Solvents delivery system

The solvent delivery system consists of a solvent reservoir, an in-line filter and a pumping system. 

The reservoir may be as simple as the flask in which the solvent was delivered. Whatever is used, a degassing of polar solvents should be made in the reservoir in order to avoid disturbance of column packing and detector signal by released air. 

Several methods of solvent degassing have been tested [7], and besides refluxing the most efficient method has shown to be 5-10 min of bubbling through of the solvent with helium and then just to maintain a slight over-pressure of helium in the reservoir. 

Evacuation and ultrasonic agitation were shown to be less efficient. 

Many types of pumps have been brought on to the market, and they may be characterized in several ways. One is to divide them into constant pressure and 

The solvent delivery system is responsible for delivering the pressurized mobile phase with the desired composition and chosen flow rate to the head of the column. To achieve this goal a number of components work together under the supervision of the system computer or microprocessors to achieve the tight specifications typical of a modem liquid chromatograph. Table 5.2 [15-19]. Suitable tests for performance evaluation of solvent delivery systems are briefly described at the end of section 5.2.2. In retention terms a relative standard deviation of better than 0.15% for retention factors under normal operating conditions is expected. 

Typical specifications for a solvent delivery system for use with conventional diameter packed columns 

Description of some properties of the solvent delivery system  

Resetability The ability to reset the pump to the same flow rate repeatedly. 

Flow rate accuracy The ability of the pump to deliver exactly the flow rate indicated by a particular setting. 

---

The solvent delivery system must be capable of pumping solvent at a constant, pulse-free flow rate of 0.3 ml/min. Traditionally, SEC pumps have been optimized to operate at 1.0 ml/min. 

Toluene and dichloromethane (CHjCy were purified by a JT Baker Cycle-Tainer Solvent Delivery System. 

The instrument used in this study was an in-house constructed HPGPC composed of a Waters Associates M-6000 solvent delivery system, Waters Associates U6K injector, Varian Instruments fixed... 

HPLC has also been used to determine the residue levels of dinifroaniline herbicides. Pendimethalin was quantified by HPLC under the following conditions apparatus, Spectroflow 400 solvent delivery system. Model 430 gradient former, and Kratos Model 783 with UV absorbance detection at 239 nm column, Cig reversed-phase (25cmx 3.0-mm i.d.) temperature, 40 °C mobile phase, acetonitrile-water (7 3, v/v) flow rate, 1 mL min . ... 

The solvent delivery system is one of the most important components of the liquid chromatograph since its performance directly affects retention time reproducibility d detector baseline stability [1,2,39,40]. As well as the pump, other components such as check valves, flow controllers, mixing... 

Solvent delivery system stainless steel columns injection port flow-through detector, recorder. Applications... 

Figure 4.31(b) from Euston and Glatz, A new Hplc Solvent Delivery System, Techn. Note 88-2 (1988) by permission of Hewlett-Packard, Waldbronn, Germany. 

The //PLC system described in this chapter is equipped with 24 parallel columns for liquid chromatography, each with its own sample introduction port and exit port for connection to detectors of choice (UV absorbance and/ or fluorescence). Flow from a binary solvent delivery system is divided evenly across 24 channels and results in 1/24 of the programmed pump flow rate through each column (i.e., total flow of 300 /zL/ min will produce a flow of 12.5 /zL/ min in each column). Samples are introduced to the columns by a multichannel autosampler configured to sample from either 96-or 384-well SBS standard plates. Figure 6.2 depicts a general view of the system. 

A modern solvent delivery system consists of one or more pumps, solvent reservoirs, and a degassing system. HPLC pumps can be categorized in several ways by flow range, driving mechanism, or blending method. A typical analytical pump has a flow range of 0.001-10 mL/min, which handles comfortably the flow rates required for most analytical work (e.g., 0.5-3 mL/min). Preparative pumps can have a flow range from 30 mL/min up to L/m. 

Supercritical fluid chromatography pressure gradient solvent delivery system Pierce Chemicals Life Science Laboratories Ltd Sedgewick Road Luton... 

The solvent delivery system includes a pump that delivers the appropriate solvent from a reservoir at a preselected rate. The use of fine particle columns, and the high flow rates demanded, require relatively high pressures... 

The proportioning accuracy and precision of the solvent delivery system is more important in the chromatography of proteins and peptides than in the... 

In most cases, calibration curves were determined at ambient or elevated temperatures using the Waters 150C High Temperature Gel Permeation Chromatograph which includes a sensitive refractive index detector. Otherwise, a modular system consisting of a Waters Model M6000A Solvent Delivery System, a Waters Model U6K Injector and a Waters Model 401 Refractometer, were used at ambient temperature. The mobile phase at room temperature was... 

Chromatographic System. The isocratic liquid chromatograph used was a Waters Associates (Milford, MA) Model 24A alc which included a Model 6000A Solvent Delivery System, a Model 401 Differential Refractometer and a Model 440 Absorbance Detector operating at 254 nm and was fitted with a WISP automatic injector. The analog outputs of the UV absorbance detector or differential refractometer were recorded with a Model 730 Data Module (printer, plotter, integrator)(Waters). Eluent flow rate was 1.0 ml/min unless otherwise noted. 

A Waters Associates ALC/GPC-244 instrument with M6000A solvent delivery system, M720 system controller, M730 data module, 710B WISP auto-injector and M440 UV detector was used for the SEC analyses and operated under the following conditions ... 

---