Bulk Sample Analysis

The purpose of bulk analysis is to detect U and Pu at the lowest possible levels and to measure both their concentration and isotopic composition. This process involves destruction of the 

Nuclide Half-life y-line (keV) Nuclide Half-life 7-line (keV) 

The primary tracers used for bulk analysis are shown in O Table 63.16. They are produced by the Institute for Reference Materials and Measurements in Geel, Belgium. 

Tracers used for isotope dilution mass spectrometry 

Tracer Isotope ratio Isotope amount ratio 

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In the analysis of trace elements or thin films on substrate using electrons, however, one finds that the MDL, may be increased by choosing Eq such that Uis just greater than 1. The reason for this is that the k factor, which is the ratio of the intensity from the sample to that from the standard, increases as Uapproaches 1 for thin films. Thus, by maximizing the k factor, the sensitivity is increased. For bulk sample analysis, however, the k factor will usually be a maximum ax. U- 2.5. 

A bulk sample is the last choice and the least desirable. It should be submitted "for laboratory use only" if there is a possibility of contamination by other matter. The type of bulk sample submitted to the laboratory should be cross-referenced to the appropriate air samples. A reported bulk sample analysis for quartz (or cristobalite) will be semi-quantitative in nature because (1) The XRD analysis procedure requires a thin layer deposition for an accurate analysis. (2) The error for bulk samples analyzed by XRD is unknown because the particle size of nonrespirable bulk samples varies from sample to sample. 

Control limits for the average chart will be drawn on the basis of specihc gravity done by QC at the time of bulk sample analysis prior to hlling. 

Thin Sections or pieces of the rock about 1 mm in size or less can be also analyzed with this instrument at glancing incident irradiation, if the site to be analyzed is close to the surface of the section or the edge of a fraction. However in this mode of operation, mass resolution is severely reduced. Nevertheless ions can be identified because of their low mass numbers and the very low background in the spectra, by known cluster patterns or by comparison with reference spectra obtained with reduced laser irradiation. The spectra have shown to be highly reproducible. For more precise bulk. sample analysis, other instruments such as the LAMMA 1000 are more suited. Their lateral resolution is 1-3 pm in diameter and the depth of analysis is typically 0.1 pm. 

Bulk Sample—A sample of suspected asbestos-containing material that is obtained from a building to be analyzed microscopically for asbestos content. Bulk sample analysis can be part of a process to assess the hazard from asbestos in a building. 

The rule had allowed LEAs to use laboratories that received interim accreditation for polarized light microscopy (PLM) analysis under the EPA Interim Asbestos Bulk Sample Analysis Quality Assurance Program until the National Bureau of Standards (NBS) PLM Program became operational and laboratories accredited through that program were available. 40 C.F.R. 763.87(a). 

The determination of PN is also performed in concomitance to the automated bulk sample analysis of isotope ratio, using elemental analyzers coupled with isotopic... 

Figure 13 Comparison of isotope ratio monitoring (irm) sample preparation and introduction for bulk versus compound specific sample analysis. In bulk sample analysis, the GC follows the combustion step whereas in the oompound specific irm system CO2 and N2 from a single peak both enter the mass spectrometer at the same time. In both cases the amount of gas flowing to the ion souroe is 00m parable. The difference in sensitivity comes from the differenoe in oarrier gas flow rate (about 100 ml min- versus -1.5 ml min- ).

The echo phase does not depend on the initial position of the nuclei, only on their displacement, vA, occurring in the interval between the gradient pulses. Analysis of the phase of the echo yields a measure of flow velocity in a bulk sample. Spatial resolution is easily obtained by the incorporation of additional imaging gradients. 

Example 3 Calculating Sample Weight for Screen-Size Measurement Weight W of bulk sample for screen analysis is calculated by the Gayle model for percent retained on a specified screen with relative standard error s.e. in percent... 

If the rf source is applied to the analysis of conducting bulk samples its figures of merit are very similar to those of the dc source [4.208]. This is also shown by comparative depth-profile analyses of commercial coatings an steel [4.209, 4.210]. The capability of the rf source is, however, unsurpassed in the analysis of poorly or nonconducting materials, e.g. anodic alumina films [4.211], chemical vapor deposition (CVD)-coated tool steels [4.212], composite materials such as ceramic coated steel [4.213], coated glass surfaces [4.214], and polymer coatings [4.209, 4.215, 4.216]. These coatings are used for automotive body parts and consist of a number of distinct polymer layers on a metallic substrate. The total thickness of the paint layers is typically more than 100 pm. An example of a quantitative depth profile on prepainted metal-coated steel is shown as in Fig. 4.39. 

