Band broadening Golay equation

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)... 

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... 

The stationary phase is supported on the wall of the column, the carrier gas therefore has an uninterrupted flow through the column. The absence of column packing means that the unequal pathways term, A term, in the van Deemter equation (see section 2.5.1) is zero and band broadening is due to the effects of longitudinal diffusion, B term, and mass transfer, C term. The reduced equation is referred to as the Golay equation [15]. 

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. 

The contribution from the last factor in equation (2.1) is often relatively small and it may be neglected for simplicity (Lee, Yang and Bartle, 1984). If one neglects the band broadening in the stationary phase, the Golay equation can be solved for the minimum height of theoretical plates ... 

Equation (2.2) shows that //min is dependent on only the capillary radius and the capacity factor. Solution of the Golay equation regarding optimal mobile phase velocity, again neglecting band broadening in the stationary phase, gives ... 

Table 2.2 Order of magnitude comparison of the contribution to band broadening by non-uniform local mobile phase velocities, the flow profile (i /Dm) in capillary columns (the Cq term in Golay s equation)...

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