ASTM E3346-22

Standard Guide for Combustion, Inert Gas Fusion and Hot Extraction Instruments for use in Analyzing Metals, Ores, and Related Materials

SIGNIFICANCE AND USE
5.1 The chemical measurement processes covered by this guide are used for determination of Carbon, Sulfur, Nitrogen, Oxygen and Hydrogen in metals, ores and related materials. A test method utilizing this guidance is used to test such materials, and also form the basis for quality assurance of these materials. Thus, it is economically and scientifically critical that these instruments be understood by the laboratories that use them.  
5.2 It is assumed that all who use this guide will be trained analysts, capable of performing common laboratory procedures skillfully, and safely. It is expected that any work will be performed in a properly equipped laboratory.  
5.3 It is expected that the laboratory will prepare their own work procedures for any of the information described in this guide.  
5.4 This guide contains numerous references to “manufacturer’s recommendations”. The user of this guide is expected to refer to the instrument operation manual for the specific instrument being used or consult directly with the manufacturer to obtain instructions or recommendations.  
5.5 This guide stresses the conservation of certified reference materials (CRMs). CRMs should not be used for drift checks or conditioning measurments. Other materials should be developed and used for these operations.
SCOPE
1.1 This guide covers information for using Combustion, Inert Gas Fusion and Hot Extraction instruments to determine the mass fraction of the non-metallic elements Carbon, Sulfur, Nitrogen, Oxygen and Hydrogen in metals, ores and related materials.  
1.2 This guide does not specify all the operating conditions because of the differences among different manufacturer’s instruments. Laboratories should follow instructions provided by the manufacturer of the instrument.  
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 The information in this guide is contained in the sections indicated as follows:    
Sections  
Carbon/Sulfur by Combustion/Infrared Detection  
14 – 19  
Nitrogen/Oxygen by Inert Gas Fusion/Thermal Conductivity and Infrared Detection  
20 – 25  
Hydrogen by Inert Gas Fusion Instrumental Measurement and Hot Extraction/Various Detection Cell Technology  
26 – 31  
1.6 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-Nov-2022
• ICS: 77.040.30 - Chemical analysis of metals
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.20 - Fundamental Practices

Relations

• Refers: ASTM E135-20 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Jan-2020
• Refers: ASTM E2972-15(2019) - Standard Guide for Production, Testing, and Value Assignment of In-House Reference Materials for Metals, Ores, and Other Related Materials
• Effective Date: 01-Oct-2019
• Refers: ASTM E135-19 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2019
• Refers: ASTM E88-11(2017) - Standard Practice for Sampling Nonferrous Metals and Alloys in Cast Form for Determination of Chemical Composition
• Effective Date: 01-Sep-2017
• Refers: ASTM E50-17 - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-Sep-2017
• Refers: ASTM E882-10(2016)e1 - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• Refers: ASTM E882-10(2016) - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• Refers: ASTM E50-11(2016) - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-Aug-2016
• Refers: ASTM E135-16 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2016
• Refers: ASTM E135-15a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Jul-2015
• Refers: ASTM E135-15 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2015
• Refers: ASTM E2972-15 - Standard Guide for Production, Testing, and Value Assignment of In-House Reference Materials for Metals, Ores, and Other Related Materials
• Effective Date: 15-Feb-2015
• Refers: ASTM E135-14b - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Aug-2014
• Refers: ASTM E135-14a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Apr-2014
• Refers: ASTM E135-14 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Feb-2014

Overview

ASTM E3346-22: Standard Guide for Combustion, Inert Gas Fusion, and Hot Extraction Instruments for Analyzing Metals, Ores, and Related Materials provides comprehensive guidance on the use of instrumental techniques for determining the mass fractions of non-metallic elements, specifically carbon, sulfur, nitrogen, oxygen, and hydrogen. These analytical methods are essential for laboratories engaged in quality control, research, and certification of metals, ores, and similar materials in industrial and scientific applications.

This standard outlines best practices for using combustion, inert gas fusion, and hot extraction instruments, focusing on achieving accurate, reliable, and repeatable results while emphasizing safety, quality control, and proper instrument maintenance.

