Solvent extraction test

Leonard, R. A., D. B. Chamberlain, and C. Conner. 1997. Centrifugal Contactors for Laboratory-scale Solvent Extraction tests. Sep. Sci. Technol. 32(1-4), 193-210. 

Results of the pilot plant test of the 1iquid-1iquid solvent extraction test are shown in Table V. Only k Z of approximately 17 of americium strip product were used in the precipitation step. Decontamination from A1 and Mg was excel-... 

The test most widely used in the printed-circuit industry to measure the efficiency of a cleaning process is the resistivity of solvent extracts test known as ROSE. According to this test, after the assembly has been cleaned, the part is flushed with a solution of 75% isopropanol and 25% deionized water and the electrical resistivity of the extracts measured. Ionic residues dissolved in the extracts reduce the resistivity of the original... 

The solvent extraction test may be used to supplement visual techniques or to check inaccessible surfaces by using a solvent to extract contaminants for inspection. The surface is flushed, rinsed, or immersed in a low-residue solvent. Solvent extraction is limited by the extent to which the procedure can reach and dissolve the contaminants present and by the loss of contaminant during solvent evaporation. The equipment tested may also contain materials such as polymers or elastomers, which... 

Polyethylene has also been modified by extrusion at 200°C in the presence of isoprene-styrene rubbers or butadiene-styrene rubbers. The formation of graft copolymers has been shown by solvent extraction tests and IR spectroscopy. Grafts of the first composition are more easily induced by the tertiary proton reactions in the isoprene units. The crack resistance of polyethylene reportedly increases exponentially with the amount of graft content [234]. 

R. A. Peterson, Preparation of Simulated Waste Solutions for Solvent Extraction Testing, Report WSRC-RP-2000-00361, Westinghouse Savaimah River Company, Aiken, SC, May 1, 2000. 

Analytical and test methods for the characterization of polyethylene and PP are also used for PB, PMP, and polymers of other higher a-olefins. The C-nmr method as well as k and Raman spectroscopic methods are all used to study the chemical stmcture and stereoregularity of polyolefin resins. In industry, polyolefin stereoregularity is usually estimated by the solvent—extraction method similar to that used for isotactic PP. Intrinsic viscosity measurements of dilute solutions in decahn and tetraHn at elevated temperatures can provide the basis for the molecular weight estimation of PB and PMP with the Mark-Houwiok equation, [rj] = KM. The constants K and d for several polyolefins are given in Table 8. 

In recent years researchers at West Virginia University have developed coal-derived pitches on a laboratory scale in quantities sufficient to make 1 kg samples of calcined coke for fashioning graphite test specimens. The pitches were derived by uhlizmg solvent extraction with N-methyl pyrrohdone (NMP). This solvent is able to isolate coal-based pitches m high yield and with low mineral matter content [13]. It is this work that will form the basis of the discussion for the later part of this chapter. 

Separation techniques may have to be applied if the given sample contains substances which act as interferences (Section 21.10), or, as explained above, if the concentration of the element to be determined in the test solution is too low to give satisfactory absorbance readings. As already indicated (Section 21.10), the separation methods most commonly used in conjunction with flame spectrophotometric methods are solvent extraction (see Chapter 6) and ion exchange (Chapter 7). When a solvent extraction method is used, it may happen that the element to be determined is extracted into an organic solvent, and as discussed above it may be possible to use this solution directly for the flame photometric measurement. 

The migration of package ingredients directly into a food product is often difficult to analyze instrumentally because of interference from food ingredients. Some of these analyses have been made, but it is generally preferable to use food simulating solvents listed in FDA regulations and to carry out extraction tests under the conditions described. 

These results, considered in relation to the direct addition tests of monomer and hydrogen cyanide in the previous table, demonstrate that there is no reason to expect styrene monomer extraction into soft drinks, even at levels well below those we can measure analytically. They also reinforce our hydrogen cyanide data. Further, they indicate that these beverages are not more extractive of Lopac containers than the normal simulating solvents. The tests confirm the chemical safety of the containers as beverage packages. 

The authors have characterized the graft polymer by solvent extraction, transmission electron microscopy, dynamic mechanical analysis, mechanical testing (including measurement of tensile, tear, and impact strength), and morphology by SEM. The reaction scheme is given in Figure 11.25. 

Co (I I) complex formation is the essential part of copper wet analysis. The latter involves several chemical unit operations. In a concrete example, eight such operations were combined - two-phase formation, mixing, chelating reaction, solvent extraction, phase separation, three-phase formation, decomposition of co-existing metal chelates and removal of these chelates and reagents [28]. Accordingly, Co (I I) complex formation serves as a test reaction to perform multiple unit operations on one chip, i.e. as a chemical investigation to validate the Lab-on-a-Chip concept. 

On the other hand, single-residue methods developed by the applicants give basic information about appropriate cleanup steps and specific determination procedures. In addition, not many laboratories other than those from the applicants are able to test the real solvent extraction efficiency. The reason is that extraction studies need radio-labeled incurred residues instead of fortified samples. Hence enforcement methods provided by the manufacturers accelerate the development of methods which meet the needs of (official) food control laboratories. 

In alluvial soil, there was no great difference in the extraction efficiencies among the various solvent combinations tested, with acetone, acidic acetone or alkaline acetone, for reflux extraction. 

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