Soxhlet extraction direct

Flumetralin was extracted from tobacco using Soxhlet extraction. A 5-g amount of Florisil (5% deactivated) was transferred directly on to the filter disk of a Soxhlet extractor followed by another 5 g of Florisil mixed with 5 g of ground tobacco sample as an upper layer. A 60-mL volume of hexane and 3mL of a 4 agmL internal standard solution were placed in a 250-mL round-bottom flask prior to attaching the Soxhlet extractor. The unit was placed on a heating mantle and the hexane was refluxed through the extractor at the rate of about 250 mLh for 4.5 h. After cooling, 0.5 pL of the extract was injected directly into a GC/FCD or GC/MS system. 

Soxhlet extraction of the dry gum (250 g) serially with hexanes, ether, and methanol resulted in an activity rich ether fraction (600 mg, dried in vacuo) that was partitioned between CCI4 and 50% aqueous MeOH. The dried aqueous layer (300 mg) was applied directly to droplet countercurrent chromatography (DCC), CgHg/MeOH/CHC /H ... 

Applications Most plasticisers can be removed almost quantitatively from PVC by Soxhlet extraction or direct refluxing with diethyl ether for several hours. With the dissolution (THF)/reprecipitation (n-hexane) method, PVC compounds can be isolated. However, reliable results are also obtained by using a short cut in which a PVC compound (0.3g) is dissolved in THF (lOg), insoluble material is allowed to settle and then the THF solution including PVC is injected on to the GC column [12]. Although direct gas chromatographic analysis... 

Reaction of CpH with excess Co2(C0)s (CH2CI2, 40°C, 40-48 h) yielded CpCo(C0)2 5, (0.8-1.0 mmol Co/g., IR (KBr), 2012 and 1953 cm-1). Residual Co2(C0)s was removed via Soxhlet extraction with benzene or CH2CI2. Interestingly, reaction of 4 with C02 (C0)8 yielded 5 directly and as efficiently. Apparently, dehydration of 4 occurred under these conditions. The "overall yield" (based on cobalt incorporation) for this synthetic sequence is 15%. 

Soxhlet extraction can be used with organic solvents or water and often results in a solution that can be analyzed directly. Figure 12.4 shows the results of extracting 10 g of soil using Soxhlet extraction. The two flasks on the left were extracted for 8 hours using a Soxhlet extraction procedure. The leftmost flask is a hexane extract that is absolutely colorless, while the center flask is a... 

Maskarinec and Harvey [61] have described a method for the screening of solid wastes and sludges for organic compounds. The technique involves sequential extraction with acidic, basic and neutral media and the extracts are all analysed directly by gas chromatography with fused silica columns. Results achieved using the technique are discussed. The method is compared with traditional Soxhlet extraction. 

Producing data that cannot be compared directly with other total petroleum hydrocarbons data or guidelines because one data set is the result of a Soxhlet extraction method and the other reflects a sonication or other alternative extraction method. 

Most existing methods are based on instrumental analysis involving exhaustive sample pretreatment and preconcentration steps, followed by purification and fractionation before final chromatographic separation and detection. For fat and oil samples, dissolving the lipids in an appropriate solvent is usually the first treatment. This has been achieved by melting the fat at 90°C followed by LLE or direct solid liquid extraction (SEE) with an apolar solvent [37], column extraction with a mixture of apolar solvents after drying of the sample with anhydrous Na2S04, Soxhlet extraction and/or sonication with apolar solvents. Typically, sample intake is between 0.5 g and 1 g and quantitative recoveries >60% have been reported. 

Before TPO analysis it was necessary to Soxhlet extract the FCC samples to remove nonvaporized hydrocarbons and avoid their accumulation in the pores of the catalyst as carbonaceous residue with high hydrogen content. As a result, the interference during TPO analysis caused by the desorption and decomposition of these compounds at high temperatures was eliminated. In this study it was observed that this type of coke is directly related to the Conradson carbon content of the feedstock. 

Figure 1. Capillary GC analysis of resin-cleaning Soxhlet extraction solvents 900 mL of solvent/700 mL of resin was successively extracted with methanol, acetonitrile, and ethyl ether for 24 h each. Direct injection of 1.5 xL was used. (See Table 11 for GC-MS...

