ASTM D7621-16(2021)

Standard Test Method for Determination of Hydrogen Sulfide in Fuel Oils by Rapid Liquid Phase Extraction

SIGNIFICANCE AND USE
5.1 Excessive levels of hydrogen sulfide in the vapor phase above residual fuel oils in storage tanks can result in health hazards, violation of local occupational health and safety regulations, and public complaint. An additional concern is corrosion that can be caused by the presence of H2S during refining or other activities. Control measures to maintain safe levels of H2S require a precise method for the measurement of potentially hazardous levels of H2S in fuel oils. (Warning—Safety. Hydrogen sulfide (H2S) is a very dangerous, toxic, explosive and flammable, colorless and transparent gas which can be found in crude oil and can be formed during the manufacture of the fuel at the refinery and can be released during handling, storage, and distribution. At very low concentrations, the gas has the characteristic smell of rotten eggs. However, at higher concentrations, it causes a loss of smell, headaches, and dizziness, and at very high concentrations, it causes instantaneous death. It is strongly recommended that personnel involved in the testing for hydrogen sulfide are aware of the hazards of vapor-phase H2S and have in place appropriate processes and procedures to manage the risk of exposure.)  
5.2 This test method was developed so refiners, fuel terminal operators, and independent testing laboratory personnel can rapidly and precisely measure the amount of H2S in residual fuel oils and distillate blend stocks, with a minimum of training, in a wide range of locations.  
5.3 Test Method D5705 provides a simple and consistent field test method for the rapid determination of H2S in the residual fuel oils vapor phase. However it does not necessarily simulate the vapor phase H2S concentration of a fuel storage tank nor does it provide any indication of the liquid phase H2S concentration.  
5.4 Test Method D6021 does measure the H2S concentration of H2S in the liquid phase, however it requires a laboratory and a skilled operator to perform the complex procedure an...
SCOPE
1.1 This test method covers procedures (A and B) for the determination of the hydrogen sulfide (H2S) content of fuel oils such as marine residual fuels and blend stocks, with viscosity up to 3000 mm2s-1 at 50 °C, and marine distillate fuels, as measured in the liquid phase.
Note 1: Specification fuels falling within the scope of this test method are: ASTM Specification D396, MIL-DTL-16884, and ISO 8217.  
1.2 Procedure A has been shown to eliminate interferences such as thiols (mercaptans) and alkyl sulfides. Procedure B can give elevated results if such interferences are present (see Annex A2).
Note 2: A procedure for measuring the amount of hydrogen sulfide in crude oil can be found in Appendix X1. Full precision for Appendix X1 has not yet been determined.  
1.3 Valid ranges for the precision are given in Table 2 and Table 3. Measurements can be made outside these ranges however precision has not been determined.  
1.4 Samples containing FAME do not affect the measurement of hydrogen sulfide by this test method.  
1.5 The values stated in SI units are to be regarded as standard. Non-SI units given in parentheses are for information only.  
1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 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.

General Information

• Status: Published
• Publication Date: 30-Jun-2021
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.14 - Stability, Cleanliness and Compatibility of Liquid Fuels

Relations

• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Dec-2023
• Refers: ASTM D396-19a - Standard Specification for Fuel Oils
• Effective Date: 15-Dec-2019
• Refers: ASTM D6300-19a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2019
• Refers: ASTM D396-19 - Standard Specification for Fuel Oils
• Effective Date: 01-May-2019
• Refers: ASTM D396-18a - Standard Specification for Fuel Oils
• Effective Date: 01-Oct-2018
• Refers: ASTM D396-18 - Standard Specification for Fuel Oils
• Effective Date: 01-May-2018
• Refers: ASTM D396-17a - Standard Specification for Fuel Oils
• Effective Date: 01-Dec-2017
• Refers: ASTM D396-17 - Standard Specification for Fuel Oils
• Effective Date: 01-Jul-2017
• Refers: ASTM D396-16 - Standard Specification for Fuel Oils
• Effective Date: 01-Oct-2016
• Refers: ASTM D396-16e1 - Standard Specification for Fuel Oils
• Effective Date: 01-Oct-2016
• Refers: ASTM D6300-16 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Apr-2016
• Refers: ASTM D396-15c - Standard Specification for Fuel Oils
• Effective Date: 01-Oct-2015
• Refers: ASTM D6300-15 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2015
• Refers: ASTM D396-15b - Standard Specification for Fuel Oils
• Effective Date: 01-Jun-2015

Overview

ASTM D7621-16(2021) is the internationally recognized standard test method for the determination of hydrogen sulfide (H₂S) in fuel oils using rapid liquid phase extraction. Published and maintained by ASTM International, this standard is designed to provide refiners, fuel terminal operators, and independent laboratories with a means to accurately measure H₂S in residual fuel oils, blend stocks, and marine distillate fuels. Excessive hydrogen sulfide poses significant health risks, violates occupational safety regulations, and can cause public complaints or equipment corrosion. This standard supports essential control measures to assess and maintain safe H₂S limits in fuel oil products.

