Defatting solutions

Cyanide salts (plating solutions) (Mathias 1982) Defatting solutions (metal cleaners alkaline soaks and alkalis sodium hydroxide, potassium hydroxide, sodium carbonate, trisodium phosphate, various solvents)... 

Defatting solutions (hydrocarbons trichloroethylene, perchloroethylene, 1,1,1-trichloroethane, methylene chloride, isopropylbenzene, toluene, methylbenzene, xylene)... 

Prior to the application of TCA, a thorough cleaning is of vital importance for defatting the skin to allow for even penetration of the peeling solution. The skin is first cleaned with either Hibiclens or Septisol. Subsequently either acetone or alcohol is used to remove the residual oils and scale until the skin feels dry. 

Rapid dermal absorption of trichloroethylene is evident from a study in which peak blood and exhaled air concentrations occurred within 5 minutes after a human subject immersed one hand in a solution of unspecified trichloroethylene concentration for 30 minutes (Sato and Nakajima 1978). Studies on dermal absorption of trichloroethylene in humans, as well as animals, are complicated by the fact that exposure in these studies is usually by direct contact of the skin with the undiluted chemical. Trichloroethylene is a lipophilic solvent that defats the skin and disrupts the stratum comeum, thereby enhancing its own absorption. Thus, the rate of absorption probably increases in a nonlinear fashion with greater epidermal disruption. Although the extent of absorption through the skin may be relatively modest with normal industrial use (Sato and Nakajima 1978 Stewart and Dodd 1964), there is insufficient information to evaluate the effects of chronic, low-level exposure in hiunans, especially when multiple routes may be involved. 

The Water Unextractable Solids were isolated from dehulled, defatted, untoasted soy bean meal (particle size < 0.5 mm) by removal of cold water solubles, proteins and starch. The soy bean meal was extracted with cold water, a solution containing sodium dodecylsulphate and 1,4-dithiothreitol, and incubated with a-amylase, to yield the CWS, SDSS and HWS... 

Xylose-rich pectic polysaccharide was extracted from defatted and protein-free cell wall preparation (5) using HCl solution (pH 1.6) at 85° C for 4 h. The extract was adjusted to pH 5.0 with ammonia, concentrated on a rotary evaporator under reduced pressure at 40°C, and precipitated with 5 volumes of 96% ethanol. After washing twice with 80% ethanol and drying in an air circulated oven at 40°C for 2 h, the pellet was ledissolved with distilled water and then precipitated with 4 vols 96% ethanol. Before the pellet was gently ground, the precipitated pellet was washed twice with 70% ethanol and dried at 40 ° in an air circulated oven for 16 h. The resultant white powder was labelled "xylose-rich pectic polysaccharide" and stored in a refrigerator. 

Table 1. The composition of neutral sugars and content of anhydrogalacturonic acid (%) in XRPP extracted with pH 1.6 HCl solution at 85° C for 4 h (1 g wheat straw/100 mL extractant) from defatted, protein-free wheat straw.

Following solubilization of the PHA from the defatted plant material, recovery of PHA from the solvent can be accomplished in various ways (Fig. 5) [74-78]. Addition of a PHA non-solvent to the solution would lead to PHA precipitation. If a solvent was used which dissolves PHA only under high temperature and pressure, cooling the solvent may be used to recover the polymer. Alternatively, evaporation of the solvent could also lead to polymer precipitation. Each of these methods have their disadvantages. Precipitation of PHA... 

Because of the importance of soybean and soybean products in both human and animal nutrition their flavonoid content has been investigated many times. Thus, HPLC-UV and HPLC-MS have been applied for the determination of flavonoids and other phytochemicals in soybean extracts and in onion with and without hydrolysis, lg of onion was homogenized and mixed with 8 ml of methanol-water (8 2, v/v). After 2h the suspension was centrifuged at 4°C and the supernatant injected. Powdered soybean (500 mg) was defatted by 2 X 10 ml of hexane and further treated as the onion sample. Flavonoids were hydrolyzed by mixing 2 ml of extract with 2 ml of 2 M HC1 and heated to 130°C for 2 h. The solution was neutralized with 4 M of NaOH. Separation was performed in an ODS column (125 X 4.6 mm... 

