-------
TABLE 3. RELATIVE PERFORMANCE OF A THREE-STAGE SORBENT TUBE FOR
COLLECTING DRY MULTlLITER TO-14 SAMPLES AT 2 PPBV CONCENTRATION.
Sample*
Compound
1L
2 L*
3L*
1) dichlorodifluoromethane
1.00
0.63
059
2) methyl chloride
1.00
0.90
0.79
3) 1^-dichloro—1,12,2—tetrafluoroethane
1.00
0.78
0.49
4) vinyl chloride
1.00
1.12
125
5) 13-butadiene
1.00
0.95
0.90
6) methyl bromide
1.00
1.49
1.49
7) ethyl chloride
1.00
1.19
1.18
8) trichlorofluoromethane
1.00
0.82
0.49
9) 1,1—dichloroethene
1.00
1.11
1.68
10) dichloromethane
1.00
1.17
1.10
11) 3-chloropropene
1.00
1.02
0.71
12) 1,12—trichloro—1,2,2—trifluoroethane
1.00
0.95
0.94
13) 1,1-dichloroethane
1.00
1.06
1.00
14) cis-12-dichloroethene
1.00
1.04
1.13
15) trichloromethane
1.00
1.13
1.10
16) 12-dichloroethane
1.00
1.08
1.13
17) 1,1,1-trichloroethane
1.00
0.97
0.86
18) benzene
1.00
0.95
0.95
19) carbon tetrachloride
1.00
0.84
050
20) 12-dichloropropane
1.00
1.04
1.05
21) trichloroethene
1.00
0.98
1.00
22) cis- 13-dichloropropene
1.00
1.04
1.13
23) trans—13-dichloropropene
1.00
0.95
0.82
24) 1,1^-trichloroethane
1.00
1.15
1.17
25) toluene
1.00
1.02
1.04
26) 12-dibrotnoe thane
1.00
120
1.15
27) tetrachloroethene
1.00
1.09
1.11
28) chlorobenzene
1.00
1.02
1.02
29) ethylbenzene
1.00
1.06
1.04
30) m+p-xyiene
1.00
1.05
1.04
31) styrene
1.00
132
1.44
32) 1,1A2—tetrachloroethane
1.00
1.15
130
and o-xylene
34) 4-ethyItoluene
1.00
0.95
0.97
35) 135-trimethylbenzene
1.00
1.03
0.97
36) 1,2,4-trimethylbenzene
1.00
1.06
1.00
37) benzyl chloride
1.00
127
132
and m—dichlorobenzene
39) p - dichlorobenzene
1.00
120
139
40) o-dichlorobenzene
1.00
1.18
1.10
41) 12,4-trichlorobenzene
1.00
150
151
421 hexachlorobutadiene
1.00
0.95
0.78
* normalized to 1L sample
32
-------
The data indicate that, in general, the TO-14-based target compounds are collected
and recovered linearly up to a sample volume of 3-L. There are indications that some of the
earlier eluting species in the 2- and 3-L samples exhibited breakthrough based upon the low
recovery values obtained. Carbon tetrachloride is also not recovered as well as expected.
This is most likely due to poor analytical resolution from benzene resulting in poor inte-
gration results. Recovery for hexachlorobutadiene was also poor. This was thought to be
due to incomplete desorption from the sampler tube, although a repeat desorption of a
processed tube did not result in more of this compound being recovered. (Another possible
explanation for this low recovery will be discussed later in this report.)
When the total peak areas from these experiments were compared to the results for
the 0.5-L samples loaded directly onto the trap, it was noted that the increased area response
scaled linearly with sample volume. This shows that the process of loading the dry sample
onto the sampler tube does not adversely affect the recovery of most of the target compounds
in 1-, 2-, and 3-L samples.
"Train" Experiment
A "train" experiment was performed to determine the distribution of the target
compounds between the sorbents in the tube and to further identify breakthrough problems.
The data in Table 4 show the percent recovery of the compounds of interest from
each of the tubes in the train, in their order of elution from the GC column. These values
were determined by taking the total area counts for a compound from the six tubes, and
relating that total to the portion collected in any one tube. It should be noted that the total
areas for the six tubes were generally within ± 20 percent of those obtained earlier for a 3-L
sample collected on a single tube packed with the three sorbents.
The data show that, generally, the first 11 components of the TO-14 mix are retained
by the Carbosieve S-III, although they are also present to some extent in the other sorbents.
We believe that these extraneous recoveries were actually artifacts associated with Carbotrap
and Carbotrap C, and this was subsequently confirmed by the analysis of the tubes as blanks.
However, the first three compounds were present in both the primary and
33
-------
TABLB 4. RECOVERY EFFICIENCY OFTO-t4 TAROET COMPOUNDS IN A SIX-TUBB TRAIN* OF SORBENT BEDS.
Percent Recovery1
Carboaleve
Carboaime
Carbotrap
Carbotrap
Carbotrap
Carbotrap
S—III
S—III
C
C
Compound
Primary
Secondary
Primary
Secondary
Primary
Secondary
1) dichlorodlfluaromelhane
46.1
11.3
42.6
0.0
0.0
0.0
2) methyl chloride
84.7
15.3
0.0
0.0
0.0
0.0
3) l^-dichloro-l.l^-tetrafluoroethane
35.5
23.9
13.4
10.8
9J
7.1
4) vinyl chloride
88.9
0.0
2.6
0.0
8.5
0.0
5) 1,3-butadiene
10.1
0.0
36.5
53.4
0.0
0.0
6) methyl bromide
100.0
0.0
0.0
0.0
0.0
0.0
7) ethyl chloride
100.0
0.0
0.0
0.0
0.0
0.0
8) trichlorofluoromethane
100.0
0.0
0.0
0.0
0.0
0.0
9) 1,1-dichloroethene
0.0
0.0
55.9
44.1
0.0
0.0
10) dichlorotnethane
100.0
0.0
0.0
0.0
0.0
0.0
11) 3-chloropropene
0.0
0.0
64.2
35.8
0.0
0.0
12) l,l,2-trichloro-l,2,2-lrifluoroelhane
0.0
0.0
100.0
0.0
0.0
0.0
13) l,l~dichloroethane
15.9
0.0
84.1
0.0
0.0
0.0
14) ci»- 1,2-dichloroetherte
0.0
0.0
100.0
0.0
0.0
0.0
15) trichloromethane
0.0
0.0
100.0
0.0
0.0
0.0
16) 1,2—dichloroethane
0.0
0.0
89.1
0.0
10.9
0.0
17) 1,1,1 -trichloroethane
0.0
0.0
100.0
0.0
0.0
0.0
18) benzene
3.0
1.5
59.9
4.7
16.3
14.6
19) carbon tetrachloride
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
20) 1,2-dichloropropane
0.0
0.0
44.6
0.0
41.0
14.3
21) trichloroethene
0.0
0.0
46.6
0.0
43.6
9.8
22) els- 1,3-dichloropropene
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
23) trans-13-dichloropropene
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
24) 1,1,2-trichloroethane
0.0
0.0
23.5
0.0
59.3
17.2
25) toluene
0.0
0.0
3.3
0.0
93.2
3.5
26) 1,2-dibromoethane
0.0
0.0
0.0
0.0
100.0
0.0
27) tetrachloroethene
0.0
0.0
0.0
0.0
100.0
0.0
28) chlorobenzene
0.0
0.0
0.0
0.0
97.3
2.7
29) ethylbenzene
0.0
0.0
0.0
0.0
100.0
0.0
30) m-fp-tylene
0.0
0.0
0.0
0.0
88.4
11.6
31) styrene
0.0
0.0
0.0
0.0
100.0
0.0
32) 1,1,2,2-tetrachloroethane
0.0
0.0
0.0
0.0
100.0
0.0
and o-xylene
34)4-ethyltoluene
0.0
0.0
0.0
0.0
100.0
0.0
35) 1,3,5-trimethylbenzene
0.0
0.0
0.0
0.0
100.0
0.0
36) 1,2,4-trimethylbenzene
0.0
0.0
8.4
0.0
72 2
19.4
37) ben^l chloride
0.0
0.0
0.0
0.0
89.7
10.3
and m-dichlorobenzene
39) p-dichlorobenzene
0.0
0.0
2.9
3.3
84.2
9.5
40) o-dichlarobenzene
0.0
0.0
6.6
0.0
79.5
13.9
41) 1,2,4-trichlorobenzene
0.0
0.0
8.7
4.5
73.7
13.1
421 hexachlarobutadiene
0.0
0.0
0.0
0.0
92.6
7.4
-------
secondary Carbosieve S-III tubes, indicating that these species were indeed breaking through
with a 3-L sample volume.
The Carbotrap sorbent plays a dominant role in retaining the compounds from
3-chloropropene through benzene. Two compounds that indicated the effects of breakthrough
are 1,1 -dichloroethene and 3-chloropropene. Although the total area counts for these two
compounds compared well with that observed in a single tube collection, there may be
concern for incomplete recovery if these compounds migrate to the Carbosieve S-III where
desorption was not indicated.
From benzene onwards, Carbotrap C becomes the sorbent that collects most of the
TO-14 species. Generally, the primary tube retains most of the compounds, and whatever
breaks through is retained and subsequently desorbed by the primary Carbotrap tube. From
these data, indications are that from benzene to hexachlorobutadiene in the chromatogram,
the Carbotrap/Carbotrap C sorbent combination collects the compounds with high efficiency.
Several compounds were not identified by the data system during this test. Carbon
tetrachloride, as stated earlier, is incompletely resolved from benzene using the thick film
nonpolar dimethyl polysiloxane column. The isomers cis-l,3-dichloropropene and trans-1,3-
dichloropropene were not detected at all. This may be due to an affinity of these compounds
for the metallic surfaces in the partially packed tubes or for the coupling hardware between
the tubes. The "train" experiment indicates that the mass of Carbosieve S-III being used in
the three-stage sampler tubes is not enough to completely retain some of the early eluting
TO-14 species. The test also shows that all three sorbents play an important role in
collecting various portions of the calibration mixture. Figures 9 to 11 show the FID
chromatograms obtained from the six tubes.
