Axially adjustable-type column device

To form a gel bed in a cylindrical column for liquid chromatography, a gel bed section is provided between upper and lower liquid-tight partition members, positioned apart from each other at upper and lower positions in the column. Liquid is continuously percolated downward through the gel bed section to form a gel bed in the gel bed section and a liquid pressure is applied onto the upper partition to move the partition member downward following a downward movement of the upper surface of the gel bed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention: 
This invention relates to a column structure of liquid chromatography used 
for separating and purifying materials and a method of high-performance 
packing of gels into this column. 
2. Discussion of the Background: 
In conventional liquid chromatographic devices, a column wherein slurry 
dispersed with gel is packed by liquid-flow is generally used for the 
column as the main component for separation and purification. 
This method of packing the gels by liquid-flow is called a slurry packing 
method and is generally operated as shown in FIGS. 5(a) through 5(e). A 
reservoir 4 is connected to the upper end of a column body 1 having a 
lower flange 2 blocking the bottom thereof. A homogeneous gel slurry 5 of 
predetermined quantity and density is poured into the reservoir from above 
(see FIG. 5(a)). Then, an upper flange 3 is attached to the upper end of 
the reservoir 4. And a gel bed 6 is formed within the column body 1 by 
liquid-flow through the column body and reservoir and pressurization with 
a high pressure pump (see the top and bottom openings for liquid flow and 
for pressurization, shown only in FIG. 5(b)). After the liquid-flow and 
pressurization, supernatant liquid in the reservoir 4 is discharged by a 
pump and the like (see FIG. 5(c)), and the reservoir 4 is removed from the 
column body 1. The gel bed 6 heaps up over the top of the column body 1 
when the reservoir 4 is removed therefrom (see FIG. 5(d)). 
After the heap of the bed is removed, the upper flange 3 is fixed to the 
top of the column body 1 to finish the packing operation (see FIG. 5(e)). 
This slurry packing method has been practiced as one of most common and 
superior packing methods because the advantages that stable gel beds and 
remarkably increased performance of the column can be obtained. 
However, in conjunction with recent developments in biotechnology and its 
increasing importance to studies in related fields of biochemistry, many 
kinds of gels for liquid chromatography have been in development. It has 
been desired that the users can themselves easily pack and replace these 
gels into a column which is most suitable for the objective ingredients 
and matching size (diameter and length) for a required quantity to be 
treated. 
In order to so form stable gel beds in a column for separation and 
purification or to fill, as another object, a void in the top of liquid 
inlet due to the volume change of the gel bed during the liquid 
chromatographic operation, a method to move a liquid dispersing plate and 
a liquid collecting plate situated at the upper and lower ends of the 
inside of the column has been proposed. A device utilizing this method to 
move a liquid dispersing plate (or a liquid collecting plate) may be 
classified as an axially adjustable-type column for preparative liquid 
chromatography interconnected with a pneumatic, hydraulic, or mechanical 
driving mechanism for compressing and pressurizing gel beds and the method 
may be called a pressurized packing method. 
An example utilizing such a pressurized packing method as disclosed in 
Japanese Patent Publication No. Sho 58-20284 is shown in FIG. 6. In FIG. 
6, a piston-like sliding body 8 having a head 9 is fit liquid-tightly and 
vertically movably in the column body 10. The liquid collecting plate 13 
is attached to the upper end of the above mentioned head 9. While the 
sliding body is at the lower dead point of its travelling path, 
homogeneous gel slurry 11 is poured into the column body 10. After that, 
the liquid dispersing plate 16 and a cover 12 are fixed to a fixing flange 
14 on top of the column body. 
When the sliding body 8 is moved upward from its lower dead point by a 
drive shaft 15, for example by utilizing a pneumatic or hydraulic jack, 
pressure is applied to the homogeneous gel slurry 11 to form the gel bed. 
Removal of the gel bed for replacement is performed by lifting the sliding 
body 8 with the cover 12 removed. Then it is ready for the next 
chromatographic operation. 
FIG. 7 shows another example of the pressurized packing method as disclosed 
in Japanese Laid-Open Patent Application No. Sho 61-28864. A column for 
liquid chromatography 23 is fixedly attached to a column pedestal 24. 