Gonads (10 g) of the pufferfish Fugu pardalis are extracted with 25 mL of 0.02 M acetic acid in a boiling water bath for 10 min. After being cooled to room temperature, the extract is filtered. The filtrate is passed through an Amberlite CG-50 column (NH, 1.2x3 cm). The column is developed with 50 mL each of water and 0.5 M acetic acid. A defatting step may be introduced prior to the column treatment when fat-rich tissues like livers are employed. The toxic eluate is concentrated in vacuo and made up to 20 mL with water. A 50- jaL portion of the solution is analyzed by HPLC. 

Ovaries (100 g) of the pufferfish Fugu vermicularis porphgreus are extracted with 1% acetic acid in methanol. The extract is concentrated in vacuo and defatted by shaking with chloroform. The defatted extract is treated with activated charcoal. The toxin adsorbed is eluted with 1% acetic acid in 20% ethanol. The eluate is evaporated in vacuo to dryness. The residue is dissolved in a small a-mount of water and adjusted to pH 6 with 1 N NaOH. The toxic solution is applied to an Amberlite IRC-50 column (NH, 2.5 x 45 cm) and developed with 2 L of water, and then 1 L each of 1 and 10% acetic acid. The toxic fractions are freeze-dried, dissolved in 1 mL of water and analyzed by HPLC. 

Melt Reagent A in a water bath or in a microwave oven. Dilute some milliliters of the molten solution with hot water to get 0.5% agar or agarose. Pour this solution onto a carefully defatted slide (3x7 cm) and dry in a stream of warm air. Store a stock of these pre-coated slides dusdess they are stable at RT for months. 

To determine the amylose content of starch, the iodine reaction has been most commonly used because amylose and amylopectin have different abilities to bind iodine. The methods such as blue value (absorbance at 680 nm for starch-iodine complex using amylose and amylopectin standards), and potentiometric and amperometric titration have been used for more than 50 years. These procedures are based on the capacity of amylose to form helical inclusion complexes with iodine, which display a blue color characterized by a maximum absorption wavelength (kmax) above 620 nm. During the titration of starch with iodine solution, the amount (mg) of iodine bound to 100 mg of starch is determined. The value is defined as iodine-binding capacity or iodine affinity (lA). The amylose content is based on the iodine affinity of starch vs. purified linear fraction from the standard 100 mg pure linear amylose fraction has an iodine affinity of 19.5-21.0mg depending on amylose source. Amylopectin binds 0-1.2mg iodine per 100mg (Banks and Greenwood, 1975). The amylose content determined by potentiometric titration is considered an absolute amylose content if the sample is defatted before analysis. 

On the basis of the above observations, a common extraction and cleanup procedure was developed and applied in two recently reported liquid chromatographic methods for the determination of either chlorothiazide and hydrochlorothiazide (558) or chlormethiazide (559) in bovine milk. Both of these methods involve a defatting step by milk centrifugation. Tire defatted milk (4.75 ml) is mixed with 2 ml 5% lead acetate solution and extiacied with 9 ml acetonitrile. Following centrifugation, the supernatant is extracted with 25 ml water-saturated... 

A more comprehensive approach was reported in 1975 by Brabander and Verbeke (612). In this method, tissue samples were extracted with methanol and the acidified extract defatted with petroleum ether to be loaded onto a Dowex 50W-X8 anion-exchange resin. Following elution with aqueous methanol, the concentrated buffered extract was further defatted with diethyl ether. The sample was derivatized with 7-chloro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-Cl) to be further spotted on a silica high-performance thin-layer chromatographic plate developed in two dimensions using chloroform/ethanol and chloroform/propionic acid consecutively as eluents. Detection of the propylthiouracil, phenylthiouracil, and tapazole residues was carried out on the basis of the fluorescence induction of the NBD derivatives of the drugs with an alkaline cysteine solution. 

