Eluant flow rate

Calculations for Rp as a function of the relevant experimental parameters (eluant ionic species concentration-including surfactant, packing diameter, eluant flow rate) and particle physical and electrochemical properties (Hamaker constant and surface potential) show good agreement with published data (l8,19) Of particiilar interest is the calculation which shows that at very low ionic concentration the separation factor becomes independent of the particle Hamaker constant. This result indicates the feasibility of xmiversal calibration based on well characterized latices such as the monodisperse polystyrenes. In the following section we present some recent results obtained with our HDC system using several, monodisperse standards and various surfactant conditions. 

Fig. 1. —Elution Pattern of Material Precipitated by Ethanol from the Mild-Acid Hydrolyzate of Acacia elata Gum. [Bio-Gel P-300, 90 x 1.5 cm column, M sodium chloride as the eluant flow rate, 3 ml/hr sample, 2 mg in 1 ml of M sodium chloride.]...

Table I Kr-81m Available at 6 inch Output Line for Various Eluant Flow Rates from a 10 mCi Generator...

Figure 2. Kb-8l washoff vs. eluant flow rate (.20 mCi generators).

In this procedure a Waters Associates liquid chromatograph was connected to anion exchange columns. Column packings used were p-Bondapak-NH2 and Nagel SA. The outlet of the liquid chromatograph was connected to the crossflow nebuliser of the ICP spectrometer (Jarrell-Ash-Atom-Comp 750) with Teflon tubing (0.15 x 13cm). Eluant flow rate was set at 1ml min 1... 

Figure 18-3 middle) shows that for 3.2 cm column, an eluant flow rate of 5 cm/min through the column is optimal. 

As a consequence of the large back pressures encountered, due to the small particle size of packing used in HPLC columns, pumps must be employed to achieve acceptable eluant flow rates. The pumps may be classified as either those which provide constant inlet pressure or those which provide constant outlet flow and should be capable of delivering up to 7000 psi (48.3 MPa). They are constructed from materials which are resistant to the organic solvents and aqueous buffer solutions commonly used as eluants. The system may also have provision for microprocessor control of the... 

ELSDs respond to any non-volatile solute and thus approach the ideal of a universal detector. Sensitivity is enhanced using lasers as light sources with detection limits of 5 g per 25 pi reported, a considerable improvement compared to RI detection. In addition, ELSDs are not as sensitive to ambient conditions such as temperature and pressure and eluant flow rate. 

In conclusion, it must be emphasised that each reactor must be tailored to its particular application. For every post-column reaction [67] there will be a set of optimum operating parameters such as temperature, concentration of reagent, flow-rate of reagent, reaction time, etc. These variables have to be studied in detail in order to optimise the configuration and operating conditions of the reactor. Thus, each final reactor design will tend to be specific for a particular application, and it may well be limited to a small range of eluant flow-rates. 

Particle beam LC-MS is a rapidly developing complimentary interface to thermospray techniques and provides a method of linking conventional HPLC systems with eluant flow-rates of 0.3-1.0mlmin , to an El ion source to obtain the classical El spectra which can be compared to conventional reference spectra (Figure 7.12). A capillary GC column may be connected to the same interface [10]. LC eluant enters the interface together with a stream of helium to form an aerosol of droplets which move through the desolvation chamber maintained at room temperature and pressure. The... 

The interfacing of the eluant from an HPLC column to a flame AAS has been achieved by matching the eluant flow-rate of approximately 1 ml min to the intake rate of the nebuliser. Five tetra alkyl lead compounds were analysed on a reverse phase Cjg column using acetonitrile/water mobile phase directly connected to the inlet capillary of the AAS nebuliser [29]. Each compound was detected at the 10 ng level. 

The airanonium carbonate/water eluant flow rate was 5 ml/ min and the gradient mode was linear for each application. The gradient composition range and duration, however, differed ... 

The comparatively higher suppression capacity of a micromembrane suppressor is not only caused by the higher diffusion efficiency of eluant cations to the membrane wall. The screen s ion-exchange characteristics have an even greater impact they are directly proportional to the suppression capacity. In continuously regenerated suppressors, one talks about the dynamic cation exchange capacity. Therefore, the suppression capacity is defined for both the hollow fiber suppressor and the micromembrane suppressor according to Eq. (68) as the product of eluant concentration and eluant flow rate ... 

General Parameters Affecting Retention Eluant Flow Rate... 

Fig. 3-151. Representation of log (Ifms- fdl/Kj as a function of log R for various inorganic and organic anions using an lonPac AS5A separator and a NaOH eluant. - Flow rate 1 mL/min solute concentrations ...

The background noise is typically caused by small fluctuations in the eluant flow rate, vortexing in the detector cell, or small temperature variations. Electrode materials with slow kinetics naturally produce less background than do fast-kinetic materials because their response times with regard to interferences are... 

Even with such careful design of the cam drive mechanism, single reciprocating piston pumps produce significantly pulsed eluant flow-rates and hence some dampening or other appropriate course of action must be taken by the instrument maker to overcome this limitation since otherwise they would not be suitable for use in HPLC. 

In a simple (low cost) HPLC system using a single reciprocating piston pump it is common practice to install a pulse damper in order to achieve a smooth eluant flow-rate. To do this a combined expansion restriction device is employed—a coiled tube (Bourdon tube) or pressure gauge provides the expansion volume and this is followed by a capillary restrictor. Unfortunately this solution to the experimental problem requires that a large resistance be used so that a considerable pressure build up occurs within the pulse dampener. In turn this leads to a marked lowering of the useable pressure... 

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