After the homogeneous gel slurry is poured through the top of the column 
23, an adjustable plug (not shown) is attached to the top of the inside of 
the column. A shaft 22 connected with this adjustable plug is extended 
upward out of the column. The upper end thereof is fixed to an adjustable 
plug transfer pedestal 21. Under this condition, threaded rotation shafts 
18 are rotated, via the reducing mechanism 19, by the rotation of a motor 
20. Since rotation shafts 18 are threaded in the transfer pedestal 21, 
they cause the pedestal to move vertically. A gel bed is formed by 
lowering the adjustable plug transfer pedestal 21 and the adjustable plug 
at a fixed rate to apply pressure to the homogeneous gel slurry in the 
column 23 and by discharging only the liquid to the outside through piping 
on both sides of the column (not shown). When the gel in the column is no 
longer usable, the lower flange 17 is removed, the adjustable plug 
transfer pedestal 21 is lowered, and the gel is discharged from the bottom 
of the column 23 to prepare the column for the subsequent packing. 
Though quite different from the above method which applies pressure for the 
formation of a gel bed, a column of such a structure that an adjustable 
plug is built therein has also been proposed for packing by pressure the 
void at the liquid inlet in the column, which void occurs due to the 
volume change of the gel bed during the liquid chromatographic operation. 
An example is disclosed in Japanese Utility Model Publication No. Sho 
43-22959, and shown in FIG. 8. In the figure, if the top of the gel bed 25 
is lowered in the course of time due to the inflow of liquid through a 
treating liquid inflow passage 29, pressurized gas is supplied into a 
pressurized gas chamber 27 through a flow-in duct 26 and an adjustable 
body 28 always applies pressure on the gel bed 25 and moves downward as 
required. Therefore, the void is not formed during that time. Element 30 
is a seal ring for sealing air and liquid. 
In an axially adjustable column for separation and purification according 
to the conventional pressurized packing method, a special mechanism is 
required to constantly maintain the travel speed of the adjustable plug by 
a pneumatic, hydraulic or mechanical driving mechanism and to provide a 
large overload for pressurizing the gel bed as in the cases of Japanese 
Patent Publication No. Sho 58-20284 or Japanese Laid-Open Patent 
Application No. Sho 61-28864, described above, in order to move either one 
or both of the liquid dispersing plate and the liquid collecting plate. In 
order to meet with these requirements, the pneumatic, hydraulic or 
mechanical driving mechanism will inevitably be structured in large scale. 
Moreover, such a mechanical driving mechanism forms a gel bed by pressing 
it with a strong force, and accordingly the density distribution of the 
gel bed is liable to become uneven in the axial direction, and it is 
difficult to achieve a high column performance as has been attained by 
conventional slurry packing methods. 
The method described in Japanese Utility Model Publication No. Sho 43-22959 
has as its object to fill the void which arises between the gel bed and 
the adjustable plug during liquid chromatographic operation, and has no 
object to form the gel bed. Further this method seems to provide no 
effective method for forming the bed. For instance, even if this method of 
moving the adjustable plug with use of pressurized gases is applied to the 
gel bed formation, the transfer speed of the adjustable plug cannot be 
controlled at a fixed rate due to the cushion effect of the pressurized 
gas, and desired separation performance cannot be constantly accomplished. 
And when leakage happens to occur at the sealing surface between the 
adjustable plug and the inner wall of the column, a problem arises that 
separation performance of the column will be decreased drastically due to 
the flow of the pressurized gases through the gel bed. 
As has been described above, in contrast to the slurry packing method 
wherein high column performance is achieved, it is difficult to form a 
satisfactory gel bed by any of the conventional pressure packing methods 
described in Japanese Patent Publication No. Sho 58-20284 and Japanese 
Laid-Open Patent Application No. Sho 61-28864, or the method of Japanese 
Utility Model Publication No. Sho 43-22959 utilizing the similar axially 
adjustable-type column. 
It may be said that the features of the conventional slurry packing method 
for obtaining high performance and those of the pressurized packing method 
for rapidly forming the gel bed effectively by applying pressure on the 
adjustable plug are mutually exclusive. 
SUMMARY OF THE INVENTION 
An object of the present invention is to solve these problems by achieving 
the performance of the conventional packing method with the convenience of 
the pressure packing method. 
Another object of the present invention is to provide an axially 
adjustable-type column having a structure capable of performing a slurry 
packing method and provide a packing method utilizing this column. 
