Chloroform emulsion

Mix 1 mL of solution 3 with 1 mL of solution 1 by vortex agitation. Then mix (vortex for 15 s) the resulting water-in-chloroform emulsion with a similar mixture composed of solution 2 and solution 4 (2.5 ml). 

Mix the resulting water-in-chloroform emulsion by vortexing for 15 sec with solution 2 and 2.5 ml solution 4. 

The initial HC1 wash results in an emulsion and up to 2 hr may be required for phase separation. At that point, any remaining emulsion should be separated and added to 100 mL of chloroform and 100 mL of LON HC1 solution. The chloroform layer is then combined with the other organic phases. 

Physical methods for endpoint detection have been suggested. Hellsten [226] proposed an instrumental turbidimetric method to determine the endpoint, which does not need indicators. Since chloroform is emulsified by the anionic surfactant, changes in the optical density can be followed by a colorimeter thus detecting the endpoint when the emulsion breaks. Another turbidimetric method based on commercially available automatic titrators has also been proposed [227],... 

Add 3-4 ml CPC solution (-0.005 N in distilled water). After each addition of CPC turn the graduated cylinder upside down 10 times. Too vigorous shaking leads to the formation of a stable emulsion. Add as rapidly as possible more CPC until the red chloroform layer settles out rapidly and clearly. Continue titrating slowly until the two layers have the same color. 

The lipids are dissolved in an organic solvent (diethyl ether, diisopropyl ether, or a mixture of one of the two with chloroform depending of the solubility properties of the Upids used). The aqueous phase is added to the organic phase at a ratio of 1 3 when diethyl ether is used and at a ratio of 1 6 when a mixture of diisopropyl ether and chloroform is used. The mixture is sonicated in order to form an emulsion, followed by slow removal of the organic phase via rotary evaporation under reduced pressure. 

Multivesicular Liposomes Kim and his colleages described a method for the preparation of cell size liposomes with high encapsulation efficiency the so-called multivesicular liposomes (Kim et al., 1983). The lipid phase consists of a combination of amphiphatic lipids and a small amount of triglycerides (triolein or trioctanoin) dissolved in chloroform-diethyl ether (1 1). The aqueous phase is slowly added to the organic phase and after vigorous shaking a water-ip-lipid emulsion is formed (Fig. 2A-B). Via a narrow Pasteur pipet the emulsion is subsequently added to a sucrose solution. 

Lippi et. al (87) and Dirstine (88) circumvented titration by converting the liberated fatty acids into copper salts, which after extraction in chloroform are reacted with diethyldithio-carbamate to form a colored complex which is measured photometrically. While the end point appears to be more sensitive than the pH end point determination, the advantages are outweighed by the additional steps of solvent extraction, centrifugation and incomplete extraction when low concentrations of copper salts are present. Other substrates used for the measurement of lipase activity have been tributyrin ( ), phenyl laurate (90), p-nit ro-pheny1-stearate and 3-naphthyl laurate (91). It has been shown that these substrates are hydrolyzed by esterases and thus lack specificity for lipase. Studies on patients with pancreatitis indicate olive oil emulsion is definitely superior to water soluble esters as substrates for measuring serum lipase activity. 

PtRu nanoparticles can be prepared by w/o reverse micro-emulsions of water/Triton X-lOO/propanol-2/cyclo-hexane [105]. The bimetallic nanoparticles were characterized by XPS and other techniques. The XPS analysis revealed the presence of Pt and Ru metal as well as some oxide of ruthenium. Hills et al. [169] studied preparation of Pt/Ru bimetallic nanoparticles via a seeded reductive condensation of one metal precursor onto pre-supported nanoparticles of a second metal. XPS and other analytical data indicated that the preparation method provided fully alloyed bimetallic nanoparticles instead of core/shell structure. AgAu and AuCu bimetallic nanoparticles of various compositions with diameters ca. 3 nm, prepared in chloroform, exhibited characteristic XPS spectra of alloy structures [84]. 

Extract the chloroform-methanol layer from the strawberry, rice grain, barley grain and rice straw samples twice with 30 mL of 0.1 M phosphate buffer solution (pH 7.0). Since an emulsion is formed, the first extraction should be conducted with very gentle shaking. Centrifuge the extract at 2500 rpm for 10 min, when an emulsion is formed. Discard the chloroform-methanol layer. 

TEST OF THE EMULSION MECHANISM. The above hypothesis suggests that at the equivalence point all the SDBS is complexed with hyamine and, effectively, only a brine and chloroform system is present. 

If sodium hydroxide is used to liberate the amino alcohol from its salt, extraction with chloroform produces unworkable emulsions. 

