Fraction collectors

However, for quantities substantially less than this level, 7- to 10-mm i.d. analytical columns can often be used in a semipreparative mode. By repeatedly injecting 300 to 500 ju,l of up to 1% polymer, reasonable quantities of polymer can be isolated. An autosampler and automated fraction collector can be setup to perform such injections around the clock. Although the larger injections and higher concentrations will lead to a loss of resolution, in some situations the result is quite acceptable, with a considerable savings in time being realized over other means of trying to make the same fractionation. 

A detector is used to determine when to initiate collection of the eluent by a fraction collector. A differential refractometer can be used if the polymer... 

Any type of fraction collector with a drop counter will do. When the solvent is volatile, attention has to be paid so that the solvent does not dry from the concentrated eluent at the tubing vent. 

A switching valve (low pressure) may be used to divert the eluent from the detector to the fraction collector as soon as the polymer is detected. Another switching valve can be used to select the polymer solution or the solvent for introduction into the pump. 

Stalcup aiid co-workers [14] adapted this method to a continuous elution mini-prep electrophoresis apparatus shown in Fig. 11-3. In this apparatus, the end of the electrophoretic gel is continuously washed with elution buffer. The eluent can then be monitored using an HPLC detector (Fig. 11-4) and sent to a fraction collector where the purified enantiomers, as well as the chiral additive, may be recovered. In this system, the gel configuration was approximately 100 mm x 7 mm, and was aircooled. The number of theoretical plates obtained for 0.5 mg of piperoxan with this gel was approximately 200. A larger, water-cooled gel was able to handle 15 mg of... 

Fig. 17.5. Experimental configuration for integrated bead milling and fluidised bed adsorption 1. Feedstock 2. peristaltic pump 3. bead mill 4. flow through/waste 5. fluidised bed contactor 6. elution buffer 7. fraction collector/ waste 8. loading buffer.

The conditions for gas chromatography are given in Note 9. The product was found mainly in fractions 2-20 by the submitters. The first 25-ml. fraction contained considerable amounts of byproducts, while fractions 21 and higher contained 1-adamantanol. The checkers collected 10-ml. fractions with an automatic fraction collector. 

Figure 4-1. Components of a simple liquid chromatography apparatus. R Reservoir of mobile phase liquid, delivered either by gravity or using a pump. C Glass or plastic column containing stationary phase. F Fraction collector for collecting portions, called fractions, of the eluant liquid in separate test tubes.

Figure 2, Block diagram of a liquid chromatograph. A, solvent reservoir B, filter C, pump D, pulse dampener (optional) E, pre-column (used only in liquid-liquid chromatography) F, pressure gauge G, infector H, column I, detector J, fraction collector K, recorder or oth readout device.

FIGURE 10.5 Elution profile on OH-B12 treated by microwave heating for 6 min during silica gel 60 column chromatography. Fifty milliliters of the treated OH-B12 solution (5 mmol/1) was evaporated to dryness and dissolved in a small amount of w-butanol/2-pro-panol/water (10 7 10, v/v) as a solvent. The concentrated solution was put on a column (1.4 X 15.0 cm) of silica gel 60 equilibrated with the same solvent and eluted with the same solvent in the dark. The eluate was collected at 4.0 ml with a fraction collector. Fractions I to V were pooled, evaporated to dryness, dissolved with a small amount of distilled water, and analyzed with silica gel TLC. Inset represents the mobile pattern of the OH-B12 degradation products of fractions I to V on the TLC plate. Data are typical, taken from one of five experiments. (Reprinted with permission from Watanabe, F. et al., J. Agric. Food Chem., 46, 5177-5180, 1998. Copyright (1998) American Chemical Society.)... 

Muller, O., Foret, F., and Karger, B. L., Design of a high-precision fraction collector for capillary electrophoresis, Anal. Chem., 67, 2974, 1995. 

Linking TLC with a tandem instrument differs from combining GC or LC with an appropriate spectrometer. Hyphenation of planar chromatographic techniques represents a niche application compared to HPLC-based methods. Due to the nature of the development process in TLC, the combination is often considered as an off-line in situ procedure rather than a truly hyphenated system. True in-line TLC tandem systems are not actually possible, as the TLC separation must be developed before the spots can be monitored. It follows that all TLC tandem instruments operate as either fraction collectors or off-line monitoring devices. Various elaborate plate extraction procedures have been developed. In all cases, TLC serves as a cleanup method. 

The core - flood apparatus is illustrated in Figure 1. The system consists of two positive displacement pumps with their respective metering controls which are connected through 1/8 inch stainless steel tubing to a cross joint and subsequently to the inlet end of a coreholder 35 cm. long and 4 cm. in diameter. Online filters of 7 im size were used to filter the polymer and brine solutions. A bypass line was used to inject a slug of surfactant solution. Two Validyne pressure transducers with appropriate capacity diaphragms are connected to the system. One of these measured differential pressure between the two pressure taps located about one centimeter from either end of the coreholder, and the other recorded the total pressure drop across the core and was directly connected to the inlet line. A two - channel linear strip chart recorder provided a continuous trace of the pressures. An automatic fraction collector was used to collect the effluent fluids. 

