Extraction completeness

This is the complete factor solution which admittedly contains uncorrelated variables but all the k factors are extracted completely and no reduction... 

Emara [53] developed a rapid, simple, accurate and reproducible method for the quantitative determination of niclosamide ethanolamine salt (NES), the most widely used molluscicide against snail vectors of schistosomiasis, in both distilled and natural canal waters. The biocide was extracted completely from water samples by passing through Sep-Pak Ci8 cartridge and eluting the cartridge with methanol. The eluate was then analyzed directly for NES by UV Vis spectrophotometry at 330 nm [53]. 

Schneider et al. (S6, S7, S8) have demonstrated that wheat gluten and certain gluten fractions cause inhibition of the isolated small intestine of the rat. In the Trendelenburg preparation, as modified by Biilbring et al. (B21), inhibition of the peristaltic reflex occurred if the material was placed outside the intestine so that it could reach the muscle without traversing the mucous membrane. If it was placed inside the lumen no inhibitory effect was seen. If the gluten or gluten fractions were incubated with rat mucous membrane extract, complete inactivation of the inhibitory effect was obtained. This action of mucous... 

Theory First and foremost the active ingredient i.e., glyceryl trinitrate is extracted completely from the tables by shaking with glacial acetic acid. To an aliquot of the resulting acetic acid solution an excess of phenoldisulphonic acid is added to produce a yellow colour which is subsequently intensified by adding an excess of ammonia. The following reactions take place ... 

Histamine Extraction. Some secondary plant metabolites are very difficult to extract from their natural matrix and require lengthly soxhlet extractions. Complete histamine extraction was relatively simple. The HPLC separation was used to design a technique to confirm a complete extraction. The histamine peaks from three serial extractions on the same 3 grams of cotton plant leaves are shown in Figure 6. Post-column fluorescence detection of the fourth extraction showed only the slightest response even at the highest detector amplitude. Three extractions accounted for from 95% to 99% of the histamine content. The plant residues from these extractions yielded no additional histamine after standing at ambient conditions for two weeks. 

Reports of effects on mice observed for maitotoxin closely resemble the effects of ciguatoxin, with the exception of diarrhea, hypersalivation, and convulsions before death. The symptoms observed here for ESAP did not include hypersalivation and only occasionally was mild diarrhea observed. The vasodilation in the ears, ptosis of the eyelids and abdomen were observed in this study but not in other accounts. Crude extracts produced irreversible inhibition of the frog nerve muscle preparation, affecting first the synapse, secondly the nerve and lastly the muscle (23). At. 04 mg/ml the crude extract completely inhibited the isolated guinea pig ileum preparation. 

Very high sensitivity (to ppt) can be obtained with compounds that are extractable by SDE. However, highly water-soluble compounds are not extracted completely and compounds with very low boiling points, such as methanethiol, can be lost during concentration. In addition, compounds with gas chromatographic elutions simultaneously with the solvent are hidden from view. Quantification can be made by addition of an internal standard to the sample matrix. 

Commonly used extraction solvents are ethyl acetate, diethyl ether, methanol, and aqueous methanol, but the majority of the free phenolic compounds can be extracted with alcohols (methanol or ethanol) or alcohol-water mixtures (1). Due to the differences in polarity between components (40), neither diethyl ether nor ethyl acetate are able to extract completely all the phenolic compounds in a liquid-liquid extraction. Thus, successive extraction with diethyl ether and then ethyl acetate has been used for phenolics in fruit juices (41). When using alcohol-water mixtures (40), repeated extraction or reflux for 1 h are necessary to extract free phenolic acids as well as their glycosides. 

Currently, there is no doubt that the most widely used method for extraction of tissue lipids is that of Bligh and Dyer (1959). Basically, this is a modification of the Folch method and employs a careful calculation of the amount of sample (tissue) water such that the overall mixture will have a final composition of chloroform-methanol-water of 1 2 0.8 (v/v). Thus, a singlephase extract can be obtained and extraction completed very rapidly, even within minutes. Recovery of the lipid in a chloroform-rich phase can be achieved by addition of equal volumes of chloroform (under certain conditions) and water to produce a two-phase system. The lower (CHC13) phase is subsequently washed with a methanol-water (1 0.9, v/v) mixture to allow removal of a substantial amount of the nonlipid contaminant with little or no problems with interfacial fluff formation or emulsions. However, even though this is a highly efficient method, it is still advisable that one take steps... 

A simple alkaline extraction method, at elevated temperatures (90°C) in a sealed vessel was applied to the determination of I, employing TMAH and ICP-MS [31]. All the I present in the samples (milk powder, egg powder, cod muscle, pig kidney) was extracted completely by TMAH. The results were con-brmcd by decomposition of the samples. 

Meat extracts. Completely remove liquid and semiliquid preparations including sediment from the container, and mix thoroughly, warming if necessary. Grind in a mortar, a representative quantity of products in solid form. 

With the extractions completed the organic extract needs to be dried. A lot of the dissolved water can be removed by extracting with saturated brine and it is advisable to do this. The organic extract is then dried fully by... 