Two-Stage Sorbent Sampler Tube
To improve the retention of the lighter compounds that broke through the three-stage
sorbent tube, a two-stage tube packed with larger amounts of Carbosieve S-III and Carbotrap
was evaluated. The use of this tube configuration with a 3-L sample resulted in only a slight
improvement in collection efficiency for the low molecular weight components and some loss
of efficiency for the heavier species. Increasing the mass of Carbosieve S-III from 125 mg
35
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to 251 mg was apparently still not sufficient to prevent breakthrough. At the same time, the
heavier species migrated deeper into the stronger sorbent bed so that it was difficult to
desorb them. No further effort was made to modify the sampler tube configuration and all
the remaining work was done with the three-stage sorbent tube.
Humidified Multiliter Samples Loaded Onto
Multi sorbent Tubes
In order to simulate atmospheric conditions that are normally encountered in field
sampling studies, humidified 3-L samples were loaded onto the three-stage sorbent tubes.
The first sample was analyzed under the same conditions that were used for dry
samples, including a 3 minute desorption of the tube at 325°C with the trap at -30°C. This
resulted in the FID flame being extinguished by the moisture transferred from the tube to the
trap and with the ECD exhibiting no response for the first — 22 minutes of the run.
To allow the moisture in the tube to be swept from the trap, the trap temperature was
raised to 4°C for the next sample. Personnel at Perkin Elmer suggested that this would
allow a large portion of the moisture in the desorbed sample to pass through the trap while at
the same time still retaining the volatile organics. (17) Once again, however, the detector
flame was extinguished.
In an attempt to remove more moisture from the sample, the tube desorption time was
extended from 5 min to 10 min. This additional time was designed to provide a longer
period for the moisture to be purged from the trap, which was still operated at 4°C. The
flame remained lit under these conditions, but a retention time delay of 0.2 to 0.3 min was
observed for the compounds on the chromatogram. It was also noted that the area counts,
particularly for the later-eluting components of the TO-14 mix, were greater than they had
been for a dry sample of the same concentration and sample volume. Under these
conditions, the ECD still gave a flat baseline for the first ~ 22 minutes of the run.
To see if an even longer drying period would regain the ECD response, the tube was
desorbed for 15 minutes. The early-eluting peaks showed lower area counts, indicating that
breakthrough of these components was occurring in the trap. For example, 1,1-
dichloroethane showed a 50 percent decrease in FID response compared to that for the
39
-------
10-min desorption time. Later-eluting peaks also displayed a drop in area counts, although
the decrease was not as great ( — 25 percent). There was no improvement in ECD response.
The final test involved increasing the trap collection temperature from 4°C to 10°C
with a 10-min tube desorption time. Recovery efficiencies for the later-eluting compounds
(ethyl benzene and later) were satisfactory and, although the area counts for the earlier peaks
were greater than when the tube was desorbed for 15 minutes, they were still less than those
obtained with a 10-min tube desorption with the trap at 4°C. The ECD still gave limited
signal response.
These tests led to the decision to operate the ATD 400 with a 10-minute tube desorp-
tion time at 325 °C and the trap at 4°C. Three consecutive sample loadings and analyses
were carried out, and the results are presented in Table 5. The RSDs for the early-eluting
peaks still indicate some breakthrough problems in this region. The remaining compounds
show acceptable levels of precision. The results obtained here indicated that the
desorption/analytical system could be used under these conditions for the evaluation of the
samplers when collecting humidified air. A calibration table was generated using the area
counts from the data in Table 5. An expanded FID chromatogram of a humidified 3-L sam-
ple at 2 ppbv is shown in Figure 12, along with a condensed presentation of an ECD trace
for the same run in Figure 13.
A second effort was made to resolve the problem associated with the loss of ECD
response since the qualitative information from this detector was desired. By monitoring the
millivolt signal from the ECD during the processing of a humidified sample it was
determined that the detector was not being affected by the water vapor in the sample but
rather that the 0.1 mm I.D. splitter line was being physically plugged with moisture, which
prevented any sample material from reaching the detector. When the oven temperature
reached ~95°C, approximately 22 minutes into the run, the moisture plug vaporized and
sample once again began to flow to the ECD. This problem may be solved by attaching an
independent heater to the splitter to maintain any moisture in the vapor phase when the oven
temperature is < 100°C. This modification was not made during this study, so FID data
alone was used.
40
-------
TABLE 5. AVERAGE FID PEAK AREAS AND PRECISION DATA FOR HUMIDIFIED
3-L TO-14 STANDARDS COLLECTED ON CARBOTRAP C, CARBOTRAP,
AND CARBOSIEVE S-IH TUBES (THREE RUNS)
Average
Cone.
Area
Compound
(ppbv)
Counts
RSD, %
1) dichlorodifluorom ethane
2.46
367344
20
2) methyl chloride
2.11
463807
23
3) 1,2-dichloro-1,1,2,2—tetrafluoroethane
2.44
810726
10
4) vinyl chloride
6.33
2731003
5
5) 1,3-butadiene
2.81
1710764
11
6) methyl bromide
2.90
265805
14
7) ethyl chloride
2.66
930053
14
8) trichlorofluoromethane
2.39
139841
33
9) 1,1—dichloroethene
2.85
1089031
7
10) dichloromethane
3.76
755082
3
11) 3-chloropropene
3.00
808306
9
12) 1,1,2-trichloro— 1,2^-trifiuoroethane
2.39
679123
8
13) 1,1—dichloroethane
2.87
924949
9
14) cis-l,2-dichloroethene
3.06
1244552
5
15) trichloromethane
3.07
527305
6
16) 1,2-dichloroethane
2.95
1221626
7
17) 1,1,1-trichloroethane
1.31
521067
7
18) benzene
2.57
3964751
9
19) carbon tetrachloride
2.71
194902
11
20) 1,2-dichloro propane
2.47
1506310
5
21) trichloroethene
2.55
1516751
4
22) cis-l^-dichloropropene
2.75
534324
8
23) trans-1,3-dichloropropene
2.98
575697
9
24) 1,1,2-trichloroethane
2.55
870787
8
25) toluene
2.17
2812267
4
26) 1,2-dibromoethane
2.90
748685
7
27) tetrachloroethene
2.29
1081445
3
28) chlorobenzene
2.38
2891783
3
29) ethylbenzene
2.06
1718436
8
30) m+p-xylene
1.93
1652205
8
31) styrene
2.15
2520014
1
32) 1,1,2^-tetrachloroethane
2.14
2414730
6
and o-xylene
2.07
34) 4-ethyltoluene
1.75
910544
6
35) 1,3,5-trimethylbenzene
1.74
1517935
4
36) 1,2,4-trimethylbenzene
1.80
1155921
2
37) benzyl chloride
2.30
2433001
5
and m-dichlorobenzene
2.13
39) p-dichlorobenzene
2.00
2435966
7
40) o-dichlorobenzene
2.06
2170459
9
41) 1,2,4-trichlorobenzene
1.48
1357213
11
42) hexachlorobutadiene
1.31
943121
5
41
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Typical FID chromatogram for a humidified 3-L volume TO-14 calibration run at 2 ppbv.
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Figure 13. Typical ECD chromatogram for a humidified 3-L volume TO-14 calibration run at 2 ppbv.
-------
The increased FID response observed when a humidified sample was processed
deserves comment. This effect appears to be due to the moisture in the sample that tends to
enhance the desorption of the collected organies because of the interaction of the water vapor
with the carbon sorbents. According to Coutant, (18) the combination of the relatively high
concentration of water vapor and its polarizability causes the water to selectively occupy the
most active sorption sites in the sorbent bed. As a result, the release of the trapped organies
during thermal desorption is improved.
To investigate this effect further, two sorbent tubes were loaded with a dry 3-L
sample of the TO-14 mix at 2 ppbv concentration. These tubes were desorbed and analyzed,
giving FID area counts that were typical of those observed for dry samples during this study.
The same two tubes were then loaded with 3-L samples of Aadco high purity air. One of the
tubes was loaded with dry air and the other loaded with humidified air. The two tubes were
analyzed again. Some of the later eluting compounds were obtained from the dry tube,
however, the humidified sample yielded these same late-eluting species at twice the level
observed for the dry sample (see Figures 14 and 15). This suggests that moisture may
indeed enhance the recovery of heavier VOCs from carbon sorbents. Further investigation of
this effect seems to be warranted.
Analysis of Polar Compounds
The polar calibration mixture was loaded onto the three-stage sorbent tubes as a
humidified sample at 2 ppbv concentration. Sample volumes were 1, 2, and 3-L.
Analysis of these tubes showed that several of the target compounds were detected,
and their peak areas increased with sample volume. However, the peaks, other than 1,3-
butadiene, benzene, and toluene, were broad and compound identification by elution order
was difficult. It appeared from this test that the analytical conditions used for TO-14
analysis are inappropriate for the polar species, and no further effort was made to establish a
method specifically for these compounds. A FID chromatogram for the 3-L sample is
presented in Figure 16.
45
-------
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Figure 14.
FID chromatograms for two tubes loaded with dry 3-L volume TO-14 calibration mixtures.
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FID chromatogram for humidified 3-L volume polar mixture at 2 ppbv.
-------
Environmental Chamber Evaluation
Prior to evaluating the STS 25 under controlled conditions in the environmental
chamber, the empty chamber was challenged with pure air and TO-14 loadings. Canister
grab samples were collected and the results obtained from the analysis of these samples,
using Battel]e's cryogenic analytical system, are presented. For Aadco pure air (background)
runs, the only target compound observed above the detection limit was benzene, which
occurred at sub-ppbv levels. Table 6 lists the recoveries obtained for the TO-14 compounds
at the 2 ppbv level. The recovery efficiencies for most compounds exceed 80 percent at this
concentration. It appears that cis-1,3-dichloropropene may be coming from some source in
the chamber, particularly at the higher temperature, and that trans-l,3-dichloropropene may
be adsorbed on a chamber surface. The results also indicate that the higher boiling species
probably condense to some extent on the walls of the chamber, since these recovery
efficiencies are less than 80 percent. The results are presented in Table 7 for the 10 ppbv
standard. The pattern of recovery is similar to that obtained for the 2 ppbv sample. In
addition, the recovery efficiency for benzyl chloride at 25°C was low (-35 percent), but
when the temperature was raised to 37°C, the levels were elevated (-140 percent). It may
be that the compound was first deposited on the walls of the chamber, then was desorbed at
the higher temperature.
In general, the environmental chamber displayed very low blank levels and acceptable
recoveries for the 2 and 10 ppbv concentrations. Temperature effects seemed to account for
variability in the concentrations of compounds to a greater extent than did the humidity
levels.
