Extractability tests

Extraction tests are used primarily in Japan and Europe, a release test is used in the United States, and standard tests have been compared based on the sources of formaldehyde present in a finished fabric (76,78—80). Finished fabric may contain free formaldehyde, or formaldehyde released from unreacted /V-methy1o1 moieties. 

The other common objective for calculating the number of countercurrent theoretical stages (or mass-transfer units) is to evaluate the performance of hquid-liquid extraction test equipment in a pilot plant or to evaluate production equipment in an industrial plant. Most liq-uid-hquid extraction equipment in common use can oe designed to achieve the equivalent of 1 to 8 theoretical countercurrent stages, with some designed to achieve 10 to 12 stages. 

Leach or extraction testing undertaken on anhydrous salts embedded in bitumen as a matrix indicates that rehydration of the embedded compound can occur. When the sample is soaked in water, the asphalt or bitumen can swell and split apart, thereby greatly increasing the surface area and rate of waste loss. 

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. 

Bioassay of Extracts. Extracts tested for the presence of cyclohexi-mide were also bioassayed for phytotoxicity. The extracts were redis-sOlved in acetone, and 0.2 mg in 2 pi was applied to 6-cm-dia disks of filter paper. The extract was distributed on the paper with 0.2 ml of methanol. The disks were dried with warm air, placed in 1.5 x 6 cm petri dishes, and moistened with 1.5 ml distilled water. Ten cress seeds were placed on the paper, and after incubation for 3 d at 28 C radicle length of the seedlings was measured. 

Drip the chloroform wash through the column and save the extract. Test continuously by evaporating a drop on clean glass until it ceases to flouresce under a black light. 

A pilot soil vapor extraction test was performed to determine whether this method would be effective to mitigate the concern. Such a test provided information used to design a full-scale recovery and vapor treatment system. With air permeabilities on the order of 1 to 3 D and TPH vapor concentration on the order of 330 ppm (weight), the pilot test supported SVE as a viable remediation approach. 

In screening tests, it is common practice to use approximately 0.1 mol dm or 5 vol% solutions of extractant, and extraction tests are conducted at a phase ratio of 1, with a 5 min contact time. These conditions, of course, may be varied, but the object is to stay with as simple an approach as possible. Analysis of only the aqueous raffinate need be carried out, and distribution data calculated from this. 

Free radical scavenging activity was assessed using the DPPH (1, 1-di-phenyl-2-picrylhydrazyl) assay as described by Harbilas et al. [22] with incubation time increased to 65 min. Briefly, 250 tiL of 100 timol/L DPPH dissolved in methanol was added to 40 p.L of extract (tested at 5 concentrations) in a microplate well. A standard curve of ascorbic acid (positive control) was included as a reference and all data were blanked against a treatment with only methanol. Absorbance was read with a microplate reader at 517 nm. The inhibitory concentration for 50% scavenging (IC50) of each extract was calculated and compared to the IC50 of the ascorbic acid standard curve. 

Many fruits attract birds by colors, odors, and taste. After consuming the fruit, the birds will disperse the seeds to new habitat. Preference orders exist, and some fruits are rarely eaten by birds (see p. 306). For instance, the flavor of buckthorn, Rhamnus cathartica, ranked lowest of 11 fruit extracts tested in blackbirds, Turdus merula, and a song thrush, Turdusphilomelus (Sorensen, 1983). Least preferred fruits contain toxins that deter birds, perhaps to avoid seeds being dispersed to unfavorable habitat. For instance, it is disadvantageous for forest... 

Often medicinal plants known from folk-lore are picked up and their extracts tested against known plant viruses by mixing them with the inoculum and doing half-leaf experiments. Each half of the leaf is rubbed with virus suspension. 

Extractability tests prescribed by other regulatory agencies [FDA, Parenteral Drug Association (PDA)] for closures for drug packaging [69,70] are also limited to the amount of extractable residues or tests to evaluate the in vivo reaction of the extractable residue when the material fails in the in vitro tests. 

The tests, however, are neither qualitative (in the sense of showing which substances can be extracted) nor specifically quantitative since they are conceived to show only the total amount of extractable as a residue. USP (381) Elastomeric Closures for Injection, for example, recommends the calculation of the weight of the residue after evaporating the solvent (purified water, drug vehicle, or isopropyl alcohol) used for extraction. Tests in vivo are recommended only when the material does not meet the requirements of the in vitro tests. 

IPAC-RS (1991, Mar.) Extra 7 Leachables and extractables testing points to consider, available http //www.ipacrs.com/leachables.html. 

Tumor inhibition at three levels of Camptothecin (CI T), ellagic acid, and MV-extract tested in the Agrobacterium tumefaciens-induced tumor system. DMSO was used in the same concentrations as that used to test its respective dosage for each test compound. Error bars are indicative of 1 standard error, n = 15. 

California Administrative Code (1987) Title 22, Section 66700 "Waste Extraction Test". 

Chemical analysis of the HF Treatment System Sludge Cake ( 18) indicates that this material is considered to be extremely hazardous solely because of its arsenic concent. Waste Extraction Tests (WET) indicate that this arsenic is in an extremely inert form and that even in its elevated concentration it produces a WET test result with a non-hazardous leachate. Our conclusion is that a 50 percent reduction in arsenic concent in the sludge cake would produce a solid material classified as non-hazardous by the State of California except for fluoride content. 

CC>2-Extraction tests of ground cardamom showed that an extraction pressure of 350 bar is sufficient. An extraction pressure of 500 bar gives only a marginally higher extraction yield, but the quality is lower than from the 350-bar extract. 

In this connection it must be borne in mind that in some of these extraction tests on naturally coloured and raw cotton, flax, wool, hair, etc, an appreciable quantity of yellowish-brown colouring matter is removed, and that raw silks of a natural yellow or green colour exhibit special behaviour if subjected to some of these tests, eg, to treatment with concentrated acids ... 

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