Chromatographic analysis normalizer

In a chromatographic analysis system a bypass conduit operating in parallel with a chromatographic separation column diverts a portion of the sample fluid directly to the chromatographic detector prior to elution through the chromatographic separation column of the remaining portion of the sample material. Comparison of the detector response to the bypassed portion of the sample with the detector response to selected constituents or groups of constituents exiting the chromatographic separation column is used to normalize the analysis response to one or more constituents or groups of constituents eluted through the chromatographic separation column.

This invention relates to a method and apparatus for fluid chromatographic 
separation and analysis. In another aspect the invention relates to a 
method and apparatus for normalizing the response of a chromatographic 
analysis system. In still another aspect the invention relates to a method 
and apparatus for automatically normalizing a chromatographic analyzer 
output. In yet another aspect the invention relates to a method and 
apparatus for normalizing a plurality of related sequential telemetry 
signals. 
Chromatographic analysis techniques are useful in providing a quantitative 
determination of the composition of a fluid sample. For successive samples 
of predetermined size, the relative proportions of individual constituents 
or groups of constituents separated by a packed chromatographic column are 
often determined directly from the response of a chromatographic detector 
to the passage of the sample constituents or groups of constituents 
therethrough, after initial calibration of the analysis system has been 
completed. In applications where the size of the sample injected into the 
chromatographic analysis apparatus is subject to significant variation, 
calibration of the system to permit direct conversion of the 
chromatographic detector response to any preselected constituent or group 
of constituents is not possible. In analysis applications where such 
variations in sample size are expected, the usual method of determining 
the relative proportions of individual constituents of groups of 
constituents within the sampled fluid is to sum the detector response to 
all portions of the sample fluid passing therethrough by, for example, 
continuously integrating the detector response until such time as the 
entire sample has eluted through the chromatographic column, then 
comparing individual chromatographic peaks representing preselected 
constituents or groups of constituents to the entire sample response. Such 
a procedure, however, has the disadvantage of requiring all constituents 
to have eluted through the chromatographic column and passed through the 
detector before a determination can be made regarding the amount of any 
particular constituent or group of constituents within the sample. In 
addition, when the sample contains one or more constituents exhibiting 
extremely long elution times, the time following injection of the sample 
at which the meaning of the initial chromatographic peaks can be 
meaningfully interpreted is further delayed and/or additional equipment is 
required to backflush the chromatographic column in order to insure that 
all portions of the sample are presented to the chromatographic detector. 
Even when the greatest possible care is taken to insure that all portions 
of the sample are presented to the detector, some constituents present in 
relatively minute amounts may, due to the sensitivity or accuracy of the 
particular detector and detector response accumulation techniques and 
equipment, escape accurate inclusion in the overall determination of total 
sample content. The difficulties described hereinabove are most easily 
recognized in systems wherein individual samples of the same nominal size 
are introduced into a chromatographic analysis system by sampling 
techniques of obviously limited precision such as injection of samples 
into an analysis apparatus by means of a hypodermic needle in a laboratory 
analysis system. However, the same problems exist in sampling systems 
generally considered to be precise enough to permit use of an initial 
system calibration followed by direct determination of sample content 
directly from the individual constituent peaks detected. For example, some 
manufacturers' sample valves will, under process operating conditions, 
permit a variation in sample size on the order of about 1 percent. Such 
variations can be caused by the construction of the sample valve itself, 
variations in pressure of the sampled fluid, or other similar 
circumstances. While such relatively small variations in sample size can 
be tolerated in some applications without harmful effect, the increasing 
sophistication of automatic control systems and the need for automatic 
analysis equipment and methods for use in conjunction with such systems, 
as well as for laboratory use, make it desirable to provide a 
chromatographic analysis method and apparatus of improved accuracy. 
It is therefore an object of the invention is to provide a method and 
apparatus for fluid chromatographic separation and analysis. Another 
object of the invention is to provide a method and apparatus for 
normalizing the response of a chromatographic analysis system. Still 
another object of the invention is to provide a method and apparatus for 
automatically normalizing a chromatographic analyzer output. Yet another 
object of the invention is to provide a method and apparatus for 
normalizing a plurality of related sequential telemetry signals. 
