Conventional liquid chromatographic

The results for bacterial whole-cell analysis described here establish the utility of MALDI-FTMS for mass spectral analysis of whole-cell bacteria and (potentially) more complex single-celled organisms. The use of MALDI-measured accurate mass values combined with mass defect plots is rapid, accurate, and simpler in sample preparation then conventional liquid chromatographic methods for bacterial lipid analysis. Intact cell MALDI-FTMS bacterial lipid characterization complements the use of proteomics profiling by mass spectrometry because it relies on accurate mass measurements of chemical species that are not subject to posttranslational modification or proteolytic degradation. 

In this paper, an instrument is described in which the inlet liquid flow rate is held constant and the pressure regulated by a pneumatically actuated flow control valve at the exit of the column. This approach permits the use of a wide-range pressure program with a controlled flow. Also, by selecting mobile phases that are liquids at ambient laboratory conditions, several types of conventional liquid chromatographic detectors may be utilized. 

Preparation of our ultrashort capillary column and other tools such as injection and detection are presented in this chapter. These devices can be used for developing a miniaturized chromatographic system, which can be used as an alternative separation method for either a conventional liquid chromatographic system or a micro total analysis system. 

Size exclusion chromatography in the main uses conventional liquid chromatographic equipment. In most cases the polymer in solution can be injected directly onto the chromatograph, however in the case of formulated polymers which contain inorganic fillers and pigments some prior sample separation will be needed. 

Non-suppressed ion chromatography employs a conventional liquid chromatographic system with a conductivity detector cell connected directly to the outlet end of an ion-exchange separation column. No suppressor unit is required. The successful development of this method was made possible by three principal innovations (1) the use of an anion- or cation-exchange resin of very low capacity (initially 0.007 to... 

Risner, C. H., Quantitation of some tobacco anions by eluent suppressed anion exchange chromatography using conventional liquid chromatographic equipment. Tobacco Set, 1986, 85-90,... 

Size-exclusion chromatography in the main uses conventional liquid chromatographic equipment (Figure 6.2). In SEC a dilute polymer solution is injected into the solvent stream, which then flows through a column or series of columns, packed with material of narrow particle size and controlled pore size... 

Figure 6 Schematic diagrams of atypical high-pressure SF-CL systems based on special mixing modes (a) system based on conventional propelling and stopping syringe and (b) system based on liquid chromatographic (LC) pumps and stopping the flow before the mixer (M). V, six-ports valve. (Adapted from Refs. 33 and 34.)...

Several recent high-performance liquid chromatographic separation schemes are applicable since they also incorporate detectors not usually associated with conventional hydrocarbon group analyses (Matsushita et al., 1981 Miller et al., 1983 Rawdon, 1984 Lundanes and Greibokk, 1985 Schwartz and Brownlee, 1986 Hayes and Anderson, 1987). 

On-line supercritical fluid extraction/GC methods combine the ability of liquid solvent extraction to extract efficiently a broad range of analytes with the ability of gas-phase extraction methods to rapidly and efficiently transfer the extracted analytes to the gas chromatograph. The characteristics of supercritical fluids make them ideal for the development of on-line sample extraction/gas chromatographic (SFE-GQ techniques. SFE has the ability to extract many analytes from a variety of matrices with recoveries that rival liquid solvent extraction, but with much shorter extraction times. Additionally, since most supercritical fluids are converted to the gas phase upon depressurization to ambient conditions, SFE has the potential to introduce extracted analytes to the GC in the gas phase. As shown in Fig. 13.8, the required instrumentation to perform direct coupling SFE-GC includes suitable transfer lines and a conventional gas chromatograph [162,163]. 

A Waters Model 150C ALC/GPC was interfaced to a minicomputer system by means of a microcomputer for automated data collection and analysis. Programs were developed for conventional molecular weight distribution analysis of the data and for liquid chromatographic quantitative composition analysis of oligomeric materials. Capability has been provided to utilize non-standard detectors such as a continuous viscometer detector and spectroscopic detectors for compositional analysis. The automation of the instrument has resulted in greater manpower efficiency and improved record keeping. 

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