ASTM D4323-21

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Designation: D4323 − 15 D4323 − 21
Standard Test Method for
Hydrogen Sulfide in the Atmosphere by Rate of Change of
Reflectance
This standard is issued under the fixed designation D4323; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the automatic continuous determination of hydrogen sulfide (H S) in the atmosphere or in gaseous
samples in the range from one part per billion by volume (1 ppb/v) to 3000 ppb/v. Information obtained may be used for
air-pollution studies and to monitor for emission sources.studies, fence-line monitoring, and other source emission monitoring.
1.2 The range may be extended by appropriate dilution techniques or by equipment modification.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to
inch-pound units that are provided for information only and are not considered standard.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. (See Section 9 for specific safety precautionary statements.)
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D2420 Test Method for Hydrogen Sulfide in Liquefied Petroleum (LP) Gases (Lead Acetate Method)
D2725 Test Method for Hydrogen Sulfide in Natural Gas (Methylene Blue Method) (Withdrawn 1996)
D3609 Practice for Calibration Techniques Using Permeation Tubes
D4084 Test Method for Analysis of Hydrogen Sulfide in Gaseous Fuels (Lead Acetate Reaction Rate Method)
D4323 Test Method for Hydrogen Sulfide in the Atmosphere by Rate of Change of Reflectance
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6792 Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
This test method is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.03 on Ambient Atmospheres
and Source Emissions.
Current edition approved April 1, 2015Nov. 1, 2021. Published April 2015May 2022. Originally approved in 1984. Last previous edition approved in 20092015 as
D4323 – 84 (2009).D4323 – 15. DOI: 10.1520/D4323-15.10.1520/D4323-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4323 − 21
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, refer to Terminology D1356.
4. Summary of Test Method
4.1 Hydrogen sulfide is determined by use of the reaction of H S with lead acetate-impregnated paper tape and by comparing a
reading of an unknown sample with that of a known standard using a differential colorimetric detection. Detection of the rate of
change of reflectance provides measurement in ppb/v ranges with an analysis time appropriate for the application. (See Fig. 1.)
Sample gas is passed through a flowmeter and a humidifier; then across lead acetate-treated paper tape. A constant humidity is
required for a constant reaction rate of H S with lead acetate. H S reacts with lead acetate to form a brown stain on the paper. The
2 2
resultant change in reflectance is detected by a photon detection system. The rate of change of reflectance is proportional to H S
concentration. The analyzer is composed of an optical system, a photon detection system, a signal differentiation system of first
order, and a signal output system.
5. Significance and Use
5.1 Hydrogen sulfide is an odorous substance which is offensive even at low concentrations in the atmosphere and toxic at higher
levels. It may be a product of biological processes in the absence of oxygen, as may occur in municipal garbage landfills. It is
emitted from geothermal sources, occurs in oil and gas, and may be emitted from industrial processes. Measurement is required
for air pollution studies, for pollution control, environmental justice based monitoring, and for plume characterization. This test
method is intended for hydrogen sulfide content up to 3000 ppbv. Measurement of hydrogen sulfide above this concentration in
gaseous fuels, carbon dioxide or other gaseous matrices is described in Test Method D4084. Equipment described is suitable for
fixed site or for mobile monitoring.
6. Interferences
6.1 In applications of this method, high levels of some interfering compounds can result in instrument response. Methyl
mercaptan, when 1000 times the H S concentration can affect response equal to Hresult in a significant S response. Arsine,
2 2
FIG. 1 Typical Rate of Change of Reflectance Type H S System
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phosphine, and free sulfur have been reported as causing response. The operatorresponse as well. The user should take required
precautions action if the above materials are expected to be present in the sample.
6.2 In the event SO may be is present, a solution of barium acetate may be substituted for the acetic acid solution to scrub out
the SO component without removing H S. Use 3 % by weight barium acetate in deionized water. Hydrogen sulfide and SO react
2 2 2
spontaneously and prepared samples cannot be stored more than a few minutesminutes.
7. Apparatus
7.1 Rate-of-Reaction H S Analyzer—Sample is passed across a lead acetate-treated surface causing a reflectance change.
Hydrogen sulfide is determined by measuring the rate of change of reflectance resulting from darkening when lead sulfide is
formed. Equipment consists components consist of a flowmeter, humidifier, sensing surface exposure chamber, optical system, and
electronic system. (See Fig. 1.) A complete analysis results from use of Results are based upon the rate of change of color rather
than magnitude of cumulative color development. The electronic system provides an output that is proportional to the derivative
of the photocell signal, caused by a reflectance change, and this rate measurement is a measure of H S concentration. A new
sectionportion of sensing material is drawn into the sensing chamber to provide a new independent measurement.
7.2 Recorder—A method of recording the electronic signal is required. A printer or other output means, such as a microprocessor,
data logger, or data collection system (DCS), can be used.
7.3 Reference Gas Preparation:
7.3.1 Mixing—A calibrated 10-L cylinder having a movable piston for use in making volumetric mixtures of gases in the ppb/v
range may be used. Materials of construction Construction materials must be inert to H S and not lead to a deterioration of prepared
samples. A cylinder of acrylic lubricated with silicone grease and using a silicone O-ring has been found to be suitable. suitable
in many applications. Concentration remains stable to within 1 % over a 1-h period. Alternatively, a reference mixture can be
prepared by dilution using a commercially available diluter with passivated components and diluent gas. These devices are not
needed when the permeation tube method of dynamic mixing is used to prepare the reference sample since this method will
generate a reference mixture.
7.3.2 Hypodermic Syringe—Gas-tight syringes of 10 and 50-μl50-μL capacity. A side port is convenient for purging. Avoid Luer
tip syringes made of plated brass as H S reacts with brass. Other convenient small volume measurement devices such as a
microlitre valve may be used.