In accordance with the invention, a method and apparatus are provided 
whereby a bypass column is connected in parallel with the chromatographic 
separation column of a chromatographic analysis apparatus to provide 
bypass flow of a predetermined portion of fluid around the chromatographic 
separation column directly to the chromatographic detector. The remaining 
portion of the sample fluid flows into the chromatographic separation 
column and is eluted therethrough to the chromatographic detector. In 
addition to providing a bypass column of a size suitable for dividing the 
flow of fluid through the parallel combination of the separation and 
bypass columns, and thus any sample fluid introduced thereto, into first 
and second portions having a predetermined relative size one to the other, 
the bypass column is sized to provide passage of sample fluid therethrough 
prior to elution of any portion of the sample material through the packed 
chromatographic separation column. The unseparated portion of the sample 
fluid flowing through the bypass column therefore arrives at the 
chromatographic detector means and passes therethrough prior to arrival of 
the first peak from the chromatographic separation column at the detector. 
Since the portion of sample fluid entering the detector from the bypass 
column bears a known size relationship to the portion of the sample fluid 
which enters the chromatographic separation column, the response of the 
chromatographic detector to the sample fluid exiting the bypass column can 
be used as a measure of the size of the sample to be separated. The 
detector response to the portion of sample material entering from the 
bypass column will therefore be a signal from which information indicative 
of the total amount of sample material passing through the bypass column 
can be obtained, and application of an appropriate constant factor to such 
a detector response will result in the generation of a signal from which 
information relating to the amount of sample fluid passing through the 
chromatographic separation column or the total amount of fluid sample 
introduced into the analysis apparatus can be obtained. As each of the 
peaks representing a constituent or group of constituents exiting the 
chromatographic separation column is provided by the chromatographic 
detector, the information provided by such responses can be immediately 
compared with the information provided by the initial detector response to 
the unseparated sample material from the bypass column, and an immediate 
determination of the relative amount of the constituent or constituents 
represented by each chromatographic peak, corrected for any variations in 
sample size, can be made. As each separated constituent or group of 
constituents exits the chromatographic separation column, therefore, the 
signal can be adjusted for variations in sample size or normalized and can 
thereafter be immediately used for control purposes without having to wait 
for the remaining sample constituents to be eluted through the 
chromatographic column to determine the total sample size. When only one 
or a few constituents or constituent groups are of significance, a 
chromatographic separation column for rapidly separating only those peaks 
of interest can be advantageously used to save analysis time while 
providing an accurately normalized determination of the presence of the 
separated constituents. In addition, constituents present in relatively 
minute quantities which might otherwise be provided to the chromatographic 
detector in amounts small enough to escape accurate detection due to the 
sensitivity of the particular detection system will be included together 
with all other constituents in the portion of the sample fluid entering 
the detector from the bypass column for the purpose of generating a signal 
from which the total sample size can be determined. Also, use of 
additional equipment otherwise needed to backflush slow eluting 
constituents through the detector from the separation column to obtain a 
measure of total sample size, even though such slow eluting constituents 
may be of no other interest, can be avoided.

Referring to FIG. 1, there is illustrated a chromatographic sample valve 
means 11 having associated therewith a sample inlet port 12, a sample 
outlet port 13, a pair of sample loop ports 14 and 15 having a sample loop 
16 of preselected volume connected therebetween, a carrier inlet port 17, 
and a carried outlet port 18. A sample source conduit 21 is operably 
connected in fluid communication with the sample inlet port 12 through a 
sample pump means 22 for providing a supply of sample fluid under suitable 
pressure to the sample inlet port 12 of the sample valve means 11. A 
sample disposal conduit 23 is operably connected in fluid communication 
with the sample outlet port 13 to provide for disposal of sample fluid 
exiting the sample valve means 11. 