49
-------
TABLE 6. RECOVERY EFFICIENCIES OF TO-14 TARGET COMPOUNDS AT 2 PPBV VIA CANISTER
SAMPLING AND CRYOGEN1C/MSD ANALYSIS.
Percent Recovery
Compound
Cone
(ppbv)
25 C
37 C
10% RH
60% RH
10% RH
60% RH
1) dichtorodifluoromethane
2.42
883
85.7
873
91.2
2) methyl chloride
2.12
109.7
94.4
85.1
112.4
3) 1,2-dicbtoro- 1,1,2,2-tetrafluoroeUiane
235
86.2
88.1
92.9
89.9
4) vinyl chloride
5J5
69 £
75.6
78.0
79.7
5) 13-butadiene
X47
93.6
115.9
1181
1343
6) metby! bromide
2J7
84.8
MM
843
90.7
7) ettyl chtoridc
2.40
91J
873
96.6
973
8) trichlorofluoromethane
2.66
763
79.4
79.1
76.8
9) 1,1-dichloroethene
2.70
90.0
89.6
88.4
903
10) dicMotometii&ne
339
86.4
89M
90.7
85.0
11) 3-cfaloropropene
2.74
76J
70.8
813
912
12) 14^-triditoro-l^^-trifluoioeaiane
£24
80.2
863
88.8
84.6
13) 1,1-dichloroethane
2.69
85.6
79.4
85.9
91.0
14) ds-l^-dicbloroethene
3.02
70.4
633
76.6
72,6
15) trictolorome thane
zsn
80.2
81.0
83.4
86.7
16) l^-dlcbtoroetbane
ISO
74.7
80.4
74.6
77.4
17) 1,1,1-trichloroethaoe
129
84.9
83.7
802
90.6
18) benzene
232
77.6
78.0
81.2
883
19) carton tetrachloride
2.68
843
83.7
82.8
87.1
20) 1,2-dichloropropane
239
75.6
75 2
703
73.9
21) tricfatoroetbene
2.44
743
74.8
823
783
22) ds- 1,3-dicbtoropropene
2.70
983
116.9
134.4
160.0
23) t«as-l13--dichloropropene
2.91
46.6
49.6
58.1
60.1
24) 1,1^-tridiloroetbaoe
233
913
81.9
75.0
94.6
25) toluene
2.19
84.7
773
76.7
86.1
26) 1^-dibromoethane
2JS5
80.8
74.9
66.8
78.0
27) tetrachtoioetheBe
226
79.7
81.1
75.4
70.7
28)cfalorobeazene
230
79.6
823
67.6
75.8
29) ethylbenzene
2.00
98.9
883
79.9
873
30)m+p-xjrtene
1.96
933
833
71J
80.7
31)«yrcne
2.01
83.8
78.9
67.0
86.6
32) 1,12,2-tetrachtoroetbane
2.12
85.8
93.4
72.6
873
33)o-xylene
2.05
92.7
97.0
73.4
852
34)4-etbyttoluene
1.71
863
823
562
722
35) 1,3,5-trimethylbenzene
1.68
84.1
81.6
603
69.9
36) l,2j4-trimethylbeD2ene
1.76
882
97.4
61.8
76.1
37) benzyl chloride
229
35.4
54.2
66.6
68.6
38) m-dictjIorobeozeDe
2.04
70S
77.0
52.9
62.4
39) p-dicblorobenzene
2.05
603
61.1
38.6
502
40) o-tfichlorobeazcne
2.02
71.1
76.1
51.8
65.7
41) ly^-trichlorobeazene
1.49
302
753
16.8
58.2
42) hemcbloTObutadiene
131
603
70.4
44.9
50.1
50
-------
TABLE 7. RECOVERY EFFICIENCIES OF TO -14 TARGET COMPOUNDS AT 10 PPBV VIA CANISTER
SAMPLING AND CRYOGENIC/MSD ANALYSIS.
Percent Recovery
Cone.
25 C
37 C
Compound
(ppbv)
10% RH
60% RH
10% RH
60% RH
1) dichlorodifluoromethane
12.10
90.7
903
932
92.6
2) methyl chloride
10.60
97.4
88.0
95.6
99.4
3) l,2-dichloro-l,l12^-tetnifluoroethane
11.75
- 91.7
92.0
962
952
4) vinyl chloride
29.75
82.6
78.4
85.7
85.7
5) 13—butadiene
1235
115.0
132.7
111.0
1263
6) methyl bromide
1335
92.8
92.0
87.9
90.1
7) ethyl chloride
12.00
893
89.8
94.8
91.9
8) trichlorofluoromethane
1330
81.7
802
853
81.4
9) 1,1-dichloroethene
1330
94.4
96.1
97.0
97.0
10) dichtoromethane
17.95
110.6
107.0
117.0
114.8
11) 3-chloroprapeDe
13.70
1063
109.6
118.0
112.1
12) l,l,2-trichloro-l,2,2-trifluoroethane
1120
100.6
101.0
104.6
1042
13) 1,1-dichloroethane
13.45
96.1
95.4
102.8
99.4
14) cis-l^-dichloroethene
15.10
983
94.6
101.9
106.8
15) trichlorome thane
14.85
943
92.1
95.8
953
16) 1,2-dichloroethane
1430
94.4
92J&
1003
101.0
17) 1,1,1-trichloroe thane
6.45
96.1
95.8
100.0
101.4
18) benzene
12.60
902
87.4
953
94.7
19) carbon tetrachloride
13.40
963
97 2
973
100.4
20) 1,2-dichloropropane
11.95
982
993
1053
103.1
21) trichloroethene
1220
87.1
85.0
96.7
91.1
22) cis-1,3 -dkhloropropene
1330
187.9
1993
219.6
2173
23) trans-13-dichloropropene
1435
90.8
92.9
913
983
24) 1,1,2-trichloroethane
12.65
103.7
106.1
119.1
1193
25) toluene
10.95
93.0
943
101.9
1002
26) 1,2-dibromoe thane
14.15
982
103.8
101.4
113.4
27) tetrachioroethene
1130
77£
80.9
893
83.0
28) chioro benzene
1130
88.0
893
97.9
95.0
29) ethylbenzene
10.00
953
96.6
112.4
1023
30)m+p-xylene
9.80
98.6
99.0
119.0
1133
31) styrene
10.05
983
992
109.9
112.4
32) 1,1,22-tetrachloroe thane
10.60
88.1
882
96.4
93.8
33)o-xylene
10.25
93.9
94.9
107.7
100.9
34) 4-ethyltoluene
835
813
87.9
943
91.9
35)13,5-trimethylbenzene
8.40
78.9
92.1
923
92.7
36) 1,2,4-trimethylbenzene
8*0
873
91.1
92.7
93.9
37) benzyl chloride
11.45
35.1
32.6
1373
143.4
38) m-dichtorobenzene
1020
733
74.9
82.4
78.0
39) p-dichiorobenzsne
1025
683
66.4
69.0
733
40) o-dichlorobenzene
10.10
77.4
78.8
86.7
86.1
41) 1,2,4-trichlorobenzene
7.45
67.1
70.6
772
753
42) hexachlorobutadiene
635
552
56.6
543
503
51
-------
TASK 2: STS 25 SEQUENTIAL TUBE SAMPLER EVALUATION
Mechanical
The STS 25 was operated over two 24-hour periods to evaluate the operational
characteristics of the unit. The device was programmed to collect 75-min and 10-min
samples. In both cases, the system performed with no mechanical problems. The charging
system on the STS 25 also performed well. The SKC personal monitoring pump maintained
a constant flow rate (—43 cc/min) over a 24-hour period based upon flow measurements at
the beginnilng and end of the test. No mechanical problems were encountered with the
operational aspects of the STS 25.
Environmental Chamber Tests
The STS 25 was placed in the environmental chamber and used to collect background
air samples and TO-14 standard mixes at various concentrations, temperatures, and relative
humidity levels. In all cases reported here, the percent recoveries for the samples collected
by the STS 25 are based upon the levels that were generated in the empty chamber which
were validated through canister sampling and TO-14 analysis using Battelle's standard
cryogenic analytical system.
Blank Test—
The results for the background samples collected by the STS 25 are shown in
Table 8. As discussed earlier, the empty chamber contained only low levels of benzene.
With the STS 25 present in the chamber, however, several of the TO-14 target compounds
were observed. The 25°C runs indicate that the concentrations of these compounds do not
change greatly with RH. The 37°C run does show higher concentrations, which are
probably due to compounds being liberated from the STS 25 itself. It is important to note
that the conditions under which all the chamber tests were run reflect a very stringent test of
the artifact characteristics of the STS 25. Since the device is in a relatively small volume
that is being purged at 2 L/min, while the STS 25 is cycling air through itself at 30 L/min, it
is evident that any volatile compounds that may be associated with the materials used in the
construction of this sampler are being concentrated in the chamber atmosphere.
52
-------
TABLE 8. BACKGROUND AIR SAMPLES (3 L) CtLLECTED WITH THE STS 25 (USING MULTISORBENT TUBES) AND IN CANISTERS
(value* in ppbv).
Compound
25CG
J 1096RH
25Cg
? 60%RH
37C#60%RH
Tube
Canister
Tube
Canliter
Tube Canister
1) dkhlorodlfhtoromethane
n.d.
n.d.
3.4
n.d.
n.d.
n.d.
2) methyl chloride
0.4
0.1
n.d.
0.1
n.d.
0.1
3) 1,2- dichloro -1,1,2,2- telrafluoroethane
16.7
n.d.
2.6
n.d.
279.6
n.d.
4) vinyl chloride
0.4
n.d.
n.d.
0.1
2.7
n.d.
5) 1,3-butadiene
0.1
n.d.
0.4
n.d.
0.9
n.d.
6) methyl bromide
n.d.
n.d.
0.8
n.d.
n.d.
n.d.
7) ethyl chloride
0.5
n.d.
n.d.
n.d.
3.8
0.1
8) trichlorofluoro methane
11
n.d.
n.d.
0.1
1339.6
0.2
9) 1,1-dichloroeiliene
0.3
n.d.
n.d.
n.d.
0.3
n.d.
10) dichloromethane
n.d.
0.7
0.4
0.4
n.d.
1.0
11) 3-chioropropene
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
12) 1,1,2-trichloro- 1,2,2-trifluoroethane
n.d.
n.d.
