Recovery study

Moreover recovery studies on commercial spiked samples were developed in order to asses the no contribution of the matrix and evaluate the accuracy of the proposed procedure. [Pg.141]

Samples are most frequently shock deformed under laboratory conditions utilizing either explosive or gun-launched flyer (driver) plates. Given sufficient lateral extent and assembly thickness, a sample may be shocked in a onedimensional strain manner such that the sample experiences concurrently uniaxial-strain loading and unloading. Based on the reproducibility of projectile launch velocity and impact planarity, convenience of use, and ability to perform controlled oblique impact (such as for pressure-shear studies) guns have become the method of choice for many material equation-of-state and shock-recovery studies [21], [22]. [Pg.194]

The microstructure/property relationships observed in shock-recovered samples have been often tacitly assumed to result solely from the shock compression, duration, and rarefaction due to the imposed uniaxial-strain shock. Recent shock-recovery studies have, however, shown that the degree of residual strain in the sample significantly influences the measured struc-... [Pg.197]

While the structure/property behavior of numerous shock-recovered metals and alloys has received considerable attention in the literature to date, the response of ceramics, cermets, and other brittle solids (including geological materials) to shock loading remains poorly understood [9], The majority of shock-recovery studies on brittle materials have concentrated on examining... [Pg.200]

Na2S04 after a water wash. The volume was adjusted, and an aliquot equivalent to 50 or 100 mg of soil was injected on to a 5% OV-225 GC column (I). Samples were amended at 1 and 5 ppb TCDD for recovery studies. [Pg.114]

Charles MJ, Simmons MS. 1987. Recovery studies of volatile organics in sediments using purge/trap methods. Anal Chem 59 1217-1221. [Pg.257]

D. Momeni, J. R. Chen, and T. F. Yen. MEOR (microbial enhanced oil recovery) studies in a radial flow system— the research outlook. US DOE Fossil Energy Rep NIPER-351CONF-870858, September 1988. [Pg.433]

Some of the intended categories of use of radioisotopic reference material have been reviewed recently by Fajgelj et al. (1999). They include assignment of property values, establishing the traceability of a measurement result, determining the uncertainty of a measurement result, calibration of an apparatus, assessment of a measurement method, use for recovery studies and use for quality control purposes. It should be noted however that, in general, natural matrix reference materials are not recommended for calibration purposes. This should preferably be done with pure chemical forms of the element labelled with the isotope of interest. Calibrated isotopic sources of this kind are available from a number of commercial suppliers and are not the subject of this review. [Pg.144]

Organic solvents or mixtures of water and solvents such as acetone or water-acetone are commonly used to extract chemicals from sediment samples as for upland soil. An analysis of sediment, collected from waterways or extremely low Eh paddies, frequently requires the removal of sulfur-containing species, although there is little interference from sulfur if the sediments are in a not very reductive condition. Reduced copper and silver nitrate columns are usually used for the removal, but these procedures are not always successful. Recovery studies could be needed to confirm an interference with sulfur. [Pg.904]

Method validation is needed to demonstrate the acceptability of the analytical method. A recovery test on a chemical being determined should be performed in order to verify the reliability of the series of analyses. Recovery studies are usually conducted by spiking untreated sediment with the target chemical at the deteetion limit, quantitation limit and in the range of 10-50 times the detection limit. The method is considered acceptable when the recoveries typically are greater than 70%. When the recovery is less than 70%, an improvement in the analytical methods is needed. Where this is not possible for technical reasons, then lower recovery levels may be acceptable provided that method validation has demonstrated that reproducible recoveries are obtained at a lower level of recovery. Analysis is usually done in duplicate or more, and the coefficient of variation (CV) should be less than 10% to ensure that recoveries will be consistently within the range 70-110%. [Pg.904]

Commonly the absence of systematic errors is tested by recovery studies. The estimation of recovery by analyzing only one standard, as frequently be done, can give misleading results as can be seen from Fig. 4.2. In case of combined and nonlinear systematic deviations there can occur points of accidental congruence that can be hit. Therefore, if at all possible, there should be estimated the entire recovery function. However, at least two different standards should be analyzed. [Pg.94]