A carrier supply conduit means 26 in fluid communication with a suitable 
source of chromatographic carrier fluid (not shown), and a pump means 27 
provide a source of chromatographic carrier fluid under pressure to the 
carrier inlet port 17 of the sample valve means 11 and to a reference 
fluid conduit 28. 
With the sample valve means 11 in its first position as illustrated by FIG. 
1, the sample fluid from the sample fluid conduit 21 flows into the sample 
inlet port 12, to the sample loop port 14, through the sample loop 16 to 
the sample loop port 15, to the sample outlet port 13, and through the 
sample outlet conduit 23 to a suitable sample fluid recycle or disposal 
means (not shown). Meanwhile, the carrier fluid enters the carrier inlet 
port 17 and is conveyed to the carrier outlet port 18 for delivery to an 
analysis conduit 32. When the sample valve means 11 is switched to its 
second position, its internal communication between ports 12 and 14, 13 
and 15, and 17 and 18 is terminated and communication between ports 12 and 
13, 14 and 17, and 18 and 15 is established, thereby injecting the fluid 
sample contained within the sample loop 16 into the carrier stream 
entering the sample valve means 11 through the carrier inlet port 17 and 
exiting through the carrier outlet port 18 and analysis conduit 32. 
The sample fluid thus introduced into the analysis conduit 32 is provided 
to the parallel combination of a chromatographic separation conduit 33 and 
a bypass conduit 35. The chromatographic separation conduit 33 and be any 
suitable chromatographic separation column capable of providing the 
desired separation of constituents or groups of constituents within the 
sample fluid. The bypass column 35 is preferably of such length and 
provides such restriction to flow that the flow rate of carrier fluid and 
sample fluid therethrough bears a predetermined relationship to the flow 
rate of carrier fluid and sample fluid through the chromatographic 
separation column 33 while also providing for passage of carrier and 
sample fluids therethrough in a period of time which is short enough to 
provide for passage of sample material from the bypass conduit 35 to the 
downstream confluence of the bypass conduit 35 and separation conduit 33 
prior to arrival at such downstream confluence of any portion of the 
sample material eluted through the chromatographic separation column 33. 
While any suitable relative flow rates between the chromatographic 
separation column 33 and bypass column 35 can be used, the use of a bypass 
column flow to separation column flow ratio with a range of from about 
1:10 to about 1:1 is presently preferred, with ratios within the range of 
from about 1:5 to about 1:1 being particularly preferred and a ratio of 
about 1:1 being most preferred. Any suitable arrangement of column sizing 
can be utilized to achieve such ratios. For example, the chromatographic 
separation column 33 is ordinarily selected to provide the desired 
separation and degree of separation with the bypass column 35 being 
adjusted by means of incorporation of capillary tubing, other similar 
small sized tubing, or packing material capable of presenting a resistance 
to flow but incapable of seriously delaying any of the sample 
constituents. These and other similar techniques can be used to adjust the 
rate of flow through the bypass column 35 so that the desired division of 
sample material between the separation column 33 and bypass column 35 is 
achieved. In addition, the total effective length of the bypass column 35 
is preferably such that the peak of unresolved sample material passing 
through the bypass column 35 to the detector means 41 will arrive at the 
detector means 41 and pass therethrough well in advance of the arrival at 
the detector means 41 of the first portion of sample material eluted 
through the chromatographic separation column 33. Such a timing 
arrangement will insure separation of the peak representing the bypassed 
sample from the peaks representing the eluted sample in the 
chromatographic detector output signal 46. Initial flow calibration and 
flow calibration checks can be accomplished by operating the system using 
a standard sample fluid consisting of a single rapid eluting constituent. 
At the downstream confluence of the parallel chromatographic separation 
column 33 and bypass column 35 a downstream conduit 37 accepts the 
combined flows of the separation and bypass conduits and provides the 
combined flow to the sample cell 42 of a detector means 41 having a sample 
cell 42 and a reference cell 43. The detector means 41 can be any suitable 
chromatographic detector such as a differential refractometer, a 
differential thermal conductivity cell, or other suitable detector means. 
