ASTM D7550-09
(Test Method)Standard Test Method for Determination of Ammonium, Alkali and Alkaline Earth Metals in Hydrogen and Other Cell Feed Gases by Ion Chromatography (Withdrawn 2017)
Standard Test Method for Determination of Ammonium, Alkali and Alkaline Earth Metals in Hydrogen and Other Cell Feed Gases by Ion Chromatography (Withdrawn 2017)
SIGNIFICANCE AND USE
Low operating temperature fuel cells such as proton exchange membrane (PEM) fuel cells require high purity hydrogen for maximum material performance and lifetime. Analysis to part-per-billion (ppb) concentration of individual cation contaminants such as potassium, sodium and ammonium in hydrogen and related fuel cell supply gases is necessary for assuring a feed gas of sufficient purity to satisfy fuel cell system needs. More specifically, cations such as ammonium causes irreversible performance degradation of proton exchange membranes used in low temperature fuel cells by reacting with protons in the membrane to form ammonium ions.
Although not intended for application to gases other than hydrogen and related fuel cell supply gases, techniques within this test method can be applied to other gaseous samples requiring cation analysis.
SCOPE
1.1 This test method describes a procedure for the determination of cations in hydrogen and other fuel cell feed gases. It has been successfully applied to other types of gaseous samples including air, engine exhaust, and landfill samples. An ion chromatograph/conductivity detector (IC/CD) system is used to determine cations. Sensitivity from low part per billion (ppb, μg/l, μg/kg) up to part per million (ppm, mg/l, mg/kg) concentration are achievable dependant on the amount of hydrogen or other fuel cell gas sampled. This test method can be applied to other gaseous samples requiring analysis of trace constituents provided an assessment of potential interferences has been accomplished.
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
WITHDRAWN RATIONALE
Formerly under the jurisdiction of Committee D03 on Gaseous Fuels, this test method was withdrawn in November 2017. This standard is being withdrawn without replacement due to its limited use by industry.
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7550 − 09
Standard Test Method for
Determination of Ammonium, Alkali and Alkaline Earth
Metals in Hydrogen and Other Cell Feed Gases by Ion
Chromatography
This standard is issued under the fixed designation D7550; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.3 relative humidity—ratio of actual pressure of existing
water vapor to maximum possible pressure of water vapor in
1.1 This test method describes a procedure for the determi-
the atmosphere at the same temperature, expressed as a
nation of cations in hydrogen and other fuel cell feed gases. It
percentage.
hasbeensuccessfullyappliedtoothertypesofgaseoussamples
3.1.4 relative density—ratio of the density of the gaseous
including air, engine exhaust, and landfill samples. An ion
fuel, under the observed conditions of temperature and
chromatograph/conductivity detector (IC/CD) system is used
pressure, to the density of dried air, of normal carbon dioxide
todeterminecations.Sensitivityfromlowpartperbillion(ppb,
content (0.03%), at the same temperature and pressure.
µg/l, µg/kg) up to part per million (ppm, mg/l, mg/kg)
concentration are achievable dependant on the amount of
3.1.5 ion chromatography—liquid chromatographic tech-
hydrogen or other fuel cell gas sampled. This test method can
niquefortherapidseparationofionicspeciesinsolutionusing
be applied to other gaseous samples requiring analysis of trace
ion exchange columns and determined using a variety of
constituents provided an assessment of potential interferences
flow-through detection system most commonly suppressed
has been accomplished.
conductivity.
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
3.1.6 ion chromatograph (IC)—Instrument for performing
asstandard.Nootherunitsofmeasurementareincludedinthis
ion chromatography.
standard.
3.1.7 ion conductivity detector (ICD) —instrument compo-
1.3 This standard does not purport to address all of the nent that measures the total change in conductivity of the
safety concerns, if any, associated with its use. It is the eluent and analytes flowing between two electrodes.
responsibility of the user of this standard to establish appro-
3.1.8 chemical suppression—technique using a chemical
priate safety and health practices and determine the applica-
reaction to reduce the eluent conductivity and to enhance
bility of regulatory limitations prior to use.
analyte response in ion chromatographic systems using a
conductivity detector.
