Патент USA US3435666

p,
April 1, 1969
3,435,659
J. c. STERNBERG
RETENTION SPECTRUM ANALYSIS APPARATUS
Filed June 20, 1966
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ATTORNEY
April 1,1969
"J. c. STERNBERG
_
3,435,659
RETENTION SPECTRUM ANALYSIS APPARATUS
Filed June 20. ‘19,66
Sheet‘ 42
of‘ 2 ‘
FR—LA~OTW>E
CARRIER
GAS
34
2
(N)
—---
DETECTOR
-—->VENT
TRACER
GAS
33
'
RECORDER
JAMES C. STERNBERG
INVENTOR
éw/w %
ATTORNEY
United States Patent O?ce
3,435,659
Patented Apr. 1, 1969
2
1
e?luent of a single sample component through a plurality
3,435,659
James C. Sternberg, Fullerton, Cali?, assiguor to~Beck~
of columns. In one form of the apparatus a number of
chromatographic columns are connected in series to the
input of a detector. A restrictor is also connected from
man Instruments, Inc., a corporation of California
the input of each of the columns to the input of the de
Filed June 20, 1966, Ser. No. 558,679
tector. The last column may be connected directly to
Int. Cl. G01n 31/08
the detector or by way of another additional restrictor.
US. Cl. 73-231
16 Claims
If the volumes of the restrictors and connecting lines to
the detector are small, the time of transit of samples from
10 each split point to the detector can be made negligibly
ABSTRACT OF THE DISCLOSURE
small. At each restrictor the stream will split and a portion
passes through the adjacent column while the other por
One embodiment involves a source of carrier gas in
tion passes through the detector. Since the time delay
series with a ?ow controller and a sample inlet and a
through the restrictor to the detector is very small, a peak
number of chromatographic columns, each of which is
followed by a delay, with the output of the last delay 15 occurs at the output of the detector which is indicative of
the retention time in the preceding column. It should be
being fed into a detector and a source of tracer gas in
noted that the time of injection of the sample need not
serted between the detector and the last delay. A second
RETENTION SPECTRUM ANALYSIS APPARATUS
embodiment involves the series combination of a source
of carrier gas, a ?ow controller and a sample inlet with
be separately known, since the ?rst column is preceded
by a restrictor. The measured detector response to a
single sample will thus provide retention data for all four
columns.
The present invention provides new and novel appara
output of the last parallel combination being connected
tus and methods whereby the time related spectrum of a
to the detector and a source of tracer gas being inserted
sample through a plurality of columns may be obtained by
between the last parallel combination and the detector, said
tracer being detectable by the detector for the purpose of 25 utilizing a plurality of columns connected in series. Al
though providing much of the same data as provided by
indicating variations in ?owrate of the output. The tracer
the apparatus disclosed in my aforementioned copend
gas may either be inserted at a constant rate or at ?xed
ing application the apparatus and method herein dis—
thermodynamic activity.
closed has the advantage of being somewhat simpler, not
requiring the manifold disclosed in the aforementioned
application. Since the sample is not split after each col
This invention relates to apparatus for the qualitative
umn as in the prior apparatus the same amount of sam
characterization of samples and, more particularly to
ple passes each column and can, if desired, the trapped in
new and improved apparatus providing a timeerelated
toto for further study following elution from the ?nal
spectrum in its output.
35 column without ever actually passing through the detector.
For the identi?cation of substances solely from chro
The present invention also provides new and novel
a delay and a number of parallel combinations of chemi
cal modi?ers in parallel with a delay and‘ a restrictor, the
matographic data, it is necessary, except in the simplest
cases, to obtain retention data on more than one sta
tionary phase. Methods employing two-column plots,
retention volume constants or retention index diiferences
all rely on data from two different columns and ex
perience has shown that data from more than two is high
ly desirable.
Several apparatus and methods have been developed
in the prior art for obtaining such data. One approach
of maintaining several chromatographs with appropriate
columns or of changing columns in a single chromato
graph is wasteful of time and equipment. Various schemes
have been advanced by which multi-column retention data
apparatus for the qualitative characterization of separate
components and particularly the rapid identi?cation of
functional groups, elemental compositions or other struc
tural features of a sample with the output available on a
single recorder.
Other advantages of the invention will become ap
parent to those skilled in the art as the invention be—
comes better understood by reference to the following de
tailed description and the features of novelty which
characterize the invention will be pointed out with par
ticularity in the claims annexed hereto and forming a
part hereof.