Although a detector means 41 employing both a sample cell 42 and a 
reference cell 43 wherein the difference between the characteristics of 
the carrier fluid entering the reference cell 43 and the sample-containing 
carrier fluid entering the sample cell 42 produces a detector output 
signal 46 has been illustrated, the use of a suitable detector means 41 
which is not of a differential nature and employs only a single sample 
cell, such as a flame ionization detector, is within the scope of the 
invention. The effluent streams from the reference cell 43 and sample cell 
42 can be combined and provided through a disposal conduit 45 for suitable 
disposition as known in the art. 
FIG. 2 is a schematic illustration of the form of output signal 46 from the 
chromatographic detector means 41 which would be generated in response to 
a typical chromatographic separation not employing the bypass column 35 of 
the present invention. As can be seen from the FIGURE, at some time 
t.sub.1 following the injection of a sample into the analysis system at 
time t.sub.0 the first of the sample constituents or group of constituents 
eluted through the chromatographic separation column arrives at the 
detector to produce a first chromatographic output peak A. When the 
chromatographic separation column is selected so that substantially 
complete separation of successive constituents or groups of constituents 
eluted therefrom is achieved, there will be times t.sub.2, t.sub.3, 
t.sub.4 preceding each of the successive chromatographic peaks B, C, D, 
during which the output signal of the chromatographic detector is 
substantially zero. 
FIG. 3 illustrates the response of the detector 41, as embodied in the 
detector output signal 46, of the chromatographic analysis system of FIG. 
1 where a bypass column 35 is used in parallel combination with the 
chromatographic separation column 33. Although the chromatographic peaks 
A, B, C, and D representative of constituents or groups of constituents 
within the sample fluid separated by elution through the chromatographic 
separation column 33 are received in the same relative order and at the 
same relative times, the presence of the bypass column 35 having the 
preferred flow characteristics previously described, results in an 
additional peak S appearing in the chromatographic output between the 
sample injection time t.sub.0 and the time t.sub.1 at which the first 
elution of sample constituents through the chromatographic separation 
column 33 is detected. Because the detector response forming the peak S 
results from an unresolved sample portion containing representative 
amounts of each of the various sample constituents and groups of 
constituents, consideration of each of the following peaks A, B, C, D, and 
any others which may be resolved, in light of the information on relative 
sample size available from the peak S, will permit a quantitative 
determination of the amount of each sample constituent or group of 
constituents represented by the peak as soon as the peak is received. For 
example, the determination of the material represented by peak A can be 
made at any time after time t.sub.2. Similarly, by times t.sub.3 and 
t.sub.4 accurate quantitative determinations of the presence of 
constituents represented by peaks B and C respectively can be made. 
While any suitable means for utilizing the information contained in the 
chromatographic detector response to sample constituents from the bypass 
column 35 and chromatographic separation column 33 can be utilized, 
automatic analysis means have the advantage of providing unattended 
operation and can be used to particular advantage when automatic control 
of a continuous process is based on automatic periodic analysis of process 
fluids. FIG. 4 illustrates a preferred circuit by which automatic 
normalization of the information provided by the chromatographic detector 
response can be accomplished. In accordance with the circuit of FIG. 4, 
the electrical output signal 46 from the detector means 41 is received and 
applied to a plurality of scaling amplifier circuits 51S, 51A, 51B, 51C . 
. . . Each of the scaling amplifiers comprises an operational amplifier 
52S, 52A, 52B, 52C . . . having the noninverting input thereto connected 
to ground and receiving at the inverting input thereto, through a first 
scaling resistor 53S, 53A, 53B, 53C . . . , the detector output signal 46. 
A second scaling resistor 54S, 54A, 54B, 54C . . . is connected between 
the output of each respective operational amplifier and the inverting 
input thereof with the relative values of the two scaling resistors, 
specifically the resistance of the second or feedback resistor divided by 
the resistance of the first or input resistor, being determinative of the 
scaling factor applied by each scaling amplifier. The output of each 
scaling amplifier circuit is also connected to one terminal of a 
respective switch means 56S, 56A, 56B, 56C . . . , closure of which 
supplies the output of the associated scaling amplifier to a respective 
integrating circuit 61S, 61A, 61B, 61C . . . . 
