Column Packer for Gas Chromatography R. G. McKeag‘ and F. W. Hougen+ Depadtnent of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
Mechanized methods employed for packing gas chromatographic columns include tapping of the column (1,2),tapping followed by gas pressure (3),and vibration with simultaneous gas pressure (4).A major problem, particularly with long columns, is to obtain a high packing density without crushing the support particles. As Giddings (5)has shown, the principal contribution to plate height in the gas phase arises from irregularities in the packed bed. The present paper describes an inexpensive device for rapid packing of columns with high packing density and with a minimum formation of “fines”. A similar apparatus is available from suppliers of chromatographic equipment. The column packer (Figure 1) is constructed from commonly available materials. It consists essentially of a tube reservoir (C) from which the column packing is blown by pressurized gas into the column. Two modifications are made to the Swagelok fittings. Part B is reamed with a $-in. bit, and a fine-mesh steel screen is inserted to prevent blow-back of packing material. Part G is drilled completely through with a ?,$-in. bit to allow free passage of packing material. To pack a column, the column tubing (with the usual Swagelok fittings and glass wool plug) is supported vertically in a groove in a long narrow board. An excess amount of column packing is poured (through G) into the reservoir of the inverted column packer. The packer, still inverted, is then connected to a source of dry nitrogen (at A) and, by bending tube E, to the column (at G).The packing is blown into the column by again inverting the packer and immediately applying a suitable gas pressure (50 psi for a 15-ft X %-in.0.d. column) while gently tapping the column-board vertically against the floor. The gas pressure and tapping are maintained until no additional packing material enters the column, as observed by the level in the transparent tube (E).Finally, the gas pressure is reduced to atmospheric; this must be done gradually to prevent blow-back of material from the column. Use of the column packer in our laboratory has provided columns of reproducible and high efficiencies. This may be attributed, a t least in part, to the packing densities, which generally were 2-3% higher by the column packer method than by vibration. Two identically prepared SE-30 columns had packing densities of 0.346 and 0.355 glft and efficiencies of 1149 and 1190 theoretical plateslmeter, respectively. Two
Present address, The Griffith Laboratories Ltd., 757 Pharmacy Ave., Scarborough, Ontario, Canada M1L 358.
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ANALYTICAL CHEMISTRY, VOL. 49, NO. 4, APRIL 1977
4 Flgure 1. Assembled column packer (A) Teflon or other tubing to nltrogen supply. (B, 0)Swageiok reducing union (catalogue No. 400-6-2). (C) Stainless steel tubing (40 In. X %-In. 0.d.). (D, F) Hose clamp. (E) Polyethylene tubing (12-111. X %-In. 0.d.)
identically prepared OV-17 columns had packing densities of 0.373 and 0.349 glft and efficiencies of 709 and 746 plates/ meter, respectively. All four columns were 15-ft X Ye-in. o.d., stainless steel, the liquid phase coated on Anakrom ABS, 80-90 mesh, 1:20 by weight. The efficiencies were tested with n-octane at 92 O C and 45 psi nitrogen inlet pressure. The packing of a 15-ft X Y8-in. column is completed in 20 min.
LITERATURE CITED (1) (2) (3) (4) (5)
H. Ven Horst and K. O‘Connor, J. Chem. Educ., 37,593 (1960). J. R. P. Clarke, Chem. lnd., (London),42, 1830 (1962). E. Bayer, K. P. Hupe, and H. Mack, Anal. Chem., 35,462 (1963). R. Vlllabolos, J. Gas Chromatogr., 6,367 (1968). J. C. Olddings, Anal. Chem., 34, 186 (1962).
RECEIVEDfor review October 7, 1976. Accepted December 29,1976. The work was supported by the National Research Council of Canada. Contribution No. 377, Department of Plant Science, University of Manitoba.