Key Topics

• Scope of Application: Covers residual fuels, blend stocks with viscosities up to 3000 mm²/s at 50°C, and marine distillate fuels.
• Testing Procedures: Describes two main procedures (A and B). Procedure A is optimized to eliminate interferences from substances such as thiols and alkyl sulfides, while Procedure B may show elevated readings in their presence.
• Safety Considerations: Highlights the risks associated with hydrogen sulfide – a highly toxic, flammable, and explosive gas, and underscores the importance of strict safety protocols during sampling and testing.
• Sampling and Handling: Offers detailed guidance for sample collection, handling, and preservation to minimize loss of H₂S and ensure accurate analysis.
• Precision and Reliability: Details the repeatability and reproducibility ranges for measurement accuracy and provides specific steps to ensure the reliability of results.
• Interference Elimination: Procedure A employs a vapor phase processor and a cooled filter cartridge to remove interfering compounds, ensuring more accurate H₂S quantification.

Applications

ASTM D7621-16(2021) is critical for various sectors in the petroleum and marine industries where reliable hydrogen sulfide testing in the liquid phase is essential. Practical applications include:

• Compliance & Regulatory Testing: Ensures that fuel oil products are within permissible H₂S concentration limits, aiding compliance with occupational health and safety standards.
• Quality Control: Supports refiners and fuel terminals in monitoring fuel oil quality and enforcing H₂S thresholds to prevent corrosion and equipment failure.
• Hazard Management: Facilitates rapid, on-site, and laboratory assessment of H₂S in fuel oils, thus enhancing worker safety and environmental protection.
• Marine Fuel Certification: Applicable to fuels falling under marine fuel specifications such as ASTM D396, MIL-DTL-16884, and ISO 8217.
• Distillate Blend Stock Analysis: Useful for blend stock evaluation to ensure compatibility and regulatory adherence before blending or shipment.

Related Standards

ASTM D7621-16(2021) is closely associated with several other international fuel testing standards, supporting a comprehensive approach to fuel quality management:

• ASTM D396 – Specification for Fuel Oils
• MIL-DTL-16884 – Specification for Naval Distillate Fuel
• ISO 8217 – Specification for Marine Fuels
• ASTM D4057 – Practice for Manual Sampling of Petroleum and Petroleum Products
• ASTM D5705 – Test Method for Measurement of Hydrogen Sulfide in the Vapor Phase Above Residual Fuel Oils
• ASTM D6021 – Test Method for Measurement of Total Hydrogen Sulfide in Residual Fuels
• ISO 4259 – Petroleum Products – Determination and Application of Precision Data in Relation to Methods of Test

Summary

Adoption of ASTM D7621-16(2021) for rapid liquid phase extraction and hydrogen sulfide determination provides the petroleum industry and marine operators with a straightforward, robust, and precise testing method. The standard’s emphasis on practical, field-applicable procedures, minimizing measurement interferences, and observing safety protocols ensures improved hazard management, regulatory compliance, and fuel oil quality assurance. For organizations handling fuel oils, implementing this standard is an essential aspect of operational excellence and safety management in line with international best practices.

Standards Content (Sample)

