the carpenter form of the haldane gas analysis apparatus. changes made in the apparatus and ...

21 Pages·2003·0.99 MB·English

THE CARPENTER FORM OF THE HALDANE GAS
ANALYSIS APPARATUS.
CHANGES MADE IN THE APPARATUS AND DETAILS RE-
GARDING ITS USE.
BY THORNE M. CARPENTER, EDWARD L. FOX,
AND ARTHUR F. SEREQUE.
(From the Nutrition Laboratory, Carnegie Institution of Washington, Boston.)
(Received for publication, May 13, 1929.)
The apparatus devised in this laboratory (Carpenter, 1923) for
the analysis of chamber air has now been in use several years and
has given satisfaction in the investigations carried on in coopera-
tion with the Institute of Animal Nutrition at the University of
New Hampshire (Benedict and Ritzman, 1927). Its use in a
European laboratory has recently been described by Grafe, Strieck,
and Otto-Martiensen (1927) whose experience with it substantiates
the claims made for the apparatus in the original description. A
l
modified form of this apparatus has been described by du Vigneaud
(1927).
An important modification of the potassium pyrogallate pipette
in the Haldane apparatus has been made by Professor J. C. Bock*
of the Department of Pharmacology, University of Copenhagen,
who has placed a glass bead in a bulb of the pipette in such a way
that it acts as a one-way valve. The pipette was further modified
so that the solution would return through side tubes and thus
make fresh solution available for the absorption of oxygen. The
description of a pipette on the same principle has been given by
Strieck (1928). This form of potassium pyrogallate pipette has
been adapted in this laboratory to the Haldane-carpenterappara-
tus, which has been changed in some details. A description of the
apparatus in its present form and of a modification of the combus-
tion apparatus for methane, and further details regarding the use
of the apparatus are given in the following pages.
1 Personal communication from Professor August Krogh to Professor
Francis G. Benedict.
211
This is an Open Access article under the CC BY license.
212 Gas Analysis Apparatus
I
*!i
Cm.
FIQ. 1. The Carpenter form of Haldane gas analysis apparatus. The
apparatus consists of the burette, K, compensator tube, B, water jacket, A,
potassium hydroxide pipette, E, with its levelling bulb, P, the modified
form of potassium pyrogallate pipette, FM, and the mercury levelling bulb,
N, connected to the burette, K.
Carpenter, Fox, and Sereque 213
Changes in Apparatus.
A diagrammatic sketch of the apparatus in its present form for
determination of carbon dioxide and oxygen is shown in Fig. 1.
The following changes are a portion of the improvements which
have been made: The water jacket, A, is tapered and flared slightly
at the bottom so as to permit the use of a smaller rubber stopper.
The stopper fits tightly and makes a water-tight closure. The
lower end of the compensator tube, B, is closed by fusing instead of
being closed with a rubber tube and pinch-cock. The latter ar-
rangement has caused much trouble, because it was difficult to
remove air bubbles from the connection when the tube was partly
filled with water. The capillary tube, 6, leading from the three-
way stop-cock, D, to the potassium hydroxide pipette, E, has been
shortened and straightened and the curved capillary has been
placed on the side leading to the pipette, F, which holds the potas-
sium pyrogallate.
When the apparatus is set up, the capillary tee, G, and stop-
cock H, and the compensator, B, are adjusted at such a height that
the volume included between the level of the potassium hydroxide
in the capillary, J, and the point which the top of the water in
the jacket, A, touches on the compensator, B, just equals the
volume from the water level on the burette, K, to the level of the
potassium hydroxide in the capillary, C, of the pipette, E.
The volumes of these portions of the apparatus are determined
by filling the parts with mercury, weighing the mercury, and eal-
culating the equivalent volume from the density of the mercury
at the temperature at which the determination is made. In
practice, a mark is made on the burette, K, at the level of the water
in the water jacket. The capillary and stop-cock of the burette and
angle above the stop-cock are then filled with mercury, the weight
of which is determined. Similarly, the capillaries, L and C, of the
potassium hydroxide pipette and stop-cock D are filled with met-
cury to the point which the level of the potassium hydroxide
touches and the mercury is weighed. The sum of the two volumes
computed from these weighings gives the volume to which the part
of the compensator, B, outside the water jacket and the capillary
tee to the surface of the potassium hydroxide in J must be adjusted.