More specifically, the present invention provides a method to form the gel 
bed in a cylindrical column for liquid chromatography, in which the gel 
bed section within the cylindrical column is installed between upper and 
lower liquid tight partition members located apart from each other in the 
column, and a gel bed is formed by continuously percolating a downward 
liquid-flow through the gel bed disposed between the upper and lower 
partition members, and applying liquid pressure on the upper partition 
member which serves as an adjustable plate during the percolating step, so 
as to move downward the upper partition member in response to the downward 
movement of the upper surface of the gel bed. 
Further, the present invention provides a column device for forming the gel 
bed therein having a cylindrical column into which the gel is packed, a 
pair of upper and lower partition members to form a gel bed section 
therebetween and to liquid-tightly seal the gel bed section, with at least 
one of the pair of partition members being provided with a flow path 
therethrough to flow the liquid in one of upward and downward directions 
through the gel bed section, a pressure balance chamber to which the upper 
surface of the upper partition member is exposed, and pressure supply 
means for transferring liquid pressure of the liquid flowing through the 
flow path to the pressure balance chamber Particularly, the column device 
can be provided as an extremely simple structure by sharing the liquid 
pressure to be supplied to the pressure balance chamber with the supply 
source supplying the liquid to the gel bed section. 
The present invention has an advantage that a constant flow pump, for 
instance, may be used to supply liquid for forming the gel bed in the 
column the pump and for chromatographic operation. The axially 
adjustable-type column device according to this invention has advantages 
that a special mechanical driving mechanism used in the pressurized 
packing method is not required for forming the gel bed as it is formed by 
the slurry packing method using liquid-flow, and moreover, as the 
liquid-flow to form the gel bed is provided by the constant flow pump, a 
special adjusting mechanism is not required for pressurizing and forming 
the gel bed with a constant flow rate and pressure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Now, the structure and operation method of this device will be explained by 
way of an embodiment with reference to the accompanying drawings, but the 
present invention is not limited to the embodiment. 
A brief operational procedure will be explained first with reference to 
FIGS. 2(a)-2(c). 
FIGS. 2(a)-2(c) schematically show the axially adjustable-type column 
device for liquid chromatography according to the present invention and 
the packing procedure thereof. FIG. 2(a) shows the state when the 
homogeneous gel slurry is poured, wherein a reservoir for packing 35 is 
set on an axially adjustable-type column body 31 (hereinafter called a 
"column body") fixedly attached to a column support pole 32. A cylindrical 
body of stainless steel is preferably adopted for the column body 31, 
generally in consideration of corrosion resistance, chemical resistance, 
workability, and structural strength, but is not limited thereto. A 
reservoir cap 36 is supported by an adjustable plug transfer pedestal 37a 
through which the cap is moved vertically by a hydraulic cylinder (not 
shown) built in the column support pole 32. A slide rod 38 acts as a guide 
for the vertical movement of the transfer pedestal. A valve unit 39 is 
provided with a selector valve or the like to form a predetermined flow 
path for packing operations or liquid chromatographic operations. A 
pneumatic-hydraulic converter 40 for the cylinder operation described 
above actuates the transfer pedestal 37a described above, and the 
switching operations of the selector valve of the valve unit 39 described 
above and the vertical transfer operation of the adjustable plug transfer 
pedestal 37a and so on are automatically controlled by a controller which 
is not shown. By the way, the transfer pedestal 37a described above is 
rotatable around the slide rod 38 on a level plane, which forces an 
adjustable plug unit which will be described later to rotate into 
alignment with the column body 31 when a gel bed is formed. 
In the packing operation, the homogeneous gel slurry which has been 
adjusted in concentration is introduced into the reservoir for packing 35 
and the column body 31 which are set as shown in FIG. 2(a) and is left 
until the gel spontaneously sinks. The leftover supernatant in the 
reservoir 35 is then discharged and the reservoir 35 is removed. The 
length of the reservoir 35 to be used depends on the density of the preset 
gel slurry and the height of the required gel bed. Therefore, in some 
cases the packing can be started after the gel slurry is directly 
introduced into the column body 31, without using the reservoir 35, either 
immediately or after having been left to sink spontaneously. 
Then the gel bed is formed by the slurry which has been packed as described 
below. 
