Extraction and Separation

Ideally, to ensure the complete removal of the metal ions from the aqueous phase, the complexant and the metal complex should remain in the hydrophobic phase. Thus, the challenges for separations include the identification of extractants that quantitatively partition into the IL phase and can still readily complex target metal ions, and also the identification of conditions under which specific metal ion species can be selectively extracted from aqueous streams containing inorganic complexing ions. 

---

Step 1. Extraction and separation of the acidic components. Shake 5-10 g. of the sohd mixture (or of the residue R obtained after the removal of the solvent on a water bath) with 50 ml. of pure ether. If there is a residue (this probably belongs to Solubihty Group II or it may be a polysaccharide), separate it by filtration, preferably through a sintered glass funnel, and wash it with a Uttle ether. Shake the resulting ethereal solution in a smaU separatory funnel with 15 ml. portions of 5 per cent, aqueous sodium hydroxide solution until all the acidic components have been removed. Three portions of alkaU are usuaUy sufficient. Set aside the residual ethereal solution (Fj) for Step 2. Combine the sodium hydroxide extracts and wash the resulting mixture with 15-20 ml. of ether place the ether in the ETHER RESIDUES bottle. Render the alkaline extract acid to litmus with dilute sulphuric acid and then add excess of sohd sodium bicarbonate. 

Metallurgy. The extraction and separation of metals and plating baths have involved quinoline and certain derivatives (see Electroplating Metal SURFACE TREATiffiNTs Exthaction). 

MEMBRANE EXTRACTION AND SEPARATION OF COPPER(II) FROM PLATINUM(IV) BY DI(2-ETHYLHEXYL)PHOSPHORIC ACID DURING ELECTRODIALYSIS... 

Processes for the extraction and separation of the alkaloids are given by Kauder and Spath and Becke. < >... 

The processes used in the manufacture of morphine are believed to be still based on that described by the Scottish chemist Gregory,in 1833, with improvements devised by Anderson. A description has been published by Schwyzer, who also deals with the manufactme of codeine, narcotine, cotarnine, and the commercially important morphine derivatives, diamorphine (diacetylmorphine), and ethylmorphine (morphine ethyl ether). More recently Barbier has given an account of processes, based on long experience in the preparation of alkaloids from opium. Kanewskaja has described a process for morphine, narcotine, codeine, thebaine and papaverine, and the same bases are dealt with by Chemnitius, with the addition of narceine, by Busse and Busse, and by Dott. It is of interest to note that a number of processes for the extraction and separation of opium alkaloids have been protected by patent in Soviet Russia. ... 

Galipoline, C19H19O3N. A process for the extraction and separation of the angostura bark alkaloids was described by Spath and Eberstaller,i and from the phenolic bases obtained Spath and Papaioanou isolated this alkaloid. It crystallises from water, has m.p. 193°, contains two methoxyl groups, and on methylation by diazomethane yields galipine. 

Another extraction and separation process is described in U.S. Patent 2,992,162. 

Extractions and separations in two-phase systems require knowledge of the miscibilities and immiscibilities of ILs with other solvents compatible with the process. These are most usually IL/aqueous biphase systems in which the IL is the less polar phase and organic/IL systems in which the IL is used as the polar phase. In these two-phase systems, extraction both to and from the IL phase is important. 

Improved selectivity at the extraction and separation of divalent metal ions such as Zn, Cd, Hg, and Ca have been found [225-229]. 

It is seen that there are a large number of compounds capable of dispersive interactions with the reverse phase, contained in the serum that have been extracted and separated. Again the results have been obtained, partly as a result of the extraction and concentration properties of the sampling system, and partly as a result of the high mass sensitivity of the small bore columns. 

Many of the waste streams from U.S. process industries are water containing small quantities of metal ions that the law requires be removed before the wastewater is disposed of There is an economic incentive to recoup at least some of the cost of wastewater treatment by recovering and selling the metal content instead of merely disposing of the metals as sludge. Because the waste streams are dilute in desired materials, research is needed to devise efficient extraction and separation processes. 

Purified extracts contain higher contents of tea catechins obtained by further purification processes, for example solvent extraction or column chromatography techniques (Takeo, 2001). New techniques, such as membrane extraction and separation, may be beneficial in producing such extracts (Nwuha, 2000, Wang et al, 1995). 

The methods for extraction and separation of chlorophylls and their derivatives and the most common procedures of identification and quantification are described in this chapter. 

Extraction and Separation of Alkaloids - The air-dried ground heart-wood (2.2 kg) was extracted by percolation at room temperature with alcohol USP until a negative alkaloid test of the percolate was observed. Removal of the solvent at reduced pressure and at 40° left 71 g of residue that exhibited antimicrobial activity. A 35 g sample of the alcohol-soluble residue was partitioned between 125 ml each of ether and 2Z citric acid In water. The ether layer was extracted twice more with 125 ml of 2% citric acid, filtered to remove some lnterfaclal solids (5.8 g alkaloid negative, no antimicrobial activity), dried (sodium sulfate), and evaporated to dryness, giving 8.6 g of ether solubles that had no antimicrobial activity. 

