Efficiency extraction equipment

In this work, a method based on the reduction potential of ascorbic acid was developed for the sensitive detennination of trace of this compound. In this method ascorbic acid was added on the Cr(VI) solution to reduced that to Cr(III). Cr(III) produced in solution was quantitatively separated from the remainder of Cr(VI). The conditions were optimized for efficient extraction of Cr(III). The extracted Cr(III) was finally mineralized with nitric acid and sensitively analyzed by electro-thermal atomic absorption spectrometry. The determinations were carried out on a Varian AA-220 atomic absolution equipped with a GTA-110 graphite atomizer. The results obtained by this method were compared with those obtained by the other reported methods and it was cleared that the proposed method is more precise and able to determine the trace of ascorbic acid. Table shows the results obtained from the determination of ascorbic acid in two real samples by the proposed method and the spectrometric method based on reduction of Fe(III). 

Soybeans and soybean products contain high levels of protein, carbohydrates, and lipids (Table 11.6.1). As minor components of complex mixtures, isoflavones must first be separated from the bulk of the matrix constituents prior to analysis. Efficient extraction methods for isoflavones should account for their diverse structures, chemical properties, and the food matrix of which they are constituents. This unit describes a practical way of extracting isoflavones from soybean products in their natural forms using readily available solvents and laboratory equipment. 

Depending on the type and efficiency of the extraction equipment, the acetone/ crude lecithin ratio necessary to achieve a 95% phospholipid product is 10-20 1 (v/v). In batch extraction, the tank is charged with acetone prior to crude lecithin... 

Small drops lead to more transfer area and better extraction, but to slower settling and less capacity. Thus, selection of extraction equipment frequently involves a compromise choice balancing efficiency against capacity. 

Suppliers of extraction equipment will likely wish to participate in pilot testing to confirm the correlations for capacity and efficiency of the specific equipment being considered. 

A wide variety of solvent extraction equipment has been developed for use in counter-current, liquid-liquid extraction processes. In general they divide into vertical and horizontal types, referred to as columns or mixer-settlers respectively. In both cases, the object is to obtain suitable conditions for the transfer of solute from one phase to the other as rapidly and efficiently as possible. 

The advantages of ASE are an efficient extraction that compares favorably with the Soxhlet and sonication extractions, the use of considerably less solvent than in the classical techniques, and automated operation once the sample cells are loaded. Some of the disadvantages of ASE are the high cost of equipment, the extensive labor of preparing the sample and loading it into extraction cell, and the possibility of instrument failures such as plugging of solvent lines, leaks, and mechanical jams. 

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