Each integrating circuit 61S, 61A, 61B, 61C . . . comprises a respective 
input resistor 62S, 62A, 62B, 62C . . . through which an input signal from 
the respective associated switch means 56S, 56A, 56B, 56C . . . is 
supplied to the inverting input terminal of an operational amplifier 63S, 
63A, 63B, 63C . . . , the noninverting input of each amplifier being 
connected to ground. An integrating capacitor 65S, 65A, 65B, 65C . . . 
connects the output of each respective operational amplifier of the 
integrating circuit to the inverting input terminal thereof. Connected in 
parallel with each integrating capacitor is the series combination of a 
respective resetting resistor 67S, 67A, 67B, 67C . . . with a resetting 
switch means 68S, 68A, 68B, 68C . . . . When the resetting switch means is 
closed, the associated integrating capacitor is discharged through its 
resetting resistor to bring the signal at the output of the respective 
operational amplifier to zero. 
The output of the integrating circuit 61S is provided as an input signal 71 
to a divider circuit 72 for use as an input signal representative of the 
magnitude of the denominator of the dividing circuit 72. The outputs of 
each of the integrating circuits 61A, 61B, 61C . . . are applied to 
respective switch means 73A, 73B, 73C . . . so that closure of the 
associated switch means will provide the output signal from each of the 
respective integrating circuits as an input signal 75 to the divider 72, 
the divider 72 being adapted to accept the signal 75 for use in 
determining the magnitude of the numerator to be used in the division 
performed therein. 
The divider means 72 can be any suitable means for accepting a numerator 
signal 75 and the denominator signal 71 and delivering in response thereto 
an output signal 76 representative of the division of the numerator signal 
75 by the denominator signal 71. 
A programmer means 81 is utilized to control the operation of switch means 
56S, 56A, 56B, 56C . . . ; reset switches 68S, 68A, 68B, 68C . . . ; and 
switch means 73A, 73B, 73C . . . in a predetermined timed relationship, 
such timed relationship being coordinated with the passage of sample 
portions and separated sample constituents through the bypass column 35 
and the chromatographic separation column 33 to the detector means 41. For 
example, at or shortly following time t.sub.0 switch means 56S is closed 
while switch means 56A, 56B, 56C . . . remain in an open position. At this 
time switches 68S, 68A, 68B, 68C . . . will be closed or will have been 
closed in order to initialize the outputs of each integrating circuit 61S, 
61A, 61B, 61C . . . at a zero value and will be opened prior to closure of 
respective switches 56S, 56A, 56B, 56C . . . in order to permit operation 
of the associated integrator circuit. Switch means 73A, 73B, 73C . . . are 
also in an open position at time t.sub.0. 
As the signal 46 detector response to the passage of sample fluid from the 
bypass conduit 35 is received by the scaling amplifier 51S, it is scaled 
by proper choice of resistors 53S and 54S during standard calibration 
runs, to provide as the output of the operational amplifier 52S a signal 
which is representative of the size of the sample introduced by the sample 
valve 11 into the analysis conduit 32 of the chromatographic apparatus. 
Application of this output signal from the scaling amplifier means 51S 
through the switch means 56S to the integrating circuit 61S will result in 
production of a signal 71 at time t.sub.1 equal to the area under the 
curve S of FIG. 3. Since the area under a chromatographic peak or, in 
other terms, the integral of the detector response is known to bear a 
specific relationship to the amount of sample material detected, the value 
of signal 71 at time t.sub.1 is representative of the amount of total 
sample material introduced into the chromatographic analysis system. 
At time t.sub.1 switch means 56S is opened and switch means 56A is closed. 
