Noxious Gases Ref Peaks: An Alternative to Dual Inlet Bellows Paul Eby.
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Transcript of Noxious Gases Ref Peaks: An Alternative to Dual Inlet Bellows Paul Eby.
Noxious Gases Ref Peaks:An Alternative to Dual Inlet Bellows
Paul Eby
Normal Conflo Ref Gas
GC / EA
Ref Gas
He
IRMS
- Ref Gas is always flowing (0.2mL/min)
- Not okay for noxious gases
- CO, CH3Cl, SO2
- Small quantities / expensive gases
Using the BellowsGC / EA
- Consumption is very low (0.02 to 0.002mL/min)
- Continuously flows
- Noxious gas exits with the pump exhaust
IRMS
REF SAMPLE
- Requires dual inlet
37Cl Measurements
1. Precipitate chloride out as AgCl by adding AgNO3
2. Convert AgCl to CH3Cl gas by reacting with CH3I
3. Run by GC-IRMS
4. Measured as CH3Cl
ProblemsRequires an extra cup to measure masses 50 and 52
Bellows needed for toxic CH3Cl (also expensive)
$ $ $ $
Thermo Conflo IV
Allows for 5 different reference gases, 2 at a time
Thermo Conflo IV
Ref A
Ref B
Ref C
IRMS
Can we leave the ref gas off until a peak is needed?
Does the gas need to reach a steady state by constantly flowing?
How long does it take to reach a steady state?
Can I test this before upgrading the IRMS?
Thermo Conflo IV in Isodat
Extra columns added to the method using Configurator
Carbon Dioxide On/Off Test
ave = -0.03 stdev = 0.02 ave = -0.01 stdev = 0.04
Carbon Dioxide On/Off Test
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
1 2 3 4 5 6 7 8 9 10 11 12
d13C
/ p
erm
il
Methyl Chloride Trials
1. Upgrade the detectors
2. Add ventilation to the Conflo IV
3. Pump exhaust vented
4. Small bomb of CH3Cl
Methyl Chloride On/Off Test
ave = 0.01 stdev = 0.01 ave = -0.02 stdev = 0.02
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
1 2 3 4 5 6 7 8 9 10 11
d37C
l / p
erm
il
Methyl Chloride On/Off Test
Methyl Chloride On/Off Test
Conclusions
1. ConFlo IV can be used to limit consumption of ref gas
2. Comparing to Bellows:
Flow rate in Conflo IV 0.2mL/min
Flow rate in bellows 0.02 - 0.002mL/min?