The experiment on sulfuric acid aerosol determination in the Venusian cloud layer on board the Vega landers is described. An average content of sulfuric acid of approximately 1 mg/cu m was found for the samples taken from the atmosphere at heights from 63 to 48 km and analyzed with the SIGMA-3 chromatograph. Sulfur dioxide (SO2) was revealed in the gaseous sample at the height of 48 km. From the experimental results and blank run measurements, a suggestion is made that the Venusian cloud layer aerosol consists of more complicated particles than the sulfuric acid water solution does

Bondarev, V. B.

Dolnikov, G. G.

Drozdov, Y. V.

Dyachkov, A. V.

Gelman, B. G.

Khokhlov, V. N.

Melnikov, V. V.

Mukhin, L. M.

Nenarokov, D. F.

Rotin, V. A.

English

NASA Technical Reports Server

NASA TECHNICAL MEMORANDUM TM-88421
CHEMICAL ANALYSIS OF AEROSOL IN THE VENUSIAN CLOUD LAYER BY
REACTION GAS CHROMATOGRAPHY ON BOARD THE VEGA LANDERS
B.C. Gel'man, Yu.V. Drozdov, V.V. Mel'nikov, V.A. Rotin, V.N.
Khokhlov, V.B. Bondarev, G.G. Dol'nikov, A.V. D'yach kov, D.F,
Nenarokov, L.M. Mukhin, N.V. Porshnev and A.A. Fursov
Translation of "Khimicheskiy analiz aerozolya oblachnogo sloya
venery metodom reaktsionnoy gazovoy khromatografii na
spuskayemykh apparatakh AMS "Vega"", Pis'ma v AZh, vol. 12,
No. 2, 1986, pp. 106-109.
(NASA-TM-88421) CHEMICAL ANALYSIS OF N86-29753
AEEOSOL IN THE VENUSIAN CLOUD LAYER BY
REACTION GAS CHROMATOGRAPHY OK BOARD THE
VEGA IANDERS. (National Aeronautics and Space Unclas
Administration) 8 p CSCL 03B G3/91 . 43477
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON, D.C. 20546 MAY 1986
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4. THI. W4 J«i«;ii. CHEMICAL ANALYSIS OF AEROSOL
IN THE .VENUS IAN CLOUD LAYER BY REACTION
GAS CHROMATOGRAPHYj.-'ON-VBdARD THE VEGA
LANDERS '• ••/
7. AU&OIUI B.C.. Gel'man, Yu.V. Drozdov, V.
Mel'nikov, V.A. Rotin, V.N. Khokhlov,
V.B. Bondarev, G.G. Dol'nikov, A.V.
D'yachkov, D.F. Nenarokov, et'.'al.. '•'. \ i
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Leo Kanner Associates, Redwood City,
California «94063
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National Aeronautics and Space Ad-
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Translation
Co<;«
13. 5c;;l«r-.tn'C'r NoH
Translation of "Khimicheskiy analiz aerozolya oblachnogo
sloya venery metodom reaktsionnoy gazovoy khromatografii na
spuskayemykh apparatakh AMS "Vega"", Pis'ma v AZh, vol. 12,
No. 2, 1986, pp. 106-109.
CUDC 523.4)
|..0c-
The experiment on sulfuric acid aerosol determination
in the Venusian cloud layer on board the Vega landers is
described. .An average content of sulfuric acid of ~1 mg/m3
was found for the samples taken from the atmosphere at height
from 63 to 48 km and analyzed with the SIGMA-3 chromatograph.
Sulfur dioxide S02 was revealed in the gaseous .sample at the
height of 48 km. From the experimental results and blank
run measurements, a suggestion is made that the Venusian
cloud layer aerosol consists of more complicated particles
than the sulfuric acid water solution does.
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CHEMICAL ANALYSIS OF AEROSOL IN THE VENUSIAN CLOUD LAYER BY
REACTION GAS CHROMATOGRAPHY ON BOARD THE VEGA LANDERS
E.G. Gel'man, Yu.V. Drozdov, V.V. Mel'nikov, V.A. Rotin,
V.N. Khokhlov, V.B. Bondarev, G.G. Dol'nikov, A.V.
D'yachikov, D.F. Nenarokov, L.M. Mukhin, N.V. Porshnev and
A.A. Fursov
Ail-Union Scientific Research Institute of Chromatography,
Moscow; Institute of Space Investigations, USSR Academy of
Sciences, Moscow
Investigations of the Venusian atmosphere by the method of gas /I06*
chromatography .(GC) which were conducted on the "Venera-12" (Gel'man
et al., 1979a,b), "Venera-13", "Venera-14" (Mukhin et al., 1982,
1983) and "Pioneer-Venera" (Oyama et al., 1980) landers made it pos-
sible to obtain data on the concentrations of the gaseous components.
However, analysis of the chemical composition of particles of the
cloud layer was not done with GC. It was considered (Young, 1973;
Knollenberg and Hunten, 1980) that these particles consist basically
of drops of sulfuric acid and correspond to a 75% concentration of
