Dionex ASE 150, Руководство оператора

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E • Theory of ASE
Doc. 065207-02 9/08
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Figure E-3 is a photo of extracts obtained from a single sample of wild blueberries
extracted with hexane, followed by DCM, ethyl acetate, acetonitrile, and then
ethanol. Clearly, using a fractionation procedure like this can offer advantages
when analyzing extracts of plant materials that can contain several hundred
compounds of interest.
Another unique use of solvent selectivity was reported by Draisci et al. (12). The
authors reported the use of ASE for the extraction of corticosteroids from beef
liver prior to analytical determination by LC-MS. First, the sample was extracted
with hexane to remove the majority of lipids that would interfere in the
determinative step. Next, the samples were extracted with hexane/ethyl acetate to
remove the steroid compounds. Solvent fractionation using ASE is an area that
needs to be explored to more fully understand its potential.
The use of sorbents in the sample cell along with the sample has offered some of
the highest level of selectivity in ASE. Typically, the adsorbent is loaded into the
sample cell first (outlet end) and the sample is loaded on top of the adsorbent. This
way, the flow of the solvent during the extraction is such that unwanted
compounds will be retained in the cell by the adsorbent. Azalea et al. (13) first
reported the use of alumina in sample cells to retain lipids when extracting PCBs
Figure E-3. Selectivity in ASE. The same sample of blueberries was extracted with
hexane (most left), DCM, ethyl acetate, acetonitrile, and ethanol