Extractable substances

The term extractable substances denotes those substances which are extracted under certain conditions by an organic solvent from a sample of sludge (or water), and which then remain after elimination of the solvent and drying. This group includes oils (both mineral and plant), fats, soaps, waxes, heavy hydrocarbons, tar, etc. The results of the determination of extractable substances are given in mg kg or mg 1 in liquid samples (it is necessary to state the method used). 

For the determination of extractable substances chromatographic methods are becoming ever more important, particularly gas chromatography or gas chromatography with mass spectrometry [14]. 

In principle, solid material extraction can be divided into two different types, the selective and the total. 

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Extractables Substances that can be leached from a filter during the filtration process or under other specified conditions. 

Extraktivstoff, Extraktstoff, m. extractive substance or matter, extractive. 

Wc have seen that molecular substances tend to have low melting points, while network, ionic, and metallic substances tend to have high melting points. Therefore, with a few exceptions, such as mercury, a substance that is liquid at room temperature is likely to he a molecular substance. Liquid solvents are heavily used in industry to extract substances from natural products and ro promote the synthesis of desired compounds. Because many of these solvents have high vapor pressures and so give off hazardous fumes, luinids that have low vapor pressures hut dissolve... 

If a series of determinations is to be made on the same type of material, it is advisable to make a standard curve by adding known amounts of methoxychlor to a stripping of the material under consideration which is known to be free of methoxychlor. Any slight variation introduced into the technique by the presence of other extracted substances will be compensated for in this way. 

The isoprenoid hycrocarbons pristane and phytane (derived from the phytol side chain of chlorophyll), as well as porphyrins, have been detected in organic extracts of the Nonesuch Shale of 1.1 billion year age [23]. Their presence points to the existence of photosynthetic pigments in the Precambrian era, but it is also possible that these extractable substances could have been contributed to the rock at a later time. However, in this instance contamination appears to be less likely on account of the large abundance of organic material in this shale. 

Computerized data-base versions of RTECS give the capability of extracting substance lists by "Classification Codes." For example, one might ask the system to search for all compounds with classification Code of TUMORIGEN. How many users will have read the user s guide carefully enough to know that this means only that these compounds may have been reviewed by IARC or NTP but NOT that they have been indicted as tumorigenic ... 

Correctness of the sixth parameter equation (7) and its simplified forms for the generalization of the swelling data was proved for other coals including the Donbas coal [32] at the parameters B and VM- If to apply the equation (7) to the coal extraction data, then the factor of molar volume VM is insignificant, and the connection between quantities of extracted substance (in g/mole of the solvent) and physical-chemical characteristics can be satisfactorily described by fifth parameter equation (6) or by its simplified forms in this case possible acid-base interaction is the decisive factor, that is factor B [33 - 35], This confirmation is in good agreement with the above-said bigger molecules harder introduce... 

Charcoal is a non-polar adsorbent that will bind large or non-polar molecules from an aqueous solution, but its effects are not very predictable. However, several synthetic non-polar adsorbents have been developed, known as XAD resins, which are synthetic polymers, often polystyrene based. They are used mainly as preparative media for extracting substances from samples which, after washing the resin, can be eluted from it with a polar organic solvent. 

In 1912 a Polish scientist C. Frank pubhshed a paper in Journal of Physiology, in which he also reported an extracted compormd from rice bran with the same procedrrre as Srrzrrki reported and rramed the extracted substance Vitamin (which means vital amine). The comporrrrd is the same as that found by Srrzrrki. The Nobel Prize for Medicine and Physiology in 1929 was awarded to C. Eijkman and F. G. Hopkirrs for their discovery and contributiorrs to Vitamin, but it is obvious that the discoverer of Vitamin is SrrzuM. Vitamin A was isolated in 1914, fom years after the discovery of Oryzanin Vitamin Bf... 

The acyl chloride was treated with a solution of sodium azide in ethanol. The nitrogen content of the extracted substance was equimolar to the initial chloride content, which was hydrolyzed easily. The reaction stopped at the urethane stage ... 

