

Another source of sample matrix components, other than the sample itself, is any reagents that have been added to the sample for preservation or dissolution. The most common type of added reagent encountered is a high concentration of one or more mineral acids used to convert a solid sample to a solution. The most common types of acids encountered include HCl, HNO3, H2SO4, HF, and HClO. When these acids have been added to the sample in modest to high quantities, polyatomic molecules containing... [Pg.131]

Hild(1993) Thiazolone type preservatives Shampoos and creams Sample is extracted with MeOH 0.4% acetic acid mixture, filtered and cleaned-u by solid-phase extraction Cig cartridge eluting with HgOiMeOH mixture LC-UVA, Cjg column and MeOH 0.4% acetic acid or MeOH MeCN 0.4% acetic acid as mobile phases ... [Pg.230]

The fifteen samples analyzed for amino acid composition were compared to a human type 1 collagen standard. There are no significant differences in amino acid composition among these samples, which range in age from stillbirth to adult. Analytical error is 10%. All samples show the typical composition of type 1 collagen (Table 1.1). Based on these results there is no reason to suspect differential preservation of specific amino acids in the small bones of infants in comparison to bones of adults and older children. [Pg.5]

An interesting feature of polarized IR spectroscopy is that rapid measurements can be performed while preserving molecular information (in contrast with birefringence) and without the need for a synchrotron source (X-ray diffraction). Time-resolved IRLD studies are almost exclusively realized in transmission because of its compatibility with various types of tensile testing devices. In the simplest implementation, p- and s-polarized spectra are sequentially acquired while the sample is deformed and/or relaxing. The time resolution is generally limited to several seconds per spectrum by the acquisition time of two spectra and by the speed at which the polarizer can be rotated. Siesler et al. have used such a rheo-optical technique to study the dynamics of multiple polymers and copolymers [40]. [Pg.312]


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See also in sourсe #XX -- [ Pg.64 , Pg.69 ]




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Preserving samples

Sample types

Sampling types

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