In the drawings:
can be obtained from a single sample injected into one 50
FIG. 1 is a schematic diagram of one embodiment of
apparatus. Arrangements in which a sample traverses
the invention employing a series of columns and a single
several columns in series with detectors between them
are limited to nondestructive detectors, and require sev
eral detectors, as do arrangements in which a sample is
split among several parallel columns, each with its own
detector. Franc and Michajlova, Journal of Chromatog
raphy, vol. 12, p. 22, 1963, have employed four columns
in parallel, with the combined e?luent passing into a
common detector. If the sample has a different retention
time on each column, the detector will show four distinct
peaks. The use of this parallel column technique sulfers
from the fundamental disadvantage that the individual
peaks cannot be assigned to elution from a particular
column. The data although providing a ?ngerprint of
the sample cannot be used for other purposes. A second 65
disadvantage in this type of system occurs when similar
retention times on two of the columns have led to the
detector;
FIG. 2 is a graph of the output of the detector illus
trated in FIG. 1 as a function of time; and
FIG. 3 is a schematic diagram of a second embodi
ment utilizing selective chemical modi?ers for the char
acterization of an unknown sample.
Referring now to FIG. 1 there ‘is illustrated apparatus
for measuring the time related spectrum of a sample on
a series of columns. A source of carrier gas -10 is con
nected through flow controller FC and provides a source
of carrier gas for columns C1, C2, C3 and C4 connected
in series between the ?ow controller and detector 11. A
sample inlet 12 is provided in the carrier gas line be
tween the ?ow controller and the ?rst column and may
comprise any suitable means for introducing a sample
such as a sampling valve or a septum for injection by
way of a syringe. The columns C1, C2, C3 and C4 are each
recording of a single unresolved peak.
iIn my copending application, Ser. No. 435,931, now
U.S. Patent 3,386,279, ?led Mar. 1, 1965, for Time Res 70 separated by a delay line D1, D2 and D3 respectively and
a forth delay line D, is interposed between column C4
olution Analysis Apparatus there is disclosed an im
and detector 11. If desired, a sample trap may be in
proved apparatus which provides time resolution of the
3
3,435,659
arranged to provide a suf?cient delay to isolate the effects
of the sample on the detector when it leaves one column
from those eifects upon entering the next. Access points
15, 16, 17, 18 and 19 are provided for making pressure
?ow rate will determine whether or not the tracer reaches
equilibrium concentration. For proper functioning over the
entire range of ?ow it is desirable that the tracer always
reach equilibrium concentration. Thus, the saturator must
measurements within the system which are needed only
in the initial start-up of the operating conditions in order
to permit expression of retention volumes in standard
pressure-corrected units. When the desired ?ow has been
established, the pressure is read at these access points with
a pressure gauge or manometer.
A tracer gas is introduced into the carrier gas ?ow
just prior to the detector by any suitable means such as
from source 21.
Any type of sensor which will respond to changes in
the concentration of the tracer being introduced into the
stream may be utilized. If the sensor is concentration
sensing, such as thermal conductivity or gas density de
tectors, electron capture detectors, cross section ioniza
tion detectors, spectrophotometers an colorimeters, and
the tracer substance is introduced at a ?xed ?ow rate, the
signal output of the detector will vary as a function of
the ?ow rate of the carrier gas stream. If the tracer is intro
duced at a ?xed ?ow rate and the carrier gas stream flow
4
The temperature at which the saturator is 'held by the
constant-temperature bath, thus determining the thermo
dynamic acivity of the tracer, together with the area of
tracer exposed to the ?uid stream and the ?uid stream
serted after delay line D4. The delay lines D1—D4 are
be constructed so that the extent thereof is su?icient to
10
insure equilibrium concentration of the tracer at the high
est expected ?uid ?ow rate. The saturator temperature
should be maintained sufficiently low that the tracer activ
ity is below that which would correspond to equilibrium
with the connecting tubing between the saturator and the
detector, so that the tracer activity is actually determined
by the temperature in the saturator. If the sensor is rate
of introduction sensitive and if the sensor has an abso
lutely known response, then the output of the detector be
comes a measure of the carrier gas flow completely inde
pendent of what gases are employed or measured.