The previous chapters have demonstrated that liquid-liquid extraction is a mass transfer unit operation involving two liquid phases, the raffinate and the extract phase, which have very small mutual solubihty. Let us assume that the raffinate phase is wastewater from a coke plant polluted with phenol. To separate the phenol from the water, there must be close contact with the extract phase, toluene in this case. Water and toluene are not mutually soluble, but toluene is a better solvent for phenol and can extract it from water. Thus, toluene and phenol together are the extract phase. If the solvent reacts with the extracted substance during the extraction, the whole process is called reactive extraction. The reaction is usually used to alter the properties of inorganic cations and anions so they can be extracted from an aqueous solution into the nonpolar organic phase. The mechanisms for these reactions involve ion pah-formation, solvation of an ionic compound, or formation of covalent metal-extractant complexes (see Chapters 3 and 4). Often formation of these new species is a slow process and, in many cases, it is not possible to use columns for this type of extraction mixer-settlers are used instead (Chapter 8). 

Any biological process, usually involving microorganisms, that extracts substances, typically metals, from ores or soil. 

T. harzianum IMI 275950 isolated from wheat straw grew better on lignocellulose (Table I). Despite these differences, the enzyme yields of the cellulase/xylanase complexes did not correlate with growth rate. These observations from this empirical study indicate that strains isolated or derived for growth on extracted substances may not necessarily be the most useful strains to exploit natural substrates. 

Hamburger, M., Baumann, D., and Adler, S., Supercritical carbon dioxide extraction of selected medicinal plants — effects of high pressure and added ethanol on yield of extracted substances, Phytochem. Anal., 15, 46, 2004. 

In an optimisation procedure involving the minimal partition coefficient, the minimal partition coefficient is calculated using all compositions of the extraction liquid (all possible combinations of x, X2 and within the mixture space). The highest value calculated for this minimal partition coefficient (the maximal minimal partition coefficient) is the optimal value and hence the composition where the partition coefficient of the worst extractable substance is highest. 

Preparation and Properties. Spill 5 g of pure boric acid into an iron crucible (better use a platinum crucible why ). Cover the crucible with its lid and roast it in a muffle furnace at 800 °C up to complete removal of the water. What reactions occur To extract the boric acid anhydride, immerse the bottom part of the red-hot crucible into cold water. Transfer the extracted substance into a bottle with a good stopper. 

After sufficient extraction the dissolved substances have to be separated from the fluid in a following step. Decreasing the pressure at constant temperature reduces the fluid-density, and therefore the solvent-power of the fluid. The extracted substances are collected at the bottom of the separator, as shown in Fig. 6.6-2. To close the solvent cycle, the fluid has to be recompressed to extraction pressure. 

Most applications use a combination of pressure- and temperature change. After pressure-reduction the extraction gas is heated so that it reaches the gaseous state. In this phase, no solvent-power of the extraction gas is present for any substances and therefore complete separation of extracted substances takes place. In cycling the extraction gas after separation, it has to be condensed, under-cooled to prevent cavitation of the pump, and recompressed and heated up to extraction temperature. 

A further method separates the extracted substances by absorption. Basic for this method is that there should be a high solubility of extracted substances in the absorption material, and that the solubility of absorption substance in the circulation solvent should be as low as possible. Further, the absorption material must not influence the extract in a negative way and a simple separation of extract and absorption material has to be available. An ideal absorption material is therefore a substance which is present in the raw material. Most plant-materials contain water, which can act as a very successful absorption material. An ideal example is the separation of caffeine for the decaffeination of coffee and tea. On the one hand, water has a low solubility in CO2, and on the other, water-saturated CO2 is necessary for the process. The extracted caffeine is dissolved into water in the separator and caffeine can be produced from this water-caffeine mixture by crystallization. One advantage of this separation method is that the whole process runs under nearly isobaric conditions. 

B. Materials which allow pretreatment and where the extracted substances represent the main product. 

No other solvent extraction process other than the CO2 technology allows such a strong influence on loading, phase equilibrium, and selectivity. Unfortunately, the solubility of extracted substances in CO2 is relatively low, compared with the usual solvents which give absolute miscibility with the extracted valuable materials in most cases. The determination of solubility and solvent ratios is therefore important for the economy of the process. 

Supercritical fluids can be used to extract substances from natural products, as solvents or as anti-solvents to micronize drugs and biodegradable polymers, encapsulate drugs in polymeric matrices, resolve racemic mixtures of pharmacologically active compounds, fractionate mixtures of polymer and proteins, and sterilize bacterial organisms. 