acid in water. In descriptions of physical-chemical processes which
occur in the upper part of the planet's atmosphere (Moroz, 1981), the
chemical composition of the aerosol plays an important role and in
this connection the assumption made required direct proof; this .
determined the formulation of the experiment.
In order to solve the problem posed, a chromatographic informa- /I07
tion measurement apparatus "Sigma-3" was developed. During its
development, several questions were resolved; the most important of
these were: investigating the .chemical composition of the .aero-
sol, increasing the number of detectable components, increasing the
level of sensitivity while maintaining the reliability of the
* Numbers in the margin indicate pagination in the foreign text.
measurement apparatus. In the analytical part of the device were
universal detectors (helium and katharometer) and selective detectors
(electron capture - BCD). The katharometer in the domestic chroma-
tograph was used for the first time in interplanetary investigations
in order to increase the dynamic range of the measurements. The
introduction of various types of detectors, three blocks of reaction
cells and two independent analytical channels (gas-carriers - nitro-
gen and helium) into the device significantly broadened the poten-
tials of the chromatographic experiment. Thermoreaction cells were
equipped with a fiberglass filter coated . with carbon. The channel
with the helium detector and katharometer was intended for studying
atmospheric components and products of the reaction of carbon with
sulfuric acid from two thermoreaction cells. From a third thermore-
action cell along another analytical channel equipped with ECD and
consisting of two chromatographic columns connected in parallel (the
columns are filled with various sorbents), it is proposed to obtain
information on the concentrations of oxygen,haloid and sulfur com-
pounds and products of the reaction mentioned. Thus, the reliability
of identifying the components being determined was increased.
It is possible to do a quantitative analysis of sulfuric acid
after determining the volumes of gases released as a result of the
reaction:
j C+'~2HiS04 -> CO, + 2H20 + 2S<V
An investigation of this reaction by the method of reaction gas
chromatography showed (Porshnev and Bondarev, 1984) that the use of
the method of the preliminary accumulation of H2S04 aerosol on the
fiberglass filter coated with carbon and the subsequent running of
the reaction at elevated temperatures make it possible to do •
titative measurements at the level of 10~3 g with an error of approx-
imately 10%. However, since in the planet's atmosphere C02, H20 and
S02 are present, in order to detect H2S04 and measure its concentra-
tion, two stages of operation of the cells are envisioned. A known
volume of atmosphere was pumped through the cells. Meanwhile, two of
them were-first heated to 80°C and the third cell was heated to 50°C
as the-vehicle landed. After sampling the cells were closed and for
30 s the gas sample was fed into the column with a flow of gas carri-
er. After the gas analysis, the third cell was heated to 80°C. Then
in the second stage the hermetically sealed cell was heated to 300°C
and the reaction products were supplied for analysis by a new switch-
ing of valves with the help of the gas carrier. Such a sequence of
operations with the samples taken made it possible to separate sul-
fur dioxide as a reaction product from atmospheric S02. Information
from the analytical channels on the temperatures of the thermostat
of the columns and detectors, on the temperatures of the cells, on /1Q8
the operation of the cut-off devices, valves and suction device was
transmitted telemetrically into digital and analog forms.
Identification..of .the maxima of the peak profiles on flight
chromatograms was done according to the retention time of the com-
ponents relative to the maximum of the peak profile of CC>2. The
ratios of the components (c)/CC>2(c) obtained were compared with
preliminary ground measurements. The quantitative interpretation of
the results, as in the first case, was also done taking account of