0.2
n.d.
0.2
0.4
13) 1,1—dichloroethane
0.3
n.d.
n.d.
n.d.
n.d.
n.d.
14) cit— 1,2-dichkjroelhene
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
IS) trichloroinetliane
n.d.
n.d.
n.d.
0.1
2.2
0.6
16) 1,2—dichloroethane
n.d.
n.d.
n.d.
n.d.
0.5
n.d.
17) 1,1,1-trkhlotoelhane
0.2
0.1
0.2
0.1
0.6
0.2
18) benzene
0.4
0.1
1.3
0.1
2.8
0.2
19) carbon tetrachloride
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
20) 1,2-dichkjropropane
n.d.
n.d.
1.2
n.d.
0.5
n.d.
21) trichloroelhenc
0.3
n.d.
0.4
n.d.
1.2
0.1
22)ci»- 1,3-dichloropropene
n.d.
n.d.
0.5
n.d.
0.8
n.d.
23) Iran*- l,3-
-------
Nonetheless, the blank test does indicate that there is the potential for artifact contribution
from the STS 25 during ambient air sampling.
Canister samples were also collected from the chamber while the STS 25 was in the
last 15 minutes of drawing the sample onto the collection tube. Major differences are
identified between the tube concentrations and the canister analysis(e.g., Freon species). We
believe that these discrepancies are the first indications of the limitations associated with
quantifying complex mixtures with only an FID detector. The differences observed are
generally such that the STS 25 tube identifies compounds being present at higher levels than
the MSD canister analysis. This is easily justified inasmuch as compounds other than the
TO-14 species could be eluting at the same time as one of the target compounds and since
retention times are the only qualifier on the ATD 400/GC analytical system, they are
mistakenly being identified. A FID chromatogram from the blank run collected by the
STS 25 at 37°C with 60 percent RH is shown in Figure 17.
TO-14 Chamber Tests—
The results from challenging the STS 25 with the TO-14 calibration mixture under
controlled conditions are presented in Tables 9 and 10. The compounds will be discussed in
three sets. First, the light species from analytical start time through l,l,2-trichloro-l,2,2-
trifluoroethane; secondly, intermediates from 1,1 -dichloroethane through ethyl benzene; and
finally the heavier species from m&p-xylene to hexachlorobutadiene.
For the light compounds, trends are evident in data from both the 2 and 10 ppbv
tests. The STS 25 results tend to exaggerate the concentrations present for several of the
earliest eluting species (e.g., Freon compounds). We believe that this is a further example
of artifact compounds coeluting with compounds of interest. This exaggeration is
particularly evident during the 2 ppbv test where a slight contribution from an artifact results
in a pronounced variance in percent recovery. Relative humidity does not seem to play as
much of a role in liberating light artifacts as does the increased temperature. The
> 100 percent recovery values from the STS 25 were confirmed to be due to artifact
coelution since the canister results generally did not reflect increased TO-14 species presence
with changes in relative humidity and temperature.
54
-------
m i n u t e s
Figure 17.
FID chromatogram for environmental chamber blank sample collected by the STS 25
(60% RH, 37°C, 3-L).
-------
TABLE 9. COMPARISON OF RECOVERY EFFICIENCIES OPTO-14 TARGET COMPOUNDS AT 2 PPBV OBTAINED
WITH THE STS 25 (USINO MULTOORBENTTUBES) AND IN CANISTERS.
25C @ 1096 RH
25C@60% RH
37C@60%RH
Chancer
Tube
Canister
Chamber
Tube
Canister
Chamber
Tube
Canister
Conc,
Recovery
Remny
Cone.
Recovery
Recouety
Cone.
Recovery
Recowety
Compound
fppbv)
(%)
(p**L
(%i
(%)
(Pf*?)
r%>
(%)
1) dichlorodlftuoromethane
2,14
144.4
81.4
2.07
187.0
90.6
2.21
305.7
103.1
2) methyl chloride
23
wr?.i
456
2.00
334.5
51.5
238
301.5
50.7
3) l,2-die»ibro-l,l,22-tetrafluoroethane
2.03
428.1
112.2
2.(77
312.1
123.0
211
494.7
1143
4) vinyl chloride
4,15
1313
142.1
4.50
160.7
131.0
4.74
108.2
1493
5) l,3-buta<£ene
231
100.5
57.9
236
1163
643
332
1421
613
6) methyl bromide
2.27
610
82.7
232
3193
80,9
2.42
22.9
94.1
7) ethyl chloride
2.20
85.S
91.4
2.10
141.7
95.f
234
81.4
113.0
8) irichlcrofluoromethane
Z04
198.6
78.8
Zll
95.1
82.6
2.04
11703
44.0
9) l,l~dichlon*thene
2.43
96.9
1103
2,42
99.1
1163
2.44
84.2
104.4
10) dichlcro methane
3.10
93.9
1383
322
112.6
120.7
3.05
103.4
154.2
11) 3-chloropropene
2.11
62.0
139.7
1,94
1383
145.1
Z50
212
91.1
12) 1,1,2-trichloro-1 A2-tri8uoro«thane
130
98.1
115.6
1.93
102.0
109.9
1.90
90.5
1072
13) 1,1-dichloroethane
230
89.1
116 J
2.14
150.0
131.5
2.45
803
114.9
14) d»- 1,2-dkhlorocthene
2.13
112.4
1253
1.92
1343
147.9
2.19
116.5
127.2
15) trichlaro methane
238
81.1
123.9
241
112.1
1163
2.57
47.5
114.7
16) l^-dlchloroethsne
2.17
85.6
1173
233
110.2
103.5
2.25
713
113.2
17) 1,1,1-trichkroethane
1.10
84.7
121.8
1.08
127.4
111.7
1.17
92.0
114.5
18)benzene
1.96
98,9
109.4
1.97
1803
102.0
223
153.7
112.5
19) carbon tetrachloride
2.26
781
1117
224
109.2
107.7
233
103.4
103.5
20) M-dichlort) pro pane
1.81
83.5
139.9
130
115.1
129.0
1.77
76.6
1373
21) irichkroethene
131
105.7
123.4
133
104.2
120,4
1.92
98.9
119.0
22) da- 13-dichloroprn|)eiie
2.66
31.4
92.5
3.16
793
80.6
432
38.1
553
23) tuna- 1,3-dichloropropene
136
47.4
181.0
1.44
157.5
176.9
1.75
70.7
1833
24) 1,1^-trtchloroelhane
231
573
87.0
2.07
98.4
88 2
239
56.4
84.1
25) toluene
136
871
86.5
1.69
134,1
111.4
139
1313
993
26) 1,2-dibromoethane
229
94.1
99.5
2.12
1083
114.7
2.21
108.7
109.2
27) tetrachloroethene
im
69,0
1063
133
78.1
104.0
1.60
90.9
1293
28) chlorabenzene
tm
952
124.5
1.90
862
112.9
1.74
127.9
161.7
29) ethyfcenzene
1.98
64.9
81.2
1.77
98.7
98.4
1.75
1183
122.5
30) m+p-xyletie
1,83
81,8
87.9
1.63
129.4
90.4
1.58
196.5
195.1
31) styrene
1.68
97.0
87.7
1.59
137.2
104.9
1.74
152.6
160.5
32) 1,1,2,2-tetrachlaroethane
im
111.7
80.9
1.98
111.4
73.1
135
189.5
93.4
and o-*ylene
190
107.0
105.8
1,99
1103
107.7
1.75
200.4
298,7
34)4-ethylloluene
1.48
83.7
86.7
1.41
103.7
146.9
1.23
1283
228.8
35) 13,5-trlmethylbenasne
1.41
143.6
161.2
137
1523
199.0
1.18
5163
227.1
36) 1,2,4-trimethylbeniene
1.55
425.4
608.1
1.71
380.2
5063
134
19063
27903
37) benzyl chloride
0B1
131.2
60.2
114
90,5
29.2
1,57
88.4
42,1
and m-dkhlorobetuene
1.45
733
64.7
1.57
71.5
128.9
1.27
1093
105.5
39) p-dtchlorobenzene
124
81.9
643
1.25
82.9
117.0
1.03
126.7
184.5
40) o-dlchlorobenzene
1.44
873
93.1
1.54
943
109.7
133
117.9
141.1
41) 1,2,4 - trich larobenzene
0.45
4653
148.9
1.12
95.6
1323
037
226.0
1843
421 hocachlarobutadierte
0.79
2203
62.5
0.92
1123
80.2
0.66
14683
1213
-------
TABLE 10. COMPARISON OF RECOVERY EFFICIENCIES OFTO-14 TARGET COMPOUNDS AT 1# PPBV OBTAINED
WITH THE STS 25 (USING MULTISORBBNT TUBES) AND IN CANISTERS.
25C@60%RH
37C @ 60%RH
Chamber
Tube
Onbter
Chamber
Tube
Caniater
Cone.
