Quaternary pump

Day-to-day variations in flow rate, check valve efficiency, or mixing solenoid performance (in binary, ternary, or quaternary pumping systems) can also contribute to retenbon shifts. Therefore, compound identification should be performed only by spiking with a known standard or by direct identification with, for example, mass spectral analysis. 

A six-port valve was used in both manual and semi-automated SPME interfaces and PEEK tubing used to connect the HPLC system to the SPME probe. A Cohesive HTLC 2300 with dual pumps along with a Sciex API 3000 mass spectrometer was used for LC/MS/MS and a Symmetry Shield RP-18 (5 ji, 50 x 2.1 mm) for HPLC. A quaternary pump with flow switching was used for desorption chamber flushing along with MS make-up flow and a binary pump for LC/MS/MS. Acetoni-trile/0.1% acetic acid in water (90 10, solvent B) and 10 90 acetonitrile/0.1% aqueous acetic acid (solvent A) were used, with 10% B for 0.5 min ramped to 90% B in 2 min and held at this concentration for 1.5 min before returning to 10% B for 1 min at a flow rate of 0.5 mL/min. 

Manufacturers publish their product s performance characteristics as specifications, which are often used by the customer for comparison during the selection process. Table 1 shows the specifications of an Agilent 1100 Series Quaternary Pump, which is quite representative of other high-end analytical pumps. Note pulsation is particularly detrimental to the performance of flow-sensitive detectors (e.g., mass spectrometer, refractive index detector). Differences in dwell volumes and composition accuracy between HPLC systems might cause problems during method transfers. 

TABLE I Specifications of Agilent I 100 Series Quaternary Pump... 

High-performance liquid chromatography (HPLC) is one of the premier analytical techniques widely used in analytical laboratories. Numerous analytical HPLC analyses have been developed for pharmaceutical, chemical, food, cosmetic, and environmental applications. The popularity of HPLC analysis can be attributed to its powerful combination of separation and quantitation capabilities. HPLC instrumentation has reached a state of maturity. The majority of vendors can provide very sophisticated and highly automated systems to meet users needs. To provide a high level of assurance that the data generated from the HPLC analysis are reliable, the performance of the HPLC system should be monitored at regular intervals. In this chapter some of the key performance attributes for a typical HPLC system (consisting of a quaternary pump, an autoinjector, a UV-Vis detector, and a temperature-controlled column compartment) are discussed [1-8]. 

J,m poly(tetrafluoroethylene) (PTFE) syringe-tip filters High-performance liquid chromatography (HPLC) system equipped with Quaternary pump Diode array detector Vacuum degasser... 

LC-MS/MS System Used and Analytical Conditions An LC system from TSP, USA was used. The system consisted of an vacuum degasser, a quaternary pump (P4000) and an Autosampler (AS3000), connected to a LCQduo ion trap mass spectrometer (Finnigan MAT, USA), supplied with an APCI source (Brewer 1998). 

Modern pumps have more features and better reliability and performance than earlier models because of better designs in seals, pistons, and check valves as well as innovations such as dual-piston in-series and piston seal wash.2 Performance at low rates can be improved by variable stroke mechanism, micro pistons, or active check valves. The fluidic components in more inert pumps for bio-purification or ion-chromatography are often constructed from titanium or polyetheretherketone (PEEK). Low-pressure mixing quaternary pumps have become standard equipment in research laboratories whereas high-pressure mixing pumps are popular for LC/MS, HTS, and micro LC applications. 

LC-MS-MS analyses were carried out in a system consisting of a LC quaternary pump Finnigan SpectraSYSTEM P4000 and Thermo Finnigan TSQ 7000 Triple-Quad triple-quadruple mass spectrometer all from Thermo Electron Corporation (San Jose, USA) and binary LC pump Perkin Elmer (Fremont, USA) for post column addition. 

Liquid flow was provided by a Waters 600 quaternary pump (Waters Corp., Milford, MA). This flow was split four ways by use of a low-dead-volume Valeo eight-way splitter (Valeo, Switzerland). The separate streams were directed to the Rheodyne 7010 injection valves of a Gilson 889 liquid handler (Gilson, Middleton, Wl). The Gilson 889 was mounted on a Gilson 215 multiple injection liquid handler. All samples were presented in polypropylene microtiter plates and an injection volume of 15 fxL was employed throughout. 