Accuracy. In general, the accuracy of analytical results is assured by recovery studies (Wegscheider [1996] Danzer [1995] Burns et al. [2002]). According to the recovery function in the general three-dimensional calibration model (see Fig. 6.3), common studies on systematic deviations (Fig. 4.3), and Eqs. (4.2) and (4.3) the following recovery formulae... [Pg.167]

COMPARISON OF PRECISION AND ACCURACY FOR METHODS AND LABORATORIES USING THE GRAND MEAN FOR SAMPLES No. 1-3 (Collabor GM Worksheet), OR BY USING A SPIKED RECOVERY STUDY FOR SAMPLES No. 4-7 (Collabor TV Worksheet)... [Pg.173]

Table 34-6 Individual sample analysis accuracy using Spiked Recovery study...

The type of xanthate has a significant effect on PGM recoveries. Studies conducted on the Stillwater Complex by the US Bureau of Mines [ 12] indicated that the type of xanthate had a significant effect on PGM recovery (Table 18.4). [Pg.27]

Onuska and Terry [14] have described a method for the determination of chlorinated benzenes in bottom sediment deposits. Sample preparation methods using Soxhlet extraction, ultrasonic extraction or steam distillation were compared. The chlorinated benzenes were characterized by open tubular column gas chromatography with electron capture detection. In recovery studies using sediments with different organic matter contents, the steam distillation method was the most efficient. Detection limits were in the range 0.4-10pg kgy1. [Pg.161]

Reverz, R. and Hasty, E. (1987) Recovery study using an elevated pressure temperature microwave dissolution technique. Paper presented at the Pittsberg Conference and Exposition on Analytical Chemistry and Applied Spectroscopy, March 1987. [Pg.454]

Fig. 2.8.5. FIA-APCI-MS(+) spectra of M2D-Cg-0-(E0) -Me obtained in recovery studies from montmorillonite clay.

Verification of the proper choice of the enrichment method can be done through recovery studies under varying conditions of the most important parameters, such as amount and quality of the enrichment material, pH of the sample, as well as the amount and quality of analyte and matrix to be enriched. These parameters not only differ based on the chemical behaviour of the analyte, but are also strongly dependent on the matrix to be analysed. [Pg.427]

Singh A, Bhatnagar MK, Villeneuve DC, et al. 1985. Ultrastructure of the thyroid glands of rats fed photomirex A 48-week recovery study. J Environ Pathol Toxicol Oncol 6(1) 115-126. [Pg.284]

HCT-116 human colon carcinoma (ATCC, Bethesda MD) cells were grown in McCoy s 5A) and were routinely subcultured twice weekly. Antiproliferative assay was performed by chemoluminescence assay based on quantification of ATP. Cells in their exponential phase of growth were treated at different times (lh or 24h) with different concentrations of edotecarin or SN-38. For post-treatment recovery studies, cells were washed with PBS and left in drug-free culture medium. Then, cell medium was collected to avoid any cell loss. Cells in monolayer were washed, detached with trypsin, and collected in the medium. Cells were counted in a Multisizer 3 Coulter Counter to measure the drug s effects on growth inhibition. Samples were fixed either... [Pg.93]

T. P. Burghardt and D. Axelrod, Total internal reflection/fluorescence photobleaching recovery study of serum albumin adsorption dynamics, Biophys. J. 33, 455-468 (1981). [Pg.339]

The last step for the analyst is to show that the selected cleaning agents or procedure actually cleans the surfaces in question. The drug is applied in solution form to the surfaces as in the recovery studies. The surfaces are then cleaned, rinsed, or treated as in the official cleaning procedure. Upon completion of cleaning, the surfaces are swabbed as before and if the cleaning has been successful the analysis will show the surfaces clean and free of analyte residue. The data in Table 7 describe the addition of each of the three cephalosporins in 5-10 mg amounts applied to surfaces in separate experiments, cleaned, and tested for residue as described above. It can be seen that this is a necessary step in the procedure in that it shows that the cleaning really works. [Pg.410]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...