Autoxidation of unsaturated fatty acids is well known. Modifications of the extraction and separation procedures were made to investigate the possibility that these oxygenated fatty acids (OFAs) arise as artefacts. When exposure to light and air were minimized, no changes were noted in TLC and HPLC. 

Principles and Characteristics Mass-spectral analysis methods may be either indirect or direct. Indirect mass-spectral analysis usually requires some pretreatment (normally extraction and separation) of the material, to separate the organic additives from the polymers and inorganic fillers. The mass spectrometer is then used as a detector. Direct mass-spectrometric methods have to compete with separation techniques such as GC, LC and SFC that are more commonly used for quantitative analysis of polymer additives. The principal advantage of direct mass-spectrometric examination of compounded polymers (or their extracts) is speed of analysis. However, quite often more information can be... 

No sample handling between extraction and separation (no contamination)... 

Figure 2.4. Peptide fingerprinting by MALDI-TOF mass Spectrometry. Proteins are extracted and separated on by 2D gel electrophoresis. A spot of interest is excised from the gel, digested with trypsin, and ionized by MALDI. The precise mass of proteolytic fragments is determined by time-of- flight mass spectrometry. The identity of the protein is determined by comparing the peptide masses with a list of peptide masses generated by a simulated digestion of all of the open reading frames of the organism.

These questions refer to the extraction and separation of a2ines, that was discussed in the previous Section ... 

Schroder, H.E (2003). Determination of fluorinated surfactants and their metabolites in sewage sludge samples by liquid chromatography with mass spectrometry and tandem mass spectrometry after pressurized liquid extraction and separation on fluorine-modified reversed-phase sorbents. J. Chromatogr. A 1020(1), 131-151. 

Although the lanthanide cations most commonly give complexes with coordination numbers of 8 or 9, the [ML3(LH)3] species predominate on extraction with phosphorus(V) acids and it has been suggested that the bulk of the L- LH chelate ring favors a lower coordination number 4 The phosphorus(V) acids are very effective reagents for the extraction and separation of lanthanides.124 (See chapter 3.2). 

Singh, R. Khwaja, A. R. Gupta, B. Tandon, S. N. Extraction and separation of nickel(II) using bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex 301) and its recovery from spent catalyst and electroplating bath residue. Solvent Extr. Ion Exch. 1999, 17, 367-390. 

Mhaske, A. Dhadke, P. Liquid-liquid extraction and separation of rhodium(III) from other platinum group metals with Cyanex 925. Sep. Sci. Technol. 2001, 36, 3253-3265. 

Sherikar, A. V. Phalke, P. N. Dhadke, P. M. Solvent extraction and separation studies of platinum using bis(2-ethylhexyl) hydrogen phosphate. Bull. Chem. Soc. Jpn. 1997, 70, 805-808. 

Fig. 3.2 Rapeseeds were germinated from 12to 168 h in airlift tank. The total soluble proteins were extracted and separated by 15% SDS-PAGE. The gel was stained with Coomassie blue. Between 36 and 60 h, the degradation of storage proteins and the de novo synthesis of Rubisco is clearly visible.

Kim HJ, Lee SB, Park KA and Hong IK. 1999. Characterization of extraction and separation of rice bran oil rich in EFA using SFE process. Sep Purif Technol 15(1) 1—8. 

Property measurements of fullerenes are made either on powder samples, films or single crystals. Microcrystalline C6o powder containing small amounts of residual solvent is obtained by vacuum evaporation of the solvent from the solution used in the extraction and separation steps. Pristine Cgo films used for property measurements are typically deposited onto a variety of substrates (< . , a clean silicon (100) surface to achieve lattice matching between the crystalline C60 and the substrate) by sublimation of the Cr,o powder in an inert atmosphere (e.g., Ar) or in vacuum. Single crystals can be grown either from solution using solvents such as CS and toluene, or by vacuum sublimation [16, 17, 18], The sublimation method yields solvent-free crystals, and is the method of choice. 

The development of sensitive and rapid analytical schemes for the extraction and separation of inorganic tin and organic tin compounds and their chemical speciation products from water, sediments, and biological materials (WHO 1980 Reuhl and Cranmer 1984 Hall and Pinkney 1985 Laughlin and Linden 1985 Thompson et al. 1985 Blunden and Chapman 1986 USPHS 1992). 

We usually repeat this procedure two or three times during the practice of solvent extraction, and separate the two layers after each vigorous shake (we call this procedure running off the heavier, lower layer of liquid). Several extractions are needed because K(partition) is usually quite small, which implies that only a fraction of the solute is removed from the solution during each partition cycle. 

---