The opening of switch 56S halts any further input into the integrator 61S 
and the value of the output signal 71 of the integrator 61S is maintained 
at the value present at time t.sub.1. Closure of switch means 56A at time 
t.sub.1 starts integration by the integrator 61A of the detector output 
signal designated as peak A in FIG. 3, and integration in this manner 
continues until time t.sub.2. At time t.sub.2 the output of the integrator 
61A is representative of the constituent or group of constituents 
represented by the peak A of FIG. 3 contained within the sample fluid 
analyzed. At time t.sub.2, therefore, the switch means 56A is opened to 
terminate input to the integrator 61A of the scaled detector output signal 
46 provided thereto, thereby maintaining the output of the integrator 
means 61A equal to the value of the area under the peak A of FIG. 3. At 
time t.sub.2 switch means 56B is closed and, in a manner similar to that 
previously described with respect to the operation of integrator means 
61A, the integrator means 61B begins integrating the portion of the scaled 
detector output signal representative of peak B of FIG. 3. At time t.sub.3 
when peak B has been received, switch 56B is opened and switch 56C is 
closed in order to maintain the scaled area under peak B as the output of 
integrator means 61B and to begin the integration of the scaled area under 
peak C by integrator means 61C. This procedure can be continued and 
extended to as many peaks as may be of interest in any particular 
chromatographic analysis procedure with each successive scaling amplifier 
51A, 51B, 51C in combination with its respective integrating means 61A, 
61B, 61C . . . providing a scaled integral signal representative of the 
amount of preselected constituents or groups of constituents within the 
sample fluid. 
At any time after time t.sub.2, switch means 73A can be closed to provide a 
signal representative of the amount of the constituent or group of 
constituents represented by peak A as signal 75 to the dividing means 72. 
Since the signal 71 has already been provided by the integrating means 61S 
a signal 76 representative of the normalized value of the constituents 
represented by peak A is available as soon as the switch means 73a is 
closed any time after time t.sub.2. In a similar manner, closure of switch 
73B at any time after time t.sub.3 of closure of switch means 73C at any 
time after time t.sub.4 will result in the generation of a signal 76 
representative of the normalized amounts of the constituents represented 
by peaks B or C. In order to prevent production of extraneous or confusing 
signals, only one of switches 73A, 73B, 73C . . . is closed at any given 
time. The means for initiating closure of switch means 73A, 73B, 73C . . . 
(not shown) can also be used to provide sampling of signal 76 when signal 
76 is representative of the amount of those sample constituents of 
interest for experimental, analysis, or control purposes and to provide 
such signals to appropriate equipment. 
Following the completion of delivery of the respective output signals of 
integrating means 61A, 61B, 61C by the associated switch means 73A, 73B, 
73C to the divider 72, and following the completion by the dividing means 
72 of all activity associated with a particular analysis cycle, resetting 
switches 68S, 68A, 68B, 68C . . . can be closed to reset the outputs of 
respective integrators 61S, 61A, 61B, 61C . . . to zero in preparation for 
the next analysis cycle. Resetting of the various integrators can 
therefore be accomplished as soon as the information from that integrator 
is no longer needed for subsequent use by the divider 72 or at the end of 
the analysis cycle when all previous values can be reset in preparation 
for a succeeding analysis. 
While the circuit illustrated by FIG. 4 utilizes a separate scaling 
amplifier 51S, 51A, 51B, 51C for each chromatographic peak, it is, of 
course, within the scope of the invention to use a single scaling 
amplifier as the source of signal to a plurality of switch means 56S, 56A, 
56B, 56C . . . . One such alternate example would be the use of a scaling 
amplifier 51S along with a single additional scaling amplifier performing 
the function of amplifiers 51A, 51B, 51C . . . . Additionally, under 
circumstances where the flow rates through the bypass conduit 35 and the 
chromatographic separation conduit 33 are equal, a single scaling 
amplifier could be used to perform the desired scaling function for all 
signals to be integrated or, all scaling amplifiers 51S, 51A, 51B, 51C . . 
. could be omitted from the circuit. 
In addition to its functions in controlling the switching associated with 
the separate integration of various portions of the detector signal 46, 
the programmer 81 can be utilized to initiate chromatographic analysis 
cycles by controlling operation of the sample valve 11 and by performing 
such other timed or analysis-dependent switching or programming operations 
as may be desirable. 
