Golay equation, open-tubular

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. 

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)... 

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... 

The term A is related to the flow profile of the mobile phase as it traverses the stationary phase. The size of the stationary phase particles, their dimensional distribution, and the uniformity of the packing are responsible for a preferential path and add mainly to the improper exchange of solute between the two phases. This phenomenon is the result of Eddy diffusion or turbulent diffusion, considered to be non-important in liquid chromatography or absent by definition in capillary columns, and WCOT (wall coated open tubular) in gas phase chromatography (Golay s equation without term A, cf. 2.5). 

Analysis time increases in proportion to the square of the plate number, i.e., to the fourth power of the resolution aimed at. With open tubular columns the reduced HETP h is given by the Golay (8) equation ... 

Golay Dispersion Equation for Open-Tubular Columns... 

Now, for the dead volume peak from an open tube, n = l/0.6rf (see the entry Golay Dispersion Equation for Open-Tubular Columns). Thus,... 

The open-tubular column or capillary column is the one most commonly used in gas chromatography (GC) today. The equation that describes dispersion in open tubes was developed by Golay [1], who employed a modified form of the rate theory, and is similar in form to that for packed columns. However, as there is no packing, there can be no multipath term and, thus, the equation only describes two types of dispersion. One function describes the longitudinal diffusion effect and two others describe the combined resistance to mass-transfer terms for the mobile and stationary phases. 

Golay equation A correlation between the column height equivalent to a theoretical plate and the mobile phase velocity. This equation is valid for an open tubular colmrm (Eqs. 6.105a and 6.105c). 

The Golay equation for open-tubular columns of circular geometry is given by ... 

As we will see in Chapter 20, capillary columns are the most widely used in gas chromatography because of their high efficiency due to large numbers of plates. These columns have no packing, and so the eddy diffusion term in the van Deempter equation disappears. For open tubular columns, the modification of the van Deempter equation, called the Golay equation, applies ... 

In 1957 Marcel Golay published a paper entitled Vapor Phase Chromatography and the Telegrapher s Equation [Anal. Chem., 29 (1957) 928]. His equation predicted increased number of plates in a narrow open-tubular column with the stationary phase supported on the inner wall. Band broadening due to multiple paths (eddy diffusion) would be eliminated. And in narrow columns, the rate of mass transfer is increased since molecules have small distances to diffuse. Higher flow... 

GC capillary coliunns have a uniform geometry and in the absence of a stationary phase H in is directly proportional to the column internal diameter dc and retention characteristics, k, of the stationary phase film including polar character and film thickness [9-11]. Column design may be evaluated for efficiency and optimum mobile phase velocity using the following equation for proposed by Golay when he developed the theory for open tubular (WCOT) columns [9] ... 

Maximum column efficiency occurs at the OGV (Figure 5.6). The value of MiN can be calculated using the equation proposed by Golay from the development of the theory for open tubular columns [15] ... 

Beginning with the most favorable case, band broadening in open tubular columns is satisfactorily described by the Golay equation, extended to situations of appreciable pressure drop by Giddings, Eq. (1.22)... 

The Golay equation can also be used to predict optimum separation conditions in open tubular column liquid chromatography [128,129]. The main difference between... 

Open tubular columns. The band broadening obtained in an open tubular column can be expressed by the Golay equation (Golay, 1958). This summarizes the contribution to band broadening from longitudinal diffusion. 

Since open tubular or capillary columns do not have any packing, their rate equation does not have an /4-term. This conclusion was pointed out by Golay [4], who also proposed a new term to deal with the diffusion process in the gas phase of open tubular columns. His equation had two C-terms, one for mass transfer in the stationary phase, Cs (similar to van... 

Let us conclude this discussion by considering only two rate equations—one for open tubular columns and one for packed columns. The former is represented by the Golay equation ... 

Open-Tubular Columns Golay Dispersion Equation... 

To describe the broadening process in open tubular columns with a porous layer on the walls, Golay theoretically obtained the following equation ... 

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