Saponins are generally extracted from plants through an alcoholic extraction of the defatted vegetable material. Due to the possible contemporary presence of acidic components (phenols and their acids, flavonoids, etc.) care should be taken about the pH of the alcoholic solution, which, if too low, can produce undesidered chemical modifications. Acidic methanol can hydrolize glycosidic bonds or produce transesterification. A subsequent useful step is the partition of the total dried alcoholic extract between n-butanol and water. This operation is important to eliminate mono- and disaccharides which complicate further separations. 

Ether defatting. Multiple extraction with 1,2-dichloroethane, aqueous solution pH = 10, tartaric acid, H2S04, NaOH, CHCI3. Evaporation at 40°C. 

Initial preparative work with oxynitrilases in neutral aqueous solution [517, 518] was hampered by the fact that under these reaction conditions the enzymatic addition has to compete with a spontaneous chemical reaction which limits enantioselectivity. Major improvements in optical purity of cyanohydrins were achieved by conducting the addition under acidic conditions to suppress the uncatalyzed side reaction [519], or by switching to a water immiscible organic solvent as the reaction medium [520], preferably diisopropyl ether. For the latter case, the enzymes are readily immobilized by physical adsorption onto cellulose. A continuous process has been developed for chiral cyanohydrin synthesis using an enzyme membrane reactor [61]. Acetone cyanhydrin can replace the highly toxic hydrocyanic acid as the cyanide source [521], Inexpensive defatted almond meal has been found to be a convenient substitute for the purified (R)-oxynitrilase without sacrificing enantioselectivity [522-524], Similarly, lyophilized and powered Sorghum bicolor shoots have been successfully tested as an alternative source for the purified (S)-oxynitrilase [525],... 

With the remainder of the liquid, mixed with io c.c. of 10% potassium bisulphate solution and a few drops of acetic acid, two or three strands of well-defatted wool are heated on a water-bath for a long time. In presence of coal-tar dyes, the wool is coloured red, the colour persisting after washing with water. 

Detection and Determination of Starch.—(a) Qualitative test. A freshly-cut surface of the sample is treated with a few drops of iodine solution to see if a blue coloration is formed. If the result of this test is doubtful, a quantity of the dry, defatted substance is triturated well with a little water, and after depositing for a short time, the turbid liquid examined under the microscope. A little iodine solution is then added and the sped-men again examined microscopically for stained starch granules. 

The curcumin may be prepared as follows 30 grams of turmeric powder (Curcuma tonga) are dried at ioo° and then treated for four hours in an extraction apparatus with petroleum ether. The dry, defatted powder is then extracted in the same apparatus with 100 c.c. of benzene for 8—10 hours on cooling, the benzene solution deposits the curcumin as a fine, yellowish, crystalline powder. 

Possetto s method of testing 1 is as follows To 250 c.c. of boiling water contained in a porcelain dish are added first 20 c.c. of 95% alcohol arid 2 c.c. of 10% ammonia solution and immediately afterwards 30 grams of the material. After about 5 minutes boiling—when it is considered that the liquid is sufficiently coloured—cold water is added and the solid allowed to settle. The liquid is decanted into another dish and, after slight acidification with 10% hydrochloric acid, a small skein of defatted wool (0-5 gram) boiled in it for 10 minutes. If the wool remains yellow after repeated washing with water, the presence of a coal-tar colour is indicated. 

Konig s test. 50 c.c. of the wine are neutralised with 10% ammonia (D 0-960), an excess of 5c.c. of the same ammoniabeingaddedandthe liquid boiled gently with about 0-5 gram of defatted white wool until the alcohol and excess of ammonia are expelled. The wool is thoroughly washed with water and heated in a test-tube in a water-bath with 10 c.c. of 10% caustic potash solution until the wool is dissolved. 

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