The volumes of the latter capillaries are determined in much the
same manner as above. From the volume in a given length of one
214 Gas Analysis Apparatus
of t.he capillaries, the height to which the compensator, B, and capil-
lary tee, G, have to be set is estimated, and a determination of the
corresponding volume is made by weighing the mercury required
to fill the capillaries to the estimated points. In order to make
adequate compensation for the curves in the capillaries between
the burette, K, and the potassium hydroxide pipette, E, the capil-
lary leading to the stop-cock, H, which opens to the outside air, has
been lengthened. When this compensation in the volumes of the
capillaries outside the water jacket is exactly made, an air sample
can be analyzed with a change of 1” in the external temperature
during the half hour required, without appreciable error in the
results. In other words, the apparatus compensates for changes
in the environmental temperature.
Modified Pipette for Potassium Pyrogallate.-The most funda-
mentaI change in the apparatus is the new pipette, FM, for potas-
sium pyrogallate. A diagrammatic sketch of the pipette alone is
shown in Fig. 2, the main portion being the same as in the earlier
form of the apparatus except that the reservoir bulb, E, is much
larger. The modification is as follows: At Q on the uppermost
bulb, A, of the series of ten conical bulbs, a connecting tube, B, is
fused which projects outward at a slight angle and extends down-
wards to the point C where it is shown as open at the end. A tube,
D, similar in construction, is fused into the upper part of the large
bulb, E, and extends downwards to L. The separated portion,
FGHJ, is a device of glass which is attached at F and G to the two
side tubes, B and D, by means of rubber tubing when the ap-
paratus is in use. At M, where the tube, P, opens downward from
the bottom of the large bulb, E, is a steel ball 9.5 mm. in diameter
(standard g inch ball bearing ball) which fits snugly into the
tube, P. The tube has been ground at that point and the side
opening, N, is large enough for the steel ball to be rolled into place
from the outside. In the part, FGHJ, is also a steel ball at K
which fits snugly into the tube, J, which has been ground at K, and
at H is an opening large enough for rolling the ball in or out. At
R and S are openings which are connected with rubber tubing.
This rubber connection can be closed by a spring pinch-cock. The
open tee at U is used for the insertion of a thermometer or for filling
the pipette with the pyrogallate solution.
After the part, FGHJ, is attached to the main portion of the
Carpenter, Fox, and Sereque 215
FIG. 2. Detail of modified potassium pyrogallate pipette. The appara-
tus consists of a series of bulbs beginning at A, and a large reservoir, E,
both of which have side tubes, B and D. The large bulb, E, is sealed at the
bottom by the movable steel ball, M. The part, FGHJ, (shown detached)
is connected at F and G to C and L by rubber tubing. This part is also
sealed by the steel ball, K. When the pipette is in use the pryogallate
passes downwards from A and upwards into E, and reversely out through
D, past K, and upwards through B, and back to A. The opening, U, at the
top, is for a thermometer and for filling the pipette with the pyrogallate
solution. At P, J, and T are openings for removing and replacing liquids.
H and N are openings through which the steel balls, K and M, are rolled
into place.
216 Gas Analysis Apparatus
pipette, short pieces of rubber tubing are wired on at N, H, and J
and on these are placed screw pinch-cocks. Pieces of rubber tub-
ing and screw pinch-cocks are also attached to P and T. When all
parts have been connected, the pipette is filled with potassium
pyrogallate solution through U until the ten bulbs are full and the
large bulb is filled until the liquid is above the side tube, D. The
spring pinch-cock on the connection from R to S is then closed and
the apparatus is ready for use.
The analysis is carried out in the usual way so far as burette
reading and absorption of carbon dioxide are concerned (see Fig. 1).