2. Referenced Documents
2 3.1.9 electronic suppression—technique using an electro-
2.1 ASTM Standards:
chemicalreactiontoenhanceanalyteresponseinionchromato-
D1193Specification for Reagent Water
graphic systems using a conductivity detector.
3. Terminology
3.1.10 eluent—solventusedtotransportanalytesthroughan
3.1 Definitions of Terms Specific to This Standard: ion chromatographic column, suppressor and detector.
3.1.1 density—massperunitofvolumeofthefuelgasorair
3.1.11 dscm—dry standard cubic meter.
being considered.
3.1.2 gaseous fuel—material to be tested, as sampled, with- 4. Summary of Test Method
out change of composition by drying or otherwise.
4.1 Hydrogen or other fuel cell gas is passed through a
hydrogen quality sampling apparatus containing a calibrated
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
flow meter and a filter module loaded with a nylon filters (1.0
Fuels and is the direct responsibility of Subcommittee D03.14 on Hydrogen and
µm pore size). Alternative sampling apparatus can be used
Fuel Cells.
provided the fuel cell gas can be accurately measured and
Current edition approved Sept. 1, 2009. Published October 2009. DOI: 10.1520/
D7550-09.
collected free of contamination. When necessary a pump is
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
used to draw sample through the filter module. Filters are
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
removed from the filter module weighed and extracted into
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. volumetrically calibrated vessels. The recovered solutions are
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7550 − 09
analyzed for cations using an ion chromatograph/conductivity 6.5.2 Type 1 Water (Specification D1193-06).
detector (IC/CD) system. The cations present elute as peaks 6.5.3 Graduated Cylinder, various sizes as needed.
from the column. The area under the peaks is proportional to 6.5.4 Beakers, 150 ml.
theamountinthesample.Thesampleamountismeasuredand 6.5.5 Volumetric Pipettes, Class A borosilicate glass, vari-
compared to the amount found for standards used to generate ous sizes as needed.
a calibration curve. These functions/calculations are most 6.5.6 Volumetric Flasks, Class A, various sizes as needed.
commonly performed by chromatography software. 6.5.7 Balance, analytical, accurate to 0.1 g.
6.5.8 Magnetic stirrer, thermally insulated, and Teflon
5. Significance and Use
coated stirring bar.
5.1 Low operating temperature fuel cells such as proton 6.5.9 Micropipette, 0.1 ml to 1 ml.
exchange membrane (PEM) fuel cells require high purity
7. Apparatus
hydrogen for maximum material performance and lifetime.
7.1 Sampling is accomplished using a hydrogen quality
Analysis to part-per-billion (ppb) concentration of individual
sampling adaptor (HQSA) or other appropriate sampling ap-
cation contaminants such as potassium, sodium and ammo-
paratus fitted with a filter module containing a nylon filter (1.0
nium in hydrogen and related fuel cell supply gases is
µm pore size). The HQSAis appropriate for sampling of high
necessary for assuring a feed gas of sufficient purity to satisfy
pressure gas lines and is defined as apparatus used to interface
fuel cell system needs. More specifically, cations such as
with a hydrogen delivery receptacle such as a vehicle fueling
ammonium causes irreversible performance degradation of
nozzle and deliver sample to a collection vessel. Free flow of
protonexchangemembranesusedinlowtemperaturefuelcells
sample gas through the filter can be made by using a low
by reacting with protons in the membrane to form ammonium
pressure sample line or by drawing sample through the sample
ions.
train using a pump. Warning—Caution, hydrogen and related
5.2 Although not intended for application to gases other
flammable gas sampling should be accomplished in a well
than hydrogen and related fuel cell supply gases, techniques
ventilated locale where hydrogen gas will not build up to
withinthistestmethodcanbeappliedtoothergaseoussamples
explosive levels. Warning—Caution, hydrogen at high pres-
requiring cation analysis.
sures is an explosion hazard and may spontaneously ignite
creating an invisible flame when leaked through a seam or
6. Equipment and Instrumentation
pinhole.
