Golay equations

The silica dispersion showed the smallest retention volume. It should be noted, however, that the authors reported that the silica dispersion required sonicating for 5 hours before the silica was sufficiently dispersed to be used as "pseudo-solute". The retention volume of the silica dispersion gave the value of the kinetic dead volume, /.e., the volume of the moving portion of the mobile phase. It is clear that the difference between the retention volume of sodium nitroprusside and that of the silica dispersion is very small, and so the sodium nitroprusside can be used to measure the kinetic dead volume of a packed column. From such data, the mean kinetic linear velocity and the kinetic capacity ratio can be calculated for use with the Van Deemter equation [12] or the Golay equation [13]. 

The Golay equation [9] for open tubular columns has been discussed in the previous chapter. It differs from the other equations by the absence of a multi-path term that can only be present in packed columns. The Golay equation can also be used to examine the dispersion that takes place in connecting tubes, detector cells and other sources of extra-column dispersion. Extra-column dispersion will be considered in another chapter but the use of the Golay equation for this purpose will be briefly considered here. Reiterating the Golay equation from the previous chapter. 

If the solute is unretained (i.e., k"=0), then the Golay equation reduces to... 

Most sensor volumes, whether in LC (e.g., a UV absorption cell) or in GC (e.g., a katharometer cell), are cylindrical in shape, are relatively short in length and have a small length-to-diameter ratio. The small length-to-diameter ratio is in conflict with the premises adopted in the development of the Golay equation for dispersion in an open tube and, consequently, its conclusions are not pertinent to detector sensors. Atwood and Golay [12] extended the theory of dispersion in open tubes to tubes of small length-to-diameter ratio. The theory developed is not pertinent here as it will be seen that, with correctly designed cells, that dispersion from viscous sources can be... 

Now, it has been previously shown from the Golay equation (chapter 8) that the value of (H) is given by a function of the form,... 

The Golay equation is strictly applicable to open tubular columns with smooth walls but, with certain approximations, it can be extended to include support-coated (77) and whisker-walled (78)... 

The general approach for kinetic optiaization of open i tubular columns has been to adopt the familiar Golay equation T (equation 1.34) and to assuae that the aobile phase can be approximated by an incompressible fluid with ideal gas properties, (44-50). Circumstances that are approximate at best but serve adequately to demonstrate some of the fundamental characteristics of open tubular columns operated at low fluid densities. The column plate height equation can be written in the form given in M equation (6.1)... 

Golay equation 21, 611 gradient (LC) 490 height equivalent to a theoretical plate 11 longitudinal diffusion 16 mass transfer resistance 17 nonlinear chromatography SOS plate model 14 rate theory IS reduced parameters 78, 361, 611... 

Glass OTC (GC) drawing 134 etching HCl 140 leaching HCl 140 particle deposition 143 properties 135 whisker formation 142 Glassy carbon (GC) 204 Golay equation GC 21 LC 342 SFC 607... 

Beginning with the most favorable case, band broadening in open tubul2u eoluams is satisfactoi..iy described by the Golay equation, extended to situations of appreciable pressure drop by Glddings, equation (1.34)... 

Reduced parameters (section 1.7.10) can -be used to compare the potential of open tubular and packed columns to deliver a certain separation potential in SFC [8,43,53-56]. The Golay equation, equation 6.1, can be rewritten as... 

A sample plot showing the contribution of each term to determining H is shown in Fig. 14.2. An excellent basic discussion of the van Deemter and Golay equations can be found in the text by McNair and Miller [10]. 

It should be noted that the Golay equation for capillary columns will be discussed in detail in the next chapter.)... 

It is seen that the Golay equation produces a curve identical to the Van Deemter equation but with no contribution from a multipath term. It is also seen that, the value of (H) is solely dependent on the diffusivity of the solute in the mobile phase and the linear mobile phase velocity, It is clear that the capillary column can, therefore, provide a simple means of determining the diffusivity of a solute in any given liquid. 

The Golay equation (equation 7) can be Dut in a simplified form in a similar manner to the equations for packed columns -... 

In the Golay equation, ef is the phase thickness, D, and Ds are diffusion coefficients in the mobile phase (m) and the stationary phase (i), respectively. 

The use of electroosmotic flow (EOF) to drive the mobile-phase flow results in plug flow in the channels between particles, thus reducing CMu by a factor which can be estimated by considering such a channel as an open tube diameter dc, for which CM can be related to dc and retention factor, k, by the Golay equation [8]... 

The approximate efficiency of a capillary column operated at its optimum velocity (assuming the inlet/outlet pressure ratio is small) is given by the Golay equation. 

The dispersion that takes place in an open tube is described by the Golay equation (5),(ref. chapter 8) under conditions where there is no stationary phase and thus, k =0. As a result,the variance due to an open tube (otu )will be... 

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