FIG. 2(b) shows the state wherein the transfer pedestal 37a is rotated 
around the slide rod 38 on a level plane to position the adjustable plug 
unit (33, 41, 70) in alignment above the column body. In the Figure, 33 is 
the adjustable plug, 41 an adjustable plug rod supporting the adjustable 
plug 33 at the lower end and having an inside liquid-flow path 
communicating to the end of the adjustable plug 33, and 70 is an upper 
flange arranged to seal the column body. The adjustable plug unit which 
consists of the parts mentioned above is supported by the adjustable plug 
transfer pedestal 37b which is vertically movable along the slide rod 38 
supported by the column support pole 32 and, as described above, is 
positioned from an offset position shown in FIG. 2(a) to the alignment 
position above the column body 31 by the rotation of the adjustable plug 
transfer pedestal 37b around the slide rod 38. 
FIG. 2(c) shows the device when operating to form the gel bed from the 
sedimentation which has sunk spontaneously during the state shown in FIG. 
2(a). The adjustable plug unit described above moves downward from the 
state shown in FIG. 2(b) to insert the adjustable plug 33 into the column 
body 31 until the upper flange 70 is fixedly set onto the upper flange 34 
of the column. Thereby, a pressure balance chamber 51 (FIG. 1(b)) is 
formed as an open space between the adjustable plug 33 and the upper 
flange 70. 
Now, the operation for forming the gel bed (hereinafter called "a bed 
forming") is performed by flowing liquid by a constant flow pump, and an 
explanation of the operation will be given in detail with reference to 
FIGS. 1(a) and 1(b). 
FIGS. 1(a) and 1(b) shows cross-sectional views of the column body 31 taken 
in the direction of the arrow A of FIG. 2(c);, FIG. 1(a) illustrates the 
adjustable plug 33 when ready to be inserted into the column body 31 (that 
is, at a position corresponding to FIG. 2(b)), and FIG. 1(b) illustrates 
the adjustable plug 33 when inserted (that is, at a position corresponding 
to FIG. 2(c)). Moreover, all the parts of the device of this embodiment 
which are brought into contact with the liquid should preferably be 
composed of stainless steel (SS316) in consideration of the required 
resistance to chemical agents and the like, but are not so limited, 
depending on the nature of the liquid to be used. 
The inside of the column body is composed of the gel bed 45. The perforate 
liquid dispersing plate 46 is situated at the upper end of the bed 45 in 
case where the liquid flow direction is downward, and the perforate liquid 
collecting plate 47 is situated at the lower end. When the liquid-flow 
direction is made to be upward, the positional relation between the liquid 
dispersing plate and the liquid collecting plate described above is 
reversed. These plates also prevent the gel particles from leaking out of 
the column. 
For the liquid dispersing plate 46 and the liquid collecting plate 47 
mentioned above, stainless steel sintered porous plates are generally used 
and in this embodiment, together with the supporters 48 and 49 holding 
them; one of these plates is attached to the lower part of the adjustable 
plug 33 and the other to the upper part of the lower flange 44. 
Furthermore, supporters 48 and 49 should favorably function to rectify the 
flow of the liquid, i.e., to prevent backflow. 
A seal rings 50 are fitted in a circumferential groove of the adjustable 
plug 33 to prevent the liquid and gel in the column and the pressure 
balance chamber 51 from leaking. A seal ring 52 prevents the liquid in the 
pressure balance chamber 51 from leaking out of the column when the 
adjustable plug rod 41 is sliding. V-packing rings of 
polytetrafluoroethylene (PTFE) and the like are favorably used for these 
seal rings. 
The upper flange 70, together with the adjustable plug 33, is detachable 
from the column body 31 and may tightly fastened to the upper flange 34 
with bolts and nuts 54 when the adjustable plug 33 is inserted into the 
column body 31. The adjustable plug transfer pedestal 37b fastened to the 
upper end of the adjustable plug rod 41 and the upper flange 34 of the 
column are connected via locking means in the form of bolts and nuts 55 
after the bed forming operation, thus preventing the adjustable plug 33 
from moving upward during the liquid chromatography operation. 
Now preparations are completed for preparation of the liquid 
chromatographic processing. 
When the above mentioned device is used for liquid chromatographic 
processing and the replacement of the gels is required due to the 
deterioration of the performance or due to contamination, the gels must be 
discharged from the column body 31. In the device according to this 
embodiment, the bolts and nuts 57 connecting the lower flange 56 of the 
column and the lower flange 44 are first removed. The lower flange holder 
43 extending from the column support pole 32 (see FIG. 2(c)) and holding 
the lower flange 44 between its U-shaped arms is then rotated on a level 
plane around the column support pole to remove the lower flange 44 from 
the shaft of the column body 31. After that, the gels can be easily 
discharged downward by liquid-flow through a pipe line 58 by use of the 
constant flow pump. A receiver for extracted gels (not shown) should be 
placed below the column body 31. 