Several rate of introduction sensors are well known in
the art such as the hydrogen ?ame ionization detector
or the Hershch galvanic cell. A suitable example of the
hydrogen ?ame ionization detector is described in Chap
rate increases, the concentration of the tracer will de— 25 ter 18 of Gas Chromatography, Academic Press, New
crease. On the other hand, when the carrier ?ow rate
York, 1962, and in the copending application of W. Galla
decreases the tracer concentration will increase. Thus the
way and A. Seibel, Ser. No. 347,749 for Flame Ionization
output of the detector will be inversely proportional to the
Detector, now U.S. Patent No. 3,372,000, assigned to the
carrier gas flow. As is well known, when a chromato
assignee of the instant application. These detectors are re
graphic column containing a partitioning agent or ad
sponsive to most organic compounds which can be intro
sorbent sorbs a sample there is an accompanying decrease
duced into the system as tracer substances by a suitable
in the carrier gas ?ow. As the sample comes off the col
saturator. A suitable example of the Hersch galvanic cell
umn there is an accompanying carrier gas flow increase.
is illustrated in FIG. 2 of U.S. Patent 3,258,411. For use
Since the detector 11 is sensitive to carrier gas ?ow
in the instant invention the conversion unit 58 of FIG. 2
changes, the sorption and desorption of a carrier at col
of said patent would be replaced by an iodine saturator.
umn C1 is recorded at the instant of sorption and desorp—
Such sensors measure the rate at which the sensed gas is
tion. The time dilference between the sorption and de
introduced into the detector, and, since the carrier gas is
sorption peaks is an accurate measure of the column re
always saturated with tracer, variations in the amount of
tention time.
tracer introduced at the detector are directly proportional
Referring now to FIG. 2 there is illustrated a record of
a retention spectrum from the apparatus of FIG. 1 when
to variations in the rate of ?ow of the carrier gas. A more
complete description of the operation of the rate of intro
each of the columns absorb the sample by varying de
grees. Sample injection occurs at T1 and is accompanied
duction sensor as a ?ow monitor may be found in my
by a resulting momentary increase of ?ow rate of the car
rier gas. At T2 the sample enters column C1 and an ac
companying carrier gas ?ow decrease results in increased
concentration of the tracer at the detector and therefore
ratus and Method for Flow Monitoring, ?led concurrently
herewith and assigned to the assignee of the instant inven
tion.
a momentary increase in the signal. Upon desorption from
column C1 at T3 the carrier gas ?ow increase momentarily
sample for the differing columns C1-C4 may be obtained
copending application, Ser. No. 558,787, entitled Appa
With the foregoing apparatus a retention spectrum of a
with a single injection of the sample over a relatively
short time. Since relative retention values are widely
going peak. Thus, the retention time t1 is given by the 50 tabulated, comparison of the retention spectrum of a sam
diiference between the peaks occurring at T3 and T2. Delay
ple component with that of a reference substance pro
line D1 insures su?icient time between the desorption of
vides a means of qualitative identi?cation. In addition,
the sample from column C1 and its sorption at C2 to
the retention spectrum of a new component or compo
resolve these peaks; thus sorption at C2 occurs at T4 with
nents may be readily obtained for utilization in column
resulting in a decreased tracer concentration, or a negative—
desorption occurring at T5 giving a retention time t2. 55 design. For example, with the knowledge of pressure,
With a detector of the type that is concentration sensing
temperature and overall ?ow, complete retention infor
and the introduction of a tracer gas in the aforementioned
manner ahead of the detector, the occurrence of events
mation is furnished for a component on several columns
with a sample in a single sample run. The run can be
upstream from the detector which are accompanied by
repeated at a second temperature to give complete in
corresponding changes in carrier gas ?ow rates may be 60 formation of the elfect of temperature on retention in
recorded at the instant of occurence. Since the tracer may
each column, or a system may be constructed in which
be introduced immediately preceding the detector, and the
a series of columns at one temperature is followed fby a
detector may be placed remote from the upstream com
similar series at another temperature still utilizing only a
ponents a wide variety of tracer gases may be utilized
single detector. The number of columns interposed be
since their presence does not affect the carrier gas stream, 65 tween the sample inlet and the detector is restricted only
the sample, or the particular column. It is only essential
that the detector be responsive to changes in the concentra
tion of the tracer gas.
by the ultimate loss in sensitivity as the sample band be
comes more and more di?Fuse after traversing several
columns.
