15
X. Conclusion
A well designed and properly prepared passive sampling system helps ensure
accurate, useful information is obtained from an air sampling project. In this
guide, we describe the components of the system, procedures for assembling
the system and preparing it for sampling, and the sampling procedure.
Cleaning system options and procedures for cleaning a used sampling train
and canister for certification prior to a subsequent sampling also are present-
ed. The following section describes Restek products designed to help collect
and analyze air samples.
Dirty can
Clean can
Figure 9
Aliquots from a canister before and after cleaning with
2 cycles of humidified air while heated to 200°C.
Rtx
®
-1 60m x 0.32mm ID x 1.0µm (cat.
#10157)
50°C (hold 1min) to 165°C @ 8°C/min.
to 220°C @ 15°C/min. (hold 5 min.)
flow rate = 1.4mL/min.
Nutech 3550 Preconcentrator
conditions
sample= 300cc from canister
cryotrap = -160°C
desorb = 150°C
cryofocuser = -190°C
desorb = 150°C
MSD conditions
Instrument: HP5971 GC/MSD
5 minute solvent delay
scan range = 25-260amu
Pressure Conversion Table
Pressure
PSI
atm kg/cm
2
torr
kP
a
bar
inches Hg
PSI = 1
0.068
0.0703
51.713
6.8948
0.06895
2.0359
atm =
14.696
1
1.0332 760
101.32
1.0133
29.921
kg/cm
2
= 14.223
0.967
1
735.5
98.06
0.9806
28.958
torr =
0.0193
0.00132 0.00136
1
0.1330
0.00133
0.0394
kP
a
=
0.1450
0.00987 0.0102
7.52
1
0.0100
0.2962
bar =
14.5038
0.9869
1.0197 751.88 100
1
29.5300
in Hg =
0.49612 0.0334
0.0345
25.400
3.376
0.03376
1
Multiply units in the left-most column by the conversion factors listed in the columns to the right.
e.g., 10PSI x 0.068 = 0.68atm, 10 bar x 29.5300 = 295.300 inches Hg