When the oxygen is to be removed from the gas, stop-cock D is
opened and the sample is forced down the capillary tube into the
series of bulbs, beginning at A (see Fig. 2). As the steel ball fits
tightly at K, practically none of the gas passes into the side tube, B,
and consequently the steel ball at M is raised and the level of the
potassium pyrogallate rises in the large bulb, E. When the mer-
cury reservoir attached to the burette of the apparatus is lowered,
the steel ball at M seats, and prevents the solution from passing
downward toward P. The solution therefore flows from the top
of the large bulb, E, into the side tube, D, and passing downwards
through D, it lifts the steel ball, K, and flows through the side tube,
B, into the series of bulbs at the point &, thus flushing and rinsing
the bulbs while filling them. When all the gas has been drawn
from the series of ten bulbs, they are filled with the potassium pyro-
gallate solution which has flowed into them through the t’ubes, D
and B. There is thus a circulation of the potassium pyrogallate
solution in the operation of removing the oxygen from the gas.
The advantages of the modified pipette are that fresh unused
solution is brought into the series of bulbs and at the same time they
are rinsed so that more solution is exposed to the action of the gas,
and that the bulb, E, is much larger than the one in the earlier form
of the pipette and so the solution may be renewed less frequently.
With the earlier form of reservoir, the solution had to be renewed
after every ten analyses, but with this larger bulb, 75 analyses may
be carried out without renewal of the pyrogallate solution.
The routine for absorption of oxygen is to pass the sample into
the potassium pyrogallate pipette ten times, then t,wice into the
potassium hydroxide pipette, five times again into the potassium
pyrogallate and twice into the potash solution, five times into the
Carpenter, Fox, and Sereque 217
potassium pyrogallate, and three times into the potash solution,
and then to set the levels and read. the burette. To confirm
complete absorption of the oxygen, pass the gas into the potassium
pyrogallate pipette five times, and three times into the potash
solution, and read. During absorption the spring pinch-cock on
the rubber tube between R and S is closed, but when the level of
the potassium pyrogallate is set for the reading of the burette, the
cock should be open, because when the pinch-cock is closed, an
exact setting of the level of the potassium pyrogallate cannot be
made.
Modijication of Combustion Unit for Methanes--A modification
of the gas analysis apparatus for chamber air has been described
(Carpenter and Fox, 1926) as designed for determining combustible
gas or methane in the air of respiration chambers. The glass
tubes into which the platinum wire was fused in this arrangement
were inside the combustion pipette, and when combustions were
carried out, the tubes carrying the wires occasionally cracked be-
cause they were surrounded with cold mercury before they were
adequately cooled. In order to prevent this, a form of combustion
pipette constructed (Fig. 3) acording to Weaver and Ledig (1920)
has been adapted to the apparatus. The advantage of this form
is that it may be made up as a separate unit and easily replaced in
the apparatus in case the combustion wire is melted. At no time
does liquid come in contact with the combustion wire. The unit
contains 25 cm. of No. 33 Brown and Sharpe gauge platinum wire,
0.18 mm. in diameter, and is connected in series with an external
resistance of 40 to 42 ohms. A current of 2.3 to 2.5 amperes from
a 110 volt source is used to heat the wire.
When it is known that methane is the only combustible gas in
the air, the determination can be shortened by inserting the com-
bustion unit into the gas analysis apparatus between the burette
and the potassium hydroxide pipette. The procedure in the analy-
sis is to remove first the carbon dioxide in the air sample and then
to burn the gas. The result of the arrangement is that, as the gas
is passedb ackward and forward over the heated wire and into and
out of the potassium hydroxide pipette, the carbon dioxide is
absorbed as fast as it is produced in combustion. Thus the opera-
tions of combustion and absorption are carried on at the same time
and the procedure is simplified for the determination of methane
218 Gas Analysis Apparatus
in chamber air. As the wire, glass tubing, and contents are heated
considerably during the combustion, it is necessary to surround
FIG. 3. The Weaver and Ledig form of combustion pipette. The unit is
inserted in the Haldane-Carpenter apparatus, connection being made at A
and C to the measuring burette and the potassium hydroxide pipette.
