Chromatography HPLC pumps

Most high-performance liquid chromatography (HPLC) pumps can be used in HOPC. The back pressure rating should be at least several thousand pounds per square inch (a few hundred kg/cm ). A type of pump that does not allow bypassing the pressure transducer or a pulse damper, if it is installed, must not be used. The dead volume should be as small as possible. Pumps with a single plunger are better than those with two plungers. 

During pilot-test tank saturation and flushing, the feed tank contained Beaverton city water. During contaminant injection, the feed tank also contained the target input concentration of chromate. A 9 1 methanol PCE mixture was injected into the feed line via a high-performance-liquid-chromatography (HPLC) pump to yield the appropriate PCE input concentration. The target contaminant concentrations in the injection wells were 10 mg L 1 (0.19 mmol L"1) Cr(VI) as chromate and 1.8 mg L 1 (0.011 mmol L 1 PCE. Effluent from the extraction wells was checked for... 

One of the above-mentioned examples comprises the investigation of hydrocarbon radicals formed by pyrolysis of fluids, such as indene and phenyl-substituted alkanes at about 843 K (36). As a reaction tube, a silica capillary of 1.4 mm inner and 4.7 mm outer diameter was used, which was connected to high-pressure stainless-steel tubing through Teflon seals. It was equipped with pressure transducers on both ends and tested to withstand a maximum pressure of 28 MPa. The hydrocarbon to be pyrolyzed was cycled between a reservoir and the reaction tube by a high-pressure liquid chromatography (HPLC) pump. The tube was heated by a preheated stream of N2 as described above. 

Conventional ancillary equipment was used with these sedimentation FFF systems. Sed I, for example, utilized a model 410 high-performance liquid chromatography (HPLC) pump from Kontron Electrolab (London) and a UV Spectroflow Monitor SF770 from Kratos Analytical Instruments (Westwood, NJ). Fractions of eluted silica were collected by means of a model FC-80K Microfractionator from Gilson Medical Electronics (Middleton, WI). 

The methods employed for the miscible displacement studies were similar to those used in previous experiments (Hu and Brusseau, 1998). We connected a high-performance liquid chromatography (HPLC) pump (Model 301 from Alltech Associates Inc., Deerfield, IL) to the column, and placed a three-way valve in-line to facilitate switching between treatment solutions. Several iodine species (iodide, iodate, and 4-iodoaniline) were used to study transport behavior. We also examined the transport of tritium and bromide, commonly used conservative tracers, so that we could compare their transport behavior with iodine species. For transport experiments of 4-iodoaniline, which is used as a representative refractory organic iodine species, the solution was allowed contact only with glass or stainless steel, to avoid potential interaction of organoiodine with plastics in the column system. Column effluents were collected with an automated fraction collector (Retriever 500, ISCO Inc., Lincoln, NE) for chemical analysis, as described below. 

In addition, the total organic carbon content of the liquid phase was detmnined (TOC Analyser "DC 190" by Schmidlin), and the concentrations of acids were analyzed by ion chromatography (HPLC pump and colunrn thermostat by Bischoff column "Aminex HPX-87H", 300 mm x 7.8 eluent 0.4 mmol/1 H2SO4 UV detector "L-4250" and refractive index detector "RI71", both by Merck). Formaldehyde was determined colorimetrically by a UV-Vis spectrometer (Dr. Lange) immediately after the reaction. 

A continuous process was performed by van Eijs et al. [69] and Marty et al. [54], Substrates can be continuously injected into the SCCO2 flow by a high-performance liquid chromatography (HPLC) pump. The substrate concentration is known, an adjustment to a fixed value is possible. In this case the CO2 was not recycled. They also developed a continuous process with recycling of CO2 and post reactional fractionation (Fig. 2) [2], Table 3 shows studies of important parameters for reactivity and productivity of enzymatic reactions in supercritical media. Furthermore, some authors compare supercritical media and conventional organic solvents ... 

Figure 7.5 Schematic diagram of a high performance liquid chromatography (HPLC) system. The solvent(s) are pumped through the system, and the sample injected just before the column where separation occurs. Detection is often by UV/visible spectrophotometry at a fixed wavelength.

The HPLC pump draws the mobile phase from the reservoir via vacuum action. In the process, air dissolved in the mobile phase may withdraw from the liquid and form bubbles in the flow stream unless such air is removed from the liquid in advance. Air in the flow stream is undesirable because it can cause a wide variety of problems, such as poor pump performance or poor detector response. Removing air from the mobile phase, called degassing, in advance of the chromatography is a routine matter, however, and can be done in one of several ways 1) helium sparging, 2) ultrasonic agitation, 3) drawing a vacuum over the surface of the liquid, or 4) a combination of numbers 2 and 3. 

High Performance Liquid Chromatography (HPLC) (Chapter 30) gives an elaborate discussion of theoretical aspects. Instrumentation encompasses the various important components e.g., solvent reservoir and degassing system pressure, flow and temperature pumps and sample injection system ... 

This chapter presents an overview of current trends in high-pressure liquid chromatography (HPLC) instrumentation focusing on recent advances and features relevant to pharmaceutical analysis. Operating principles of HPLC modules (pump, detectors, autosampler) are discussed with future trends. 

Instrumentation. A Pharmacia BioPilot Column Chromatography system was used to perform large-scale size exclusion chromatography (SEC) with an 11.3 x 90 cm BioProcess column packed with Sephacryl S-200 HR gel. High performance size exclusion (HPSEC) and ion exchange chromatography (HPIEC) were conducted with Pharmacia Superose 6 and 12 (HR 10/30) and Mono-Q (HR 5/5) columns respectively, equipped with Beckman model 520 system controller and Beckman model HOB HPLC pumps. 

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