HPLC instrumentation solvent delivery systems

The assay was performed with a HPLC-system consisting of a Spectra-Physics (Spectra Physics, San Jose, CA 95134, USA) model SP8700 solvent delivery system used at a flow rate of l.Oml.min", a Kratos (Kratos Analytical Instruments, Ramsey, NJ 07446, USA) model 757 UV-detector, wavelength 260 nm, range 0.005 aufs, rise-time 1 second. Injections of extracts into a Zymark (Zymark Corporation Inc., Hopkinton, MA 01748, USA) Z 310 HPLC-injection station, equipped with an electrically controlled Rheodyne valve and a 20 pi sample loop, were performed by a Zymate II robot system. The Zymark Z 310 Analytical Instrument Interface was used to control the HPLC-injection station. 

Instrumentation. The HPLC equipment consisted of two Model 740 solvent delivery systems combined with a Model 744 solvent programmer, Model 714 pressure monitor and a Model 755 sample injector (all from Spectra-Physics, Santa Clara, CA). The column used was 25 cm x 3 mm i.d. stainless steel tube packed with either Spherisorb silica 5 y or Spherisorb ODS 5 y. Detection was made with a Schoeffel Instrument Corporation (Westwood, NJ) Model SF 770 spectromonitor. Peak areas were measured by the cut and weight method. Radioactivity was measured by direct measurement in a Searle Model 1185 Automatic Gamma System. 

A Waters Associates ALC/GPC-244 instrument with M6000A solvent delivery systems, M720 system controller, 710B WISP auto-injection system, M440 UV detector, and M730 data module was used for the HPLC analyses. The following conditions were used for reverse phase HPLC ... 

A Waters Associates ALC/GPC-2 4i( instrument with 6000A solvent delivery system, 660 solvent programmer, 71 OB WISP auto-injection system and a Perkin Elmer LC75 variable UV absorbance detector was used for the HPLC analyses. All analyses were run... 

In GPC instrumentation the pumping system delivers a single eluent throughout the analysis. It may be a single solvent, a blend of solvents, or a solvent plus an additive. See. II.C, but the composition remains constant. Solvent programming, also termed gradient elution, in HPLC requires more eapability from the solvent delivery system to ensure precise flow and repro-dueible solvent eomposition profiles. 

Each contemporary hplc instrument consists of a pump for solvent delivery, an injector device for sample introduction, column(s) for sample separation, detec-tor(s) for visualization of the separated components (solutes), and a computer for system control and data acquisition and reduction, as depicted in Figure 1. Precise temperature control of columns and some other parts of a chromatographic system becomes an important prerequisite for a successful separation. 

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