Reference tests were also performed in the absence of any desorbent (Tests 1 and 2 in Table III). Likewise, the propagation of each desorbent was examined separately, without any prior micellar slug injection. The effluents were sampled for analysis by a fraction collector. 

Since ProteinTrawler records the retention time of each protein mass, it is a simple endeavor to maintain chromatographic conditions, split the flow that exits the LC column with a small portion set to the mass spectrometer to monitor for assurance that there were no changes in the retention time that would hinder the pooling of fractions from multiple runs, and to facilitate the determination of which fractions contained the desired proteins. In our experimental setup, the flow was split after the column with 25% of the flow going to the mass spectrometer while the remaining diverted to an HP1100 fraction collector. The fraction collector was used to collect fractions at 1.0-minute intervals. 

DLC with Complete Sampling or Comprehensive Mode Table 5.2 lists several comprehensive 2DLC methods with the corresponding columns in each dimension, valves, and detectors utilized. Many 2DLC systems use 8-port valves, 10-port valves, or fraction collectors to retain the entire sample or increase the concentration for the second dimension detection. 

CF RPLC MS Breast cancer cell lysates Fraction collector Chong et al. (2001)... 

In many cases, data can be obtained offline and analyzed in a comprehensive manner from a fraction collector. For example, LC and gas chromatography (GC) can be utilized to form a 2D experiment — LC/GC. This is quite useful as the retention... 

He et al. (2002) used an off-line HPLC/CE method to map cancer cell extracts. Frozen ovarian cancer cells (containing 107 cells) were reconstituted in 300 pL of deionized water and placed in an ultrasonic bath to lyse the cells. Then the suspension was centrifuged and the solubilized proteins were collected for HPLC fractionation. The HPLC separation was carried out on an instrument equipped with a RP C-4 column, 250 mm x 4.6 mm, packed with 5-pm spherical silica particles. Extracted proteins were dissolved in 300 pL of DI water, and lOOpL was injected onto the column at a flow rate of 1 mL/min. Buffer A was 0.1% TEA in water and buffer B was 0.1% TFA in acetonitrile. A two-step gradient, 15-30% B in 15 min followed by 30-70% B in 105 min, was used. The column effluent was sampled every minute into a 96-well microtiter plate with the aid of an automatic fraction collector. After collection, the fractions were dried at room temperature under vacuum. The sample in each well was reconstituted before the CE analysis with 10 pL deionized water. The... 

A 2D experimental setup is composed of two independent HPLC systems that are connected to each other by an electrically (or pneumatically)-driven fraction transfer device. Typically, in the first dimension a detector is not used. In the case of an off-line system after the first dimension a fraction collector is used. The most efficient way to connect the first and second dimensions is to use an automatic fraction transfer valve (Kilz, 1992 Kilzetal., 1993,1995). A schematic presentation of a 2DLC experimental setup is shown in Fig. 17.3. 

Collect fractions starting from the bottom of the gradient, while recording an absorbance profile at 254 nm (which is dominated by the very abundant ribosomal RNA). We use a setup consisting of a peristaltic pump, ultraviolet (UV) detector, and fraction collector commonly used for chromatography experiments (GE Healthcare Life Sciences). 

A. Rottenbach, T. Uhl, A. Hain, A. Scharf, K. Kritzler and W. Kretschmer, Development of a fraction collector for coupling gas chromatography with an AMS facility, Nucl. Instrum. Methods B 266, 2238 2241 (2008). 

Glass columns for separation by gravity flow glass, metal or nylon tubing for pressurized systems fraction collector, detector and recorder. 

In the analysis of clinical, biological and environmental samples it is often important to have information on the speciation of the analyte, e.g. metal atoms. Thus an initial sample solution may be subjected to a separation stage using chromatography or electrophoresis. Measurements may, of course, be made on fractions from a fraction collector, but with plasma sources, interfacing in order to provide a continuous monitoring of the column effluent can be possible. This relies upon the ability of the high-temperature plasma to break down the matrix and produce free ions. 

The adsorption operation was conducted by feeding 1 mM phosphate solutions to the conditioned column at SV 10 or 20 h 1, and then 20 BV of water at SV 3 h 1. The elution operation consisted of feeding 0.1 M NaOH solution (80 BV) and then 20 BV of water at a flow rate of SV 3 h1. The regeneration of the column was conducted by feeding 0.5 M sulfuric acid (20 BV) and 20 BV of water at SV 10 h"1. All column effluents including washings in the adsorption and elution operations were collected on a fraction collector, and concentrations of phosphorus and zirconium in each fraction were determined by ICP-AES. Volume of each fraction was 5 BV for the adsorption operation and 4 BV for the elution operation. However, column effluents in regeneration operations were not analyzed. 

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