Components suitable for use in accordance with the illustrated preferred 
embodiment of the invention of FIGS. 1 and 4 are as follows: 
______________________________________ 
Sample valve 11 
Model IX valve manufactured by 
Applied Automation, Inc. 
Bartlesville, OK 74004 
Pumps 22 and 27 
Pump number 82-S-35 manufactured by 
Sprague Engineering 
P. O. Box 430 
Gardena, Calif. 90248 
Chromatographic 
Stainless steel tube 25 cm. in length, 
separation column 33 
1/4 inch O.D. packed with a material 
which would cause some delay to all 
constituents of the particular sample, 
such as Lichrosorb S160, 5 micron 
size, manufactured by 
E. M. Laboratories, Inc. 
500 Executive Blvd. 
Elmsford, N.Y. 10523 
Bypass column 35 
25 cm. in length, 1/4 inch O.D. 
with packing which would cause 
no chromatographic separation, 
such as glass beads 
Detector means 41 
Refractive Index Detector part 
number A55002 manufactured by 
Applied Automation, Inc. 
Bartlesville, OK 74004 
Amplifiers 52S, 52A, 
Burr-Brown low bias current amplifier 
52B, 52C...; 63S, 
No. 3542, manufactured by 
63A, 63B, 63C... 
Burr-Brown Research Corp., 
Tucson, Arizona 85734 
Divider 72 Analog Devices Divider AD530 
manufactured by 
Analog Devices, Inc., 
Norwood, Mass. 02062 
Programmer 81 and 
Programmer Model 102, manufactured by 
associated switches 
Applied Automation, Inc. 
Bartlesville, OK 74004 
Resistors 53S, 53A, 53B, 53C... 
10 K ohm 
Resistors 54S, 54A, 54B, 54C... 
Selected to give proper scaling 
Resistors 62S, 62A, 62B, 62C... 
10 K ohm 
Resistors 67S, 67A, 67B, 67C... 
100 ohm 
Capacitors 65S, 65A, 65B, 65C... 
10 microfarad 
______________________________________ 
One example of an application of the method and apparatus of the invention 
using alternate separation and bypass columns with the remainder of the 
apparatus being the same as listed above would be the determination of the 
relative constituent amounts in a stream containing isobutane, n-butane, 
1-butene, isobutylene, trans-2-butene, cis-2-butene, and 1-3-butadiene. 
For this analysis, a suitable separation column is 1/8 inch O.D. stainless 
steel tubing four feet in length packed with 10% by weight 
bis[2-(2-methoxyethoxy)ethyl]ether (Eastman Kodak Company, Rochester, 
N.Y.) on a 80% by weight substrate of Chromosorb P (Johns-Mansville 
Company) based on the total weight of packing material. Using this 
particular separation column, the seven components of the sample will 
elute in six peaks with 1-butene and isobutylene eluting together in a 
single peak. A bypass column suitable for use with such a separation 
column is 1/16 inch O.D. stainless steel open, unpacked tubing two feet in 
length. At specific times following injection of the sample, a large 
unseparated peak from the bypass column will be seen by the detector 
followed by six successive peaks from the separation column. With the 
first unseparated peak being provided to the denominator of the divider, 
the normalized proportion of each constituent, or group of constituents in 
the case of 1 -butene and isobutylene, can be determined as each of the 
following six peaks is received and provided to the numerator of the 
dividing circuit. There is no need to backflush the separation column to 
determine the amount of other possible slow-eluting constituents in the 
sample prior to generating a signal representing the normalized proportion 
of a specific constituent in the sample, or is there any need to wait for 
all constituents to elute prior to generating a signal representing the 
normalized relative proportion of an early eluting constituent in the 
sample. In addition, analysis for one or more key constituents can be 
terminated as soon as the key constituents arrive at the detector with the 
most expeditious procedure available under the circumstances being used to 
clear the separation column in preparation for a subsequent analysis. 
While the invention has been described in conjunction with the presently 
preferred embodiments thereof reasonable variations and modifications are 
possible by those skilled in the art within the scope of the invention and 
of the appended claims thereto.