Key Topics

• Measurement Techniques: Guidance on the determination of carbon and sulfur (by combustion/infrared detection), nitrogen and oxygen (by inert gas fusion/thermal conductivity and infrared detection), and hydrogen (by inert gas fusion or hot extraction with various detection cell technologies).
• Instrument Setup and Use: Detailed steps for equipment assembly, instrument preparation, leak testing, and the importance of following the manufacturer’s operating instructions.
• Sample Preparation: Practical recommendations for preparing specimens and handling different sample forms (solids, powders, chips), including cleaning, surface preparation, and flux utilization.
• Calibration and Drift Correction: Procedures for instrument calibration using certified reference materials (CRMs), reference materials (RMs), and the implementation of drift correction and control charts for maintaining analytical accuracy.
• Quality Assurance: Emphasis on the conservation of CRMs, development of in-house RMs, and adherence to established laboratory procedures for continuous quality improvement.
• Safety Practices: User responsibility for ensuring a safe and compliant laboratory environment and observance of relevant safety and environmental regulations.

Applications

The practical value of ASTM E3346-22 extends to a variety of fields that depend on precise measurement of non-metallic elements in metallic matrices. Key applications include:

• Metals Manufacturing and Processing: Ensuring alloy composition meets specifications for structural performance, corrosion resistance, and other critical properties.
• Mining and Ore Evaluation: Accurate determination of elemental content in ores for resource assessment, beneficiation, and process optimization.
• Quality Assurance Laboratories: Supporting the certification, validation, and cross-verification of metal and ore samples as part of broader quality control regimes.
• Research and Development: Providing foundational methodologies for the development of new materials and the improvement of existing alloys.
• Regulatory Compliance: Meeting requirements for reporting and documentation in line with international trade and safety standards.

Using ASTM E3346-22 enhances data integrity, operational safety, and compliance with both customer and legal requirements, making it an essential guideline for organizations operating high-precision analytical laboratories.

Related Standards

ASTM E3346-22 references and complements several other ASTM standards and international guidelines crucial to chemical analysis and laboratory best practices, including:

• ASTM E50: Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• ASTM E55, E88, E1806: Practices and procedures for sampling nonferrous and ferrous metals and alloys
• ASTM E135: Terminology relating to analytical chemistry for metals, ores, and related materials
• ASTM E882: Guide for accountability and quality control in the chemical analysis laboratory
• ASTM E2857: Guide for validating analytical methods
• ASTM E2972: Guide for production, testing, and value assignment of in-house reference materials

By following ASTM E3346-22 in conjunction with these related standards, laboratories ensure robust analytical processes, superior reproducibility, and alignment with global quality expectations for chemical measurements in metals and ores.