In the example shown in Figure 12, the drug substance is weighed, and solutions of 0.5, 0.3, and 0.1% of nominal concentration are made and applied to one half of the TLC plate as the control solutions. In addition, the same dilutions are made from one extracted tablet and applied to the same plate. Once the plate is developed, the two 0.1% standards are compared to each other to determine if they have the same visual response in intensity. The same comparison is made for the 0.3% and 0.5% standards. If all three standards appear to have the same intensity as their respective controls, then we state that the tablet has been extracted completely. If the standards are not the same in intensity and it is apparent that some drug substance is being retained by the filter, then another type of filter or possibly centrifugation alone would be examined until full extraction can be achieved. 

To reveal possible ultrafast processes occurring on a time scale less than 30 ps, femtosecond fluorescence upconversion experiments were performed [30] in toluene under magic angle polarization. To extract complete information of the decay times and their amplitudes in function of detection wavelength, the measurements were performed in three time windows of 5 ps, 50 ps, and 420 ps. 

It is convenient to increase the acidity of the solution from pH 4.0 to pH 2.6-3.0 before the oxinate is extracted. The extraction rate and distribution coefficient remain the same as at pH 4, and Fe(III) is also extracted completely, but the extraction of aluminium and of other partially extractable metals is reduced 3-4-fold. 

Carbon dioxide has been tested with other materials, such as corn and wheat germ, sunflower and safflower seeds, and peanuts. To a very good first approximation, the solubility of all vegetable triglycerides is identical, and all these seeds can be extracted completely if the cells are macerated to make the oil accessible. 

Tc-albumin microspheres satisfy the requirements of particles for systemic application with the indicator fractionation technique, namely, uniform size and shape, available in desired sizes, extracted completely in a single passage through capillary beds, and metabolized within hours after injection (Rhodes et al. 1969, 1971 Wagner et al. 1968, 1969 Zolle and Kropf 1982). 

By using MAE, the organic solvent and the sample are subjected to radiation from a magnetron in either a sealed vessel (pressurized) or an open vessel under atmospheric pressure. Pressurized MAE allows a large number of samples to be extracted simultaneously, whereas atmospheric pressure MAE is limited to six simultaneous vessels. The main drawback of this technique is that the solvent needs to be removed from the sample matrix upon extraction completion prior to analysis. 

The McCabe-Thiele constructions described in Chapter 8 embody rather restrictive tenets. The assumptions of constant molal overflow in distillation and of interphase transfer of solute only in extraction seriously curtail the general utility of the method. Continued use of McCabe-Thiele procedures can be ascribed to the fact that (a) they often represent a fairly good engineering approximation and (b) sufficient thermodynamic data to justify a more accurate approach is often lacking. In the case of distillation, enthalpy-concentration data needed for making stage-to-stage enthalpy balances are often unavailable, while, in the Case of absorption or extraction, complete phase equilibrium data may not be at hand. 

Because of the high selectivity of the extractant for the sulfuric acid, the only outlet for salts is the crystallizer. As the salt does not interfere with the extraction, complete removal in the crystallizer is not required. Thus, whereas the thermal processes described above (direct evaporation or spray drying) operate at a high acid concentration (low water partial vapor pressure, difficulties in controlling crystallization), the ABC extract-... 

The process design and the reaction parameters in the Haifa Chemicals process were selected to reduce the limitations imposed by the properties of the extractant. Due to the low efficiency of the extractant, completion of acid extraction from the separated reaction mother liquor is impractical. To avoid losses of reagent and of by-product, the reaction is performed in the presence of the extractant, forming an invariant system. The acidity of the aqueous phase is maintained constant throughout the extraction at a level that provides suitable extraction. The four-phase system (solid KNO, solid KCl, an aqueous solution, and an extractant phase) is, however, difficult to control, a fact that interferes with production of large, easy to wash KNO j crystals. 

Marutzky [165] found enhanced board properties at higher degrees of addition of uncondensed urea. Since, however, in these experiments the postadded urea could be extracted completely from the boards, no significant cocondensation between the urea and the phenolic resin could have occurred. Using such PUF resins, the adhesive solids content should be calculated based only on the PF resin solids content in the PUF resin. 

Torula yeast contains fat which cannot be extracted completely with ether and alcohol. The samples "IN and SN (from Lake States Corporation, Rhinelander, Wisconsin), analyzed in our laboratory contained 4.5 and 5.3% of total fatty acids, respectively. About 45% of the total fatty acids was identified as linoleic acid, and a small amount (2.6%) as linolenic acid (Dam et al., 1957b). This might contribute to the development of exudate. 

Geosmin is a natural product that smells like dirt. It is produced by several microorganisms and can be obtained from beet extracts. Complete the following decalin ring skeleton, placing the substituents of geosmin in their proper orientations. 

Where settling is slow due to small density difference, high viscosity of the continuous phase, or small particle size, centrifuges can be used to increase the rate. They are expensive machines, however, and can rarely be justified except in cases where the value of the product is high and low hold-up in settling devices is required, as in the case of penicillin extraction. Complete separation still requires coalescence, which is not affected by centrifugal force, and a stable emulsion will be merely concentrated and not broken by centrifuging (5). 

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