Solvent extraction dichloromethane

Regert et al. studied [9] a series of 30 Neolithic hafting adhesives from lake dwellings at Chalain (France) using an analytical procedure based on GC/MS analysis involving solvent extraction (dichloromethane) and trimethylsilylation. In the majority of the samples a series of triterpenoid compounds with a lupane structure was clearly identified on the basis of their TMS mass spectra. In particular, the presence of betulin, betulone, lupenone, lupeol and lupa-2,20(29)-dien-28-ol allowed birch bark tar to be identified. In other samples the co-occurrence of other plant biomarkers such as a-amyrin,(3-amyrin... 

NP Land applied sewage sludge Enhanced solvent extraction dichloromethane 126 [8]... 

One of the most widely established processes using SCCO2 is the decaffeination of coffee. Prior to widespread use of this process in the 1980s the preferred extraction solvent was dichloromethane. The potential adverse health effects of chlorinated materials were realized at this time and, although there was no direct evidence of any adverse health effects being caused by any chlorinated residues in decaffeinated coffee there was always the risk, highlighted in some press scare stories. Hence the current processes offer health, environmental and economic advantages. 

Traditionally, dried or powdered plant material is used and extracts can be obtained by mixing the material with food-grade solvents like dichloromethane or acetone followed by washing, concentration, and solvent removal. The result is an oily product that may contain variable amounts of pheophytins and other chlorophyll degradation compounds usually accompanied by lipid-soluble substances like carotenoids (mainly lutein), carotenes, fats, waxes, and phospholipids, depending on the raw material and extraction techniques employed. This product is usually marketed as pheophytin after standardization with vegetable oils. 

The oleoresin is obtained from turmeric powder by solvent extraction. Solvents approved for use by European Commission are ethylacetate, acetone, carbon dioxide, dichloromethane, n-butanol, methanol, ethanol, and hexane. The U.S. Food and Drug Administration (FDA) also authorized the use of mixtures of solvents that include those mentioned earlier plus isopropanol and trichloroethylene. After filtration the solvents must be completely removed from the oleoresin. 

The first step for the determination of PAHs is removal from the matrix by solvent extraction, which preferably is performed with boiling toluene or benzene (hot solvent extraction by refluxing see Jacob and Grimmer 1994), although other solvents (e.g. tol-uene/acetone, acetone, and dichloromethane) and other extraction procedures (ultrasonic treatment, Soxhlet extraction, and accelerated solvent extraction) can also be applied. 

Solvent extraction. Extraction of neonicotinoid insecticides from water is a simple process involving saturation with sodium chloride and extraction with diethyl ether, dichloromethane or ethyl acetate. This extraction procedure will allow the simultaneous extraction of all neonicotinoids. 

Mepanipyrim in crop samples is recovered by acetone solvent extraction. The acetone is evaporated under reduced pressure and the residual aqueous extract is hydrolyzed with enzyme (jS-glucosidases) to release hydroxylated metabolite(s). After enzyme treatment, mepanipyrim and the propanol form metabolite are extracted with dichloromethane, purified by silica gel column chromatography and quantified by gas chromatography/nitrogen-phosphoms detection (GC/NPD). 

Recovery of IC-0. Combine 20 g of the air-dried soil with 100 niL of a mixed solvent of methanol and 0.1 M ammonium chloride (4 1, v/v) in a 250-mL stainless-steel centrifuge tube, shake the mixture with a mechanical shaker for 30 min and centrifuge at 8000 r.p.m. for 2 min. Filter the supernatant through a Celite layer (1-cm thick) under reduced pressure into a 500-mL flask. Add 100 mL of mixed solvent of methanol and 0.5 M sodium hydroxide solution (4 1, v/v) to the residue and then extract and filter in the same manner. Combine the flltrates and concentrate to approximately 40 mL on a water-bath at ca 40 °C by rotary evaporation. Add 10 mL of distilled water and adjust the pH of the aqueous layer to 7 with hydrochloric acid. Transfer the aqueous solution into a 200-mL separatory funnel and shake the solution with 50 mL of mixed solvent of dichloromethane and acetone (1 1, v/v) for 5 min. Discard the mixed solvent and adjust the pH of the aqueous layer to 1.5 with hydrochloric acid. Extract the solution with three portions of 50 mL of diethyl ether. Combine the diethyl ether extracts and dry over anhydrous sodium sulfate. Concentrate to dryness on a water-bath at ca 40 °C by rotary evaporation. 