Keywords: ASTM E3346-22, combustion analysis, inert gas fusion, hot extraction, non-metallic elements, metals analysis, carbon sulfur nitrogen oxygen hydrogen, analytical instrumentation, quality assurance, chemical analysis standards, laboratory 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: E3346 − 22
Standard Guide for
Combustion, Inert Gas Fusion and Hot Extraction
Instruments for use in Analyzing Metals, Ores, and Related
Materials
This standard is issued under the fixed designation E3346; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This guide covers information for using Combustion,
Inert Gas Fusion and Hot Extraction instruments to determine
2. Referenced Documents
the mass fraction of the non-metallic elements Carbon, Sulfur,
2.1 ASTM Standards:
Nitrogen, Oxygen and Hydrogen in metals, ores and related
E50 Practices for Apparatus, Reagents, and Safety Consid-
materials.
erations for Chemical Analysis of Metals, Ores, and
1.2 This guide does not specify all the operating conditions
Related Materials
because of the differences among different manufacturer’s
E55 Practice for Sampling Wrought Nonferrous Metals and
instruments. Laboratories should follow instructions provided
Alloys for Determination of Chemical Composition
by the manufacturer of the instrument.
E88 Practice for Sampling Nonferrous Metals andAlloys in
Cast Form for Determination of Chemical Composition
1.3 Units—The values stated in SI units are to be regarded
E135 Terminology Relating to Analytical Chemistry for
as standard. No other units of measurement are included in this
Metals, Ores, and Related Materials
standard.
E882 Guide for Accountability and Quality Control in the
1.4 This standard does not purport to address all of the
Chemical Analysis Laboratory
safety concerns, if any, associated with its use. It is the
E1329 Practice for Verification and Use of Control Charts in
responsibility of the user of this standard to establish appro-
Spectrochemical Analysis (Withdrawn 2019)
priate safety, health, and environmental practices and deter-
E1806 Practice for Sampling Steel and Iron for Determina-
mine the applicability of regulatory limitations prior to use.
tion of Chemical Composition
1.5 Theinformationinthisguideiscontainedinthesections
E2857 Guide for Validating Analytical Methods
indicated as follows:
E2972 Guide for Production, Testing, and ValueAssignment
Sections
of In-House Reference Materials for Metals, Ores, and
Carbon/Sulfur by Combustion/Infrared Detection 14–19
Other Related Materials
Nitrogen/Oxygen by Inert Gas Fusion/Thermal Conductivity and Infra- 20–25
red Detection
G93 GuideforCleanlinessLevelsandCleaningMethodsfor
Hydrogen by Inert Gas Fusion Instrumental Measurement and Hot 26–31
Materials and Equipment Used in Oxygen-Enriched En-
Extraction/Various Detection Cell Technology
vironments
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
3.1 Definitions: For definition of terms used in this guide,
Development of International Standards, Guides and Recom-
refer to Terminology E135.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is under the jurisdiction of ASTM Committee E01 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct Standards volume information, refer to the standard’s Document Summary page on
responsibility of Subcommittee E01.20 on Fundamental Practices. the ASTM website.
Current edition approved Dec. 1, 2022. Published January 2023. DOI: 10.1520/ The last approved version of this historical standard is referenced on
E3346-22. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3346 − 22
4. Summary of Guide the specifications of the Committee on Analytical Reagents of
the American Chemical Society where such specifications are
4.1 This guide provides information assisting users to prop-
available. Other grades may be used, provided it is first
erly understand and utilize the various specimen decomposi-
ascertained that the reagent is of sufficiently high purity to
tion and element detection techniques to determine the non-
permit its use without lessening the accuracy of the determi-
metallic elements Carbon, Sulfur, Nitrogen, Oxygen, and
nation.
Hydrogen. The instruments described in this guide are de-
signed to perform a series of chemical reactions to convert the 6.2 Accelerators—These will typically be copper, tungsten,
iron, tin or a mixture of these metals. During combustion
elements to gaseous species, to detect those species and to
quantify the mass fractions of the elements in the original analyses,thesehelptocoupleinductionenergytothespecimen
allowing for combustion at high temperatures while also
specimens. Each analysis starts with a specimen and ends with
aquantifiedresultoftheelement(s)ofinterest.Beforereaching coating the specimen to prevent it from spattering. Different
metals allow different analysis temperatures.
that quantified result, the material undergoes intermediary
reactions that separate, and often, to purify the gases before
6.3 Acetone—Cleaning solvent used to remove surface con-
detection of the element(s) of interest. Detection methods
tamination before analysis. It should be low residue to mini-
commonly used are infrared (IR) energy cells, thermal conduc-
mize contamination that could affect results.
tivity (TC) cells or electrochemical (EC) cells.
6.4 Argon—Inert carrier gas used to transport the gases
4.2 This guide is for use with commercial instruments
released by the applied heating or fusion process through the
designed to conduct these analyses automatically, once the
various sections of the instrument and into the detectors
measurement cycle is started. Some instruments do not per-
without causing side reactions. This gas is used for nitrogen,
form all steps automatically; this guide is not intended for
