Collector Column

A small amount of collector (surfactant) or other appropriate additive in the liquid may greatly increase adsorption (Shah and Lemlich, op. cit.). Column performance can also be improved by skimming the surface of the liquid pool or, when possible, by removing adsorbed solute in even a tenuous foam overflow. Alternatively, an immiscible liquid can be floated on top. Then the concentration gradient in the tall pool of main hquid, plus the trapping action of the immiscible layer above it, will yield a combination of bubble fractionation and solvent sublation. 

By using an anionic collector and external reflux in a combined (enriching and stripping) column of 3.8-cm (1.5-in) diameter with a feed rate of 1.63 ni/n [40 gal/(h ft )] based on column cross section, D/F was reduced to 0.00027 with C JCp for Sr below 0.001 [Shou-feld and Kibbey, Nucl. AppL, 3, 353 (1967)]. Reports of the adsubble separation of 29 heavy metals, radioactive and otheiwise, have been tabulated [Lemlich, The Adsorptive Bubble Separation Techniques, in Sabadell (ed.), Froc. Conf. Traces Heavy Met. Water, 211-223, Princeton University, 1973, EPA 902/9-74-001, U.S. EPA, Reg. 11, 1974). Some separation of N from by foam fractionation has been reported [Hitchcock, Ph.D. dissertation. University of Missouri, RoUa, 1982]. 

For columns in which there is a substantial flash of the feed liquid, or in which the feed is a vapor of a different composition than the internal vapor, a collector plate can be installed above the feed point. The purpose of this plate is to provide mixing of the vapor phase in the gas risers so that a more uniform vapor composition enters the rectifying section of the column. 

Figure 11 shows a t pical liquid collector plate for a column that uses one side downcomer to withdraw the liquid. The maximum diameter for such a design is about 12 ft, which is limited by the hydraulic gradient necessary for such a liquid flow-path length, For larger diameter columns, two opposite side downcomers or a center downcomer normally is used unless the total amount of liquid collected is relatively small. 

The gas risers must have a sufficient flow area to avoid a high gas-phase pressure drop. In addition, these gas risers must be uniformly positioned to maintain proper gas distribution. The gas risers should be equipped w ith covers to deflect the liquid raining onto this collector plate and prevent it from entering the gas risers where the high gas velocity could cause entrainment. These gas riser covers must be kept a sufficient distance below the next packed bed to allow the gas phase to come to a uniform flow rate per square foot of column cross-sectional area before entering the next bed. 

Where only about 5% or less of the liquid dow iiflow is to be withdrawn from the column, a special collector box can be installed within the packed bed. This box can remove small quantities of intermediate boiling components that otherwise w ould accumulate in a sufficient quantity to interfere with the fractionation operation. Such a collector box must be designed very carefully to avoid interference with the vapor distribution above it or... 

Air Treatment Systems. Fabric filters and cyclone collectors are considered to be mechanical separation systems the treatment code for these systems is A06. The treatment code for wet scrubbers is A03. Information on each air treatment system must be entered individually in Section 7. The cyclone collector and fabric filter on the lead oxide mill exhaust are sequential treatment systems, because they treat the same wastestream in sequence. Therefore, sequential treatment must be indicated for both systems in column D of Section 7. You are required to indicate the influent concentration only to... 

A glass distillation column cracked, and water was sprayed onto the crack. A spark was seen to Jump from the metal cladding on the insulation. which was not grounded, to the end of the water line. Although no ignition occurred in this case, the incident shows the need to ground all metal objects and equipment. They may act as collectors for charges from steam leaks or steam or water Jets. 

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. 

Figure 10.4 shows a schematic representation of the multidimensional GC-IRMS System developed by Nitz et al. (27). The performance of this system is demonstrated with an application from the field of flavour analysis. A Siemens SiChromat 2-8 double-oven gas chromatograph equipped with two FIDs, a live-T switching device and two capillary columns was coupled on-line with a triple-collector (masses 44,45 and 46) isotope ratio mass spectrometer via a high efficiency combustion furnace. The column eluate could be directed either to FID3 or to the MS by means of a modified Deans switching system . 

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.)... 

By using an anionic collector and external reflux in a combined (enriching and stripping) column of 3.8-cm (1.5-in) diameter with a feed rate of 1.63 m/h [40 gaP(h fU)] based on column cross section,... 

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. 

The concept of hydrodynamic cavitation was also tested with the Coalberg seam coal in West Virginia, USA [82], By using cavitation-created tiny bubbles in a 2 in. flotation column fine coal recovery was increased by 10-30% at two-thirds to one half of the normal collector dosage (collector is the fluid such as diesel fuel used for removal of the coal particles). 

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. 

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... 

FIGURE 54 A schematic of hie flow-through immunosensor equipped with (1) fluid inlet, (2) carbon current collector, (3) disposable immuno-column, (4) highly dispersed antibody-modified carbon particles (immunosorbent), (5) carbon counter electrode, (6) Ag AgCl reference electrode and (7) fluid outlet. (Reprinted from [16] with permission from Elsevier.)... 

While the gases used in stripping are usually air, nitrogen, or helium, electrolytically evolved hydrogen has been used as a collector for hydrocarbons [49]. In this technique, the gas is not passed through a column of adsorbent, but instead collects in the headspace of the container. Since the volume of seawater and of hydrogen are known, the hydrocarbon concentration in the headspace can be used to calculate the partition coefficients and the concentration of hydrocarbon in the seawater. 

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

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