Note Ethyl acetate is a solvent impurity of ether. 900 mL of solvent/700 mL of resin was successively Soxhlet extracted for 24 h with CH3OH, CH3C=N, and ether. No compounds were identified in the ether fractions. A sample was injected directly into the GC-MS. Identifications are tentative no retention time data have yet been correlated. Identifications were completed by MS only. 

Three examples have been chosen for describing coking of zeolites. The first concerns the formation of coke during the transformation of propene, of toluene and of a mixture propene toluene at 120°C and 450°C on a HZSM5 zeolite. All the coke components are soluble in methylene chloride. Most of them are located inside the pores indeed they are not dissolved by direct soxhlet extraction of the coked zeolite samples. 

The coke formed in the 250-450 °C range, has been analysed following the technique proposed by Magnoux et al. [7]. This technique allows for the separation of the external coke from the internal coke by Soxhlet extraction using pyridine. As an example of the results, the fractions of coke extracted directly (external coke), of coke extracted once Si has been dissolved with fluorhydric add (soluble coke) and of the coke that remains insoluble in pyridine are shown in Figure 2, The results correspond to a contact time of 0.05 h and to a time on stream of 30 min. The total coke content as well as each one of their fractions increase with temperature The greater proportion of coke is internally deposited in the zeolite and is soluble in pyridine The external coke content is observed from 300 °C. Above 400 °C there is a coke fraction that is insoluble in pyridine ... 

High resolution fused silica capillary columns were used to examine, and in some cases to compare, flavor and aroma essences obtained by 1) direct headspace injection, 2) simultaneous steam distillation extraction, 3) standard Soxhlet extraction using dichloromethane, and 4) high pressure Soxhlet extraction using liquid CO2 Developments in smaller- and larger-diameter fused silica open tubular columns, and columns coated with a bonded polyethylene glycol stationary phase were also explored. 

Figure 4 shows the chromatographic results of a black pepper sample examined by (from the top) 1) direct on-column headspace injection, 2) steam distillation-extraction, and 3) Soxhlet extraction with dichloromethane, and with 4) liquid CO2. Again, the results are quite reasonable, and in good agreement with those shown in Figure 2. Note that CO2 seems fully as effective (and Indeed, in some cases more effective) an extractant as dichloromethane. ...

Exhaustive extraction of the analyte using soxhlet or reflux this method can be performed for non-volatile components. Thin samples like films can be extracted directly. Thicker materials need to be reduced in size using methods like cryogenic grinding of the material. The solvent used to extract samples can be analysed using suitable analytical equipment. 

Another example is the copper-catalyzed surface-initiated radical polymerization of MMA from S-7 at room temperature without addition of free initiator. The molecular weights and MWDs of the polymers were directly measured after removing the brushes from the surface. For example, the surface with 40 nm thickness had Mn of 68900 and MWDs of 1.45. A high graft density (180 A2/chain) and decreased surface roughens (0.54 nm) were observed. This method is free from solution and thermal polymerizations due to the absence of free initiators and a low polymerization temperature, which permits a simple washing step without Soxhlet extraction. 

The commonly used method is the Soxhlet-Extraction by using diethylether and/or pentane as solvent. The sample is extracted continuously by using an Soxhlet-extrac-tor over a period of several hours. The extract is dried and concentrated by evaporation of the solvent. The residual extract can be applied directly to GC-analysis. This method is used for solid or pasty flavourings as well as for whole fruits or plants and their parts where the composition of the volatile compounds is required [4],... 

The Soxhlet extraction method discussed in Section 6.6 can be used to separate the sol and gel fractions of a gel in the gelation regime, allowing direct determination of the gel fraction gel- Percolation theory expects the molar mass of a network strand M to be the same as the characteristic molar mass in the sol fraction. Hence, M can be determined by the size exclusion chromatography methods of Section 6.6, applied to the sol fraction. Equation (7.93) is tested in Fig. 7.19, where the shear modulus is shown to be proportional to Pgei/M. ... 

Direct evidence for chemical interaction, such as grafting, was found through initial extraction experiments with this series. Exhaustive Soxhlet extraction of xl-1.5, 3.5, and 5.5 with chloroform or tetrahydrofuran removed only 7, 9, and 18%, respectively, of the possible PBMA in these samples. 

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