oxygen and hydrogen determinations.
those. While information contained in this guide may be
6.5 Copper Oxide or Rare Earth Copper Oxide—Acatalyst
helpful to the use of those instruments, the suitability of the
used to convert hydrogen, hydrocarbon contaminants and CO,
information should be evaluated.
to water and CO for removal by other reagents.
5. Significance and Use
6.6 Helium—Inert carrier gas used to transport the gases
5.1 The chemical measurement processes covered by this
released by the applied heating or fusion process through the
guide are used for determination of Carbon, Sulfur, Nitrogen,
various sections of the instrument and into the measurement
Oxygen and Hydrogen in metals, ores and related materials.A
system without causing any side reactions. This gas is used for
test method utilizing this guidance is used to test such
the nitrogen, oxygen and hydrogen determination.
materials,andalsoformthebasisforqualityassuranceofthese
6.7 Iodine Pentoxide and H SO over Silica Gel (commer-
2 4
materials. Thus, it is economically and scientifically critical
cially known as Schutze Reagent)—Schutze reagent is used to
that these instruments be understood by the laboratories that
convert CO to CO at room temperature without affecting
use them.
hydrogen.
5.2 It is assumed that all who use this guide will be trained
6.8 Magnesium Perchlorate (commercially known as
analysts,capableofperformingcommonlaboratoryprocedures
Anhydrone)—Astrong oxidizer and desiccant. It is used to dry
skillfully, and safely. It is expected that any work will be
incoming gas streams and to remove water produced during
performed in a properly equipped laboratory.
reactions in the analyzer.
5.3 It is expected that the laboratory will prepare their own
6.9 Nitrogen—Inert carrier gas used to transport the gases
work procedures for any of the information described in this
released by the applied heating or fusion process through the
guide.
various sections of the instrument and into the detectors
5.4 This guide contains numerous references to “manufac- without causing side reactions. This gas is used for hydrogen
turer’srecommendations”.Theuserofthisguideisexpectedto determination.
refer to the instrument operation manual for the specific 6.9.1 Some manufacturers suspect that hydrogen evolved
instrumentbeingusedorconsultdirectlywiththemanufacturer from the sample can react with 1) carbon in a crucible and the
to obtain instructions or recommendations. nitrogen carrier gas to form hydrogen cyanide gas (HCN), 2)
the nitrogen carrier gas to form ammonia (NH4). The labora-
5.5 This guide stresses the conservation of certified refer-
tory should be aware of these possible reactions and determine
ence materials (CRMs). CRMs should not be used for drift
if concern is warranted.
checks or conditioning measurments. Other materials should
6.10 Oxygen—Reaction/carrier gas, used to permit a com-
be developed and used for these operations.
bustion reaction.Also used to transport the reacted combustion
6. Reagents
products through the measurement system.
The following reagents are common to instruments for most
or all of the elements discussed in this guide. Specific re-
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
agents for individual elements can be found in the section
Standard-Grade Reference Materials, American Chemical Society, Washington,
for that element. DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
6.1 Purity of Reagents—Reagent grade chemicals shall be
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
used. Unless otherwise indicated, all reagents shall conform to copeial Convention, Inc. (USPC), Rockville, MD.
E3346 − 22
6.11 Phosphorus Pentoxide—Strong oxidizer and desiccant, 7.8 An analytical program should be developed before
phosphorus pentoxide is used to dry incoming gas streams and proceeding with any other instrumental details.
to remove water produced during reactions in the analyzer.
7.8.1 All variables in the instrument that relate to an
Sicapent (registered trademark), a commercially available analytical program should be identified and determined. Many
product,iscomposedofphosphoruspentoxideandanindicator
manufacturers provide information such as application notes,
to determine when the reagent is spent. which can be used as a starting point for analytical program
development.
6.12 Platinum or Platinized Silica—A catalyst used to
7.8.2 The following parameters are important to control,
convert CO to CO at elevated temperatures.
however, not all of these are necessary for all instruments and
6.13 Sodium Hydroxide on Clay (commercially known as
measurement processes.
Ascarite II)—ACO absorbent. This is used to remove CO
2 2
7.8.2.1 Purge time—The time that the reaction area (after it
from the analytical stream.
is sealed) is flushed with the carrier gas to remove any
6.14 Flux—Flux is material that is used to promote con-
atmosphere before the measurement process begins.
trolled fusion (melting) of the test specimen and to promote
7.8.2.2 Analysis delay time—The time that elapses after the
evolution of the elemental gases. Flux is nickel, platinum,
reaction area is purged of atmosphere before the furnace
silver or tin of high purity and containing very low amounts of
heating begins.
the elements of interest.
7.8.2.3 Furnace setting—Thepowerthatisappliedtothe:1)
load coil in an induction furance; 2) tips in an electrode or
NOTE 1—These are reagents common to instruments for the elements
listed. Specific reagents for individual elements can be found in the impulse furnace; 3) heating coils in a resistance furnace.
section for that element.
7.8.2.4 Ramp rate—If the power level is to be increased
over a period of time, this setting controls how quickly and
7. Preparation of Instruments
