High-performance liquid chromatography solvent-delivery systems

Davis, M. T., Stahl, D. C., and Lee, T. D., Low-flow high-performance liquid-chromatography solvent delivery system designed for tandem capillary liquid-chromatography mass-spectrometry. Journal of the American Society for Mass Spectrometry 6(7), 571-577, 1995. 

This consists of a solvent delivery for isocratic reversed phase and gel filtration chromatography. The isocratic system (Fig. 1.1) provides an economic first step into high performance liquid chromatography techniques. The system is built around a high performance, dual-piston, pulse-free pump providing precision flow from 0.01 to 5mL min-1. 

High-performance liquid chromatography is performed using a Hewlett-Packard 1090 chromatograph equipped with a ternary-solvent delivery system, an autoinjector with a 0 -20- u.L injection loop, an oven compartment, and a diode-array UV detector. An ELS detector (Alltech Associates, Deerfield, IL) is connected in series to the UV detector. Hexane, 2-propanol, and water were used for the analysis of nonionic surfactants. Water and tetrahydrofuran (THF) are used for the analysis of anionic surfactants. No preliminary sample preparation is used other than dilution. The nonionic surfactants are diluted 1 40 (v/v) with hexane. The anionic surfactants (alkyl ether sulfates and synthetic and petroleum sulfonates) are diluted 1 20 (v/v) with water-THF (50 50). The calcium sulfonate surfactants were diluted 1 20 (v/v) with a THF-38% hydrochloric acid solution of pH 1. Hydrochloric add is required to prevent salt precipitation by converting any excess water-insoluble caldum carbonate into water-soluble calcium chloride. All diluted samples are... 

Sugars. The high performance liquid chromatography (HPLC) method described by Hunt et al. (8) was used to determine the sugars in the kiwifruit and nectars with some modifications (21). A Waters Association Chromatograph equipped with a Model 6000-A solvent delivery system, a Model R401 refractometer detector, a D6K universal injector column was a 30 cm x 4 mm i.d. stainless steel tube packed with u-bondapak-carbohydrate (Waters Associates). The precolumn was packed with CO-PELL PAC (Whatman). The eluent was acetonitril and distilled water (85/15, v/v). 

The apparatus used for SEC is relatively simple isocratic high-performance liquid chromatography (HPLC) equipment, as shown in Figure 8. The principal components are a precision high-pressure solvent delivery system, detector, and a column with particles having appropriate pore size. Detection is conveniently accomplished with a UV photometer or spectro-... 

Analytical Methods. The analytical method for carbaryl and 1-naphthol by high performance liquid chromatography (HFLC) was recently described for aqueous samples (9). Similarly, these two compounds were analyzed in these studies using a Waters 6000A Solvent Delivery System, WISF Automatic Sample Frocessor, Data Module and Automatic Integrator, and Model 4530 Variable Wave Length Detector, set at 230 nm. A Water uBondapak reverse-phase column (25 cm x 2 mm i.d.) was employed. The following experimental conditions were maintained ... 

In one approach, the microchip interface was constmcted from modified 1/16-inch high-performance liquid chromatography (HPLC) fittings [30]. It incorporates a freestanding liquid junction formed via continuous delivery of a flow of suitable solvent which carries the separation effluent through a pneumatically assisted electrospray needle located in front of the MS orifice. In some cases, stmctural features of microchips can be utilized as parts of the ion source (e.g., ESI emitter). Thus, the resulting coupled microchip-MS systems are more compact, and the delay time between the on-chip incubation and MS detection can be decreased. For example, a capillary nanoESI emitter was successfully incorporated into a microchip CE channel for on-line CE-MS analysis [31]. Such microchip-MS systems do not require the use of external pumps because analytes can be driven toward the ion source (ESI or nanoESI) by means of electroosmosis and electrophoresis [32]. 

The concentration in v ole blood and tissues of HBA and PhBA was determined by high-performance liquid chromatography (HPLC) according to the method reported by Bocker (7) with a slight modificationi. - Bie. analysis was carried out using a Shimadzu LC-3A solvent delivery system equipped with absorbance detector SPD-1 and a Chromatopac C-R1B. 

The most popular and safe supercritical fluid is undoubtedly carbon dioxide for use in SFC and SFE. Thermally labile materials chromatographed in it are unlikely to be affected because its critical temperature is only slightly above room temperature. The critical pressure of carbon dioxide (73.8 Bar) is not difficult to maintain with modern high performance liquid chromatography (HPLC) solvent delivery systems. 

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