Pump systems manufacturers

Since 1970, new analytical techniques, eg, ion chromatography, have been developed, and others, eg, atomic absorption and emission, have been improved (1—5). Detection limits for many chemicals have been dramatically lowered. Many wet chemical methods have been automated and are controlled by microprocessors which allow greater data output in a shorter time. Perhaps the best known continuous-flow analy2er for water analysis is the Autoanaly2er system manufactured by Technicon Instmments Corp. (Tarrytown, N.Y.) (6). Isolation of samples is maintained by pumping air bubbles into the flow line. Recently, flow-injection analysis has also become popular, and a theoretical comparison of it with the segmented flow analy2er has been made (7—9). 

Pumping systems, evaluation of, 21 56 Pump manufacturers, U.S., 21 87t Pump metallurgy, upgrading, 21 86 Pumps, 21 54-91... 

Manufacturer, Address Model No. LC unit Pumping system Detectors Gradient... 

Experimental. PRODAN was purchased from Molecular Probes and the purity checked by reverse phase HPLC. There were no detectable impurities. Stock solutions (1 mM) were prepared in absolute ethanol and stored in the freezer. CF3H was purchased from Matheson and passed through a single adsorptive Q trap (Matheson) prior to entering the pumping system. According to the manufacturer this gives an 02 level < 5 ppm. 

Two factors are driving the market for precise, very-low-flow HPLC pumping systems extremely limited sample sizes in biotechnology and the electrospray and nanospray interfaces that are concentration and flow-rate dependent. It is very difficult to get precise flow and gradient formation from pumps that have a 5- to 10-/iL plunger displacement, even using 3200-step stepper motor drives. This has forced manufacturers to resurrect a very old concept from the earliest days of HPLC, the syringe pump. 

Disconnect tubing at guard column (if present) or analytical column inlet. Check for flow. Purge pump at high flow rate (10 ml/ min), prime system if necessary. (Prime each pump head separately.) If system has check valve, loosen valve to allow air to escape. If problem persists, flush system with 100% methanol. If problem still persists, contact system manufacturer. 

When an O-ring needs replacement (such as in a mechanical vacuum pump), the manufacturer can provide, or recommend, an O-ring that will be resistant to the pump s vacuum fluid. On the other hand, when an O-ring is being used in varying conditions, you will be responsible for the selection of the proper O-ring material to maintain the integrity of your system and the health and safety of the operators. 

The commercial softwares, initially developed by instrament manufacturers for open-access operation, were adapted to enable unattended data acquisition and automated data processing for large series of samples from an autosampler supporting the 96-well microtitre plate format, which is the sample format of choice in combinatorial synthesis. Initially, mainly Gilson 215 or 233 XL autosamplers were used, but other systems have become available from other instrument manufacturers. The complete system is under control of the MS data system. It consists of a 96-well-plate autosampler, an LC pumping system, eventually a UV-photodiode-array detector (DAD) in series and/or evaporative hght scattering (ELSD) detector in parallel, and the mass spectrometer eqnipped with ESI, APCI, and/or atmospheric-pressure photoionization (APPI). 

Pumping systems for high-performance liquid chromatography have been described. Some HPLC and pump manufacturers have been specifically mentioned and some of their Instrumentation described in detail. This does not imply any endorsement from the authors, not does the omission of any commercially available products imply an unsatisfactory appraisal. 

The instrumentation used is part of the AutoAnalyzer system manufactured by Technicon, Inc. 19), The AutoAnalyzer modules required are the sampler, the proportioning pump, the colorimeter with range expander, and the recorder. The AutoAnalyzer sampler alternately delivers sample solution and cleansing water from a small reservoir. The quantity of sample is controlled by the sampling rate, adjusted by means of a cam on a clock mechanism, and by the diameter of the sample tube on the manifold of the pump. 

LKB manufacture a reciprocating twin-pump system with pump heads made of KEL-F. Gradients are formed by a low volume mixer which is located on the low pressure side of the pump, thereby... 

When a centrifugal pump is installed in a pumping system and operated at a particular rotational rate, N, (usually 1,750 to 3,450 rpm), the flow rate can be varied by changing the opening on a valve located in the pump discharge line. The variation of H with Q defines a unique characteristic curve for the particular pump operating at N with a fluid of a particular viscosity. Each make and model of a centrifugal pump is supplied by the manufacturer with a... 

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