Evidence of Coupled Eddy Diffusion in Gas Chromatography.

Harper, J. M. E.; Hammond, Earl G.

doi:10.1021/ac60223a011

Cited by 11 publications

(9 citation statements)

References 18 publications

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“…Diffusion coefficients in hydrogen are about 3.7 times as great as those in nitrogen ( 14), and therefore the equations : Cm = <7/(H2) + Ci cm = c/m + c, = 3.7(7/(H2) + C, (8) apply to a given solute in each of the two gases. Values of C in each gas may be measured from the slope at the origin of plots such as those of Figure 2.…”

Section: Resultsmentioning

confidence: 99%

Relative Contributions of Molecular Diffusion and Anastomosis in Gas Chromatographic Columns.

Littlewood¹

1966

Anal. Chem.

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Dispersion of chromatographic zones in packed columns caused by uneven flow of eluent through the packing is relaxed by lateral mass transfer, which consists of flow-independent molecular diffusion and flow-dependent anastomosis resulting from lateral random walk of eluent gas through the interstices of packing. The relative magnitude of the two mass transfers is discussed and the conclusion is that anastomosis is appreciable at flow rates faster than about 20 cm. per second in hydrogen or 5 cm. per second in nitrogen. By using flow rates faster than these, the extra mass transfer provided by anastomosis enables columns to be operated at more plates per second and thus

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Section: Resultsmentioning

confidence: 99%

Relative Contributions of Molecular Diffusion and Anastomosis in Gas Chromatographic Columns.

Littlewood¹

1966

Anal. Chem.

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“…Comparing the classical prediction h = 2y/v + 2X for a nonsorbing solute to the Kieselbach data, descending branch reaching h = 2 at v = 1, horizontal branch h -2 for v > 1, (4) we see indeed that the limiting cases for low and high v are w'ell represented but for the region v ~1 this is not the case.…”

Section: Nature Of Eddy Diffusionmentioning

confidence: 62%

The Nature of Eddy Diffusion.

Giddings¹

1966

Anal. Chem.

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“…The first term is the coupled eddy diffusion term proposed by Giddings (21), and we have discussed its presence and calculated contribution elsewhere (24). Bc', Cg1, and C\ are the contributions of longitudinal diffusion, resistance to gas phase mass transfer and liquid phase mass transfer, respectively, to H. The effective linear flow velocity, u', or the ratio of the volume flow rate at 1 atm.…”

Section: Calculationsmentioning

confidence: 99%

Solid Support Characteristics and Plate Height in Gas Chromatography.

Harper¹,

Hammond²

1965

Anal. Chem.

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Constants for a plate heightvelocity equation were determined for stationary phase supports, made by lyophilizing a mixture of inorganic salts, and Chromosorb P. This allowed a study of the effect of porosity and pore size distribution on the equation constants. The value of the obstructive factor, , in the longitudinal diffusion coefficient, B/, increased with increases in intraparticle void. This suggests that 7 is the sum of intraand interparticle contributions. The values of C/ decreased as the intraparticle void increased. This term should be a measure of resistance to mass transfer in the stagnant gas inside the particles, but it may also contain a contribution from the coupled eddy diffusion term. The values of C/, the

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Evidence of Coupled Eddy Diffusion in Gas Chromatography.

Cited by 11 publications

References 18 publications

Relative Contributions of Molecular Diffusion and Anastomosis in Gas Chromatographic Columns.

Relative Contributions of Molecular Diffusion and Anastomosis in Gas Chromatographic Columns.

The Nature of Eddy Diffusion.

Solid Support Characteristics and Plate Height in Gas Chromatography.

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