the real operating regime of the device while reproducing the flight
conditions of chromatography. In addition, a cycle of idle measure-
ments of "Sigma-3" was taken (without taking a sample, according to
the standard program). From these chromatograms the possible level
of contamination of the gas communications of the chromatograph and
cells by terrestrial components during the storage of the device
(the earth to Venus flight) was found. This made it possible to
evaluate the operating sensitivity of the detectors, in particular
the BCD. Examining the results of the experiment on the
flight chromatograms after processing of the telemetric information
and comparing them with ground control measurements made it possible
to identify and determine quantitatively H2SC>4 in the form of aerosol
CO,
• H2o
fc
CO.
b
tOO
I-T.S,i • i
IT:. S .
600 BOO 1000 1200 1HOO 1600 t,i
in the cloud layer of Venus
(figure). Starting from the
volume of atmosphere pumped
through the cell (0.07 m3) ,
100% effectiveness of recovery
and retention of sulfuric acid
aerosol by the filter, com-
pleteness of running its reac-
tion with carbon, we found
that in the sample taken at
the range of altitudes from 63
to 48 km, the average H2S04
concentration was ~1 mg/m3.
In the gas sample of atmos-
phere at altitude 48 km, sul-
fur dioxide was identified
(figure). We must note that
in the process of analyzing
gas samples from 48 km and
especially the integral sample
of aerosol at altitudes from 63 to 48 km, a sharp drop was observed
in the sensitivity of the helium and electron capture detectors,
along with drift of the zero line of the informing devices. The re-
production of chromatography conditions and the detected level of con-
tamination of the analytical part of the device still do not make it
possible to explain the reasons for anomalies in the behavior of the
detectors and the shift in the zero line. This circumstance makes it
possible to propose that the cloud layer may consist of particles of
more complex composition than an aqueous sulfuric acid solution. In
this case in thermoreaction cells at elevated temperatures, in addi-
tion to reaction C+H2S04, there may be more complex processes, in-
cluding dissociation of the sample.
Chromatograms of the separation
of samples of the Venusian cloud
layer (column 54 cm long, filled
with Porapack T, gas carrier -
nitrogen, electron capture de-
tector, temperature 82°C). a-
sample of atmospheric gas taken
at an altitude of approximately
48 km, b-sample of aerosol from
the cloud layer, taken in the
range of altitudes from 63 to 48
km. I^-background current of the
detector, T.S.-electrical test-
signal
Supplementing and refining the results obtained will require
model experiments which consider the role of both instrument
factors and the chemical activity of the materials being studied.
REFERENCES
Gel'man, E.G., Zolotukhin, V.G., Lamonov, N.I., Levchuk, B.V., .
Lipanov, A.I., Mukhin, L.M., Nenarokov, D.F., Rotin, V.A. and
Okhotnikov, B.P., Kosmi ch. is sled. 17, 708 (1979b).
Gel'man, E.G., Zolotukhin, V.G., Lamonov, N.I., Levchuk, B.V.,
Mukhin, L.M., Nenarokov, D.F., Okhotnikov, B.P., Rotin, V.A. and
Lipanov, A. I., Pis'ma v Astron. zhurn. 15_, 217 (1979a) .
Knollenberg, R.G., Hunten, D.M., J. Geophys. Res. 85, 8039 (1980).
Moroz, V.I., Space Sci. Revs 21, 3 (1981).
Mukhin, L.M., Gel'man, E.G., Lamonov, N.I., Mel'nikov, V.V., Nenaro-
kov, D .F., Okhotnikov, B.P., Rotin, V.A. and Khokhlov, V.I., Pis '-
ma v Astron. zhurn. 8_, .399 (1982).
Mukhin, L.M., Gel'man, B.C., Lamonov, N.I., Mel'nikov, V.V., Nenaro-
kov, D.F., Okhotnikov, B.P., Rotin, V.A. and Khokhlov, V.I., Kos-
mich. issled. 21, 225 (1983).
Oyama, V.I.,- Carle, G.C., Woeller, F., Pollack, J.B., Reinolds, R.T.,
Graig, R.A., J. Geophys. Res. 85, 7891 (1980).
Porshnev, N.V. and Bondarev, V.B., Zhurn. ana1it. khimii 39, 642
(1984).
Young, A.T., Icarus 18, 568 (1973).


Chemical analysis of aerosol in the Venusian cloud layer by reaction gas chromatography on board the Vega landers

Chemical analysis of aerosol in the Venusian cloud layer by reaction gas chromatography on board the Vega landers

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