The structural arrangements described above, including the arrangements for 
discharging the used gels, are also features of the present invention. 
In the axially adjustable-type column of the above structure, the 
adjustable plug 33 equipped with the liquid dispersing plate (or a liquid 
collecting plate), is moved downward when the bed is formed by the 
liquid-flow introduced through the pipe line 58 in conjunction with the 
downward movement of the upper surface of the bed. 
Generally, as has been described in the explanation of the related art, 
fine adjustment of the speed is difficult for movement driven by pneumatic 
or hydraulic forces. In a mechanical driving system, large scale equipment 
is required to reduce the rotation speed of the motor by a worm gear or 
the like. 
Contrary to the above, this invention has an advantage that the liquid feed 
from the constant flow pump to the pipe line 58 is branched into a liquid 
feed pipe line 59, and the slurry packing is attained by the liquid-flow 
and a rapid bed formation is achieved by moving the adjustable plug 33 in 
response to movement of the upper surface of the gel bed 45. 
That is to say, when the formation of the gel bed 45 is performed by the 
liquid-flow from the pipe line 58, an opposing force to push the 
adjustable plug upward is exerted. It is not easy to move the adjustable 
plug 33 so as to follow the movement of the upper surface of the bed at a 
fixed rate by pneumatic, hydraulic mechanical driving means against the 
opposing force which changes with time during the packing operations. In 
this embodiment, the adjustable plug 33 is moved in proportion to the 
quantity of pressurized liquid supplied into the pressure balance chamber 
51 through the liquid feed pipe line 59. 
The total volume of pumped liquid equals the volume of the liquid fed to 
the liquid feed pipe line 59, and that fed-through pipe line 58, which is 
discharged from the pipe line 60; that is, the slurry packing is made 
possible by a constant liquid feeding volume. Further, the liquid feeding 
to the liquid feed pipe line 59 and the pipe line 58 may be made by two 
separate pumps, or a shut-off valve may be attached in the midway between 
the lines of the pipe line 58 and the liquid feed pipe line 59. By 
controlling them, it is possible that the slurry packing and the movement 
of the adjustable plug 33 accompanying the upper surface of the gel bed 45 
are performed simultaneously or the operation for moving the adjustable 
plug 33 is performed only after the gel bed 45 has been formed. Meanwhile 
it is necessary to open the exhaust pipe line 61 to exhaust air from the 
pressure balance chamber 51 and to close the exhaust pipe line 61 when the 
packing is performed. 
The degree of the liquid pressure applied to the pressure balance chamber 
51 described above should be basically determined by the relation between 
the downward liquid pressure working on the adjustable plug 33 (that is, 
the liquid pressure from the pressure balance chamber) and the upward 
liquid pressure (that is, the liquid pressure from the formed portion of 
the gel bed), but the latter may decrease considerably when the liquid is 
discharged from the lower pipe line 60. Accordingly, required functions 
and performances are satisfactorily achieved by the liquid supply from the 
same supply source even with the adjustable plug 33 having differences 
between the upper and lower pressures applied to the surfaces as explained 
in the above FIG. 1. 
Also, there is an extremely great difference between the liquid pressure 
required for moving the adjustable plug 33 downward following the downward 
movement of the upper surface of the gel bed and the liquid pressure 
required for the packing method explained in the conventional methods. 
Accordingly, strict controls on the setting of the pressure for the 
pressure balance chamber 51 are not specially required in this invention. 
And generally, it is particularly preferable that the supply source for 
flowing the liquids to form the gel bed is shared with the pressure 
balance chamber as described above, from the points of view of limiting 
the required equipment making the whole system smaller in size, lowering 
the production cost and other factors. 
After the completion of the bed formation, the bolt and nut 55 and the 
adjustable plug transfer pedestal 37b, hence the adjustable plug 33, are 
fixed to the upper flange of the column of the column body 31. Then, this 
device as arranged above is used for liquid chromatography. 
FIG. 3 schematically shows the liquid-flow when the gel bed is formed. In 
this figure, the packing solvent from the constant flow pump 62 is 
branched midway to flow through a valve 63 on the adjustable plug side and 
a valve 64 on the pressure balance chamber side to form the gel bed 71 and 
to move the adjustable plug 68 downward. The discharge of the packing 
solvent from the column body 67 is performed through the drain valve 65, 
and after the exhaust of the pressure balance chamber 72 is finished, the 
exhaust valve 66 is closed. 