A second type detector may be utilized in the system
Referring now to FIG. 3 there is illustrated a system
70
of FIG. 1 which may ‘be sensitive to the rate of intro
‘for the characterization and identi?cation of a sample
duction of the tracer to the detector. In this system a
component by its various chemical characteristics. Car
saturator may be placed in the carrier gas line at 22 for
rier gas from source 30 passes ?ow regulator PC’ into
introducing a tracer gas at ?xed thermodynamic activity,
a. system which is provided with a sample inlet 31 which
thus at ?xed concentration.
75 may be a septum or sampling valve. A delay line D1’ is
3,435,659
5
6
of one component or constituent with respect to another
and are not considered “active elements.”
There has been illustrated and described an apparatus
provided in the main conduit after which the sample en
counters a series of chemical modi?ers CM1, CM2, CMn
having connected in parallel therewith respectively a delay
line and a restrictor. Thus delay line D2’ and restrictor
R1 are connected in parallel with chemical 'modi?er CM1
and delay line D,’ and restrictor R2 are connected in
in which a retention spectrum or identi?cation of a sam
ple may be obtained utilizing a series of columns or
chemical traps and a single detector which is capable of
recording events occurring upstream from the detector
parallel with chemical modi?er CM2. Any other number
at the time of occurrence. The apparatus and methods
disclosed may also be utilized in evaluating column de
(n) of such groupings may be provided. A tracer gas is
introduced into the conduit from tracer gas source 33
upstream of detector 34 which may be located at any point 10 sign for use with particular samples and provide conven
ient reference retention spectrum for a particular sample
within the system prior to where the carrier gas is vented.
in a single sample run. The apparatus is also useful in
Detector 34 may have its output connected to a recorder
quantitative and qualitative identi?cation of samples.
to provide a permanent record of its output as a function
While the invention has been described in connection
of time.
The sample after injection at 31 is divided at the vari 15 with the illustrated embodiment it is to be understood
that many variations and modi?cations thereof are pos
ous split points into a stream through a selective modi
sible and will be obvious to those skilled in the art in light
?er, such as CM1 and a stream through the delay line
of the teachings herein contained without departing from
and its restrictor, such as D2’, R1. When the sample hits
the spirit and scope of the appended claims.
such a grouping it is divided in a preset ratio such as a
What is claimed is:
20
fraction
1. A ?uid analysis apparatus comprising:
L
means for providing a ?ow path for a ?uid stream;
means for introducing a sample into said stream;
at least two active elements connected in series in said
?uid stream which produce a change in the ?ow upon
n+ 1
which ?ows through the chemical modi?er and a fraction
25
contact of the sample therewith;
n+1
which ?ows through the delay line and the restrictor.
means for continuously introducing a tracer substance
into said stream at a location downstream from said
The delay line and restrictor are chosen to match the
volume and restriction of the chemical modi?er.
30
If the detector 34 measures the concentration of the
elements;
sensor means sensitive to the tracer for detecting and
indicating changes in the ?ow of said tracer substance
as a ‘function of time, the sensitivity of sensor to
tracer gas passing therethrough, the output of the detector
is proportional to the ?ow rate of the carrier gas through
detector 34. As in the previous embodiment, the detecting
said tracer substance being substantially unalfected
by presence of other substance in said ?uid stream,
system may comprise a saturator and a rate of introduc
tion detector. In either case the detector output will be a
measure of ?ow in the system. Let it now be presumed
whereby corresponding changes in the ?ow of said
that the chemical modi?er CM1 is such as to remove a
2. The ?uid analyzer of claim 1 wherein said tracer
stream due to the action of said elements on a sample
can be determined.
substance is introduced at a ?xed ?ow rate and said sensor
component from the introduced sample. This is accom
panied by a resulting decrease in carrier gas ?ow in a 40 detects and indicates the relative concentration of said
tracer substance in said ?uid stream.
step-wise function. The time of decrease indicates which
3. The ?uid analyzer of claim 2 wherein said sensor
chemical modi?er removed the sample while the magni
means includes a thermal conductivity detector.
tude thereof indicates how much of the sample was re
4. The ?uid analyzer of claim 1 wherein said tracer
moved. This results in a binary record of the form indi
is introduced in said ?uid stream at ?xed thermodynamic
cating that a particular component was present, since
activity and said sensor detects and indicates the quantity
it was removed by the ?rst chemical modi?er, or that this
per unit time of tracer substance introduced to said de
component was not present, since it was not removed.