In addition to the isolation of these four pure gibberellins, a vast body of evidence indicates the widespread occurrence in higher plants of extractable substances with gibberellin-like biological properties. It is instructive to compare published Rf values for unidentified gibberellin-like substances of crude extracts with the Rf values of the known gibberellins. 

A number of undesirable substances could be present on the surface or sorbed into the matrix of the closures, but the predominant contaminants are particles of the closure matrix itself, other rubber compounds, metallic particles, micro-organisms, endotoxins, and template lubricants, which are usually organic in nature. In addition, various extractable substances used in the formulation of... 

In order to integrate further some of the various reactions mentioned, and to detect its presence by other methods, the vessels of the rat s mesoappendix were employed as a test object (Chambers-Zweifach preparation, 12). A good correlation between the presence of a vasoexcitor material-like substance in the extracts and the presence of hypertension was found. When the whole rat was used for assay, a much cruder index, sizable quantities of active pressor material were isolated from the blood only of those patients showing at least a degree of renal impairment (lessened ability to concentrate urine, etc.). In general it may be stated unequivocally that patients with severe hypertension have in their arterial blood extractable substances which are pressor for the rat there are less or undemonstrable amounts in blood of less severe or neurogenic hypertensive patients there is little or none in blood of normotensive subjects a vasoexcitor material-like activity is exerted by blood from most hypertensive patients adenyl compounds, having a depressor action, present in extracts of blood are less prevalent in those from hypertensive patients the active rat pressor material (pherentasin) is probably aminelike in nature, is not a protein, but may be a simple peptide or an amine. 

The last two decades have seen an increased interest in the use of supercritical fluids in separation science. Supercritical C02 has often been employed as a naturally occurring medium for the separation, purification, and determination of organic substances in environmental samples. However, there are only limited reports on the use of supercritical fluid as solvent in the separation of metal ions from solutions as well as various solid matrices. The supercritical fluid extraction (SFE) technology offers several advantages over conventional solvent-based methods, including the ability to extract radionuclides directly from solids, easy separation of solutes from C02, and minimization of waste generation. It can easily be removed from the extracted substances by degasification under atmospheric pressure and temperature. 

As mentioned previously, we have found that certain product(s) could be extracted with ether from the early stages of the reaction between glucose and n-butylamine in aqueous system, and have assigned glyoxal dialkylimine as the main product. Recently, it has been shown that the ether-extractable substance is not itself a radical product but when it is dissolved in an aqueous solution of ascorbic acid or acidic ferrocyanide, an... 

In liquid-liquid extraction (LLE), phases A and B are both liquids. The two liquid phases must be immiscible. For that reason, LLE has also been referred to as immiscible solvent extraction. In practice, one phase is usually aqueous while the other phase is an organic solvent. An extraction can be accomplished if the analyte has favorable solubility in the organic solvent. Chemists have used organic solvents for extracting substances from water since the early nineteenth century [38]. 

The dispersion of extracted substances in the must wine, following the equilibrium laws for their different phases. 

Hemicellulose Group of carbohydrates found in the cell wall in more or less intimate contact with cellulose. The hemicelluloses are more soluble than cellulose and much more readily hydrolyzed into sugars. Holocellulose Total carbohydrate fraction of wood remaining after the removal of lignin and solvent extractable substances. 

Extractant Substance added to the solvent in order to enhance the extraction process. 

Now, depending on the extraction process, and what is begin extracted, the filtered solvent mixture is either treated with chemical reagents, filtered, and then evaporated, or simply evaporated to remove the solvent and leave behind the extracted substance. In some cases, this step can be quite complex, as some extraction process require treatment with multiple reagents, titrations, filtrations, ect., in order to facilitate proper extraction. It should be noted that exact instructions will be given for each extraction process where applicable. 

The application of higher pressures for herbs and spices like camomille flowers, cinnamon bork, clove and others gives no advantage at all, because the yield regarding essential oils is equal and additional extracted substances are not desired. 

Main advantages of using such on-line-analytics are the direct identification and quantification of extracted substances during the extraction process. Hence, the monitoring and control of SFE processes would be possible. 

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