Recovery
Recovery
Cone,
Recovery
Recovery
Compound
(pptw)
r*>
m
(PPt*)
r%)
(%)
1) dtchforodifltnromethane
10.9
1815
141.0
112
121.0
125.6
2) methyl chloride
9.3
mi
78.9
10.5
963
101.7
3) 1,2~dlchlaro-l,l,22-tetrafluoroethane
10.8
108.7
114.1
112
138.3
112.6
4) vinyl chloride
23.3
131.0
120.8
25.5
1212
1415
5) 1,3-butadiene
16.4
68.4
77.7
15.6
56.9
76.9
6) methyl bromide
12.3
137,4
1213
12.0
89J
121.4
7) ethyl chloride
10.8
140.6
124,3
11,0
100.3
109,3
8) irkhlaroduaromethaite
10.7
667.7
10&1
10.8
210.7
853
9) 1,1 -dichloroethene
13.0
96.2
106.4
13.1
78.6
1013
10) dfchloromethane
192
89.7
100.5
20.6
88.7
96.3
11) 3-chloropropene
15.0
46.5
107.1
15.4
4.4
1082
12) l.l^-trkhlaro-l^-Ulfluoroethaiie
11.3
96.5
80.6
11.7
792
68.8
13) 1,1-didiloroethane
12.8
73.8
117.0
13.4
21.4
1022
14) cli-12—dichloroethene
14.3
94.6
102.2
16.1
75.5
89.3
15) trichloromethane
13.7
74.3
110.7
142
88.6
104.2
16) 1,2-dldiloroethiine
13.5
77.9
108.5
14.7
SIS
97.0
17) 1,1,1-trichloroethane
6.2
75.1
106.3
6.5
73.3
1025
18) benzene
11.0
100.9
105.9
11.9
882
1022
19) carbon tetrachloride
13.0
68.3
104.0
13.5
70.3
100.6
20) 1,2-dichloropropane
11.9
80.8
100.5
12.3
68,1
101.1
21)trichloroethene
10.4
79.8
106.0
11.1
84.0
102.0
22)cis-l,3-dichloropropene
26.9
39.3
48.8
29.3
323
452
23) trans- 1,3-dichIoropropene
13.5
73.1
134.8
14 J
623
134.0
24) 1,1,2-trichloroethane
13.4
70.1
81,9
15.1
57.6
92.3
25) toluene
103
105.5
129.7
11.0
88.9
1214
26) 1,2-dibromoethane
14.7
83.4
78.5
16.1
41J
69.3
27) tetrachloroethene
92
101.1
1023
9.4
872
105.8
28) chlorobenzene
10.3
83.9
110.9
10.9
68.0
116.6
29) ethylbenzene
9.7
81.5
95.7
102
60.7
96.9
30)m+p-xylene
9.7
92.8
98.0
11.1
72.0
1324
3I)«tyrene
10.0
82.4
88.7
11.3
643
1022
32) 1,1^^-tetrachloroethane
9.4
104.8
802
10.0
92.1
85.9
and o-xylene
9.7
100.7
10&8
10.3
886
125.7
34) 4-ethyl toluene
7.5
81.6
94.5
7.9
61.6
109.9
35) 1,3,5 -trimethylbenKne
7.7
11319
97.0
7.8
127.8
80.9
36) 12,4-trimethylbenzene
8.0
2737
240.6
8.3
321.9
507.2
37) benzyl chloride
15.6
39.9
37.8
16.4
28.7
35.1
and m-dkhkrobeiuene
7.6
81.8
105.2
8.0
59.1
97.6
39) p-dkhkxobenzene
6.8
76,3
892
7.5
56.0
105.0
40) o-dichlorobenzene
8.0
66.7
892
8,7
53.5
95.5
41) 12,4-trichlorobenwne
5.3
99.0
94,3
5.6
52.4
123.8
42) hexachlorobutadiene
3.7
146.8
83.1
3.3
268.3
109.3
-------
The 37°C test gave indications of breakthrough for 3-chloropropene in both the 2 and
10 ppbv tests while methyl bromide displayed this trend for only the 2 ppbv tests.
The canister analysis for TO-14 species in this initial region were generally consistent
with expected levels. The noticeable deviations were that methyl chloride and 1,3-butadiene
were consistently reported with low recoveries. This could be indicative of compound
affinity for the STS 25 sampler. It was not possible to validate this since the STS 25 values
reported were high, once again being affected by artifact coelution.
The second set of compounds in the TO-14 mixture exhibited predictable recoveries.
The 10 percent relative humidity STS 25 recovery data were generally lower than the
60 percent relative humidity test at the same 25°C. This is in agreement with the results
reported earlier where the presence of humidity seems to enhance the desorption of these
TO-14 species from the multisorbent collection bed. Also, agreement with the canister
results was generally more reproducible. It appears that this region of the chromatogram
was impacted less by artifact contribution from the STS 25. Therefore, FID quantitation was
more reliable and this was reflected in the reported percent recovery values for the 25°C and
37°C tests. Cis-1,3-dichloropropene did exhibit breakthrough for two of the 2 ppbv tests
with recoveries in the 30 percent range. The 10 ppbv test results for this compound were
questionable because of the higher than expected chamber concentration reported at
— 27 ppbv. The MSD data was validated for this concentration but this high level was not
readily explainable. An upward drift in reported levels for this compound was observed
during the chamber and STS 25 testing period and may be indicative of some external
contamination. The canister and STS 25 results for cis-1,3-dichloropropene gave consistently
low results.
The final set of compounds in the TO-14 mixture were the latest eluting species.
From the STS 25 blank test run it was observed that there was a region of artifacts eluting
where these heavy TO-14 species are detected. Because of this, artifact coelution, with
contribution to the STS 25 values reported, was expected and observed. For the 2 ppbv test,
higher percent recovery values were regularly reported when compared to the canister
results. This was particularly true for the 37°C test. However, canister recoveries were also
> 120 percent in this region indicating that the STS 25 at 37°C was liberating TO-14 species
58
-------
along with non-target compounds. One particular compound, 1,2,4-trimethylbenzene, was
identified by both the tube and canister results as being a major TO-14 artifact associated
with the sampler.
The artifact contribution during the 10 ppbv test was not as severe. Since these tests
were the last performed using the STS 25 it is conjectured that artifact liberation may have
been subsiding with the continued purging of the STS 25 system.
At 25 °C, with the relative humidity at 10 percent, the canister data indicated some
affinity of the target compounds to the chamber/STS 25 test system. This was overcome
with the addition of moisture during the 60 percent relative humidity test.
There was no definitive indication of breakthrough occurring for these compounds.
This was expected since the limited breakthrough data for compounds in this group indicated
very large volumes for the adsorbents used. (10) Benzyl chloride did exhibit consistently
low recoveries but this was thought to be due to an adsorptive affinity for the testing
apparatus.
The general statement that can be made from evaluating the STS 25 under laboratory
conditions is that the sampler will collect TO-14 compounds onto sorbent tubes. However,
these tests resulted in as much of an evaluation of the sorbents as it was for the STS 25. The
Perkin Elmer sampler apparently does contribute artifacts to the sampling process when
operated in a confined environment that does not afford an air changeover rate that is as
great as that of the STS 25 itself. Also, the analytical system employed was limited by the
use of only the FID detector which was affected by coeluting artifacts. Nonetheless, the
STS 25 operated acceptably within the confines of the testing environment, sorbents, and
analytical system used. Figure 18 shows the tube analysis of the 10 ppbv, TO-14 atmosphere
collected by the STS 25 at 60 percent RH and 37°C.
Indoor Sampling—
The indoor air sampling results from the analysis of the two sorbent tubes using the
ATD400/GC and the canister using the GC/MSD system are presented in Table 11.
Agreement between the two tube samples was quite good with the same compounds
being identified and comparable concentrations reported. From this information it was
evident that when used in a non-confined environment the STS 25 collects a representative
-------
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Figure 18. FID chromatogram for environmental chamber TO-14 mixture collected by the STS 25
(60% RH, 37°C, 3-L volume, 10 ppbv).
-------
TABLE 11. INDOOR AIR SAMPLING RESULTS OBTAINED USING STS 25,
TYLAN/SORBENT TUBE SAMPLER, AND CANISTER SAMPLER
(values in ppbv).
STS 25
Tylan
Tube
Tube
Canister
Compound
3L
3L
Sample
1) dichlorodifluoromethane
n.d.
n.d.
4.2
2) methyl cbloride
n.d.
n.d.
n.d.
3) 1 ,2 -dichloro -1,1,2,2 -tetrafluoroethane
12.4
12.3
n.d.
4) vinyl cbloride
n.d.
0.5
n.d.
5) 1,3-butadiene
15.1
7.4
n.d.
6) methyl bromide
0.8
n.d.
n.d.
7) ethyl chloride
15.6
33.1
n.d.
8) frichlorofluoromethane
53.8
48.6
4.9
9) 1,1—dichloroethene
n.d.
n.d.
5.4
10) dichloromethane
160.7
138.2
28.2
11) 3-chloropropene
n.d.
n.d.
n.d.
12) l,l,2-uichloro-l,2,2--trifluoroethane
1.0
1.6
2.6
13) 1,1-dichloroe thane
0.8
n.d.
n.d.
14) cis - 1,2 -dichloroe thene
n.d.
n.d.
n.d.
15) trichloromethane
4.6
5.6
0.2
16) 1,2-dichloroe thane
0.8
1.0
" n.d.
17) 1,1,1 - trichloroethane
374.8
367.8
873.7
18) benzene
1.6
1,4
1.2
19) carbon tetrachloride
n.d.
n.d.
0.2
20) 1,2-dichloropropane
12
1.1
n.d.
21) trichloroethene
19.2
24.1
0.3
22) cis—13-dichloropropene
0.9
1.2
n.d.
23) trans -13-dichloropropene
0.3
0.3
n.d.
24) 1,1,2-trichloroethane
0.3
0.4
n.d.
25) toluene
3.6
4.4
4.2
26) 1,2-dibromoe thane
1.0
0.7
n.d.
27) tetrachloroe thene
1.1
1.1
1.0
28) chlorobenzene
0.5
0.6
n.d.
29) ethylbenzene
0.6
0.8
0.9
30) m+p-xylene
2.6
3.5
2.7
31) styrene
0.7
0.8
0.3
32) 1,1,2,2-tetrachloroethane
0.9
12
n.d.
and o-xylene
0.9
1.2
1.0
34) 4-ethyltoluene
5.5
7.1
0.9
35) 1,3,5-trimethylbenzene
1.3
1.5
0.5
36) 1,2,4-trim ethyl benzene
10.8
13.8
2.2
37) benzyl chloride
0.1
0.1
n.d.
and m-dichlorobenzene
0.1
0.1
n.d.
39) p—dichlorobenzene
1.4
1.6
n.d.
40) o-dichlorobenzene
0.9
1.0
n.d.
41) 1,2,4-trichlorobenzene
1.6
1.7
n.d.
42) hexachlorobutadiene
1.1
0.9
n.d.
n.d. = compound not detected.
61
-------
air sample. This was further confirmed by comparing the FID traces for the analysis of the
two tubes (Figure 19). The qualitative duplication was very good, except for slight variances
in peak height.
The canister samples quantitative results however did not reflect exact duplication of
the tube data. This was particularly true for the early eluting peaks. Apparently non-target
compounds were eluting at times designated for the TO-14 species and the FID was
mistakenly identifying them. As the analytical run time continues, the tube/canister data
tended to agree more acceptably. The multiple peaks eluting at the end of the chromatogram
would account for the FID analysis identifying the later eluting TO-14 species while the
MSD indicated that these compounds were not present.
An obvious contradiction in reported concentrations between the tubes and canister
was the value for 1,1,1 -trichloroethane. Data for this compound was rechecked for each
analysis and no explanation for this discrepancy was found.
