Stability
A 55ppbv reference standard (11ppbv each sulfur compound, dry standard)
was analyzed three times each day for six days. Eighteen SilcoCan
™
canisters
and two electropolished canisters were used. The sulfurVOCs showed excel-
lent stability in the SilcoCan
™
canisters. The electropolished canisters allowed
rapiddegradationof hydrogen sulfide,methylmercaptan, and ethylmercap-
tan (Figure 1).
HumidityEffects
Five SilcoCan
™
canisters that were used in the stability test were cleaned
according to US Environmental Protection Agency (EPA) Compendium of
Toxic Organic Method TO-14 and reused for the humidity study.
3
After
adding 100µL of deionized H
2
O to each canister, the relative humidity was
50%. Two mL of the stock sulfur standard was added to each canister and
aliquotswereanalyzedover sixdays (Figure1).The results shownodifference
in the performance by the SilcoCan
™
canisters for storing humidified sulfur
VOCs as compared todry standards.
Conclusion
This study confirmed the stability of very low-level sulfurVOCs (1-20ppbv)
inSilcoCan
™
canisters.Usingdryorhumidifiedconditions, sulfurcompounds
exhibitedvirtuallyno loss inSilcoCan
™
canisters after sixdays. Samplingwith
electropolished canisters leads to degradation of hydrogen disulfide, methyl
mercaptan, and ethylmercaptan.
References
1.QuangTran, You-ZhiTang;
Stability of Reduced Sulfur Compounds inWholeAir Samplers
, 1994
AWMA/EPA International Symposium ofMeasurement ofToxic andRelatedAir Pollutants.
2. Hoyt, Steven; Longacre, Vivian; and Stroupe, Michale;
Measurement of OxygenatedHydrocarbons
andReduced Sulfur Gases by Full ScanGC/MS: EPA TO-14
in:
Sampling andAnalysis of Airborne
Pollutants
, EricWinegar, and LawrenceKeith, editors. CRCPress, 1993 384pp (Restek cat.#20468).
3. MethodTO-14A,
Determination of VolatileOrganic Compounds (VOCs) inAmbient Air Using
Specially PreparedCanisterswith Subsequent Analysis byGas Chromatography
in:
Compendium of
Methods for theDetermination of ToxicOrganic Compounds inAmbient Air
. US EPA, Jan 1997.
References 1 and 3 not available fromRestek.
Table1
Concentrationsof sulfur compoundsused in stability study.
Stock Conc.
Standard Conc.
Standard Conc.
Compound
(ppmv)
(ppbv)
as Sulfur (ppbv)
hydrogen sulfide (H
2
S)
105
11.51
10.83
carbonyl sulfide (COS)
98
10.74
5.73
methyl mercaptan (CH
3
SH)
101
11.07
7.38
ethyl mercaptan (CH
3
CH
2
SH)
101
11.07
5.71
dimethylsulfide (CH
3
SCH
3
)
●
99
10.85
6.81
dimethyldisulfide (CH
3
SSCH
3
)
100
10.96
7.46
●
Internal standard
Figure2
Rtx®-1 column is ideal for trace-level sulfur analysis.
1. hydrogen sulfide
2. carbonyl sulfide
3. methyl mercaptan
4. ethyl mercaptan
5. dimethyl sulfide
6. dimethyl disulfide
Rtx
®
-1 60m, 0.53mm ID, 7.0µm (cat.# 10193)
Oven temp.:
30°C (hold 1min.) to
180°C@ 10°C/min. (hold 5min.)
Carrier gas:
helium
Flow rate:
8.5mL/min.
1
2
3
4
6
5
min.
5
GC_AR00477
For other Rtx
®
-1 column dimensions, please request our general
catalog or visit ourwebsite.
Rtx
®
-1Column (fusedsilica)
(Crossbond
®
100% dimethyl polysiloxane)
ID df (µm)
temp. limits
length
cat.#
0.32mm 4.00 -60 to 280/300°C 30-Meter
10198
0.53mm 7.00 -60 to 240/260°C 60-Meter
10193
Rt-XLSulfur
™
PackedColumns
Purchase installation kit separately. Please see our catalog.
*Please add configuration suffix number to cat.#when ordering.
Please see our catalog.
OD
ID (mm)
1-Meter*
2-Meter*
1
/
8
"
2.0mm
80484-
80485-
3
/
16
"*
3.2mm
80482-
80483-
Rt-XLSulfur
™
MicropackedColumns
Purchase installation kit separately. Please see our catalog.
OD
ID (mm)
1-Meter
2-Meter
1
/
16
"
1.0mm
19804
19805
0.95mm
0.75mm
19806
19807
Rt-XLSulfur™Packed/Micropacked
Columns
• Optimized for lowpbbv sulfur analyses.
• Eliminate theneed forTeflon
®
tubing.
• Column and end-fittings are Sulfinert
®
-treated
formaximum inertness.