6.1 SamplingApparatus—Developmentofasuitablehydro-
7.2 Determining the Target Minimum Cation Concentration
gen and other fuel cell feed gas sampling apparatus and
(TMCC)—The user should identify the target minimum cation
appropriate sampling practices is on-going. Any appropriate
concentration needed for the application.When the determina-
apparatus can be used provided it can safely provide a
tion of multiple cations is desired, the cation chosen should be
contamination free filtered sample of a volumetrically mea-
the one likely to be present in the lowest concentration.
sured fuel cell feed gas.
7.2.1 Determining the TMCC:
6.2 Nylon filters - 1.0 µm pore size.
7.2.1.1 Assumptions: :
6.3 Metering System—Typically, the metering system in- (1)All the cations in the sample are recovered from the
cludes a thermometer(s) capable of measuring temperature to
filter
within 3 °C (5.4 °F), a dry gas meter capable of measuring (2)Evaporative loses of substances such as ammonium are
volume to within 2 percent, and related equipment. An alter-
insignificant.
native to the thermometers and dry gas meters is an equivalent 7.2.1.2 Calculations:
temperature compensated dry gas meter. When needed, a
MDCC 5 C /V (1)
1 R
leak-free pump is interfaced between the filter module and the
Where:
dry gas meter.
MDCC = Minimum Detectable Cation Concentration
6.4 Sampling Line—The sampling line and any other sam-
C1 = lowest concentration on a calibration curve.
pling apparatus shall be made of material which is inert to the
VR = assumed liquid volume for the recovery solution,
gas sampled and cations including ammonia.
ml
6.5 IC Analysis:
7.2.2 Planned Sampling Volume (PSV)— The planned
6.5.1 Ion chromatograph (IC) standard manufacture fitted
sample volume is the volume of gas that must be sampled to
with a conductivity detector, autosampler, and interfaced to a
collect for analysis a quantifiable mass of a particular cation.
computer or other data storage/collection device. The follow-
The PSV is based on the TMCC and the target contaminant
ing conditions have been successfully used:
concentration, and is further adjusted by a safety margin to
6.5.1.1 Cation Exchange Separator Column:IonPacCS12A
assure quantification.
(4×250mm).
7.2.2.1 Calculations:
6.5.1.2 Cation Exchange Guard Column: IonPac CG12A
PSV 5 TMCC/STC 3F (2)
(4×50mm).
6.5.1.3 Eluent: 20mM MSA, Flow rate: 1.0 ml/min.
Where:
6.5.1.4 Detection: Suppressed conductivity, recycle mode
PSV = planned sample volume, dscm
6.5.1.5 Suppressor: CSRS 300 (4mm).
D7550 − 09
0.002 M NH4Cl, or 28 mg NH3-N/L. Calibration Verification
TMCC = analytical target minimum cation concentration,
must be prepared prior to use.
mg
STC = target contaminant concentration, mg/dscm
8.4 Methanesulfonic acid (MSA): 1.0 M—Used in prepara-
F = safety margin, F ≥ 1
tion of eluent for IC analysis
7.2.3 Planned Sampling Time (PST)—The planned sam-
8.5 Water—Deionized or distilled to conform to Specifica-
pling time is the time required to collect the minimum sample
tions D1193-99e1, Type 3. Water should be blank-checked for
volume at the proposed volumetric sampling rate (VSR). The
ammonium ion prior to use.
user should use an average volumetric sampling rate appropri-
8.6 Sulfuric Acid Solution—0.1N 8.8
ateforthefuelsourcetested.IftheVSRcannotbeachievedin
the field, the sampling time should be revised using the 8.7 IC Sparge gas (optional)—Helium of high purity
following equation to achieve the target PSV. 99.995%, low nitrogen content.