Outdoor Sampling-
The same collection/analytical scenario used for the indoor sampling was applied to
an outdoor environment. The resulting data are presented in Table 12.
Similar trends for this sampling and the indoor test were observed. There was again
good agreement between the two tube analyses. Also, the canister analysis did not quantify
several of the early eluting species; agreed well for the middle TO-14 target compounds; and
did not identify as being present the later compounds. Variability is again judged to be
associated with the qualitative/quantitative differences of the FID and MSD detectors and not
necessarily indicative of deficiencies with the STS 25 as a sampling unit or the sorbents used.
In general, analytical agreement for this sampling was quite good and may be attributed to
the less complex nature of the sample allowing better FID identification and quantification.
A copy of the FID traces from the two collection tubes is provided in Figure 20. It
should be noted, that the relative humidity during the collection of these samples was at
~ 90 percent. It can be seen on both of the FID traces that there was a negative deflection
in the baseline prior to the elution of the VOCs. Although the flame did remain lit, the
conditions may have been close to the tolerable moisture limit for the FID.
62
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Figure 19. FID chromatograms for indoor air sample collected on multisorbent tubes by the STS 25 (upper)
and a Tylan-controlled pump sampler (lower).
-------
TABLE 12. OUTDOOR AIR SAMPLING RESULTS OBTAINED USING STS 25,
TYLAN/SORBENT TUBE SAMPLER, AND CANISTER SAMPLER
(values In ppbv).
STS 25
Tylan
Tube
Tube
Canister
Compound
3L
3L
Sample
1) dichlorodifluoromethane
3.1
0.8
0.5
2) methyl chloride
43
17.2
n.d.
3) 1,2 - dichloro -1,1,2,2 -tetrafluoroethane
02
0.2
n.d.
4) vinyl chloride
0.7
0.6
n.d.
5) 13-butadiene
32
2.7
n.d.
6) methyl bromide
37.4
34.3
n.d.
7) ethyl chloride
13
0.8
0.2
8) trichlorofluoromethane
128.9
109.4
0.5
9) 1,1-dichloroethene
3.1
2.5
n.d.
10) dichloromethane
22.5
19.8
24.6
11) 3-chloropropene
n.d.
n.d.
0.2
12) 1,1^-trichloro-l^-trifluoroe thane
n.d.
n.d.
1.7
13) 1,1-dichloroethane
n.d.
n.d.
n.d.
14) cis -1 ,2 -dichloroethene
0.1
0.2
n.d.
15) trichloromethane
12.8
8.7
0.5
16) 1,2-dichloroe thane
1.9
2.9
n.d.
17) 1,1,1-trichloroethane
3.3
4.4
4.2
18) benzene
1.4
1.8
1.5
19) carbon tetrachloride
n.d.
n.d.
0.2
20) 1,2-dichloropropane
0.1
1.0
n.d.
21) trichloroethene
0.3
0.6
n.d.
22) cis-13-dichloropropene
0.5
1.4
n.d.
23) trans -13- dichloropr opene
0.7
0.9
n.d.
24) 1,1 ,2 -trichloroethane
0.5
0.7
n.d.
25) toluene
3.0
3.5
3.4
26) 1,2-dibromoethane
0.5
0.6
n.d.
27) tetrachloroethene
0.3
0.4
02
28) chlorobenzene
0.1
0.0
n.d.
29) ethylbenzene
0.6
0.6
0.7
30) m+p-xylene
2.2
22
2.4
31) styrene
0.3
02
0.2
32) 1,1^2-tetrachloroethane
0.6
0.6
n.d.
and o-iylene
0.6
0.6
0.7
34) 4-ethyltoluene
1.2
1.1
03
35) 13^-trimethylbenzene
0.5
0.5
0.3
36) 1^,4-trimethylbenzene
1.3
1.2
0.7
37) benzyl chloride
n.d.
n.d.
n.d.
and m -dichlorobenzene
n.d.
n.d.
n.d.
39) p-dichlorobenzene
0.3
0.2
n.d.
40) o-dichlorobenzene
0.3
0.2
n.d.
41) 1^,4-trichlorobenzene
0.3
0.3
n.d.
42) hexachlorobutadiene
n.d.
0.2
n.d.
n.d. = compound not detected.
64
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Also noted, was that with the ambient air sampling, neither the independently
collected tube or the STS 25 tube displayed an elevated baseline at the end of the analytical
run. This feature had been seen in both the chamber tests and the indoor air sampling. The
outdoor test confirmed that the STS 25 does not contribute compounds to this region.
TASK 3: TIME MONITOR EVALUATION
The sampler tubes were analyzed at Battelle using the Perkin Elmer ATD 400/GC
system. FID and ECD chromatograms were obtained for each sample. Problems were,
however, experienced with the response of the ECD due to moisture in the samples, and the
ECD results are ignored in this review of the data. Besides the eight exposed tubes that
were analyzed, one blank tube was analyzed to assess the effects of any inadvertent con-
tamination. One 3-L TO-14 standard at 2 ppbv concentration was also analyzed under the
same operating conditions for comparison purposes and to assist in the interpretation of the
field data. The concentrations determined from the analyses were based on response factors
generated at Battelle for three samples. Because the microenvironments sampled with the
TIME monitor generally did not correspond to a sample volume of 3 L, the concentrations
provided by the ATD 400/GC data system were corrected for the actual volume sampled in
liters. An example of a FID chromatogram obtained from the analysis of a sampler tube
exposed during field tests of the TIME monitor is shown in Figure 21. The output showing
the corresponding concentrations of the target compounds identified in this experiment are
shown in Figure 22.
The TIME monitor provides seven pieces of exposure information simultaneously:
(1) mobility patterns; (2) exposure indoors in the residence; (3) exposure indoors in the
workplace; (4) exposure outdoors; (5) exposure in-transit; (6) total exposure; and (7)
VOC concentrations for the TO-14 target compounds in each of the microenvironments.
The mobility patterns for the two field experiments were within 6 minutes of the
values for the time intervals spent in each microenvironment, as logged by a field
experimentalist. The mobility pattern component of the TIME monitor has been improved
to identify the subject's location once every 30 s, which represents an improvement of 90 s
66
-------
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~ 0 D.
ilution: 1.00000e*0
EXTERNAL STANDARD ( AREA )
RT
Area
BC
ExpRT
RF
ppbv
Nase
2.366
95174
T
1.00000e+0
95174.0000
Unknown
2.44S
879091
T
1.00000e+0
879091.8125
Unknown
2.793
62867
T
1.00000e+0
62867.8750
Unknown
2.937
159034
T
1.00000e+0
159034.1250
Unknown
3.060
69233
3.211
7.34966e-6
0.5088
FREON-12
3.574
S.07430e-6
METHYL CHLORIDE
3.725
3016333
T
3.80S
3.l2280o-6
9.4194
FREON-l14
4.087
2.3401le-6
VINYL CHLORIDE
4.389
1.6S0S9e-6
1,3-BUTADIEHE
4.983
1.10392e-5
METHYL BROMIDE
5.495
661544
5.376
2.87807o-6
1.9040
ETHYL CHLORIDE
6.545
520081
T
1.00000e+0
520081.7500
Unknown
7.11S
749908
7.147
1.96027e-S
14.7003
TRICHLOROFFLUOROMETH
8.748
2.62912e-6
1,1 -DICHLOROETHENE
8.890
64186
9.020
4.98269e-6
0.4195
DICHLOROMETHANE
9.382
3.68914e-6
3-CHLOROPROPENE
9.667
275584
T
9.805
3.S5772«-6
0.9805
TRICHLOROTRIFLUOROET
10.S73
111918
1.00000e+0
111918.5000
Unknown
12.563
3.11557e-6
1,1-DICHLOROETHANE
15.765
2.49728e-6
CI8-1,2-DICHLOROETHE
16.761
5.84395e-6
TRICHLOROHETHANE
18.865
2.43144e-6
1,2-DICHLOROETHANE
19.365
140245
V
19.510
2.51576o-6
0.3528
1,1.1-TRICHLOfiOETHAN
20.607
6.57860«-7
BENZENE
20.919
1.39713e-S
CARBON TETRACHLORIDE
22.369
1.64307o-6
1,2-DICHLOEOPROPANE
22.842
1.68275o-6
TRICHLOROETHENE
24.463
5.10582o-6
CIS-1,3-DICHLPROPENE
2S.409
5,11109e-6
TRANS-113-DICHLPROPE
25.741
2.9281Oe-6
1,1,2-TRICLETHANE
26.265
95864
V
26.265
7.71180©-7
0.0739 S TOLUENE
27.358
133757
T
27.463
3.85046e-6
0.5150
1,2-DIBROMOETHANE
27.811
427854
T
1.00000e*0
427854.0000
Unknown
28.288
338698
T
28.238
2.12052e-6
0.7182
TETRACHLOROETHENE
28.598
91557
T
1.00000«*0
91557.5000
Unknown
28.992
213670
T
1.00000e+0
213670.7500
Unknown
29.350
416673
T
29.416
8.27379e-7
0.3447
CHLOROBENZENE
29.666
295857
T
1.00000e+0
295657.0000
Unknown
29.990
184387
T
30.010
1.20336e-6
0.2219
ETHYLBENZENE
30.276
113712
T
30.322
1.17139e-6
0.1332
M+P-XYLENE
30.587
56245
T
1.00000e+0
56245.5000
Unknown
30.852
92460
T
30.936
8.53102e-7
0.0789
8TYRENE
31.142
147378
31.127
8.55992e-7
0.1262
O-XYLENE/TTTCLETHANE
32.935
98709
1.00000e+0
98709.0000
Unknown
33.312
2.27261e-6
4-ETHYLTOLUENE
33.566
96323
V
33.432
1.15667o-6
0.1114
1,3,5-TRIMETHBENZENE
34.258
1.50552e-6
1,2,4-TRIKETHBENZENE
34.465
286420
T
1.00000e+0
286420.2500
Unknown
34.590
368227
T
34.640
9.43370e-7
0.3474
BENZCHLOB/a-DICHLRBN
34.755
100067
T
34.771
8.73804e-7
0.0874
p-DICHLOROBENZEKE
34.948
192063
T
1.00000e+0
192063.187S
Unknown
35.307
419971
T
35.496
9.286S0e-7
0.3900
o-DICHLOROBENZENE
36.816
51479
T
1.00000e+0
51479.2500
Unknown
37.368
117526
T
1.00000e+0
117526.5000
Unknown
38.155
283977
T
1.00000e+0
283977.0000
Unknown
38.577
171434
T
1.00000e+0
171434.0000
Unknown
38.813
159613
V
1.00000e+0
159613.1875
Unknown
39.693
58015
T
1.00000e+0
56015.0000
Unknown
40.008
496403
T
40.228
1.51937e-6
0.7542
1,2,4-TRICHLOROBENZE
40.480
680651
T
1.00000e+0
680651.1250
Unknown
41.647
184884
T
1.00000e+0
184884.2500
Unknown
41.897
133300
T
41.919
1.57675e-6
0.2102
HEXACHLOROBUTADIENE
42.195
85231
V
1.00000e+0
85231.6250
Unknown
44.217
53381
1.00000e+0
53361.0000
Unknown
44.837
111295
T
1.00000e+0
111295.5000
Unknown
4S.398
151595
V
1.00000e+0
151595.5000
Unknown
Figure 22. Data system listing of target compound concentrations from
sample chromatogram shown in Figure 21.