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.
Designation:D7621 −16 (Reapproved 2021)
IP 570/15
Standard Test Method for
Determination of Hydrogen Sulfide in Fuel Oils by Rapid
1,2
Liquid Phase Extraction
This standard is issued under the fixed designation D7621; 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 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This test method covers procedures (A and B) for the
ization established in the Decision on Principles for the
determinationofthehydrogensulfide(H S)contentoffueloils
Development of International Standards, Guides and Recom-
such as marine residual fuels and blend stocks, with viscosity
2 -1 mendations issued by the World Trade Organization Technical
up to 3000 mm s at 50 °C, and marine distillate fuels, as
Barriers to Trade (TBT) Committee.
measured in the liquid phase.
NOTE 1—Specification fuels falling within the scope of this test method
2. Referenced Documents
are: ASTM Specification D396, MIL-DTL-16884, and ISO 8217.
2.1 ASTM Standards:
1.2 Procedure A has been shown to eliminate interferences
D396 Specification for Fuel Oils
such as thiols (mercaptans) and alkyl sulfides. Procedure B can
D4057 Practice for Manual Sampling of Petroleum and
give elevated results if such interferences are present (see
Annex A2). Petroleum Products
NOTE 2—Aprocedure for measuring the amount of hydrogen sulfide in D5705 Test Method for Measurement of Hydrogen Sulfide
crude oil can be found in Appendix X1. Full precision for Appendix X1
in the Vapor Phase Above Residual Fuel Oils
has not yet been determined.
D6021 Test Method for Measurement of Total Hydrogen
1.3 Valid ranges for the precision are given in Table 2 and Sulfide in Residual Fuels by Multiple Headspace Extrac-
Table 3. Measurements can be made outside these ranges
tion and Sulfur Specific Detection
however precision has not been determined. D6300 Practice for Determination of Precision and Bias
Data for Use in Test Methods for Petroleum Products,
1.4 Samples containing FAME do not affect the measure-
Liquid Fuels, and Lubricants
ment of hydrogen sulfide by this test method.
2.2 ASTM Adjuncts:
1.5 The values stated in SI units are to be regarded as
ADJ6300 D2PP Determination of Precision and Bias data
standard.Non-SIunitsgiveninparenthesesareforinformation
for Use in Test Methods for Petroleum Products
only.
2.3 ISO Standards:
1.6 This standard does not purport to address all of the
ISO 4259 Petroleum Products–Determination and Applica-
safety concerns, if any, associated with its use. It is the
tion of Precision Data in Relation to Methods of Test
responsibility of the user of this standard to establish appro-
ISO 8217 Fuels (Class F) Specification of Marine Fuels
priate safety, health, and environmental practices and deter-
2.4 Energy Institute Standards:
mine the applicability of regulatory limitations prior to use.
IP 399 Test Method for Determination of Hydrogen Sulfide
in Fuel Oils
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
The technically equivalent standard as referenced is under the jurisdiction of the contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Energy Institute Subcommittee SC-G-5. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved July 1, 2021. Published August 2021. Originally the ASTM website.
approved in 2010. Last previous edition approved in 2016 as D7621 – 16. For referenced ASTM adjuncts contact ASTM Customer Service at
DOI:10.1520/D7621-16R21. [e-mail].
2 5
This test method has been developed through the cooperative effort between Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
ASTM and the Energy Institute, London.ASTM and IPstandards were approved by 4th Floor, New York, NY 10036, http://www.ansi.org.
ASTMandEItechnicalcommitteesasbeingtechnicallyequivalentbutthatdoesnot Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,
imply both standards are identical. U.K., http://www.energyinst.org.uk.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7621−16 (2021)
IP 570 Test Method for Determination of Hydrogen Sulfide during handling, storage, and distribution. At very low
in Fuel Oils–Rapid Liquid Phase Extraction Method concentrations, the gas has the characteristic smell of rotten
eggs. However, at higher concentrations, it causes a loss of
2.5 U.S. Department of Defense Specifications:
smell, headaches, and dizziness, and at very high
MIL-DTL-16884 Fuel, Naval Distillate
concentrations, it causes instantaneous death. It is strongly
3. Terminology
recommended that personnel involved in the testing for hydro-
gen sulfide are aware of the hazards of vapor-phase H S and
3.1 Definitions:
have in place appropriate processes and procedures to manage
