Organic extraction liquids

Fig- 23(F) shows a similar distillation assembly for isolating a pure liquid which is present in an organic extract and which may finally require fractional... 

Two-Phase Aqueous Extraction. Liquid—Hquid extraction usually involves an aqueous phase and an organic phase, but systems having two or more aqueous phases can also be formed from solutions of mutually incompatible polymers such as poly(ethylene glycol) (PEG) or dextran. A system having as many as 18 aqueous phases in equiHbrium has been demonstrated (93). Two-phase aqueous extraction, particularly useful in purifying biological species such as proteins (qv) and enzymes, can also be carried out in combination with fermentation (qv) so that the fermentation product is extracted as it is formed (94). 

PhenoHc-based resins have almost disappeared. A few other resin types are available commercially but have not made a significant impact. Inorganic materials retain importance in a number of areas where synthetic organic ion-exchange resins are not normally used. Only the latter are discussed here. This article places emphasis on the styrenic and acryHc resins that are made as small beads. Other forms of synthetic ion-exchange materials such as membranes, papers, fibers (qv), foams (qv), and Hquid extractants are not included (see Extraction, liquid-liquid Membrane technology Paper.). 

Transfer the solution to a 250 mL separatory funnel, rinsing out the beaker with a little water. Add 5 mL of the 2 per cent NaDDC reagent and allow to stand for one minute, and then add a lOmL portion of 4-methylpentan-2-one (methyl isobutyl ketone), shake for one minute and then separate and collect the organic layer. Return the aqueous phase to the funnel, extract with a further lOmL portion of methyl isobutyl ketone, separate and combine the organic layer with that already collected. Finally, rinse the funnel with a little fresh ketone and add this rinse liquid to the organic extract. In these operations the lead is converted into a chelate which is extracted into the organic solvent. 

Nc>tc 5). The mixture is stirred for 30 minutes to ensure complete hydrolysis. The upper organic layer is separated, and the aqueous layer is extracted with three 25-ml. portions of ethyl acetate. The organic extracts are combined, washed with sodium chloride solution, dried with anhydrous magnesium sulfate, and evaporated under reduced pressure. Distillation of the residual liquid under reduced pressure through a 10-cm. Vigreux column affords a... 

Note Empirical volume of organic extract (Vex) acetone (200 mL) - - ethyl acetate-cyclohexane [1 1 (v/v), 100 mL] — empirical volume shrinkage (5mL) — empirical transfer of acetone into the aqueous phase during the liquid-liquid partition (10 mL) = Vex = 285 mL. 

Hogenboom A.C. et al., 1999b. Accurate mass determination for the confirmation and identification of organic microcontaminants in surface water using online solid-phase extraction liquid chromatography electrospray orthogonal-acceleration time-of-flightmass spectrometry. Rapid Commun Mass Spectrom 13 125. 

DDT Metabolism.-- The metabolism of DDT has been studied in R and S fish, following similar protocols to chlorinated cyclodiene metabolism organic extraction (acetonitrile), thin layer chromatography of organic extracts, and liquid scintillation counting of the resultant spots (4). When S and R fish were exposed to 60 yg/l of 14C-labelled , -DDT for 4 hr, radioactivity was found in the spots which co-chromatographed with... 

Organic extraction and sample preparation Separatory funnel liquid-liquid extraction Continuous liquid-liquid extraction Solid-phase extraction (SPE) (3535A in update IVB)... 

Waste water, soil, sediment, solid waste Extraction (liquid-liquid, Soxhiet, sonication) with organic solvent such as dichloromethane, removal of water, volume reduction. GC/MS (EPA method 8270) 20 g/L (ppb) for wastewater 1,300 g/kg (ppb) for low soil, sediment 110 at 100 g/L (100 ppb) EPA 1986a... 

Fig. 1.1 A schematic representation of solvent extraction (liquid-liquid distribution). A solute A is distributed between the upper layer, for example an organic solvent, and the lower layer, an aqueous phase. 

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