A routine method was developed to measure benzo(a)pyrene in airborne particulates. Samples were collected on a filter and the organic portion was extracted with cyclohexane. The polynuclear hydrocarbon (PNHC) fraction was separated from the aliphatics by column chromatography. An internal standard was added to the extract and a portion of it was injected into a gas chromatograph. Although the gas chromatographic method has often been reported in the literature, satisfactory separation of benzo(a)pyrene and benzo(e)pyrene has not been achieved. With the introduction of a nematic liquid crystal as the stationary phase good separation is now possible

Luedecke, E.

English

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NASA TECHNICAL	 NASA TM X-71872
MEMORANDUM
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Q (NASA-TM-X-71872)	 ANALYSIS OF	 N76-18247Z
BENZC(A)PYEENE IN AIR.EORNE PARTICULATES BY
GAS CHECMATOGRAPHY (NASA) 	 11 p HC $3.50
CSCL 07D	 Unclas
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ANALYSIS OF BENZO(A)PYRENE IN AIRBORNE
PARTICULATES BY GAS CHROMATOGRAPHY
by Eva Luedecke
Lewis Research Center
ClevelF.nd, Ohio 4435
February 1976
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	 Report No 2	 Government Accession No 3.	 Recipient's Catalog No
NASA TM X-71872
4	 Title and Subtitle 5	 Report Date
ANALYSIS Or BENZO(A)PYRENE IN AIRBORNE
6	 Performing Organization CodePARTICULATES BY GAS CHROMATOGRAPHY
7.	 Author(s) 8	 Performing Organization Report No
Eva Luedecke E-8645
10. Work Unit No.
9, Performing Organisation Name and Aduress
Lewis Research Center
National Aeronautics and Space Administration
11	 Contract or Grant No
Cleveland, Ohio	 44135 13. Type of Report and Period Covered
Technical Memorandum 12. Sponsoring Agency Name and AddressNational Aeronautics and Space Administration
Washington, D. C.	 20546
14. Sponsoring Agency Code
15. Supplem:niary Notes
16	 Abstract
A routine method was developed to measure benzo(a)pyrene in airborne particulates.	 Although
uther techniques are involved, the method is designated as a gas chromatographic procedure.
Samples were collected on a filter and the organic portion was extracted with cyclohexane.
The polynuclear hydrocarbon (PNHC) fraction was separated from the aliphatics by column
chromatography. 	 An internal standard was added to the extract and a portion of it was injected
into a gas chromatograph. 	 Although the gas chromatographic method has often been reported in
the literature, satisfactory separation of benzo(a)pyrene and benzo(e)pyrene has not been
achieved.	 With the introduction of a nematic liquid crystal as the stationary phase good
separation is now possible.
17. Key Words (Suggested by Author(s)) 18	 Distribution Statement
Unclassified - unlimited
19	 Security	 Class if	 (of this report) 20	 Security Classif	 (of this page) 21 !2	 Price*
Unclassified Unclassified
For sale by the Natrona: Technical Informalion Service Spnngfleld Vlrglnla 12161
ANALYSIS OF BENZO!:A)PYRENE IN AIRBORNE PARTICULATES
BY GAS CHROMATOGRAPHY
by Eva Luedecke
Lewis Research Center
SUMIILA RY
00
W
A routine method was developed to measure benzo(a)pyrene in airborne
particulates. Although other techniques are involved, the method is designated
as a gas chromatographic procedure. Samples were collected on a filter and
the organic portion wss extracted with cyclohexane. The polynuclear hydro-
carbon (PNHC) fraction was separated from the aliphatics by column chroma-
tograp' y. An internal standard was added to the extract and a portion of it was
injected into a gas chromatograph. Although the gas chromatographi^ method
has often been reported in the literature, satisfactory separation of benzo(a)
pyrene and benzo(e)pyrene has not been achieved. With the introduction of a
nematic liquid crystal as the stationary phase good separation is now possible.
INTRODUCTION
The objective was to demonstrate the ability to routinely measure benzo(a)
pyrene (BaP) in the presence of benzo(e)pyrene (BeP). Many techniques have
been described for analyzing BaP by gas chromatography but up to now no
