Isolation of nonionics

This is the simplest of all ion-exchange separations, and it may be done equally well in a column or batch wise. The suggested ratio of resin volume to sample weight is based on an assumed exchange capacity of 0.75 meq/ml. The residue obtained at step 8 will include sulphobetaines (SS amphoterics). 

Calculate how much mixed-bed resin will be required to remove all ionic matter from the test portion, and use three times this amount. As a guide, use 15 ml resin for every gram of solids in the test portion. 

Measure out the resin as described earlier, and either pack it into a column or place it in a beaker with 100 ml solvent. 

Prepare a solution of the sample in 80% methanol or other suitable solvent, and use a test portion containing about 0.5 g total nonionic matter. 

If operating batch wise, pipette the test portion into the beaker containing the resin and stir mechanically or magnetically for 15 min. 

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In this procedure, the interferences are removed by SPE and the analytes pass through the sorbent. An example is the isolation of nonionic herbicides from soil, atrazine and alachlor. Because soil is commonly extracted with methanol or acetonitrile, there is a substantial amount of humic material extracted at the same time. Both methanol and acetonitrile are miscible with water and readily penetrate the pores and surfaces of soil organic matter, which is hydroscopic and contains sorbed water. Because soil organic matter is attached to silicate surfaces and iron and aluminum hydroxides, it readily binds water to its... 

The following sections describe the isolation of each of the four main classes of surfactant. It is not practicable to give precise instructions for every conceivable mixture, but most practical situations are covered. The isolation of nonionics (section 4.6.2) is described in a fair amount of detail, which is omitted from later sections. Amphoterics are classified as WW, WS, SW and SS, as defined in section 2.2.4. 

Corti A, Frassinetti S, Vallini G, D Antone S, Fichi C, Solaro R (1995) Biodegradation of nonionic surfactants. I. Biotransformation of 4-(l-nonyl)phenol by a Candida maltosa isolate. Environ Pollut 90 83-87... 

Cell fractionation procedures were fundamental to the biochemical identification of steroid and thyroid hormone receptors in brain as well as in other tissues. Isolation of highly purified cell nuclei from small amounts of tissue from discrete brain regions generally is accomplished with the aid of a nonionic detergent, such as Triton X-100 [7],... 

Aiken, G. R., D. M. McKnight, K. A. Thorn, and E. M. Thurman. 1992. Isolation of hydrophilic organic acids from water using nonionic macroporous resins. Organic Geochemistry 18 567-573... 

Solid-Phase Extractions Using XAD Resins. The Amberlite XAD series (Rohm and Haas Co., Philadelphia, PA, USA) have been most often used for isolation of marine DOM by SPE. XAD resins are nonionic macroporous copolymers that differ in pore size, surface area, and polarity. Their generally large specific surface areas and more-or-less reversible adsorption of organic solutes from aqueous solution have made them well-suited for isolation of selected fractions of DOM from natural waters. Even though XAD resins have been used far more often to... 

Other applications of intermacromolecular interaction and complexes are picked up as follows. Some water-soluble nonionic polymers have been applied to the isolation of some serum proteins from human serum under mild conditions different from former techniques such as Cohn method579 and... 

Weiss, H., and Kolb, H. J., 1979, Isolation of mitochondrial succinate ubiquinone reductase, cytochrome c reductase and cytochrome c oxidase from Neurospora crassa using nonionic detergent, Eur. J. Biochem. 99 139nl49. 

Attempts to develop the sieving process as a tool for the isolation of a pure peptide containing the chromophore were not successful because it was found that the resins did not act as pure ionic sieves (Partridge, 1952) the colored peptides displayed strong adsorptive effects which appeared to be nonionic in character. However it was found that the strong adsorptive affinity of the colored peptides could itself be utilized for further enrichment of the fractions. 

One of the methods for synthesis of iohexol (7b), a nonionic contrast agent, is shown in equation (10.5) (246). Nonionic contrast media are more costly to manufacture than are ionic constrast media. The cost of nonionic contrast media is determined by the number of synthetic steps, overall yield, cost of the intermediates, difficulties in isolation and purification, and other associated manipulations. Many alternate paths of synthesis and purification of nonionic contrast agents have been reported. For example, the nonionic contrast agent ioxilan (7j) can alternately be prepared... 

Kupfer" ° applied the same sublation procedure for isolation of cationic surfactants. Eor separation of anionic and nonionic surfactants, the sublation extract is passed through a cation exchanger. Afterwards, the adsorbed cationic surfactants are eluted with methanolic HCl. 

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