Reference materials resins

TXRF is frequently used for contamination control and ultrasensitive chemical analysis, in particular in relation to materials used in semiconductor manufacturing [278,279], and metallic impurities on resin surfaces, as in PFA sheets [279,280], TXRF has been used by Simmross et al. [281] for the quantitative determination of cadmium in the four IRMM polyethylene reference materials (VDA-001 to 004). Microsamples (20-100 ig) from each reference material were transferred by hot pressing at 130 °C as 3 xm thin films straight on to quartz glass discs commonly used for TXRF analysis. The results obtained were quite satisfactory (Table 8.50). Other reports of the forensic application to plastic materials by TXRF have appeared [282], including a study of PE films by elemental analysis [283],... 

In the following sections, the instrumental features of direct mass spectrometry based techniques (DI-MS, DE-MS and DTMS) are presented, followed by a discussion of some mass spectra of standard compounds and reference materials. Finally, a series of case studies related to the presence of resinous materials in archaeological findings and works of art are reported and discussed. 

Beck et al. [61] used flow injection magnetic sector ICP-MS to determine cadmium, copper, nickel, zinc, and manganese in estuarine waters. The online preconcentration system used Toyopearl A-T Chelate 650 H as chelating resin, and was validated for an alkaline water standard reference material (SLEW-2). 

At present, soil derived humic matter and fulvic acids extracted from freshwater are available commercially and are commonly used to test techniques for DOM detection and also used as model compounds for trace metal chelation studies. The results obtained using these model compounds are frequently extrapolated to the natural environment and measurements on "real" samples provide evidence that this DOM is a good model compound. In the past, some investigators also made available organic matter isolated from marine environments using C18 resins. While these compounds come from aquatic sources, this isolation technique is chemically selective and isolates only a small percentage of oceanic DOM. Reference materials are not currently available for these compounds, which inhibits study of the role they play in a variety of oceanographic processes. 

Fig. 1. Stress—strain curves for ionomer and polyethylene resins. Test speed is 5 cm/min. The reference material is high molecular weight conventional...

Most recent studies describing fluidic automation of TRU-Resin separations have been directed to ICP-MS analysis. Evans et al. used a FI system with a TRU-Resin column to concentrate U and Th from a variety of aqueous and biological standard reference materials.131 After the wash step with 2 M HNQ3, these analytes were... 

Plastic materials consist at the minimum of polymers (sometimes referred as resins ) and one or more additives the additives can be added to improve the processability of the polymer (e.g., antioxidants, slipping agents, etc.) or to impart specific physical and technological properties to the finished product... 

In this work, several approaches such as direct dilution, wet-ashing, and a newly developed microwave digestion technique were used to prepare and analyze petroleum samples for the purposes of method and result comparison. The samples used for this study were a NIST lubricant additive Standard Reference Material (SRM) 1848, Residue Fuel oil SRM 1634B, 1634C, and a polymer resin. 

NMR quantitation of materials synthesized on solid-phase beads is challenging, since resin dynamics and susceptibility differences within the sample contribute to broad lines in the spectrum. Spectral resolution of the desired analyte resonances from those of the resin as well as the reference material is important for both precise and accurate quantitation of the combinatorial product. Several quantitation methods, each of which will be addressed individually, have emerged to meet these challenges. 

The Pb imprinted resins were then applied to chemical analysis [26]. Experiments were carried out to determine and compare percent recoveries of Pb from the seawater samples by using different ion exchange resins, such as Chelex-100, Duolite GT-73, a proprietary NASA resin, and the Pb imprinted ion exchange resin. The percent recoveries from the Pb imprinted resin were greater than 95% over a broad range of pH. The Pb imprinted ion exchange resin did not suffer from interferences from other metal ions in seawater matrix. The Pb imprinted resin gave superior performance when used for separation and preconcentration prior to analysis by either AAS or spectrophotometry. The utility of the Pb imprinted resin was demonstrated by analysis of a standard reference material. Coastal reference seawater (CASS-3). The resin extract was of suificient purity to be analyzed by spectrophotometry with the nonspecific indicator dithizone. 

The botanical species exploited in the past for the collection of resins vary according to the geographical area, and thus, the availability of adequate reference materials of a known botanical origin is crucial for resin identification. Pine resin and resin-derived pitch, mastic, frankincense, myrrh, benzoe, and birch bark tar are the most common terpenoid materials in archaeological artifacts from the Mediterranean area. Terpenic resin composition depends on aging and exposure to air and light, so the biomarkers used for their identification are... 

A range of modem resin samples from the Dipterocarpaceae, Pinaceae and Burseraceae families (Table I), encompassing both diterpenoid and triterpenoid resins, have been examined using GC and GC-MS to act as reference materials against which to compare results from the archaeological samples. Wherever possible, the higher terpenoid peaks have been identified by comparison with previously published data. 

For samples of a few millimeters in diameter, thinned sections can be glued to a polished metallic cylinder using one of the epoxy resins described above or afixed using double sided tape. The latter will, however, de-gas more heavily. For even larger sized samples, a Petro-graphic cross-sectional disc should be cut with the face of interest polished in the same manner as mentioned earlier. This can be a stand-alone disc or may be supported in an epoxy resin puck of dimensions amenable to the sample holder to be used. On the other hand, a thinned section can be supported on a glass slide or amenable dimensions along with a suitable reference material. The epoxy preparation will be similar to that above. 

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