how much the change in power is applied.
7.1 Assemble the apparatus as recommended by the manu-
7.8.2.5 Integration delay—The time from the start of the
facturer and provide the necessary laboratory environment.
combustion, fusion or extraction operation in the furnace until
Conditions in the immediate vicinity of the instrument can
the computer begins accumulating the signal from the detector.
directly affect the analyses performed on that instrument.
When the signal is detected, the instrument operating software
7.2 The ambient temperature of the environment, as it
begins to integrate the area of the response curve.
increases or decreases, can affect the calibration of the instru-
7.8.2.6 Comparator level—This allows the sensitivity of a
ment. It is important to maintain the required temperature
detection cell to be set at different levels to optimize detection
range.
of very weak or very strong signals. Many instruments have
wide range detectors that do not require this.
7.3 Make the required electrical and gas connections.
7.3.1 Maintain the required and stable voltage supply to 7.8.2.7 Significant digits—Allows the computer to record a
given number of digits after the decimal point. Commonly four
enable the instrument to function correctly.
7.3.2 Gas lines should be clean (G93), and free of leaks and or five significant digits are chosen when the reporting unit is
%.
kinks or other restrictions, as the continuous and stable flow of
gas will permit correct calibration and quantified results.
7.9 Condition the instrument before commencing analyses.
Warning—Residual organic oils on metal tubing can cause
7.9.1 Make at least two measurements of a specimen,
spontaneous combustion when under pressure in the presence
accelerator or flux and a crucible. This permits the instrument
of oxygen.
tooperateinitsanalyticalmodebeforebeingcalibratedorused
7.4 Fill the reagent tubes as recommended by the manufac-
for analysis. It also permits correct, consistent and stable
turer.Compressingreagentstootightlycancauserestrictionsin
function of the instrument to be observed. Materials used for
the gas flow.
conditioning measurements can be any available material,
preferably similar in composition to the specimens, and should
7.5 Perform regular monitoring and maintenance of the
exclude CRMs.
reagent tubes at intervals recommended by the manufacturer or
as determined by the laboratory to be appropriate for their
8. Maintenance
needs.Performthesameforanyfilterscontainedinthesystem.
Depleted reagents or clogged filters can have similar effects as
8.1 Maintenance will be performed on the instrument in
leaks or incorrect gas flows. Damaged filters can allow
accordance with a schedule based on the manufacturer’s
particles to flow into the detection areas of the instrument
recommendations or the laboratory’s experience. The amount
causing decreased sensitivity.
and frequency of maintenance can be affected by the specimen
load. Each laboratory must optimize the recommended main-
7.6 Test the instrument to ensure the absence of leaks in all
tenance schedule.
partsofthesystem.Thisensuresthatallconnectionswithinthe
instrument are functioning correctly and no errors will occur
8.2 Common maintenance items are gas supplies, catalysts,
due to loss of gas or contamination with air.
reagents, reagent tubes, filters, combustion tubes, reaction
7.7 Stabilize the instrument for the time recommended by tubes, pedestals, grippers, O-rings, connections, dust
the manufacturer or as determined by the laboratory to be collectors, tongs and ancillary equipment such as balances,
appropriate for their operational readiness. furnaces and desiccators.
E3346 − 22
8.3 The general area around the instrument should be kept in-house RMs. In-house RMs should be characterized as
clean, organized, and free from particles of accelerator, flux, described by a guide such as E2972.
specimens, reagents, and dust. This helps minimize contami-
NOTE 2—Primary standards are pure chemicals that offer known mass
nation.
fractions of the elements of interest. Examples are Barium Sulfate for
sulfur, Calcium Carbonate for carbon or Potassium Nitrate for nitrogen.
8.4 Balances should be calibrated, clean and preferably
covered so air currents do not affect the weighing process. 10.1.1 Gas dosing can also be used on some instruments to
develop a calibration.
8.5 A record of maintenance should be kept summarizing
the maintenance and repairs performed, and the date and the 10.2 Calibrations may employ a single point or multiple
person performing the maintenance. points. Multiple point calibrations are typically drift corrected
rather than being recalibrated, while single point calibrations
9. Drift Correction are typically recalibrated.
9.1 Drift correction adjusts for changes in a calibration 10.3 The intercept of the calibration regression with the X
based on the physical aspects of the instrument, that may have axis can be determined in two ways. Blanks can be measured
in two ways: 1) Blanks may be measured as calibration points
changed since the original calibration. Examples of variables
causingdriftare:1)environmentalconditionsoftheimmediate on some instruments. These blanks determine the intercept
taking into account any variance caused by crucibles,
area (for example, temperature changes over time); 2) expan-
sion and contraction of instrument components; 3) changes in accelerator, flux and anything else added to the analytical
carrier gas pressure and flow. An example would be tempera- specimen; 2) A second method mathematically forces the
ture changes over time within the room where analysis is being calibration curve through the origin. Compensation of vari-
performed. Drift correction can compensate for these types of ances in analysis due to crucibles, accelerators, flux and