The HPLC analysis was performed on an Agilent 1100 series LC (Santa Clara, CA), equipped with a quaternary pump (G1311A) and a UV multiwave length detector (G1365B), set at 220 and 280nm. The injector was a Rheodyne manual injector valve, model 77251 (Santa Clara, CA), equipped with a 20-1 sample loop. The column temperature was controlled using a ThermaSphere TS-130 oven from Phenomenex set at 40 °C. 

The pump forces the mobile phase through the column at high pressure and is monitored and controlled by the pressure regulator. Different pump types are available binary and quaternary pumps are the most frequently employed. A binary pump can drive two mobile phases at the same time, whereas a quaternary pump can drive four different mobile phases at the same time, if required. The pump must be able to generate high pressures, deliver flow rates from 0.1 to 10 mL min h have reproducibility of 0.5% (or better), and be resistant to corrosion by a variety of solvents. 

It is more common with multicomponent mobile phases to utilise the mixing facility within the quaternary pump. The quaternary pump operates by means of a proportioning valve and a single pump that draws the individual components from the solvent bottles into an inlet valve. The piston pushes the mobile phase into a damper, through a purge valve, and onto the column. This is an example of a low-pressure quaternary system. A high-pressure system would operate using four individual pump heads to draw the components into the system, rather like the binary system described previously. Most manufacturers supply low-pressure quaternary systems, most likely due to cost implications, ease of maintenance, and size. 

Will this require specialised equipment For example, will a low-flow pump, quaternary pumping system, large sample volume, column heater, etc. be needed ... 

Chromatography System A Hewlett-Packard 1050 Liquid Chromatography System (HP 1050) with a Quaternary Pump was used for separations. The separations were monitored with a Hewlett-Packard 1050 Variable Wavelength Detector (280 nm) and an autosampler was used to introduce samples into the column. For this application a TSK-Gel column (SP-5PW 07161, TosoHaas, Stuggart, Germany) with dimensions 7.5 cm X 7.5 mm was used. Data were acquired with the Hewlett-Packard ChemStation software which controls the HP1050 Liquid Chromatograph. 

Agilent 1100 Series Quaternary Pump, Reference Manual, 12. Agilent Technologies Waldbronn, Germany, 1999. 

The three treatments were immediate press, hot press (60 °C for 15 min), or skin fermentation (7 and 13-14 days). Total phenolics were measured as gallic acid equivalents (GAE) /L and were separated and measured by HPLC (Lamuela-Raventos and Water-house, 1994). A Perkin Elmer HPLC quaternary pump (Model 400) was fitted with a Rheodyne 7125 injector and Waters Novapack C18 (30 cm x 0.39 cm., i.d., 4 yum particle size) column. A diode array detector (Perkin Elmer model LC 135) was connected to a Perkin Elmer Model 1022 integrator. The solvent system used was described earlier (Lamuela-Raventos and Waterhouse, 1994). 

Hewlett-Packard HP 1100 Quaternary pump w/degasser, thermostatted column compartment, w/fluorescence and refractive index detectors... 

Hardware required Two quaternary pumps Alternative to steps 1-2, as follows ... 

Configuration of a method development system Autosampler Quaternary pump Photodiode array detector Column thermostat Switching valve/solvent (6 positions) Switching valve/columns (6 positions) Autosampler Quaternary pump Photodiode array detector Column thermostat Switching valve/solvent (12 positions) Switching valve/columns (6 positions) Autosampler at present, binary pump Photodiode array detector Column thermostat Switching valve/solvent (plan 12 positions) Switching valve/columns (12 positions)... 

The HPLC system that is to be used for such a imiversal development of a chromatographic separation method consists in the optimal case of a quaternary pump with a solvent switching valve (6-12 positions), an autosampler, a programmable column thermostat (for 6-12 columns), a photodiode array detector and other detectors, depending upon the need. A personal computer with suitable software is needed for the automatic control system. The method development software controls the HPLC system via this software and produces the chromatograms necessary for development and optimization. 

Diode array HPLC was performed using a Hewlett-Packard (Bracknell, UK) 1050 quaternary pump, autosampler and diode array detector and data were analyzed using HP Chemstation software. Separations were performed using an ODS2 column and a linear water/methanol gradient. Full experimental details are given in Bailey et... 

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