3.1.1 dead crude oil, n—crude oil with sufficiently low
the risk of exposure.)
vapor pressure that, when exposed to normal atmospheric
pressure at room temperature, does not result in boiling of the
5.2 This test method was developed so refiners, fuel termi-
sample. naloperators,andindependenttestinglaboratorypersonnelcan
3.1.1.1 Discussion—The term ‘stabilized crude oil’ is fre-
rapidly and precisely measure the amount of H S in residual
quently used for a dead crude oil that has been produced by fuel oils and distillate blend stocks, with a minimum of
‘flashingoff’(distilling)lightcomponentsfromalivecrudeoil.
training, in a wide range of locations.
3.1.2 residual fuel oil, n—fuel oil comprising a blend of
5.3 Test Method D5705 provides a simple and consistent
viscous long, short or cracked residue from a petroleum
field test method for the rapid determination of HSinthe
refiningprocessandlighterdistillates(blendstocks)blendedto
residual fuel oils vapor phase. However it does not necessarily
a fuel oil viscosity specification, burned for the generation of
simulate the vapor phase H S concentration of a fuel storage
heat in a furnace or firebox or for the generation of power in an
tank nor does it provide any indication of the liquid phase H S
engine.
concentration.
3.2 Definitions of Terms Specific to This Standard:
5.4 Test Method D6021 does measure the H S concentra-
3.2.1 liquid phase extraction, n—technique to determine the
tionofH Sintheliquidphase,howeveritrequiresalaboratory
concentration of H S gas trapped in a liquid by continuous
and a skilled operator to perform the complex procedure and
analysis of gases extracted by bubbling air through the test
calculations, and does not offer any reproducibility data. This
specimen.
test method (D7621) offers a 15 min automated test, simplicity,
full precision, and a degree of portability.
3.2.2 vapor phase processor, n—apparatus enabling low
temperature removal of interfering vapors.
5.5 H S concentrations in the liquid and vapor phase at-
3.2.2.1 Discussion—The vapor phase processor holds a
tempt to reach equilibrium in a static system. However, this
specific filter cartridge at –20 °C during the Procedure A test.
equilibriumandtherelatedliquidandvaporconcentrationscan
vary greatly depending on temperature and the chemical
4. Summary of Test Method
composition of the liquid phase. The equilibrium of the vapor
4.1 Aweighed test specimen is introduced into a heated test
phase is disrupted the moment a vent or access point is opened
vessel containing a diluent base oil.Air is bubbled through the
to collect a sample.
oil to extract the H S gas. The air with the extracted HSis
2 2
passed, via a vapor phase processor (Procedure A only), to an
6. Apparatus
H S specific electro-chemical detector enabling the H S con-
2 2
6.1 General—The apparatus, as detailed in Annex A1,
tent of the air to be measured and the amount in the liquid
comprises an air pump, test vessel, heating jacket, filters, H S
phase to be calculated in mg/kg.The filter cartridge (see 7.4)is
specific detector, integral computer, automatic solenoid valves
not required for Procedure B.
and gas flow detectors.
6.1.1 ProcedureArequires the use of a vapor phase proces-
5. Significance and Use
sor capable of cooling a specific filter cartridge (see 7.4)to
5.1 Excessive levels of hydrogen sulfide in the vapor phase
–20 °C 6 2 °C.
above residual fuel oils in storage tanks can result in health
6.2 Analytical Balance, single pan or double pan balance
hazards, violation of local occupational health and safety
capable of weighing to the nearest 0.001 g.
regulations, and public complaint. An additional concern is
corrosion that can be caused by the presence of H S during
2 6.3 Syringe or Burette, able to dispense 20 mLfor introduc-
refining or other activities. Control measures to maintain safe
tion of the diluent oil (see 7.1), accuracy 61%.
levels of H S require a precise method for the measurement of
6.4 Refrigerator (optional), for storing the test sample (see
potentially hazardous levels of H S in fuel oils. (Warning—
8.3). The refrigerator shall be of a type suitable for storing
Safety. Hydrogen sulfide (H S) is a very dangerous, toxic,
flammable, volatile materials.
explosive and flammable, colorless and transparent gas which
6.5 Oven/Water Bath (optional), for warming the sample to
can be found in crude oil and can be formed during the
manufacture of the fuel at the refinery and can be released 40 °C with an accuracy of 62 °C (see 8.4.1.1). The oven shall
be of a type suitable for use with volatile materials.
6.6 Pipette, 1 mL positive displacement pipette, for the
Available online at https://assist.dla.mil/quicksearch/ or http://assistdocs.com/