68
-------
over the shadow sensor developed earlier to measure mobility patterns. (11) Although the
field experiments were designed to evaluate the performance of the TIME monitor, not to
determine mobility patterns, the following point should be noted. If it is assumed that a
person changes microenvironments 40 times a day, and if it is further assumed that a full
30 s is required before each change is registered by the monitor, the total discrepancy would
be 20 m over 24 h, or less than 1 percent. It follows therefore that the rest of the difference
is due to false reading from misleading surfaces, such as trees, high indoor ceilings, or other
surfaces that may not reflect the ultrasound waves.
The decomposition of the total exposure is illustrated for the two field samples in
Table 13. The TIME monitor provides the required decomposition directly. The following
observation bears further investigation. Vinyl chloride, one of the target compounds, was
selected for this analysis. The investigator spent 33 percent of his time indoors in his
residence, 11 percent in his workplace, 38 percent outdoors, and 17 percent in-transit. The
measured concentrations of the test compound were 16.5, 0.98, 5.0, and 0.0 ppbv,
respectively. The total exposure estimated by summing the component concentrations is 22.5
ppbv. If we were to decompose the total exposure into its microenvironmental components
in the conventional way, by time-weighting the total exposure, i.e., by multiplying the total
exposure with the portion of time spent in each microenvironment, the microenvironmental
exposures would be substantially different from the measured values. This finding is of
some interest, and although it was reinforced with an evaluation of other components and
with data from other days, measurements by typical subjects and typical time patterns are
needed before the importance of this preliminary finding can be properly assessed.
It is important to remember that the magnitude of the exposures in these field tests is
not particularly meaningful because the investigators spent predetermined periods in each
microenvironment. These tests were not performed to measure typical human exposures, but
were carried out to demonstrate that the TIME monitor was functioning as expected.
69
-------
TABLE 13. CONCENTRATIONS (IN PPBV) OF TARGET COMPOUNDS OBTAINED FOR TWO FIELD TESTS OF THE
TIME MONITOR
COMPOUND
m
T28
T29
T30
Total
T32
T33
T34
T35
Total
FREON-12
0.284
0.509
0.000
0.000
0.793
0.000
0.000
103.100
107.860
210.960
METHYL CHLOWDB
0.000
0.000
0.000
0.000
0.000
0.000
0.000
91.816
0.000
91.816
FREON-II4
0,221
9.419
90.712
66.680
167.100
199.340
25.833
64.530
191.710
681.420
VINYL CHLORIDB
5.020
0.000
0.910
16.463
22.463
10.325
0.710
5.410
3,667
M.I 12
1,3-BUTADIENE
0.000
0.000
0.442
0.30J
0.747
32.945
0.000
2.096
2.047
37.089
METHYL BROMIDE
0.000
0.000
0.000
0.000
0.000
6.394
0.000
0.000
1.618
8.011
ETHYL CHLORIDE
0.000
1.904
30.J32
27.646
59.882
105.700
4.164
165.360
144.310
419.530
TRICHLOROFFLUOROMETH
107.800
14.700
363.440
96.960
582.890
0.000
6680.300
0.000
5.782
6686.tOO
1,1 -DICHLOROETHENB
0.130
0.000
2.170
1.589
5.288
2.072
0.350
1.568
1.091
5.082
DICHLOROM ETHANE
16.848
0.420
10.161
15.483
43.620
5.168
0.496
17,830
10,497
33.991
J-CHLOROPROPENE
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
TRICHLOROTRIFLUOROET
98,845
0.911
69.177
119.54
288.550
40.489
2.913
68.497
42.290
154.190
1.1 -DICHLOROETH ANE
0.000
0.000
0.000
0.000
0,000
0.000
0.000
o.ooo
29.327
29.327
CIS-1,2-DICHLOROETHE
0.535
0.000
4.804
1.940
7.278
1.609
1.089
4.274
1.999
8.972
TRICHLOROMETHANE
0.690
0.000
0.000
0.625
1.315
9.291
0.000
0.000
5.723
15.014
1,2-DICHLOROETHANE
0.278
0.000
0.000
0.000
0.278
1.897
0.000
5.858
0.521
8.277
I.I.I -TRICHLOROETHAH
2.321
0.353
3.210
3.314
9.268
10.269
1.788
7.273
16.666
35.997
R BENZENE
0,919
0.000
1.182
1.474
4.335
9.482
1.182
2.547
4.632
17.844
CARBON TETRACHLORIDE
9.017
0.000
62.122
31.577
102.790
4,305
16.019
61.555
21.295
110.170
1,2-DICHLOROPROPANB
0.336
0.000
0.000
0.297
0.633
2.553
0.116
0.000
0.972
3.641
TRICHLOROETHENB
3.145
0.000
5.013
3.661
11.825
12.944
1.441
9.303
1.156
31.845
CIS-1,3-DICHLPROPENB
0.355
0.000
1.273
0.683
2.311
1.249
0.792
2.751
0.758
5.551
TRANS-1.3-DICHLPROPE
0.160
0.000
0.000
1.100
1.261
0.770
1.078
4.743
9.859
16.452
1,1,2-TRICLETH ANE
0.332
0.000
0.000
0.368
0.700
4.027
0.000
0.000
2.439
6.466
R TOLUENE
2.60«
0.074
3.500
3,426
9.607
17.938
1.555
6.443
10.615
36.552
1,2-DIBROMOETHANE
0.243
0.515
3.215
1.781
5.754
3.183
1.1 IS
1.343
1.412
7.057
TETRACHLOROETHENE
0.257
0.711
13.763
4.315
19.053
1.854
3.273
16.843
1.251
23.222
CHLOROBENZENE
0.023
0.345
0.000
0.158
0.526
1.620
0.537
0.554
0.871
3,5iJ
ETHYLBENZENE
0.091
0.222
1.859
1.012
3.190
2.903
0.969
1.668
1.496
7,037
M + P-XYLENE
0.160
0.133
1.283
0.790
2.367
5.616
0.415
2.811
4.038
12.882
STYRENE
0.128
0.079
0.798
0.469
1.473
3.226
0.000
2.636
2.696
8.558
O-XYLENEfTETCLETHANi
0.123
0.126
2.130
0.647
3.027
3.916
1.715
2.861
2.342
10.836
4-ETMYLTOLUENE
0.000
0.000
0.000
0.000
0.000
1.756
4.170
0.000
0.000
5.926
1,3,5-TRIMETHBENZENB
0.365
0.1 II
4.984
1.532
6.992
2.151
1.011
0.611
0.681
4.454
1,2,4-TRlMETH BENZENE
0.200
0.000
1.127
0.772
2.099
15.677
0.828
3.214
4.538
24.260
BENZCHLOR/m-DlCHLRBN
0.187
0.347
0.625
0.114
1,273
7,319
0.130
0.569
0.709
8.728
p-DICHLOROBENZENE
0.235
0.087
0.864
0.211
1.398
0.303
0.168
0.621
0.150
1.243
o-DICHLOROBENZENE
0.368
0.390
0.801
0.221
1.781
0-131
0.388
0.572
0.475
1.567
1,2.4-TRlCHLOROBENZE
0,807
0.754
5.471
1.738
8.770
10.867
1.466
7,312
2.253
21,899
HEXACHLOROBUTADIENE
0.276
0.210
4.982
1.426
6.895
7.074
4.651
18.961
10.766
41.452
-------
REFERENCES
1. Molhave, L., Bach, B., and Pedersen, O.F., "Human reactions to low concentrations
of volatile organic compounds," Environ. Int. 12, 167-175, 1986.
2. Brown, R.H. and Purnell, C.J., "Collection and analysis of trace organic vapour
pollutants in ambient atmospheres," J. Chromatogr. 178. 79-90, 1979.
3. Krost, K.J., Pellizzari, E.D., Walburn, S.G., and Hubbard, S.A., "Collection and
analysis of hazardous organic emissions," Anal. Chem. 54, 810-817, 1982.
4. Bishop, R.W. and Valis, R.J., "A laboratory evaluation of sorbent tubes for use with
a thermal desorption gas chromatography-mass selective detection technique," L
Chromatogr. Sci. 28, 589-593, 1990.
5. Ciccioli, P., Cecinato, A., Brancaleoni, E., Frattoni, M., and Libert:, A., "Use of
carbon adsorption traps combined with high resolution gas chromatography-mass
spectrometry for the analysis of polar and non-polar C4-CI4 hydrocarbons involved in
photochemical smog formation," J. High Res. Chromatogr. 15. 75-84, 1992.
6. McClenny, W.A., Pleil, J.D., Holdren, M.W., and Smith, R.N., "Automated
cryogenic preconcentration and gas chromatographic determination of volatile organic
compounds in air," Anal. Chem. 56. 2947-2951, 1984.
7. Otson, R. and Fellin, P., "Volatile organics in the indoor environment: Sources and
occurrence," in Gaseous Pollutants: Characterization and Cycling, edited by Nriagu,
J.O., John Wiley & Sons, New York, pp. 335-421, 1992.
8. Pleil, J.D., McClenny, W.A., and Oliver, K.D., "Temporal variability measurement
of specific volatile organic compounds," Int. J. Environ. Anal. Chem. 37, 263-276,
1989.
