High Pressure Liquid Chromatographic Data

High Pressure Liquid Chromatographic Data Systems HB to HD 1123... 

The pharmacokinetics of rifaximin after oral administration has been studied in healthy volunteers and patients with intestinal infections or IBD. The aim of these studies was to confirm the low, if any, systemic absorption of the drug metabolism and excretion data are scant. In all these investigations a sensitive high-pressure liquid chromatographic (HPLC) method was used to measure rifaximin in body fluids. 

A schematic diagram of a typical high-pressure liquid chromatograph is shown in Figure 3.12. The basic components are a solvent reservoir, high-pressure pump, packed column, detector, and recorder. A computer is used to control the process and to collect and analyze data. The similarities between a gas chromatograph and an HPLC are obvious. The tank of carrier gas in GC is replaced by the solvent reservoir and high-pressure pump in HPLC. 

THIS SYSTEM IS COMPOSED OF XXX SUBPROGRAMS WHICH ACQUIRE DATA FROM A DUAL BEAM MULTIPLE WAVELENGTH DETECTOR IN A CONFIGURATION FOR USE WITH A HIGH PRESSURE LIQUID CHROMATOGRAPH. 

In the previous chapters the individual components of a high-pressure liquid chromatograph have been discussed. Complete instruments are generally a compromise between performance and price. In this chapter specifications of compact or modular commercial instruments are given. The data, which are presented in tabular form, were collected from the manufacturers. There are no prices listed, since they vary from country to country. Only those manufacturers are listed who offer a compact chromatograph or a modular system including all parts of an HPLC-systera. 

Aulakh, J.S., Malik, A.K., and Mahajan, R.K., Solid phase microextraction-high pressure liquid chromatographic determination of Nabam, Thiram, and Azamethiphos in water samples with UV detection preliminary data, Talanta, 66, 266, 2005. 

The high pressure, liquid-phase hydrogenation of 3-methyl crotonaldehyde was carried out in a well-stirred batch autoclave under 4 MPa Ha (Air Liquide, 99.995% purity) pressure using 0.1 mol of 3-methyl crotonaldehyde (UAL) (Merck) and 0.6 g catalyst. Isopropanol (37.5 cc) was used as a solvent. The catalyst was activated by stirring under 4 MPa Ha pressure at 373K for two hours prior to introduction of the unsaturated aldehyde UAL reactant at the same temperature. The reaction products were monitored by repetitive sampling and gas chromatographic analysis. Since this was a batch reaction, data are reported as selectivity vs. conversion. Time of reaction to reach about 30% conversion was close to 60 minutes for Ru/NaY and 150 minutes for Ru/KY. 

Williams et al. used a high performance liquid chromatographic assay method for dipyridamole monitoring in plasma [71]. The HPLC system uses a Waters model 6000 A solvent delivery pump equipped with a U6K injector, a pBondapak C 9 column (30 cm x 39 mm 10 pm), and a Model 440 absorbance detector. The signal from the detector was quantified using a Shimadzu data processor and an Omni-Scribe recorder. A mobile phase flow rate of 1.5 mL/min was produced by a pressure of approximately 102 atm (1500 p.s.i.). The mobile phase was 50 50 mixture of acetonitrile and 0.01 M sodium phosphate in water (adjusted to pH 7). The absorbance reading of dipyridamole in methanol was made at 280 nm. 

Since ISEs can be used in continuous flow systems or in flow systems with sample injection (flow injection analysis, FIA)21 their application is wide, not limited to discrete samples. Analysis time becomes shorter, with faster recycling. Additionally, in flow systems the experimental assembly and data analysis can be controlled automatically by microcomputer, including periodic calibration. Another development is the use of sensors for the detection of eluents of chromatographic columns in high-pressure liquid chromatography (HPLC). Miniaturization has permitted an increase in the use of sensors in foods, biological tissues, and clinical analyses in general. 

The ultraviolet and infra-red data have been completely revised, as have the chromatographic data which now include high pressure liquid chromatography. Analytical information on many major metabolites is presented for the first time, and many monographs include the eight major mass spectral peaks for the substance and its major metabolites. 

Mackay, D., Shiu, W.Y., Wolkoff, A.W. (1975) Gas chromatographic determination of low concentrations of hydrocarbons in water by vapor phase extraction. ASTM STP 573, pp. 251-258, Am. Soc. Testing and Materials, Philadelphia, Pennsylvania. Macknick, A.B., Prausnitz, J.M. (1979) Vapor pressures of high-molecular-weight hydrocarbons.. /. Chem. Eng. Data 24, 175-178. Mac/ynski. A., Wioeniewska-Goclowska, B., Goral, M. (2004) Recommended liquid-liquid equilibrium data. Part 1. Binary alkane-water systems. J. Phys. Chem. Ref. Data 33, 549-577. 

Phase equilibria and pressure-temperature coordinates of critical points in ternary systems were taken with a high-pressure apparatus based on a thermostated view cell equipped with two liquid flow loops which has been described in detail elsewhere [3]. The loops feed a sample valve which takes small amounts of probes for gas-chromatographic analysis. In addition to temperature, pressure and composition data, the densities of the coexisting liquid phases are measured with a vibrating tube densimeter. Critical points were determined by visual oberservation of the critical opalescence. 

When the carrier is a liquid, the instrumentation includes a pump, an injector, a column, a detector and a recorder or a data acquisition system, connected to a computer. The heart of the system is the column where the separation occurs. Since the stationary phase is composed of micrometric porous particles, a high-pressure pump is required to move the mobile phase through the column. The chromatographic process begins by injecting the solute into the top of the column by an impulse type injection. The separation of the components occurs during the elution of the mobile phase through the column. 

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