7.3.3 Pump—A sample pump capable of providing 500 mL/min flow at approximately 35 kPa [5 psi].(5 psi). The pump wetted
parts must be inert to H S and not lead to a deterioration of the sample.sample deterioration.
8. Reagent and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise noted, all reagents shall conform to
the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are
available.
8.2 Acetic Acid Solution (50 mL/L)—Dilute 50 mL of glacial acetic acid (CH COOH), reagent grade, to make 1 L of solution using
Type III water prepared as described in Specification D1193.
8.3 Sensing Tape—Prepare sensing tape as described in Test Method D2420 or use commercial sensing tape that has been
prepared in a similar manner. Keep sensing tape in a sealed container to prevent exposure to ambient H S.
8.4 Hydrogen Sulfide (99.5 %)—Commercially available H S has been found to be insufficiently pure. Purity certification is
Smith, A. F., Jenkins, D. G., and Cunningworth, P. E., Journal of Applied Chemistry, Vol 11, 1961, pp. 317.
Kimbell, C. L. and Drushel, H. V., “Trace Sulphur Determination in Petroleum Fractions,” Analytical Chemistry, Vol 50, 1978, p 26.
Reagent Chemicals, American Chemical Society Specifications,ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for
Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. PharmaceuticalPharmacopeial Convention, Inc.
(USPC), Rockville, MD.
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recommended or use of H S generators using permeation devices may be used. Alternatively, a certified H S mixture at
2 2
concentrations as low as 1000 ppbv can be obtained from a gas standard vendor in an air or nitrogen matrix. These mixtures can
be either a primary standard, which is then diluted to the desired H S concentration using a 10-L cylinder with a piston, or piston
or commercially available dilution apparatus, or a standard in a pressurized cylinder containing the desired H S concentration.
Because of the potential for degradation, H S mixtures obtained from a gas standard vendor must be properly stored and used only
within the stated certification period.
8.4.1 Compressed Gas Standards—The protocol for compressed gas standards contained in Appendix X3 can be used to ensure
uniformity in compressed gas standard manufacture and provide for traceability to a NIST or other standard reference materials.
8.4.1.1 Compressed gas standard regulators must be appropriate for the delivery of sulfur gases and attached fittings must be
passivated or inert to sulfur gases.
8.4.2 Permeation Devices—Hydrogen Sulfidesulfide standards can be prepared using a permeation tube gravimetrically calibrated
and certified at a convenient operating temperature. At constant temperature, calibration gases covering a wide range of
concentration can be generated by varying and accurately measuring the flow rate of diluent gas passing over the tubes. These
calibration gases are used to calibrate the analyzer analyzer.
8.4.2.1 Permeation System Temperature Control—Permeation devices are maintained at the calibration temperature within
0.1°C.0.1 °C.
8.4.2.2 Permeation System Flow Control—The permeation flow system measures diluent gas flow over the permeation tubes
within 62 percent.62 %.
8.4.2.3 Permeation tubes are inspected and weighed to the nearest 0.01 mg on at least a monthly basis using a balance calibrated
against NIST traceable “S” class weights or the equivalent. Analyte concentration is calculated by weight loss rate and dilution
gas flow rate as in accordance with Practice D3609. These devices are discarded when the liquid contents are reduced to less than
ten percent of the initial volume or when the permeation surface is unusually discolored or otherwise compromised. Used
permeation tubes should be disposed of in accordance with local, state, or federal environmental regulations, or combination
thereof.
8.5 Dilution Gas—A chemically pure grade or purified gas similar to the gas to be sampled, H S-free. Mixture can be prepared
using the 10-L cylinder or commercially available diluter as described in 7.3.1.
8.6 Lead Acetate Sensing Paper—Prepare in accordance with Test Method D2420, using appropriate size strips and drying in an
H S-free environment. Commercially available test paper has been found satisfactory. Used Lead Acetate Sensing Paper should
be disposed of in accordance with local, state, or federal environmental regulations, or combination thereof.
9. Hazards
9.1 Hydrogen Sulfidesulfide contained in lecture bottles, permeation tubes or compressed gas cylinders may be flammable and
harmful or fatal if ingested or inhaled. Hydrogen sulfide is toxic at levels above 10 000 ppb/v. Use only under an appropriate fume
hood. Use protective glasses if liquid H S in cylinders is handled. Sense of smell may be lost on exposure to H S and is unreliable
2 2
as a warning of danger. (See 6.1 and 6.2 on Interferences.)
9.2 Lecture bottles, permeation tubes and compressed gas standards should only be handled in well ventilated locations away from
sparks and flames. Improper handling of compressed gas cylinders containing air, nitrogen, or hydrocarbons can result in
explosion. Rapid release of nitrogen or hydrocarbon gasses can result in asphyxiation.
9.3 Compressed air supports combustion.
9.4 Concentrated acetic acid fumes are an irritant and can cause damage to skin and mucus membrane. Handle carefully to avoid
injury.
9.5 Lead acetate is a cumulate poison; wash hands after handling and do not breathe any dust containing lead acetate.
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10. Sampling
10.1 Sample lines and containers must not absorb sample H S. Suitable materials are fluorocarbon resins, aluminum, borosilicate
glass, silica lined metal tubing, and suitable inactive acrylic. Stainless steel (Type 316) may be used when required by regulations
but is not preferred.
10.2 Avoid materials containing copper, brass, or having petroleum lubricant coatings.
11. Calibration and Standardization
11.1 Reference Standard—Reference standards are prepared by volumetric measurement or reference standard dilution to the
desired concentration at the time the reference material is to be used. This minimizes deterioration of the sample. The permeation
tube method or compressed gas cylinders certified as to concentration by the manufacturer may be
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