Organic peroxide are used to polymerise the esters by solvent or emulsion polymerisation. They form tough and pliable film. They are also used as plasticising agents for vinyl polymers. The polymer is soluble in benzene, toluene, chloroform, ethylene dichloride, ethyl acetate, etc. 

Onium salts, such as tetraethylammonium bromide (TEAB) and tetra-n-butylammonium bromide (TBAB), were also tested as PTCs immobilized on clay. In particular, Montmorillonite KIO modified with TBAB efficiently catalyzed the substitution reaction of a-tosyloxyketones with azide to a-azidoketones, in a biphasic CHCI3/water system (Figure 6.13). ° The transformation is a PTC reaction, where the reagents get transferred from the hquid to the solid phase. The authors dubbed the PTC-modified catalyst system surfactant pillared clay that formed a thin membrane-hke film at the interface of the chloroform in water emulsion, that is, a third liquid phase with a high affinity for the clay. The advantages over traditional nucleophilic substitution conditions were that the product obtained was very pure under these conditions and could be easily recovered without the need for dangerous distillation steps. 

The unsulfonated random copolymers are reportedly synthesized at 50 °C over a period of 48 h using emulsion polymerization with dodecylamine hydrochloride surfactant in water as the reaction system and potassium persulfate as the initiator. The copolymer is then dissolved in an appropriate solvent such as dichloroethane or chloroform and sulfonated using reagents such as chlorosulfonic acid or a sulfur trioxide complex. It has been reported that this generation of BAM membranes exhibited some su-... 

The aqueous and organic layers are separated using a 500-mL separatory funnel. The organic layer is washed 3 times with 100 mL of deionized water. An emulsion commonly forms during this step, so saturated sodium chloride may be added to the mixture or used instead of water to aid in the separation of the layers. The organic layer is separated, filtered to remove precipitates, and evaporated to dryness under flowing nitrogen. The crude product is transferred to a 500-mL Erlenmeyer flask with 35 mL of chloroform. To this solution, 300 mL of pentane is added to precipitate the product. 

Conducting composite polymer materials have also been prepared from the dispersed phase of concentrated emulsions. Polyurethane/polypyrrole composites [165] were obtained by blending an aqueous suspension of polypyrrole with a HIPE of a chloroform solution of polyurethane in aqueous surfactant... 

On completion of the two pre-incubation steps, 10 pi of the preincubated sample will be added to 500 pi of the preincubated emulsion in triplicate, and the LPL-cata-lyzed triglyceride hydrolysis will be allowed to proceed for 1 h at 28°C. The reaction is stopped by adding 5.33 ml of methanol chloroform heptane (56 50 4 by volume) and vigorous shaking. 

Anode solution contains an alcohol, a base, S02, I-, and possibly another oiganic solvent. Methanol and diethylene glycol monomethyl ether (CH3OCH2CH2OCH2CH2OH) are typical alcohols. Typical bases are imidazole and diethanolamine. The organic solvent may contain chloroform, formamide, or other solvents. The trend is to avoid chlorinated solvents because of their environmental hazards. When analyzing nonpolar substances such as transformer oil, sufficient solvent, such as chloroform, should be used to make the reaction homogeneous. Otherwise, moisture trapped in oily emulsions is inaccessible. (An emulsion is a fine suspension of liquid-phase droplets in another liquid.)... 

In order to prevent the formation of a stable emulsion at any stage of the extraction procedure, the water content of the hydrated WPC has to be controlled so as not to obtain a biphasic solvent system during extraction with mixtures of chloroform and methanol. Besides, nonlipid contaminants are removed from the extract by gel filtration on nonlipophilic Sephadex G-25 instead of traditional aqueous washing total lipids were eluted with a 19/1 (v/v) mixture of chlo-roform/methanol, saturated with water, whereas a 1/1 (v/v) mixture of water and methanol eluted nonlipid contaminants. The method yields a similar total lipid content to the Folch method, but it is about four times faster (24). 

The Extrelut cleanup method is suitable for most foodstuffs, such as cheese, yogurt, and other samples that tend to form emulsions during extraction. The prepacked or refilled Extrelut column in a plastic tube consists of a wide-pore kieselgel column. A sample is homogenized in 0.5 N sulfuric acid, diluted with water, and applied onto the Extrelut column for at least 15 min. The absorbed preservatives are eluted with a chloroform - isopropanol (9 1) mixture, and the elu-ate is collected and evaporated carefully nearly to dryness. The last few milliliters of solvent are removed with a gentle flow of nitrogen to prevent substantial losses of BA and SA, which have relatively high vapor pressures. The residue is transferred with methanol into a 10-ml volumetric flask and diluted to volume with methanol. To speed up the dissolution, the use of an ultrasonic bath is recommended. The filtered extract is analyzed on a /zBondaPak Cl8 column, with a... 

---