Waters Sep-Pak DNPH-Silica Cartridges - Manual (Page 6)

[ Care and Use ManUal ]
Waters Sep-Pak DNPH-Silica Cartridge
6
IV. APPLICAtIon eXAMPLes
a. Estimating Sample Volume
An expected formaldehyde concentration in a paper mill is estimated
to be 1000 ppbv. Refer to Figure 4 to find the sample volume to
collect. For this example, a sample volume of 10 liters is sufficient.
The pump used in this example generates 17 inches (Hg) of vacuum,
resulting in a flow rate through the cartridge of 2 L/min. Therefore,
five minutes of pumping at 2 L/min yields the 10 liter sample
required for the analysis.
b. Analysis of Auto Exhaust Emissions
A typical analysis of diluted exhaust emissions from car fueled by
gasoline is shown in Figure 8. The sample* was collected using a
constant volume sampler dilution tunnel. The car was operated on a
prescribed driving schedule on a chassis dynamometer.
The cartridge was connected to a heated (100 °C) sampling manifold
using a short piece of Teflon tubing. The sample was collected using
a metal bellows pump and a mass flow controller.
Figure 8 represents an 8.4 liter sample collected at 1 L/min.
Formaldehyde is the most abundant carbonyl compound emitted
(ca. 2000 ppbv). Smaller amounts of other aldehydes and ketones
also appear.
* The sample was provided by Dr. S.B. Tejada of the US EPA
Atmospheric Research and Exposure Assessment Laboratory.
Figure 8: Analysis of Auto Exhaust Emissions
Time (minutes)
1. DNPH
2. Formaldehyde-DNPH
3. Acetaldehyde-DNPH
4. Acetone-DNPH
5. Acrolein-DNPH
6. Propionaldehyde-DNPH
7. Crotonaldehyde-DNPH
8. Butanone-DNPH
9. Butyraldehyde-DNPH
10. Benzaldehyde-DNPH
11. o-Tolualdehyde-DNPH
12. m, p-Tolualdehyde-DNPH
13. 2,5-Dimethylbenzaldehyde-DNPH
c. Analysis of Residential Air
An example of an analysis of indoor air in a conventional home is
shown in Figure 9. A 108 liter sample was collected at 0.6 L/min
using a portable sampling pump. The chromatogram shows
formaldehyde (31 ppbv), acetaldehyde (9 ppbv), acetone (62 ppbv),
and hexaldehyde (2 ppbv).
Figure 9: Analysis of Residential Air
d. Analysis of Research Lab Air
The sample in Figure 10 was collected in a chemical research labora-
tory using a portable sampling pump. A 100 L air sample was drawn
through the cartridge at flow rate 0.65 L/min. The chromatogram
shows formaldehyde (4.8 ppbv), acetaldehyde (1.2 ppbv), acetone
(118 ppbv), butanone (0.8 ppbv), and isovaleradehyde (0.7 ppbv).
Figure 10: Analysis of Research Lab Air
Time (minutes)
Lab Air Sample
Cartridge Blank
1. DNPH
2. Formaldehyde-DNPH
3. Acetaldehyde-DNPH
4. Acetone-DNPH
5. Butanone-DNPH
6. Isovaleraldehyde-DNPH
Time (minutes)
Residential Air
Cartridge Blank
1. DNPH
2. Formaldehyde-DNPH
3. Acetaldehyde-DNPH
4. Acetone-DNPH
5. Hexaldehyde-DNPH