introductionofthetestspecimen.Theaccuracyasstatedbythe
or from the Standardization Document Order Desk, 700 Robbins Avenue, Building
4D, Philadelphia, PA 19111-5094. manufacturer should be typically 60.25 %.
D7621−16 (2021)
6.7 Disposable Syringe,5 mLor10 mL,fortheintroduction 8.2 If a dedicated H S sample cannot be taken, then the H S
2 2
of the test specimen. Typical accuracy 61 %. This may be measurement shall be the first test carried out on the sample as
fitted with a needle or extra tube to allow sample to be taken anyadditionalhandlingcanleadtolossofH Sandlowresults.
from 3 cm below the surface, if appropriate.
8.3 Take the samples to the laboratory as soon as is
practicable after sampling. Test immediately if possible. If
7. Reagents and Materials
samples are not tested immediately, store in a cool place such
7.1 Diluent Oil, proprietary water whiteAPI Group 2 base as a refrigerator (6.4), and analyze within 3 days after
2 -1
oil with a typical viscosity of 100 mm s at 40 °C. sampling.
7.2 Reference Materials: 8.4 Test Specimen Preparation—To minimize the loss of
7.2.1 Reference material, pressurized nitrogen, of at least H S gas, do not homogenize or transfer the sample to another
99.999 % (volume percent) purity, containing a certified level container, and avoid shaking the sample before taking a test
of H S (23 µmol⁄mol (ppm v/v) to 27 µmol⁄mol (ppm v/v)) specimen.
traceable to a national standard.
8.4.1 Thesampleneedstobeflowingfreelyenoughtoallow
7.2.2 Verification solution containing a known concentra- the test specimen to be drawn into the syringe or pipette (see
6.7 and 6.6).
tion of liquid phase hydrogen sulfide.
8.4.1.1 A sample that is not free flowing at ambient tem-
7.3 Cleaning Materials, technical grade.
perature shall be gently warmed in a water bath or oven (see
7.3.1 Toluene.
6.5) set at a temperature not exceeding 40 ºC.
7.3.2 Petroleum Ether (60/80).
2 -1
8.4.2 Samples with viscosities greater than 3000 mm s at
7.3.3 Acetone.
50 °Cmaybetested,buttheprecisionhasnotbeendetermined.
7.4 Filter Cartridge, see Fig.A1.5, individually packed in a
NOTE 4—It has been found that samples with a viscosity over
sealed envelope, required for use in the vapor phase processor
2 -1
500 mm s , at 50 °C, usually require warming.
required for use in Procedure A only.
8.4.3 By using a smaller volume of sample it is possible to
extend the range of the instrument to over 200 mg⁄kg but the
8. Sampling and Test Specimen Preparation
precision has not been determined.
8.1 Unless otherwise agreed, samples shall be taken in
accordance with Practice D4057.
9. Preparation of Apparatus
8.1.1 During sampling operations, care shall be taken to
9.1 General—Followthemanufacturer’sinstructionsforthe
ensure that the integrity of the material is maintained and the
correct set up, verification, calibration and operation of the
possiblelossofH Siskepttoaminimum.Theprecisionofthis
apparatus.
method is critically dependent on the sampling, thermal
history, and handling of the test sample.
9.2 Location of Apparatus—Use the apparatus under a
8.1.2 Collect the sample directly in a suitable clean H S
suitable fume hood or equivalent well-ventilated work space,
inert container, of a minimum volume of 500 mL, with an
and vent the gas exit tube to a suitable extractor as the test will
impervious gas-tight closure. Suitable containers include am-
release small amounts of H S gas during test specimen
ber glass bottles and epoxy lined containers. The closure
introduction and during the measurement.
aperture shall allow the drawing of a test specimen with the
9.3 Filters and Tubing:
syringe or pipette (see 6.7 and 6.6).
9.3.1 Atthebeginningofeachtestinspectthemoisturefilter
8.1.2.1 Epoxy lined containers shall be visually inspected to
and the liquid trap.
ensure that the lining has not been damaged and that the
9.3.1.1 Replace the moisture filter if any discoloration is
containers are not dented.
visible.
8.1.3 To ensure sample integrity fill the sample container to
9.3.2 Replace the tubing that connects to the test vessel if
approximately 95 % full and cap immediately.
any discoloration is visible.
8.1.4 Where samples are drawn in a manner which does not
9.3.3 The inlet air filter shall be replaced every 3 months, or
minimize vapor loss (for example, continuous drip sampling)
earlier if any discoloration is visible.
collect a dedicated sample for H S determination.
9.3.4 Follow the manufacturer’s instructions regarding the
8.1.5 When samples cannot be collected directly into the
replacement intervals of the air pump and moisture filters.
samplecontainer,transferthesamplefromthesamplingdevice
into the sample container and ensure that H S loss is kept to a 9.4 Test Vessel—Before each test ensure that the test vessel
