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Silica column fused, resolution enhancement

Sub-samples of 1 g were taken for the analysis. The PAHs were extracted under reflux with toluene/acetone (1 1 v/v, 150 mL) for 30 minutes. The efficiency of the extraction procedure was tested by adding an internal standard (indeno[l,2,3-c t/]fluoranthene) and was found to be 95 99%. An additional extraction with tetrahydrofurane did not enhance the PAH yield. The extract was evaporated to about 2 mL. A cydohexane/dimethylformamide (DMF)/water (100 mL cyclohexane, 90 mL DMF and 10 mL water) partition was performed. The cyclohexane phase was discarded and the DMF/water phase diluted with 80 mL water. This phase was re-extracted with cyclohexane. The cyclohexane phase was evaporated to a volume of 2 mL and cleaned-up over a silica column (5 g, 9.1% water). The PAHs were eluted with 80 mL cyclohexane, which was evaporated afterwards to a volume of 0.1-0.5 mL. The obtained concentrate was placed on a Sephadex LH 20 column (10 g) and eluted with propanol-2. The fraction of 0-46 mL was discarded. The fraction from 46-170 mL was evaporated to a small volume and analysed by high resolution gas chromatography (on column injection) using a fused silica capillary column of which the conditions are described elsewhere [26]. [Pg.439]

WCOT columns of glass or fused silica have so far only been used to obtain plasma lipid profiles to a limited degree [518,528,544,647]. but greatly enhanced resolution is obtained and they will surely be employed more often in the future. Figure 8.17 illustrates the separation that can be achieved with... [Pg.136]


See other pages where Silica column fused, resolution enhancement is mentioned: [Pg.111]    [Pg.97]    [Pg.157]    [Pg.169]    [Pg.461]    [Pg.118]    [Pg.764]    [Pg.1489]    [Pg.934]    [Pg.438]    [Pg.814]    [Pg.52]    [Pg.201]    [Pg.157]    [Pg.692]    [Pg.1417]    [Pg.553]    [Pg.390]    [Pg.2176]   
See also in sourсe #XX -- [ Pg.31 ]




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