Any number of chemical modi?ers may be provided to
provide an identi?cation of the sample from the various
components either present or absent from the system. As
an example, the ?rst chemical modi?er or trap CM1 may
comprise concentrated H2SO4 on glass beads and the sec—
ond modi?er or trap CM2 a solution of AgNO3 in N
tector.
5. The ?uid analyzer of claim 4 wherein said means
' for introducing said tracer substance comprises a thermo
stated iodine saturator and said sensor is an iodine sensitive
galvanic cell.
6. The ?uid analyzer of claim 4 wherein said tracer
substance is an organic compound and said sensor means
methyl pyrrolidone on glass beads. In the following binary
table “1” indicates that the sample passes the trap and 55 a hydrogen ?ame ionization detector.
7. The ?uid analyzer of claim 1 wherein said active
“0” indicates that it does not.
elements comprise chromatographic columns.
Sample
CM;
CM;
Hexane _______________________________ __
1
Propylene _ _ _ . _ _ _ _
_ _ _ _
0
0
____
1
0
Diisopropyl other _____________________ __
0
1
Methyl iodide _____ __
_ _ _ _ . _ .
1
It is seen that with only two chemical modi?ers, \four
samples may be distinguished. As hereinbefore indicated
the downstream detector will provide an output change 65
when the ?ow rate of the carrier changes upon removal
of component by the trap at the time such reaction
occurs.
Chromatograph columns such as C1-C4 and chemical
modi?ers, such as CM1 and CMZ are herein de?ned as 70
“active elements” and this term is meant to apply, here
inafter in the claims, to any such devices which selectively
change ?ow rates of one or more constituents with re
spect to others. A restrictor, such as restrictors R1 and
R2, shown in FIGURE 3, do not change relative ?ow rates 75
8. The analyzer of claim 1 wherein said active elements
comprise selective chemical traps.
9. The analyzer of claim 2 wherein said active elements
comprise chromatographic columns.
10. The analyzer of claim 3 wherein said active ele
ments comprise chromatographic columns.
11. A ?uid analysis apparatus comprising:
a continuous conduit system for conducting a ?uid
stream therethrough;
means for connecting said conduit system to a source
of carrier ?uid;
means connected in said system for introducing a sam
ple to said carrier ?uid; ‘
at least two chromatographic columns connected in
series following said sample introduction means in
the conduit system;
delay means connected between each of said columns
such that elution of ?uid from one column is time
7
3,435,659
8
separated from introduction of said ?uid to the sub
stated iodine saturator and said sensor is an iodine sensi
sequent column;
tive galvanic cell.
16. The ?uid analysis apparatus of claim 14 wherein
means connected in said system downstream of the last
said tracer substance is an organic compound and said
of said columns for continuously introducing a tracer
5 sensor is a hydrogen ?ame ionization detector.
substance to said ?uid stream;
sensor means sensitive to the tracer for detecting and
References Cited
UNITED STATES PATENTS
indicating changes in the ?ow of said tracer substance
as a function of time, the sensitivity of sensor to said
tracer substance being substantially una?ected by the
presense of other substance in said fluid stream, 10
whereby various processes accompanied by corres
ponding changes in ?uid ?ow occurring upstream of
said sensor and tracer introducing means may be
indicated as each occurs.
12. The ?uid analysis apparatus of claim 11 wherein 15
said tracer substance is introduced to said ?uid stream
at a ?xed ?ow rate and said sensor detects the relative
concentration of said tracer substance in said ?uid stream.
13. The ?uid analysis apparatus of claim 12 wherein
3,117,225
3,304,170
1/1964
2/ 1967
Willis ___________ _.. 250-435
Hinsvark ___________ __ 75-34
3,068,686
12/1962
Harmon __________ __ 73—-23.1
3,120,749
3,156,548
2/1964
11/1964
3,177,700
4/1965
Paglis et al. _______ __ 73—23.1
Perry ____________ __ 73—-23.l
Sier ________________ ..._ 73—-19
OTHER REFERENCES
Pecsok, Robert L.: Principles of Gas Chromatography,
1959, John Wiley & Sons, pp. 132 and 133.
said sensor is a thermal conductivity detector.
2° RICHARD c. QUEISSER, Primary Examiner.
VICTOR I. TOTH, Assistant Examiner.
said tracer substance is introduced at a ?xed thermody
14. The ?uid analysis apparatus of claim 11 wherein
namic activity.
US. Cl. X.R.
15. The ?uid analysis apparatus of claim 14 wherein
said tracer substance introducing means includes a thermo
25 73-194