minimum. and screw cap are clean and dry. Fit the screw cap tightly.
NOTE 3—The precision has not been determined for smaller volume
9.5 Liquid Trap—Empty and clean the liquid trap if any
containers.
liquid or discoloration is visible.
NOTE 5—Toluene, followed by petroleum ether (60/80), and acetone,
are effective in cleaning the test vessel, cap, and liquid trap (see 7.3).
The following reagents and materials were used to develop the precision
9.6 H S Detector—Follow the manufacturer’s instructions
statements: Seta Diluent SA4000-004 and Seta Verification Gas SA4001-001.
for installing a new calibrated detector and verify the perfor-
Stanhope-Seta, Chertsey, Surrey, KT16 8AP, UK. This is not an endorsement or
certification by ASTM International. mance immediately afterwards as described in 10.2.3.
D7621−16 (2021)
9.7 Switch on the apparatus in accordance with the manu- 10.2.5.1 Stabilized verification solutions are available by
facturer’s instructions. means of participation in a proficiency testing scheme.
10.2.5.2 Non-stabilized verification solutions, derived
9.7.1 ProcedureA—Afterswitchon,initiatethevaporphase
within the testing lab using local procedures, may be used.
processor cooling.
9.7.1.1 Confirm that the temperature of the heater jacket is
NOTE 6—Non-stabilized verification solutions should be standardized
60.0 °C 6 1.0 °C and the vapor phase processor is –20.0 °C 6
by titration before use and have a very short life of only a few hours.
2.0 °C. Air purging of the H S detector commences.
10.2.5.3 For commercially supplied verification solutions, if
9.7.2 Procedure B:
the result is not within R/√2 of the accepted reference value,
9.7.2.1 Confirm that the temperature of the heater jacket is
check the validity date. If the validity date has not expired,
60.0 °C 6 1.0 °C.Air purging of the H S detector commences.
2 carry out checks as described in 10.2.5.5. For verification
solutions from a proficiency testing scheme (PTS), if the
10. Calibration and Standardization
resultisnotwithinR/√2oftheconsensusoracceptedreference
value, carry out checks as described in 10.2.5.4.
10.1 Ensure that all of the manufacturer’s instructions for
10.2.5.4 For non-stabilized verification solutions, if the
verification and calibration of the mechanical and electronic
result is not within R/√2 of the calculated value, then make a
systems, and operation of the apparatus are followed. Calibra-
new batch and repeat the test.
tion functions are separated from the usual operator controls
and are all implemented electronically using the integral
NOTE 7—This calculation assumes that the uncertainty in the ARV for
the commercially supplied verification solution, or consensus value from
display and keyboard.
the PTS, is negligible relative to R/√2. Users are advised to validate this
10.2 Verification:
assumption.
10.2.1 Air Flow Rate—Verify that the air flow rate is
10.2.5.5 If it is not possible to meet the criteria in 10.2.5.3
375 mL⁄min 6 55 mL⁄min, at least once a month using a
or 10.2.5.4, check the air flow rate (10.2.1) and validate the
suitable calibrated flow meter connected to the air output
H Ssensor(10.2.3).Ifitisstillnotpossibletomeetthecriteria
connection. If the flow rate is incorrect, recalibrate the flow
in 10.2.5 or 10.2.5.4, then follow the manufacturer’s instruc-
(see 10.3.1).
tions regarding fault finding and calibration.
10.2.2 Test Vessel Heater Jacket—Verify that the tempera-
10.3 Calibration:
ture of the heater jacket is 60.0 °C 6 1.0 °C, at least every six
10.3.1 Air Flow Rate—The air flow adjustment is imple-
months, by inserting a calibrated temperature sensor into the
mented electronically (see 10.1).
heater jacket. If the temperature is incorrect, recalibrate (see
10.3.2 Test Vessel Heater Jacket—The temperature adjust-
10.3.2).
ment is implemented electronically (see 10.1).
10.2.3 H S Detector—Verify the performance of the detec-
10.3.3 H S Detector—The detector is factory calibrated
tor at least every month, or when a new detector is fitted, at
using the reference material (see 7.2) (static calibration) and
zero using air, and at a nominal 25 µmol⁄mol (ppm v/v) vapor
using factory calibration liquids with known mg/kg liquid
concentration level using pressurized nitrogen (see 7.2) con-
concentrations of H S (dynamic calibration). This calibration
taining a certified level of H S. This verification shall be
information is held digitally on the detector assembly and is
carried out at ambient temperature. If the measurement is not
read directly by the computer in the apparatus. The calibration
within 10 % of the certified value of the vapor concentration,
enables results in mg/kg to be calculated fro
...