9. "Installation and operating instructions for the Sequential Tube Sampler (Model STS
25) for the ATD 400," Perkin Elmer Preliminary Draft L428 9005.
71
-------
10. Pollack, A J. and Holdren, M.W., "Evaluation of an automated thermal desorption
system," Final report on Contract 68-D0-0007 (Work Assignment No. 11) from
Battelle to U.S. Environmental Protection Agency, Research Triangle Park, NC,
September 1991.
11. Moschandreas, DJ. and Relwani, S., "The shadow sensor: An electronic activity
pattern sensor," J. Exposure Anal. Environ. Epidemiol. 1. 357-367, 1991.
12. Moschandreas, DJ., "Decomposition of total exposure into its microenvironmental
components using a personal exposure monitor," Presented at conference on
Measuring, Understanding, and Predicting Exposures in the 21st Century, Atlanta,
GA, November 1991.
13. The Determination of Volatile Organic Compounds (VOCs) in Ambient Air Using
SUMMA® Passivated Canister Sampling and Gas Chromatographic Analysis.
Compendium Method TO-14. In: Compendium of Methods for the Determination of
Toxic Organic Compounds in Ambient Air (EPA-600/4-84-041), Quality Assurance
Division, Environmental Monitoring System Laboratory, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina 27711, May 1988.
14. Smith, D.L., "Method evaluation of TAMS network sampling," Final report on
Contract 68-02-4127 from Battelle to U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1989.
15. Holdren, M.W. and Pollack, A J., "Development and evaluation of an automated gas
chromatograph equipped with a multi-adsorbent preconcentration device," Final
report on Contract 68-02-4127 from Battelle to U.S. Environmental Protection
Agency, Research Triangle Park, NC, September 1989.
16. Smith, D.L. and Holdren, M.W., "Development of procedures for performance
evaluation of ambient air samplers for volatile organic compounds," Final report on
Contract 68-02-4127 from Battelle to U.S. Environmental Protection Agency,
Research Triangle Park, NC, March 1990.
17. Tipler, A., Perkin Elmer, personal communication, 1992.
18. Coutant, R.W., Zwick, T., and Kim, B. C., "Removal of volatile organics from
humidified air streams by adsorption," Final report on Contract F08635-85-C-0122
from Battelle to Air Force Engineering and Services Center, Tyndall AFB, FL,
Report No. AFESC/ESL-TR-87-24, December 1987.
72
-------
APPENDIX A
TIME MONITOR OPERATING INSTRUCTIONS
-------
APPENDIX A
TIME MONITOR OPERATING INSTRUCTIONS
I Sample Tube Change and start-up
II Motor Speed Control
III Data Collection
I. SAMPLE TUBE INSTALLATION AND CHANGE
A Remove the cover with four screws on front panel.
B Loosen but do not remove two screws on intake manifold.
C Slide manifold toward the flow valves far enough to slip the four sample tubes
(GROOVES TOWARDS THE VALVE MANIFOLDS in place between the two
manifolds.
D Using finger pressure, squeeze the two manifolds forcing a seal on the rubber seal
rings inside the manifolds.
E Tighten the two screws on the intake manifold while holding pressure on the rubber
seals.
F Reset the Microprocessor by depressing the switch located inside the box adjacent to
the flow valves.
G Being careful not to pinch the wiring, close the front panel cover and tighten the four
screws.
H The TIME SENSOR is now operational and sampling air depending on the location of
the ultrasonic sensor.
II. MOTOR SPEED SETTING
A Using GW Basic load the MONITOR program.
B Select the comminution port and hit enter until the "OK" prompt is observed then
using the CAPS LOCK input the letter M
C This will display the four motor speeds as described below.
D Type the letter M and follow it with the new motor speeds required for:
I HOME
II WORK
III TRANSIT
IV OUTSIDE
74
-------
Note: The Hex values 0 to 100 percent flow are 0 to FF
Example: M0025FF45
I 00= motor off
II 25 = low flow (value to be monitored by flow meter)
III FF = full flow (motor speed)
IV 45 = higher speed and flow
E Open the front cover with four screws.
F Remove the long hose (about 6 inches) which is connected to the center valve, from
the box wall and attach the flow meter at the top fitting and repeat step D.
G After all four speeds have been set remove the hose from the flow meter and replace
the hose in the intake hole in the box corner.
H If required reset the microprocessor database using the reset button.
I Replace the cover and tighten the four screws.
III. DATA REMOVAL/EXAMINATION
A Load GW Basic and run the EPALD program
B Using the prompts from this program a data file will be written to the disk for future
manipulation.
75
-------
APPENDIX B
SUMMARY OF COMMAND STRUCTURE TO TRANSFER
MOBILITY DATA FROM TIME MONITOR TO PC
-------
APPENDIX B
SUMMARY OF COMMAND STRUCTURE TO TRANSFER
MOBILITY DATA FROM TIME MONITOR TO PC
RS232 Command Summary for EPA1.ASM
This is a summary of the commands to which the reader (portable air quality
monitor) will respond via the RS-232 Serial Port. The port is configured at
9600 baud with 8 data bits, 1 stop bit, and no parity. All data is transmitted
in ASCII hexadecimal form (i.e. "00" through "FF") unless otherwise noted.
-Carriage Return. The reader follows Xon/Xoff protocol, where data
transmission will be suspended after receipt of Xoff {*S) , and resume after
reception of Xon ('Q). Conversely, if the host receives Xoff, it should suspend
data transmission until after receipt of Xon. After receipt of Xoff, the reader
will timeout and sleep after two minutes to avoid battery drain in the event of
cable disconnection.
Command: The null command. Host software should issue this command
until the OK response is received to insure proper
intialization of the reader's serial port.
Response: 0K =00H
Command: xx If an invalid character or unrecognized command is sent,
the reader will respond with a NO response, xx is any
invalid command. This response may also be sent the
first time communication is attempted.
Response: N0 =00H
D Dump all 2048 records in the reader's circular data
buffer.
Dnn Dump the most recent nn records (nn= 01 to FF).
D00 Dump all records since the last tube reset.
nnyyoottgghhmmssuu000000Q000Q000
{more records}
nnyyoottgghhmmssuu00000000000000
00K
or
DN0 Illegal character in nn.
nn =tube number
yy =Year in decimal {i.e. "90")
oo =Month in decimal ("01" - "12")
tt =Date in decimal ("01" - *31*)
gg =Day in decimal ("01" - *07*, *01*=Monday)
hh =Hours in decimal ("00" -"23")
mm =Minutes in decimal ("00" - "59")
ss =Seconds in decimal ("00" - "59")
00000000000000
Each record is 16 bytes long, and the unused bytes in each record are
nn indicates that the reader has switched to tube number nn at the
date and time indicated in that record. In this case nn will be 01, 02, 03, or
04. nn-FF indicates that the power was switched on at the date and time in that
record. nn=FE indicates that the power was switched off on the date and time
indicated in that record. nn=80 indicates that the tube change button mounted
inside the reader was pressed on the date and time indicated in that record.
Command:
Response:
Where:
77
-------
During a dump command, if DSR is removed from the RS-232 port, the data dump will
be aborted.
Command: E«er>
Response: nn
nn
EOK
Single pulse the transducer, and return the location of
the first echo. This is done at two different freq's.
Result from first frequency.
Result from second frequency.
nn=00 to FF. 4.8 counts/mS, so FF=> 255/4.8 = 53mS
Command: H
2048 hex digits are sent.
Command:
M
Read the 4 motor speed settings.
Response: aabbccddMOK aa = Motor speed for tube 1
bb = Motor speed for tube 2
cc = Motor speed for tube 3
dd = Motor speed for tube 4
00=> speed=0, FF=> speed=maximum
Command: Maabbccdd Set the 4 motor speed settings.
The format is as described above.
Response: M0K If settings were changed,
or
MN0 Illegal character in nn.
Command: N This is a diagnostic routine. This returns the values of
three registers, along with the current environment. There are three integrating
registers, one each for Transit, Inside, and Outside. Each time a pulse is
emitted and analyzed, the respective register is incremented depending on the
echo position. If any register fills to 33 (21H) readings, all three registers
are decremented. Whenever the difference between the fullest register (always
containing 32 pulses), and the second fullest register exceeds 20 (14H), the
reader decides that the environment has changed.
Response: aa Number of readings in the "Transit" register.
bb Number of readings in the "Inside" register.
cc Number of readings in the "Outside" register.
dd The current Environment, 0l=Transit, 02=Inside, and
03=0utside.
Command: R Read the state of processor port 1. A diagnostic.
Response: aaR0K In aa, 1=on, o=off
MSB=>DTR,DSR,Speaker,Motor,Soli,Sol2,Sol3,Xducer Drive<=LSB
Command: Rnn Write the state of processor port 1.
Format is as described above.
78
-------
Illegal character in aaaa.
T Read the current date and time.
Tyyoottgghhmmssuu
yy =Year in decimal (i.e. "90")
oo =Month in decimal ("01" - "12")
tt =Date in decimal ("01" - "31")
gg =Day in decimal ("01" - "07", "01"=Monday)
hh =Hours in decimal ("00" -"23")
mm =Minutes in decimal ("00" - "59")
ss =Seconds in decimal ("00" - "59")
uu hundredths of seconds in decimal ("00" - "99")
Command:
Tyyoottgghhmmssuu Set the current date and time.
The data fields are as defined above.
Response:
T0K
or
TN0
Date/Time successfully saved, however no checking is done
to insure a valid date/time has been set.
Illegal character in data.
Command:
U
Read the 8 bit checksum of the reader software.
Response:
hhl)0K
hh is the checksum in ASCII hexadecimal.
Command: V Read the reader software version number.
Response: v.vtttttttttttttVOK v.v is the version number, and t..tt is an
ASCII message, usually containing the date of the
revision and the reader serial number. The entire
field is 16 characters long.
Response: R0K
or
RN0
Command:
Response:
Where:
79
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1
LOAD
2
TXD
2
RXD
3
RXD
3
TXD
4
DTR
4
DSR
5
GROUND
5
GROUND
6
DSR
6
DTR
7
RTS
y
CTS
8
CTS
8
RTS
9 ND CONNECT
4 0.
9 ^
NORMAL OPERATION
READER
COMPUTER
6
7
8
9
f
pm
w
Pi
•
7*
•
4 m
1
W
*•
V H
w
READER
FOR LOADING NEW PROGRAM
COMPUTER
80
-------