Combine 50 g of the air-dried soil with 100 mL of acetone and shake the mixture with a mechanical shaker for 15 min. Filter the mixture through a fluted filter paper into a 500-mL flask. Wash the residue on the filter with 50 mL of acetone. Combine the filtrates and remove acetone by rotary evaporation. Transfer the residue with 150 mL of a potassium chloride solution into a separatory funnel, extract the solution with two portions of 50 mL of dichloromethane and collect the organic extracts in a flask. Filter the combined solvent extracts, together with the washings of the collecting flask, through anhydrous sodium sulfate into a 300-mL flask. Remove dichloromethane by rotary evaporation. Dissolve the residue in 10 mL of carbon tetrachloride. 

GC of aqueous simulant or water extract of olive oil using cold on-column injector. 1,4 butane diol internal standard Solvent extraction with dichloromethane and concurrent derivatisation with 9-(methylaminomethyl)anthracene. Fluorescent derivatives analysed by HPLC with fluorescence detection... 

However, Emi et al. [50] have prepared LS with a method established in their laboratory using a solvent extraction. In particular, the method is based on the dissolution of the triglyceride (i.e., tripalmitin) and the cationic lipid in the organic solvent (i.e., dichloromethane), and on the addition of an aqueous polyvinyl alcohol (PVA)... 

Difrancesco etal. [18] 22 FMs including PCMs and NMs Digested sewage sludge U.S. - Accelerated solvent extraction with dichloromethane - Silica gel chromatography - GC-MS... 

Because of the low detection limit requirements, a concentration factor from the usual 1 litre of sample of between 1000- and 10 000-fold is required. This is usually achieved by solvent extraction, followed by evaporation of the extract to a small volume. However, the introduction of the Control Of Substances Hazardous to Health Regulation, 1989 (COSHH) has caused concern about the relatively large volumes of solvent used for extraction—especially chlorinated solvents such as dichloromethane. In order to reduce the volume of solvent used, solid phase extraction, using commercially available C 3 bonded-phase cartridges, is being introduced. 

An example of a schematic for sample treatment, extraction, and separation procedures is given in Simoneit, and it follows the method first used by Simoneit and Mazurek with minor modifications for data comparison purposes. The samples are powdered and dried, then typically extracted using ultrasonic agitation multiple times with a mixture of dichloromethane (CH2CI2) and methanol (3 1 v/v). The solvent extracts are filtered through an annealed glass fiber filter for the removal of insoluble particles, concentrated by rotary evaporation and then by a stream of filtered nitrogen gas. 

Carotenoids A large number of solvents have been used for extraction of carotenoids from vegetables matrices, such as acetone, tetrahydrofuran, n-hexane, pentane, ethanol, methanol, chloroform [427-431], or solvent mixtures such as dichloromethane/methanol, tetrahydrofuran/methanol, -hexane/acetone, or toluene or ethyl acetate [424,432-435], SPE has been used as an additional purification step by some authors [422,426], Supercritical fluid extraction (SEE) has been widely used, as an alternative method, also adding CO2 modifiers (such as methanol, ethanol, -hexane, water, methylene chloride) to increase extraction efficiency [436-438], In addition, saponification can be carried out, but a loss of the total carotenoid content has been observed and, furthermore, direct solvent extraction has been proved to be a valid alternative [439],... 

A convenient and frequently used procedure is sequential solvent extraction. A first step, with dichloromethane, for example, will extract flavonoid aglycones and less polar material. A subsequent step with an alcohol will extract flavonoid glycosides and polar constituents. 

Essences of pink and white fresh guava obtained by direct extraction of flesh juices with dichloromethane revealed that the total amount of Cs aldehydes, alcohols, and acids comprised 20 and 44% of the essence of fresh white and pink guavas, respectively [49]. The flavour of the Costa Rican guava has been described as sweet with strong fruity, woody-spicy, and floral notes [53]. One hundred and seventy-three volatile compounds were isolated by simultaneous steam distillation-solvent extraction. The terpenes and terpenic derivatives were found in this fruit in major concentrations and were strong contributors to tropical fruit notes (Fig. 8.1). The aliphatic esters contributed much to its typical flavour. 

Solvent extraction is an excellent choice for aroma-compound isolation from foods when applicable. Unfortunately, many foods contain some lipid material, which limits the use of this technique since the lipid components would be extracted along with the aroma compounds. Alcohol-containing foods also present a problem in that the choice solvents (e.g. dichloromethane and diethyl ether) would both extract alcohol from the product, so one obtains a dilute solution of recovered volatiles in ethanol. Ethanol is problematic since it has a high boiling point (relative to the isolated aroma compounds), and in concentration for analysis, a significant proportion of aroma compounds would be lost with the ethanol. As one would expect, the recovery of aroma compounds by solvent extraction is dependent upon the solvent being used, the extraction technique (batch or continuous), and the time and temperature of extraction. 

The air samples should be stored in the dark at —20 °C, and the solvent (dichloromethane or DMSO) extracts should be stored in amber-colored, Teflon-lined, screw-capped bottles at —20 °C. These air samples and solvent extracts should come to room temperature prior to use. 

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