column separated BaP-BeP satisfactorily. In the search for a gas chroma-
tographic method for analyzing BaP in the presence of BeP the following sta-
tionary phases were studied: SE-30, Dexsil 300, OVl, OV7, BMBT
[N,N'-bis(p-methoxvbenzylidene-cwce l -bi-p-toluidine)] (ref. 1). Of these the
only stationary phase was BMBT as shown in figure 1.
EXPERIMENTAL
The method consists of three separate steps:
t~`
Extraction of sample with solvent.
Column chromatography to separate aromatic hydrocarbons
from aliphaties.
3. Separate aromatic hydrocarbons into components usinggas chroma-
PNHC's decompose if exposed to light and it is therefore important to perform
the analysis while protecting the sample from light. This can be accomplished
by using aluminum foil screens especially during extraction, evaporation, and
column chromatography.
All chemicals were used as supplied by the manufacturer unless otherwise
Benzo(a)pyrene, Eastman Organic Chemical-
Benzo(e)pyrene, Pfaltz and Bauer
1, 3, 5 Triphenylbenzcne. Aldrich Chemical Co.
Cyclohexane, 99 \Iol% pure Fisher Scientific Co. was purified by perco-
lating it over activated charcoal, dried overnight at 200 0 C (473 K). The puri-
fication was judged satisfactury when 150 ml of purified cyclohexane concen-
trated to 50 p  sho%^ed no impurity peaks by- gas chromatography (Dexsil 300)
at 2x t 0-1 1, A FS (ampere full scale) .
Benzene, GC Spectrequality, J. T. Baker Chem. Co. , purified and ana-
lyzed like cyclohexane.
2 2, 4-Trimethv1pentane, GC Spectroquaiity
Carbon Disulfide, Spectroquality, MCB
Silica G PI, 60/200 mesh, Baker A. R for chromatography was activated
according to oral communication from Dr. William Prater (ref. 2) as follows:
1. Wash with diethyl ether.
2. Wash with evelchexane (as received).
3. Spread on aluminum foil which has been washed with cyclohexane (as
received) . Air dry until the diethyl ether smell is gone.
4. Dry in an oven for 48 hours at 1400 C (413 K).
5. Store in stoppered bottle in a desiccator over Drierite.
4Columns, supplied by Analab (ref. 5)
1/8 inch x 4 feet stainless steel, packed with 1. 5 percent BMBT on
190/200 mesh BP chromosorb W
Injector T: 2650 C (538 K)
Detector T: 2650 C (538 K)
Temperature program: Initial T: 185 0 C (458 K) hold 2 minutes
Program rate 40 C/min (4 K/min)
Final T: 265 0 C (538 K)
Sample size: 2µI
N2 flow: 50 ml/min
The columns should be conditioned overnight at 265 0 C (538 K) with a slow
flow of nitrogen. The life of the column can be lengthened by not allowing it to
be held unnecessarily at 2650 C (538 K) except when conditioning. Nubile using
the column, do not cool it below 1850 C (458 K) maintaining always a slow flow
of nitrogen. Column bleeding restricted the minimum concentration analy-
zable to about 0. 3 µg of BaP because at sensitivities higher than ?v10-10 AFS
bleeding was a problem even using dual columns.
The area ratios (BaP/Int. Std.) were plotted against the weight ratios
(BaP/Int. Std.) to obtain a calibration curve as shown in figure 2. Table I
shows the reproducibility of the data. After extraction and column chroma-
tography of the sample, the benzene fraction was evaporated to dr yness at
room temperature. It was then taken up with (<5 ml) cyclohexane and trans-
ferred to a 5 ml micro reaction vessel (MR IV) with Teflon lined cap. An
accuratel y known amount of the internal standard TIP B was added to the un-
known sample in the MRV. The solution was evaporated to drymess at room
temperature under the hood and the residue taken up with CS,) so that the TPB
concentration was equal to the one in the calibration. It was thenchromato-
graphed under the same condition as the calibration. Area ratios were meas-
ured using an integrator and from the calibration curse the weight ratio of the
unknown to the standard was read. Since the amount of the internal standard
added was known, it was a simple calculation to determine the amount of BaP
present.
RESULTS AND DISCUSSION
A synthetic mixture of internal standard and BaP was analyzed i
and gas chromatography. Two µl of injected sample contained 3. 5 µ
