Elution tests

The concentrations of amino acids in the buffered aqueous solutions (pH 6.2) were selected to give a total organic carbon content of 1-3 mg/L, and chlorination conditions were as described for the chlorination of mixtures of model compounds. The chlorinated solutions were concentrated by XAD-2 adsorption/ethyl ether elution, tested for mutagenicity, and analyzed by GC-MS. 

Report results in a Data Table with all the pertinent information and measurements. List reagents and their concentrations used for elution tests. 

Three in vitro biological tests exist the agar diffusion test, the direct contact test, and the elution test. Each test evaluates the interaction of the polymer with... 

The elution tests were conducted in a water-jacketed glass column. The adsorbent was placed in the column and deionised water passed through the column to remove air pockets in the adsorbent bed. Hot water, heated to a specific temperature, was pumped through the outer jacket of the column when needed. A volume of 300-400 mL of eluant solution was prepared and pumped at a specified flow rate (bed volume per hour) into the bottom of the column and out the top. At the end of the test, DI (wash) water was pumped to collect residual aqueous gold. Some tests were ran on a shaker table by placing a loaded adsorbent into known composition of eluant for a pre-determined reaction time. 

The US Pharmacopeia (USP) describes the in vitro and in vivo biological reactivity tests of elastomerics, plastics, and other polymeric materials with direct or indirect patient contact. Agar diffusion, direct contact, and elution tests are in vitro tests using L-929 mammahan fibroblast cehs. Systemic injection, intracutaneous, and implantahon tests are in vivo tests. A brief summary of these tests is listed in Table 20.4. For detailed informahon, readers are referred to USP chapters 87 and 88. 

Elution test L-929 mammalian fibroblast cells Prepare monolayer cell culture and replace the culture medium with extracts of samples and controls for incubation Cell morphology (round or loosely attached) and cell lysis... 

MEM Elution (Test on Extracts) The test material is extracted for 24 h in Minimum Essential Medium (MEM). An extract is prepared from the test material, which is then placed on cell monolayers. The cells are examined for morphologic changes and cytolysis to determine a toxicity score. 

Tests on extracts L929 elution test Neutral red uptake test Colony formation test 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and related tests Direct contact test Indirect contact test Agar diffusion test Filter diffusion... 

Now, the average pH at the surface layer of seawater is 8.1 [6]. Acidification of the ocean is progressing by an increase in the concentration of carbon dioxide in the air. It may be necessary to revise the pH of a solvent used in the elution test if the pH continues to fall in the future. 

There is a regulation on using burned ash of municipal wastes as construction materials for roads. The standard value is determined about Hg, Cd, Pb, Cr, Cu, Zn, Ni, Cl, SO4, CN, conductivity and pH. The elution test method is regulated by the DIN 38414. This method is applied to solid- and paste-like wastes or slime. We add 100 g of samples of which size is adjusted to less than 10 mm into distilled water of 1 1. The solution is mixed for 24 h using a rotary agitation device. After filtrating it by a membrane filter with a pore size of 0.45 pm, the concentrations of metals, conductivity, and pH will be measured. 

In addition to these general analyses of the waste products themselves, elution tests are required for the assessment of water pollution caused by seepage water escaping from waste deposits. 

Elution Test of Dye-Adsorbed Chitin and Modified Chitin under Caustic Conditions by Using Water and 1 M NaOH as Eluents... 

Using the USP elution test, LYOGUARD trays were tested to determine the potential for cytotoxicity. Under the conditions of the test, LYOGUARD trays were determined to be not toxic. 

Testing Metal Mobility in Soils by Elution Tests... 

Metals associated with hydrophobic organics cannot be extracted by aqueous solutions. Therefore, elution tests have to be improved considerably. Furthermore, the presence of humic acids should be accounted for and it would be desirable to apply just one elution test for inorganic as well as organic pollutants simultaneously. Some steps towards these aims and two phase elution test) will be... 

In extension of the above mentioned S4 elution test, other tests based on acid-aqueous solutions (often together with complexing agents, e.g. (Crosland et al. 1993) are in practical use in The Netherlands, Switzerland, and the United States. a summary is given on p. 387 in Ulrich Forstner s book (1993). 

Fig. 2.1. Elution test to evaluate metal pollutant mobility in waste (Obermann and Cremer 1991)...

Anaerobic Environments. When handling anaerobic samples, extreme care is necessary to avoid contact with oxygen during sampling, transport, storage, and elution (Wallmann et al. 1993). Another method is to simulate the transition from oxic to anoxic environments by elution tests. Although the observed effects may be significant (e.g. release of As and Fe by reduction of Fe(III) to Fe(II) Cu and Cd fixation by sulfide formation), the time necessary for redox experiments is in the order of weeks, as compared to hours typical for pH experiments. 

Every elution test is tailored for a specific environmental scenario, as is the pH 4 test for waste deposition (Obermann and Cremer 1991 Hirner and Forstner 1993). The latter is not representing the usual situation in soil chemistry at the earth s surface the ideal, environmentally relevant elution test is not available yet. This is schematically depicted in Fig. 2.4 together with the unrealistic results of the S4 and S7 elution tests as emphasized in the introduction. The pH 4 test will defi-... 

Himer AV (1994) Testing metal mobility in soils by elution tests (this volume)... 

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