Wires G and H are sealed into the glass cups, E and F, which are fastened
to the tube, ABC, by Khotinsky cement. The combustion wire, D, is
wound in the form of a spiral and dips into mercury in the cups, E and F.
The beaker, J, contains water surrounding the combustion unit, and over-
flow through K provides for the running off of the water.
this portion with water at room temperature. A side outlet is
provided in the upper portion of the beaker containing the water so
that excess water may how out into a receptacle. A container
suspended above the gas analysis apparatus furnishes the supply
Carpenter, Fox, and Sereque 219
for changing the water in the beaker by additions of cold water.
Experiments with mixtures of air and methane have shown that
when the gas has passed ten times over the hot wire and into the
potassium hydroxide solution and five times over the cold wire and
into the potassium hydroxide solution, all of the methane is burned
and the carbon dioxide absorbed. Care must be taken to have the
cooling bath at the same temperature at the end as it was at the
beginning of the analysis.
Short Method of Calibrating Burette.
A simpler method of calibrating the burette than that given ear-
lier (Carpenter, 1923) has been devised. If the bore of each of the
TABLE I.
Tests of Uniformity of Bore in Graduated Capillaries of Measuring Burette.
Upper portion of burette, readings on Lower portion of burette, readings on
Position in mercury bubble. mercury bubble.
capillary.
Left end. Right end. Difference. Left end. Right end. Difference.
78.452 78.898 0.446 98.527 99.447 0.920
78.569 79.014 0.445 98.720 99.637 0.917
i8.676 79.121 0.445 98.850 99.760 0.910
78.836 79.284 0.448 99.059 99.960 0.901
78.986 79.433 0.447 99.201 100.101 0.900
79.115 79.562 0.447
graduated capillary sections is uniform in diameter, it is not neces-
sary to determine the volumes for the individual graduations, but
simply the volume of the entire graduated section. The uni-
formity of the bore is estimated by readings of the burette at the
ends of a column of mercury which takes up about 0.5 per cent
(i.e. circa 50 mm.) in length, the burette being held horizontal.
The column is read at different sections of the graduated capillary
and the differences between the readings at the ends of the mercury
should be uniform to within 0.003 per cent. If the bore in each
graduated capillary is found uniform, the weight of mercury
in the burette is then obtained from the stop-cock to the beginning
of the graduated capillary, then for the upper graduated section,
then for the lower bulb, and lastly for the lower graduated section.
220 Gas Analysis Apparatus
The corrections may then be computed and interpolated for the
individual graduations to the nearest 0.001 per cent.
UPPER LOWER
.018 .096
.016 .094
.014 .092
.012 .090
.OlO .008
.008 .086
.006 -084
.004 .082
,002 .080
.OOO .078 I-
98.4 98.6 98.8 99.0 992 99.4 99.6 99.8 100.0 LOWER
78.4 78.6 78.8 79.0 792 79.4 7Q.6 UPPER
FIG. 4. Sample calibration of graduated portions of burette. The cor-
rections for the upper portion of the burette are shown as a straight broken
line from f0.000 at the reading 78.418 to f0.016 at 79.562, because of the
uniformity of the bore in this part of the burette. The scale at the extreme
left of the drawing provides for interpolations for intermediate graduations
of the capillary. Drawn across the broken line is the irregular full line
representing corrections on the lower portion of the burette. The correc-
tions are plotted as obtained from weighings of mercury at nine points
from 98.477 to 100.083. These corrections range from $0.095 to +0.079
on the upper section and from +0.079 to $0.086 on the lower section of this
portion of the burette.
A sample of the testing of uniformity of bore is shown in Table I.
The upper graduated capillary showed a high degree of uniformity
throughout its length. There was a range of 0.003 per cent in the
measurements of a column equal to about 0.4 per cent of the total
volume of the burette. On the contrary, the lower part of the bu-