theoretically - 3.4 µg BaP were found.
—r
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5
The following two samples were analyzed for BaP according to the proposed
method:
1. Composite sample of W141 filters taken upwind from coke ovens in
July 1975. The volume of air sampled was 21'1 m3 . Figure 3 shows a gas
chrom-t_orrnm of BaP, BeP, TPB, and other not identified aromatics.
2. Compos'te sample of W41 filters taken downwind from coke ovens in
July 1975. The volume of air sampled was 290 m 3 . Figure 4 shoi s a gas
chromatogram of BaP, BeP, TPB, and other not identified aromatics.
Because of the small amounts of BaP collected only an estimate of the BaP
could be made. It, was estimated that sample 1 contained about 0. 3 pg BaP or
1 ng/ m3
 of air in the suspended particulate matter. Sample 2 contained about
0.6 pg BaP or 2 ng/m 3
 of air in the suspended particulate matter.
In the above samples the composition may have changed due to exposure
to light (ref. 6) . Samples were received in July 1975 and analyzed in
December 1..5. They were also handled previous to this analysis since part
of the filters were sent out for trace element a_alysis. Difficulty was en-
countered b ,v working with carbon disulfide which is the recommended final solvent
for dissolving the sample (ref. 5). Even though all samples were kept in a
freezer at about -loo C (263 N) between analyses, CS  evaporated rapidly due to
its high vapor pressure.
Since only two samples were available for use with this nematic liquid
crystal (BMBT) column, more investigation is advisable. From the number of
peaks as shown in the gas chromatograms of figures 3 and 4 it is obvious that this
column will also separate other aromatics.
Bused on retention data from Ana-l abs (ref. 5) the peaks in fig-,fires 3 and 4
could indicate the presence of fluorene, fluoranthene, benzo(a)anthracene and
other unknowns.
CONCLUSIONS
The described method for the gas chromatographic separation of BaP from
BeP is good on the nematic liquid crystal (BMBT) column. The disadvantage
lies in column bleed at high sensitivities. It is estimated that the lowest limit
of detection is 0.3 pg since at sensiti ,,-ity -et::ng above 2x10-10 A FS the column
bleeding gives too much distortion to quantitatively determine the BaP. Column
and gas chromatog,aphy of a synLhetic mixture of BaP and TPB sl
recovery of component,-:.
6REFERENCES
1. Janini, George M.; Johnston, Kevin; and Zielinski, Walter, Jr.: Use of
Nematic Liquid Crystal for Gas-Liquid Chromatographic Separation of
Polyaromatic Hy I rocarbons. Anal. Chem. , Vol. 47, No. 4, April 1975,
pp. 670-674.
2. Prater, Dr. William: Environmental Research Group, Inc., Ann Arbor,
Mich., Oral Communication.
3. Rosen, A. A.; and Middleton, F. M.: Identification of Petroleum Refinery
Wastes in Surface Waters. Anal. Chem. , Vol. 27, No. 5, May 1955,
pp. 790-794.
4. McNair, H. M.; and Eonelli, E. J.: Basic Gas Chromatography, Varian
Aerograph, 1967, p. 124.
5. Analabs, North Haver., Coruiecticut. Special Note on BMBT column for
PAH Analusis.
6. Blokzijl, P. J.; and Guicherit, R.: The Occurrence of Polynuclear Aro-
matic Hydrocarbons (PAH) in Outdoor Air. TNO-Nieuws 27 (1972),
pp. 653-'660.
f^
P ON BMBT COLUMN
BENZENE (TPB) 1. 91 µg/2 µl
BaP
µg/2 µl
Theor. Found
3.48 3.47
3.48 3.52
3.48 3.25
2.90 2.86
2.90 2.94
2.32 2.08
2.32 1.97
2.32 2.08
ORIGINAL PAGE IS
F POOR QUALITY 
15	 20	 15	 10
.M!NLJTES
Figure 1. - Separation of BaP and BeP
I	 i
35	 30
'XE IBLA-VK NOT FILMED
2.0 f—	
. -- - 1 11 — -1	 1 1 . . —	 .1
ca
1.
cn
0.
0.
0.
0.
V. 1.0	 2.0
V,'EIGHT RATIO Ball
 TPB
Figure 2- - Calibration for BaP on BmBT Column
7TABLE I. - CALIBRATION FOR BaP ON BMBT COLUMN
INTERNAL STANDARD - 1. 3. 5-TRIPHENYLBENZENE (TPB) 1. 91 µg/2 µl
Area ratio Weight ratio
BaP BaP BaP
TPB TP:i µg/2 µl
Theor. Found
Sul.	 1	 1.81 1.82 3.48 3.47
1.82 3.48 3.52
1.68 3.48 3.25
Sol.
	
2
	 1.49 1.52 2.90 2.86
1.52 2.90 2.94
Sol. 3	 1.08 1.21 2.32 2.08
1. 0i 2. 32 1.97
1.08 2.32 2.08


Analysis of benzo(a)pyrene in airborne particulates by gas chromatography

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