changes to instrument calibration without the need for a full anything else added to the analytical specimen are mathemati-
recalibration. cally compensated for before the regression occurs.
9.1.1 The laboratory must determine which parameters
10.4 Depending on the mass fractions of element(s) to be
separate the need for drift correction versus a recalibration.
determined in given specimens it may be beneficial to develop
9.2 Examples of variables causing drift are: 1) environmen- more than one calibration to cover the ranges needed.
tal conditions of the immediate area (for example, temperature
10.5 A multipoint calibration is accomplished using RMs
changesovertime);2)expansionandcontractionofinstrument
that are below the lowest expected specimen value to greater
components; 3) changes in carrier gas pressure and flow.
than the highest expected specimen value. Single RM calibra-
9.3 A material should be selected for a drift control speci- tions use a point just greater than the expected value of the
men; this can and should be different from the drift correction analyte.Itisacceptabletoreportresultsthatareextrapolatedto
material and should not be a CRM. The drift control specimen a maximum of 10 % above the highest calibrant in either
isusedtoverifythattheinstrumentcalibrationisundercontrol, calibration algorithm.
requires drift correction or requires full recalibration.
10.6 Before any calibration is conducted, the instrument
9.4 Before any drift control specimen analyses are daily maintenance should be completed, and the instrument
should be stable with no leaks.
performed, the instrument daily maintenance should be
completed, and the instrument should be stable with no leaks.
10.7 Calibration should be conducted in accordance with
9.5 The drift control specimen analyses should be per- the manufacturer’s recommendations, and once started, should
formed at the beginning and end of every analytical sequence. be completed without interruption.
Drift should be checked during a lengthy analytical sequence.
10.8 Recalibration frequency and the factors determining if
The time between drift analyses should be determined by the
recalibration is necessary must be determined by the labora-
laboratory and be based on specimen load, environmental
tory. Examples of factors indicating when an instrument needs
factors and equipment stability.
recalibrationare:driftcorrectionfactorsexceedingsomepreset
9.6 If the drift control material result indicates a significant value or repairs made to the instrument.
change, for example, it exceeds the uncertainty of the material,
11. Analytical Overview
the calibration should be drift corrected to compensate for
changes from its original condition. 11.1 Analysis should always be conducted on a properly
maintained instrument that has been leak checked, conditioned
9.7 Control charting is an acceptable method to check for
and is stable.
drift. See E882 and E1329 for information on control charts.
11.2 The prepared specimen is weighed.
9.8 The manufacturer’s recommended practice for drift
correction should be followed. 11.3 The mass is entered into the instrument operating
software.
10. Calibration
11.4 For combustion analysis, the specimen is placed into
10.1 Calibration of the instrument is accomplished using the crucible with the accelerator and the crucible is placed on
primary standards, CRMs, RMs or other materials of well- the pedestal or in the crucible loading device. For inert gas
established homogeneity and known element content such as fusion, the specimen is placed in the specimen delivery device
E3346 − 22
and the crucible with the flux is placed into the crucible 12.2 Use care when handling hot crucibles and operating
delivery device. For hot extraction analysis, the specimen is electrical equipment to avoid personal injury by either burn or
placed into the reaction tube. electrical shock.
11.5 The analysis cycle is started.
13. Method Validation
11.6 All modern equipment calculates the mass fraction
13.1 Laboratories using the analytical directions described
based on the actual mass of the specimen, and reports it via the
in this guide should ascertain that the methods they use will
instrument operating software.
provide sufficient levels of performance for testing the mate-
11.7 Whenanalysishasconcluded,thecrucible,accelerator/ rials of interest.
flux and specimen are removed either manually or by the
13.2 Qualities that should be identified and measured are
instrument. It is a good practice to observe the specimen or the
selectivity, precision (S ), limit of detection (LOD), limit of
R
reacted materials in the crucible before discarding to check for
quantification (L ), bias, calibration model, working range and
Q
combustion, fusion or extraction problems.
ruggedness. Information about these qualities can be found in
11.7.1 Someproblemsthatcouldbeobservedintheanalysis
E2857. For additional information, consult the IUPAC Orange
process are: 1) incomplete combustion; 2) incomplete fusion; 5
Book and the Currie paper.
3) no combustion or fusion; 4) cracking of crucibles allowing
part or all of the specimen to escape.
12. Hazards
L. A. Currie, "Nomenclature in Evaluation of Analytical Methods Including
12.1 For hazards to be observed for this guide, refer to
DetectionandQuantificationCapabilities,"PureAppl.Chem.,Vol67,No.10,1995,
Practices E50. pp. 1699-1723. Online, Available: http://iupac.org/publications/pac.
CARBON AND SULFUR BY COMBUSTION/INFRARED DETECTION TECHNIQUE
14. Scope
14.1 This section describes the determination of carbon and 17. Apparatus
sulfur by the combustion/IR detection technique. Quantifica-
17.1 Accelerator Scoop—Of size recommended by the
tion is in mass fractions from a few
...