In this way, by use of only the constant flow pump (this same constant flow 
pump can be used for the liquid chromatography), it is possible to perform 
the slurry packing method for preparing a high performance column by 
liquid-flow without using any specific driving mechanism and to speed up 
the packing operations by utilizing the features of the axially 
adjustable-type column. 
When the column in which has been completed the bed formation is used as a 
separation system in liquid chromatography, the supply of the eluent can 
be made through the pipe lines 58 or 60 in FIG. 1. In either case, the 
sample supply is made on the supply side of the eluent, and the output 
liquid of the constant flow pump used for the packing operation is 
introduced into the pipe lines 58 or 60 to keep the liquid chromatography 
system compact. 
EXAMPLE 1 
Tests were made on individual column performances obtained by the packing 
method according to this invention, and the conventional slurry packing 
method and mechanical pressure packing method, using the gel (TSKgel 
ODS-120T, Tosoh Corporation) for reversed-phase chromatography in which 
separations are made based on the partition and absorption utilizing the 
difference in polarity. The results of the tests will be explained as the 
example and the comparison. 
As for the pressure packing method in the comparative example, the test was 
performed by compressing the gel bed with a strengthened function of the 
hydraulic mechanism explained in FIG. 2 and moving the adjustable plug 
utilizing the driving mechanism thereof. 
By utilizing the axially adjustable-type column device of 10 cm inner 
diameter according to this invention, the gel was sunk in the state of 
FIG. 2(b), and then the reservoir was removed, the adjustable plug was 
attached, and the packing was performed at a liquid-flow rate of 3 l/min, 
under a pressure of 100 kg/cm2G. The time required for the packing was 
approximately 30 minutes and the height of the gel bed was 60 cm. 
FIG. 4 shows the results of tests using the benzene elution as a sample 
with the use of this column. Theoretical plate numbers N and asymmetry 
factors A are generally used as the indexes for evaluating the column 
performances. They are determined from the formulae (1) and (2) 
respectively shown in FIG. 4. 
The results of the performance evaluation of the packed column in this 
example formed by the packing method according to this invention was 16000 
plates for the theoretical plate number and approximately 1.14 for the 
asymmetry factor as shown in Table 1. 
TABLE 1 
______________________________________ 
Theoretical 
Asymmetry 
Packing method plate No. factor 
______________________________________ 
Packing method 16200 1.13 
by this invention 
15800 1.14 
16000 1.14 
15500 1.14 
16400 1.13 
Conventional 15600 1.14 
packing method 16100 1.13 
15000 1.15 
16800 1.12 
17500 1.12 
Mechanical pressure 
9700 1.46 
packing method 11700 1.33 
12800 1.29 
9800 1.46 
10500 1.41 
______________________________________ 
Under the same conditions, using the column of 60 cm in length, the results 
of the performance evaluation tests on the packed column formed by the 
conventional slurry packing method showed nearly the same results compared 
with that of the above mentioned system of the invention (see Table 1). 
However, in the case of the conventional slurry packing method, operations 
for separating the reservoir and attaching the upper flange are required 
and much attention had to be p id for strictly controlling them and 
maintaining the fastening force of the upper flange constant at a fixed 
rate. 
One advantage of the packing operation according to this invention is that 
need for the attention described above is not required. As understood from 
the results of Table 1, a desirable tendency is recognized in that 
irregularity of the performance of the packed column by the packing method 
according to this invention is smaller than that by the conventional 
slurry packing method. It is supposed that the operation with good 
reproducibility is caused by the above described features. 
The same lot gel was also packed by the above described mechanical pressure 
packing method at a hydraulic compression pressure of 100 kg/cm2G. The 
results of the performance evaluation tests on the column of the effective 
gel bed height of 60 cm and 10 cm inner diameter under the same conditions 
obtained by this pressurized packing method are also listed in Table 1. As 
can be seen from the table, it is clear that the performance of the 
packing method has been effectively improved according to this invention. 
The advantages of this invention are that the packing method and the 
adjustable plug column device according to this invention can offer an 
axially adjustable column system enabling easy packing operations for 
liquid chromatography for separation and purification without losing high 
column performance of the conventional slurry packing method. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically describe herein.