Exterior sampling

If there are different colored residues on different areas of the shard, e.g., the interior compared to the exterior, sample and label separately. 

Gas ventilation outlet Magnet mixer motor Porcelain dish with 16 Vol.% H2S04 and magnet mixer Spoon with KCN fixed axle, capable of tipping over magnet from exterior Sample material (here brick)... 

Full work shift samples should be collected whenever possible. Many exposure studies that are included in generic databases were of relatively short duration. For example, the USEPA (1987) guidelines require only that exterior sampling material have measurable levels of residues, resulting in some cases in samples of 10-20 min in duration. More recent guidelines stress the need for longer sampling periods (Chester, 1995 OECD, 1997). 

The MED technique described in [72] was applied to the analysis of hot water extracts taken from interior and exterior samples of the Murchison meteorite. The results were comparable to those previously obtained using GC/MS and HPLC techniques. Higher racemic ratios were found in the interior versus the exterior of the... 

CT offers the opportunity to examine slices through the sample non-destructively and is therefor the only method for measuring exterior and also interior part coordinates without mechanical cutting of the object. 

When a dilute solution of a polymer (c << c ) is equilibrated with a porous medium, some polymer chains are partitioned to the pore channels. The partition coefficient K, defined as the ratio of the polymer concentration in the pore to the one in the exterior solution, decreases with increasing MW of the polymer (7). This size exclusion principle has been used successfully in SEC to characterize the MW distribution of polymer samples (8). 

A sampling station is provided on the rear exterior wall of the facility for flow measurement and monitoring of the effluent stream. 

In 2005 it became grindingly obvious that there was a certain spot on Seattle s monorail where tram cars trying to simply pass each other by had to stop to take samples of exterior paint from each other. That was traced back to an engineering error they had made back in 1988, when the rails were brought in a little too close Somebody get me a ruler please ... 

Surface samples were collected in snow pits under ultra-clean conditions described elsewhere [13] with the exception that samples for anion analysis were collected in polystyrene cups precleaned without the use of acids. Ice core samples were cleaned to remove surface contamination using the "dry-core" procedure involving rinsing and melting of exterior surfaces with ultra-pure water [13]. Shallow-depth firn cores are permeable and the dry-core rinsing is unsuitable. Therefore an inner core of 2.5 cm diameter was taken from intervals of the 7.6 cm diameter South Pole firn core using a specially-built precleaned stainless steel corer within a -15 °C cold room. Prior to this coring, exposed ends of core sections were shaved away with precleaned stainless steel chisels. 

Essentially the same amino acids, and nearly equal quantities of D and L enantiomers, were detected in the Murray meteorite, another type II carbonaceous chondrite [6]. Recent expeditions to Antarctica have returned with a large number of meteorites, many of which are carbonaceous chondrites. These may have been protected from terrestrial contamination by the pristine Antarctic ice. Careful analysis of two of these, the Yamato (74662) and the Allan Hills (77306), both type II carbonaceous chondrites, by ion exchange chromatography, gas chromatography, and GC/MS, have detected a wide variety of both protein and non-protein amino acids in approximately equal D and L abundances [9,10]. Fifteen amino acids were detected in the Yamato meteorite and twenty in the Allan Hills, the most abundant being glycine and alanine. The amino acid content of the Yamato meteorite is comparable with that of the Murchison and Murray, but the Allan Hills contains 1/5 to 1/10 that quantity. Unlike earlier meteorites from other locations, the quantities of amino acids in the exterior and interior portions of the Yamato and Allan Hills meteorites are almost identical [9,10]. Thus, these samples may have been preserved without contamination since their fall in the blue ice of Antarctica, which js 250,000 years old in the region of collection. 

A thin film of oil-like material was visible after 28 d on the exterior surfaces of the SPMD membrane. Analysis of this film indicated that the triolein impurities, oleic acid and methyl oleate, were the major constituents. This external lipid film (Petty et al., 1993) appeared to contain imbibed particulates. Although the film was removed from the SPMDs by solvent rinsing and analyzed separately, some lipid-mediated desorption of particle-associated PCBs and subsequent diffusion into the SPMD may have occurred prior to solvent-removal of the film. This observation suggests the potential for SPMD concentrations to reflect both vapor phase concentrations and to a lesser extent, lipid-extracted particulate-associated residues (see Section 3.9.2.). Unfortunately, concentrations of more chlorinated congeners in particulates collected on GFFs from the NIOSH method were often below quantitation limits, because only a small volume of air was sampled (1 m ) using this active method. 

SPMD dialysates (extracts), rinses of the exterior membrane surface (only SPMDs exposed to air), and aliquots thereof often contain a number of classes of chemicals. Figure 6.1 shows various levels of processing and enrichment used for SPMD derived bioassay samples. We strongly recommend the use of SPMDs with triolein purified by the method of Lebo et al. (2004) for bioassays to reduce the probability of false-positive results or for controls that fail to meet quality control... 

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