Shaker table technique

Shaker table techniques have been developed with increased efficiency for acidic and basic compounds. The sample is placed in an extraction vessel (Erlenmeyer flask or glass jar) together with an extracting solvent, dichloromethane methanol H2SO4 (70 29 1) for acidic compounds or dichloromethane methanol NaOH (70 29 1) for basic compounds. The vessel is placed on a platform shaker for 1 h and then the liquid is decanted into a separatory funnel-containing water. The separatory funnel is gendy shaken, the layers are allowed to separate as for a normal liquid liquid extraction, and the solvent is collected for further processing. 

In the production of a crystalline material to be sold as a consumer product, crystal size, shape, and uniformity are often quite important. Sometimes a crystal product can be manufactured most economically by a particular process, but the product may not have the desired sales appeal. In such instances more costly manufacturing techniques may have to be employed in order to achieve the desired crystal characteristics. Factors such as these must be considered in economic calculations on a crystallization process. Often, as in the case of table salt, size and uniformity of size are important for practical reasons. Fines are undesirable, since they may be lost as an objectionable dust, while coarse crystals may not fit through small salt shaker openings. Uniform size also aids in... 

Most of the extraction techniques of phenolic compounds from vegetables are based on ultrasound-assisted extraction (UAE) [27,44,45], In addition, other techniques have been successfully applied to the pretreatment of phenolic compounds in fruits and vegetables, including pressurized liquid extraction (PLE) [46], solid-phase extraction (SPE) [47], supercritical fluid extraction (SFE) [48], microwave-assisted extraction (MAE) [49], rotary shaker-assisted extraction (RAE), [50] and QuEChERS (acronym of quick, easy, cheap, effective, rugged and safe) [51], as can be observed in Tables 16.3 and 16.4. In some cases, an acid treatment [52] was applied to hydrolyze the glycosides in order to determine the content of free and conjugated flavonoids as aglycons. 

R AE is considered one of the simplest extraction techniques because it is easy to perform with common laboratory equipment (i.e., a rotary shaker). When RAE is nsed, the sample is mixed with the appropriate solvent and placed into the rotary shaker. Solvents snch as methanol [74] or mixtures of methanol and water [29,50,75] at different proportions have been used for the extraction of phenolic componnds from several matrices, although for some compounds as anthocyanins, acidified organic solvents can be nsed [72] (see Table 16.4). 

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