Preparative fraction collection

Altria, K.D. Dave, Y.K. Peak homogeneity determination and micro-preparative fraction collection by capillary... 

S. Blomherg and J. Roeraade, Preparative capillary gas cliromatography. IF Fraction collection on rtaps coated with a very tliick-film of immobilized stationary phase , J. Chromatogr. 394 443-453 (1987). 

Fig. 3-9. Preparative HPLC of 100 mg of the test racemate 8 in a single 2 mL injection using a 250 x 4.6 mm i.d. column containing (5)-Glu-(5)-Leu-DNB CSP. Conditions mobile phase ethyl acetate, flowrate 2.0 mL min , UV detection at 380 nm. Injection 2 mL of 50 mg mL racemate solution. Fractions collected before and after the indicated cut point were 98.4 % ee and 97 % ee pure, respectively. (Reprinted with permission from ref. [86]. Copyright 1999, American Chemical Society.)...

Packed column SFC has also been applied to preparative-scale separations [42], In comparison to preparative LC, SFC offers reduced solvent consumption and easier product recovery [43]. Whatley [44] described the preparative-scale resolution of potassium channel blockers. Increased resolution in SFC improved peak symmetry and allowed higher sample throughput when compared to LC. The enhanced resolution obtained in SFC also increases the enantiomeric purity of the fractions collected. Currently, the major obstacle to widespread use of preparative SFC has been the cost and complexity of the instrumentation. 

C18 used as preparative column, collected different fractions... 

Lipids can be identified and quantified using thin-layer chromatography (TEC) and gas chromatography (GC) (Galliard, 1968). Extraction of lipids is achieved by homogenizing potato tubers with isopropanol in a blender, followed by a series of filtrations and extractions with chloroform-methanol (2 1). Chloroform is removed by rotary evaporation and the residue is redissolved in benzene-ethanol (4 1). This extract is passed through a DEAE-cellulose column, and the fractions collected are subjected to TEC on 250 p,m layers of silica gel G, using three solvent systems. Fatty acid methyl esters for GC analysis are prepared by transmethylation of the parent lipids, or by diazomethane treatment of the free fatty acids released by acid... 

Figure 5. Composite MWD diagram showing the calculated distributions of four of the five master fractions obtained from preparative chromatography of organosolv aspen lignin (fraction number 4 to 1 from left to right). The Mw values for the master fractions from left to right are 1,110, 1,310, 2,420, and 8,050, respectively. The insert shows the elution profile of organosolv aspen lignin from the YMC preparative /z-Styragel column (5 x 200 cm). The 30 fractions collected were pooled into the five master fractions shown.

Materials. Ethanethiol, obtained from the Eastman Kodak Co., was distilled under nitrogen at atmospheric pressure. The middle fraction collected had a boiling range of less than 0.1°C. and was stored under nitrogen at 0°C. in a vessel fitted with a rubber serum cap. Alkaline solutions were prepared from AnalaR sodium hydroxide (Hopkin and Williams) and deionized distilled water and were stored in steam-cleaned screw-capped polyethylene bottles. 

A Waters Associates Anaprep GPC fitted with one 4 ft X 2.4 inches od Styragel column having a nominal porosity of 104 A was used for the preparative fractionation of the PMMA blend in tetrahydrofuran at a temperature of 25 °C and at a flow rate of 30 ml/min. The degasser and differential refractometer were operated at 35° and 25 °C, respectively. Samples having concentrations of 0.25 wt-vol % were respectively, automatically injected from a 100 ml loop over a 5-minute period. Ten 125 ml fractions were automatically collected for each sample injection. Upon... 

If a emitters are separated and collected by fraction collection, the preparation of very thin counting sources in a consistent matrix is required to obtain high-energy resolution. These are placed in close proximity to a diode detector, typically in vacuum. Nevertheless, a energy peak overlap can still occur for various combinations of radionuclides if they are not chemically separated, for example, M1AmPPu and 237Np/234U. 

Thus, RRF information can be obtained without fraction collection or purification, without standards, and without even knowing the concentration of analyte. As a result, sample preparation is greatly simplified, and the stability of the impurity is not an issue. 

Six different detoxification treatments were performed using both weak and strong anion-exchange resins (Table 1) in an analytical experiment (Fig. 1) and a preparative experiment (Table 2, Fig. 2), in which the fermentability of the fractions was assayed. Figure 1 shows how the pH and the concentrations of glucose, furan aldehydes, phenols, aliphatic acids, and sulfate varied in hydrolysate fractions collected from columns packed with the six different resins in the analytical anion-exchange experiment. 

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