Waters Porapak Gas Chromatography Column Packing Materials - Manual (Page 2)

[ Care and Use ManUal ]
Waters PoraPak Gas Chromatography Column Packing Materials 2
II. CoLuMn PACKInG teCHnIQues
Porapak packing materials are rigid, cross-linked polymers which
may be packed into gas chromatography columns using the same
basic technique as used with conventional packing materials.
Since the particles do not crush or fracture easily they may be placed
in the column by using a vacuum to pull the particles into the column
while vibrating the column to cause the particles to settle in a tightly
packed bed. If the columns are packed in this manner, plate counts of
1200 to 2200 plates per meter may be obtained.
NOTE: Porapak packing material can, under certain conditions, pick up a surface
charge during shipping. This may make the packing appear wet and agglomer-
ated when the container is opened for the first time. The material is in fact quite
dry and clean. The surface charge should have no affect on your analysis or
present column packing method.
III. PreCAutIons In use
Porapak porous polymer beads should not be exposed to
temperatures above 250 °C since thermal degradation will occur
above this temperature. The upper temperature limit (in an oxygen-
free atmosphere) for types N and T is 190 °C.
The gas chromatograph used with a porous polymer bead column
must have low adsorption and reaction with the material being
analyzed. If the instrument has adsorption characteristics, this
will cause spreading or tailing, particularly of water or other polar
compounds.
IV. Inst ruMent resPonse
The response of the gas chromatograph can be tested prior to
installing the column simply by using a short unfilled column. Dirt,
oil, cold sections, and components with chemical reactivity in the
instrument can contribute to spreading of the peak. In order to get
good results the instrument must be non-reactive, clean, have small
hold-up volume, and be operated at a suitable elevated temperature.
NOTE: Purging is recommended. To purge, place the Porapak column in an oven
at 250 °C (190 °C for type N and T) with a slow flow of N
2
or He carrier gas and
let it remain there for at least two hours. Porapak beads may discolor upon heat-
ing, but this will not affect analysis. It may also be advisable to dry the packing
material in an oven under the initial conditions prior to packing the column.
Type Surface Area (m2/gm) Density (g/cm3) Maximum Temp. (°C)
P 100-200 0.27 250
Q 500-600 0.34 250
R 450-600 0.30 250
S 300-450 0.35 250
N 225-350 0.38 190
T 250-350 0.43 190
Table 1: Typical Properties for Porapak Porous Polymers
V. orderInG InForMAtIon
Particle Size (Mesh)
50-80 80-100 100-120
Porapak Porous Packings Part Number
N WAT027047 WAT027048 WAT027049
P WAT027053 WAT027054 WAT027055
Q WAT027059 WAT027060 WAT027061
R WAT027065 WAT027066 WAT027067
S WAT027071 WAT027072 WAT027073
T WAT027077 WAT027078 WAT027079
PS WAT027083 WAT027084 WAT027085
QS WAT027089 WAT027090 WAT027091
Table 2: Ordering Information