PST 5 PSV/VSR (3)
9. Standards
9.1 Working standards are prepared each week and are
PST = planned sampling time, unit time
storedinarefrigeratorat10°C.Calibrationisperformedusing
PSV = planned sample volume, dscm
the identical instrument parameters as are used in the analysis
VSR = achievable volumetric sampling rate, dscm/unit time
samples.
7.3 Sampling Operation—Sample the required amount of
9.2 Prepare initial calibration standards using 1000 mg/l
gas as per the determination under 7.2. Upon completion of
stock standards. Prepare at least four standards spanning the
sampling, isolate the filter sampling module and remove it
desired calibration range. For each calibration point, transfer
fromthehydrogensamplingapparatus.Transferfiltersampling
the stock solution using a pipette directly into the appropriate
module to the sample recovery area. This area should be clean
sized volumetric flask, add 0.1 N H2SO4 and bring to volume
and rigorously free of cation contamination. Sample recovery
using deionized water.
should be performed in a laboratory.
NOTE 1—Ammonium calibration standards will evolve ammonia over
8. Reagents and Materials time at room temperature; therefore, they should be prepared as close as
possible to use.
8.1 Ionic strength adjustor (ISA), pH adjusting solution.
9.3 For analysis of cations present in the recovered sample
8.2 Standard solutions - certified reference material quality.
solutions at 1 ppm or above a typical calibration curve can be
The following analytes as needed
prepared using the 1000 ppm stock standard by first preparing
8.2.1 Ammonia - 0.1M NH4Cl or 1400 ppm as N.
a 100 ppm standard. This standard is prepared by volumetri-
8.2.2 Nitrate - Stock 1000 mg/L as N Nitrate standard,
callyadding5mlofstockstandardtoa500mlvolumetricflask
which is equivalent to 4428.6 mg/L Nitrate as Nitrate. (Op-
then adding deionized water to volume. Once the 10 ppm
tional anion analysis)
standard is prepared, a typical calibration set of points can be
8.2.3 Sulfate - 1000 mg/l sulfate standard. (Optional anion
prepared as indicated in Table 1. Refrigerate the standards as
analysis)
necessary until ready to perform the analysis.
8.2.4 Sodium - 100 mg/l sodium standard
8.2.5 Potassium - 100 mg/l potassium standard.
10. Analysis
8.2.6 Magnesium - 100 mg/l magnesium standard.
10.1 As necessary, take the recovered samples out of the
8.2.7 Calcium -100 mg/l calcium standard.
refrigerator and let them sit until they reach room temperature.
8.3 Calibration verification check standard—As part of an
10.2 Prepare a matrix spike by transfering the sample to a
overall QA/QC program calibration verification check stan-
clean beaker, and adding an appropriate amount of the 10 ppm
dards should be analyzed with each set of samples in applica-
cation standard prepared under section 10 to make a 1 ppm
tion of this standard test method. For example an ammonium
cation spiked sample.
calibration check standard at 28 mg NH3-N/L is prepared as
follows.
10.3 Charge the IC eluent reservoir with freshly prepared
8.3.1 Pipette 10 ml of 0.1M NH4Cl standard solution into a eluent. Turn on all supply gases and pump the eluent through
500 ml volumetric flask and dilute to the mark with 0.04 N
thesystemforatlease30minbeforestartingcalibration.Make
H2SO4. The Calibration verification check standard value is sure baseline and background conductivity are low.
TABLE 1 Calibration Curve Data Points
Calibration Target Amount of 10 ppm Final
Level Concentration Standard (ml) Volume
(ppm)
1 2.0 20 100
2 1.5 15 100
3 1.0 10 100
4 0.5 5 100
5 0.1 1 100
D7550 − 09
10.4 Fill autosampler vials with about 5ml of standard,
W = formula weight of cation parent (for example, NH3,
a
control, or sample. Place the vials into the autosampler tray.A
NaCl, etc.)
typical run list is shown below but these elements should be
W = formula weight of cation
i
randomized in an effort to eliminate sampling errors: V = Corrected volume of gas sample
gas
Vial number Sample I.D.
11.7 Quality Assurance:
1 Deionized water
11.7.1 Relativ
...
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