Bulk Samples are often required to assist the laboratory in the proper analysis of... 

Bulk Samples Bulk samples must be submitted for all silica analyses. They have two purposes (1) For laboratory use only, to confirm the presence of quartz or cristobalite in respirable samples, or to assess the presence of other substances that may interfer in the analysis of respirable samples. (2) To determine the approximate percentage of quartz (or cristobalite) in the bulk sample. A bulk sample submitted "for laboratory use only" must be representative of the airborne free silica content of the work environment sampled otherwise it will be of no value. The order of preference for an evaluation is ... 

Fig. 4. Spatial distribution of (a) relative elemental elongation rate (longitudinal growth rate) and (p) osmotic potential in the apical 10 mm of maize primary roots growing at various vermiculite water contents (see Fig. 3). Growth distributions were obtained by time-lapse photographic analysis of the growth of marked roots points are means from 5 or 6 roots. Osmotic potentials were measured on bulked samples from 30-50 roots points are means s.d. (n = 3-7). Root elongation rates (a, inset) were constant when the measurements were made. Modified from Sharp et al. (1988, 1989).

Even more interest exists in direct in-polymer analysis of intact bulk samples as delivered (powder, granulate, sheet, film, etc.). This is by no means a simple matter. In fact, as plastic materials usually contain several components, analysis of the levels whilst still in the plastic is usually difficult. Some additives can be analysed without extraction... 

Recovery procedures have traditionally involved some form of solvent, gas or heat extraction from the bulk sample matrix. Some of these lend themselves to precolumn hyphenation (e.g. SFE, TD, Py, HS), as opposed to others (e.g. Soxhlet, ultrasonics). Extraction of additives should not be considered as an isolated step, because it may strongly influence the subsequent chromatographic separation. The success of an analysis may very often depend more on the extraction procedure than on the chromatographic separation. In hyphenation there should be compatibility between the sample preparation and subsequent chromatographic analysis. 

Direct bulk trace analysis of both conducting and nonconducting sample materials (more problematic)... 

For concentrated or bulk samples a transmission experiment is both the simplest and the most effective. In essence, one measures the X-ray intensities incident and transmitted through a thin and uniform film of the material. Careful analysis of signal-to-noise ratio considerations indicates that optimal results are obtained when the sample thickness is of the order of 2.5 absorption lengths. Since in this case a simple Beer s law applies, the data are usually plotted as In(7//0) versus E. The intensities are measured using ionization chambers in conjunction with high-gain electrometers (see Fig. 11). 

Table 1 shows (C/N). The CMK-3 samples r (XPS) than in bulk (elemental analysis) milar, except for the OCM-.N2.00 sample. 

Headspace analysis involves examination of the vapours derived from a sample by warming in a pressurized partially filled and sealed container. After equilibration under controlled conditions, the proportions of volatile sample components in the vapours of the headspace are representative of those in the bulk sample. The system, which is usually automated to ensure satisfactory reproducibility, consists of a thermostatically heated compartment in which batches of samples can be equilibrated, and a means of introducing small volumes of the headspace vapours under positive pressure into the carrier-gas stream for injection into the chromatograph (Figure 4.25). The technique is particularly useful for samples that are mixtures of volatile and non-volatile components such as residual monomers in polymers, flavours and perfumes, and solvents or alcohol in blood samples. Sensitivity can be improved by combining headspace analysis with thermal desorption whereby the sample vapours are first passed through an adsorption tube to pre-concentrate them prior to analysis. 

Gonzalez et al. 2008). Laser ablation is a direct sampling technique by which a high energy laser is focused on the surface of a material and atoms, ions, and particles are ejected. The particles, which are chemically representative of the bulk sample, are then transported into an ICPMS for analysis. In LIBS, a luminous, short-lived plasma is created on the sample surface by the focused laser beam and its emission spectra are analyzed to provide both qualitative and quantitative chemical compositional analysis (Cremers... 

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