Separator sample procedure

Sampling Procedure. The sample extraction technique previously described was used in this work (8). However, a heated palladium thimble was also used to separate hydrogen and hydrocarbon fractions of the samples. No exchange occurred during the separation process in agreement with observations of other workers (30). In experiments using NH3 as a minor additive, the ammonia fraction was separated by means of appropriate cold traps. 

Samples that contain two phases present a special problem depending on the site of the materials of interest. If the substances are known to be associated with one phase only, the sample procedure is simply to separate the two phases by filtration or centrifugation and treat the sample as a liquid or solid sample depending on the phase that contains the materials to be determined. However, if the materials of interest are distributed between the two phases, some in solution and some adsorbed on the surface of the solid, then special extraction procedures will be necessary. 

An automated procedure to measure peak widths for peak capacity measurements has been proposed.35 Since peak width varies through the separation, the peak capacity as conventionally measured depends on the sampling procedure. The integral of reciprocal base peak width vs. retention time provides a peak capacity independent of retention time, but requires an accurate calculation of peak width. Peak overlap complicates automation of calculation. Use of the second derivative in the magnitude-concavity method gives an accurate value of the standard deviation of the peak, from which the base peak width can be calculated. 

All six samples at both sites were prepared the same way. Five separate aliquots from each sample were separately sampled and prepared for testing. Each aliquot was then measured three times. Conditions and standard operating procedures for METHODS A and B were carefully specified for both Labs 1 and 2. 

The procedure begins with three separate samples of the "comparison salt, which in this case has X- as the anion. The sizes of the cations are changed so that in one sample d0 changes to dv in a second sample d0 changes to d3l and in a third sample... 

In procedure A, a sample is mixed with pentane and centrifuged, after which the resid or asphalt solution is decanted and the precipitate is washed twice with pentane, dried, and weighed. For toluene-insoluble constituents, a separate sample of the resid or asphalt is mixed with pentane and centrifuged. The precipitate is washed twice with pentane, once with toluene-alcohol solution, and once with toluene. The insoluble material is then dried and weighed. In procedure B, procedure A is followed except that instead of pentane, a pentane-coagulant solution is used. 

The Swiss Agency of Environment and Landscape decided to re-evaluate mechanical metal separation techniques to reduce the landfill volume and to improve the BA quality for deposition by exploiting metal resources. A sampling campaign in all 28 incineration plants was initiated to verify BA quality and to establish a solid data base. A common sampling procedure, sample treatment, and analytical method were prescribed in order to obtain consistent information of chemical and structural composition and the leaching behaviour of current BA. This paper is focused on the chemical and mineralogi-cal results from the study. 

In order to avoid misleading spots on the 2-DE profile and to remove salts, lipids, polysaccharides, or nucleic acids interfering with separation, samples should be solubilized. Solubilization procedure involves disruption of all noncovalently bond protein complexes into a solution of polypeptides. It is the most critical step of 2-DE. 

Individual chapters deal with the determination of metals, non-metals, organic compounds and organometallic compounds in soil and in plants that grow in soil. A separate chapter deals with sampling procedures. A relationship between toxicant levels in soil and plants that grow in that soil has been established and is the subject of the concluding chapter. 

Separation Procedures. Cation- and anion-exchange and com-plexation chromatography were used to separate samples of both the feedstock and upgraded anthracene oil into acidic, basic, neutral-nitrogen-containing, and hydrocarbon plus ether fractions (25). 

Field duplicates for water samples are collected by sequentially filling sample containers with water from a sampling device. Water sample field duplicate precision summarily measures the analytical precision and the reproducibility of the sampling procedure. Unless gross contamination in the form of a separate phase is present, field duplicate precision for properly collected and analyzed duplicate water samples is typically below 30 percent. 

Coincident with the development of sampling procedures were the constant iterative improvements in extraction, separation, identification and quantitation of organic compounds. Special emphasis was placed on selected compound classes such as the polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated benzenes, and chlorinated dibenzo-p-dioxins (dioxins). The best available procedures were used to determine these components because they have known acute or chronic effects and previous studies suggested that they might be present in effluents from the combustion of coal alone and combination coal/RDF. 

In a work by Liu et al.,26 a cleaning-verification assay was validated for a highly potent family of compounds utilizing a swab-sampling procedure and LC-MS for separation and detection of the analytes. Due to the high potency of the compound, the LC-MS method was validated at a level of 50ng/25cm2 and 50 ng/100 cm2... 

For quality control purposes, it is recommended that 5-10% of samples are collected in duplicate. The whole sampling procedure should be duplicated for example, separate pits should be dug at a distance of several meters apart when sampling duplicate soil horizons. Duplicate samples should be identified by a special code. During water sampling, blank samples should be prepared from distilled and deionized water. The blank samples should be acidified and handled in the same way as the normal samples and identified by a special code. A blank water sample is normally prepared at the same site as a duplicate sample is collected. 

An external standard method is used when the standard is analyzed on a separate chromatogram from the sample. Quantitation is based on a comparison of the peak area/height (HPLC or GC) of the sample to that of the reference standard for the analyte of interest. The external standard method is more appropriate for samples with a single target analyte and narrow concentration range, where there is a simple sampling procedure, and for the analysis of hydrocarbon fractions. The calculation requires an accurate extract final volume and constant injection size. The peak area of an analyte is compared with that from a standard or standard curve and corrected for volume ... 

The technique of matrix isolation has been shown to produce highly characteristic spectra of individual components of complex samples combination of MI spectroscopy with separation techniques promises to increase further the analytical capabilities of the technique. While our research to date has emphasized FTIR and molecular fluorescence spectrometry, MI as a sampling procedure is not limited to these two forms of spectrometry. For example, some interesting preliminary analytical results by MI Raman spectrometry recently have been described (32). It should also be stressed that the cryogenic procedures required for the vast majority of MI spectral studies are neither difficult nor unduly expensive except in very special cases, closed-cycle cryostats requiring no cryogenic liquids (and no prior experience in low-temperature techniques) are entirely satisfactory for MI... 

Frequently industrial hygiene analyses require the identification of unknown sample components. One of the most widely employed methods for this purpose is coupled gas chromatography/ mass spectrometry (GC/MS). With respect to interface with mass spectrometry, HPLC presently suffers a disadvantage in comparison to GC because instrumentation for routine application of HPLC/MS techniques is not available in many analytical chemistry laboratories (3). It is, however, anticipated that HPLC/MS systems will be more readily available in the future ( 5, 6, 1, 8). HPLC will then become an even more powerful analytical tool for use in occupational health chemistry. It is also important to note that conventional HPLC is presently adaptable to effective compound identification procedures other than direct mass spectrometry interface. These include relatively simple procedures for the recovery of sample components from column eluate as well as stop-flow techniques. Following recovery, a separated sample component may be subjected to, for example, direct probe mass spectrometry infra-red (IR), ultraviolet (UV), and visible spectrophotometry and fluorescence spectroscopy. The stopped flow technique may be used to obtain a fluorescence or a UV absorbance spectrum of a particular component as it elutes from the column. Such spectra can frequently be used to determine specific properties of the component for assistance in compound identification (9). 

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