ISO/TS 13899-1:2004

Steel - Determination of Mo, Nb and W contents in alloyed steel - Inductively coupled plasma atomic emission spectrometric method - Part 1: Determination of Mo content

ISO/TS 13899-1:2004 specifies an inductively coupled plasma atomic emission spectrometric method for the determination of molybdenum content in steel. The method is applicable to molybdenum contents between 0,03 % (mass fraction) and 8,5 % (mass fraction).

Aciers — Dosage du Mo, du Nb et du W dans les aciers alliés — Méthode par spectrométrie d'émission atomique avec plasma induit par haute fréquence — Partie 1: Dosage du Mo

General Information

• Status: Published
• Publication Date: 31-Mar-2004
• ICS: 77.080.20 - Steels
• Technical Committee: ISO/TC 17/SC 1 - Methods of determination of chemical composition
• Drafting Committee: ISO/TC 17/SC 1 - Methods of determination of chemical composition
• Current Stage: 9093 - International Standard confirmed
• Start Date: 24-Aug-2023
• Completion Date: 13-Dec-2025

Overview

ISO/TS 13899-1:2004 specifies an inductively coupled plasma atomic emission spectrometric (ICP‑AES) method for the determination of molybdenum (Mo) in alloyed steel. The procedure covers sample dissolution, fuming and dilution, and ICP‑AES measurement using matrix‑matched calibration and optional internal standardization. The method is applicable for Mo mass fractions from 0.03 % to 8.5 %.

Keywords: ISO/TS 13899-1, molybdenum determination, ICP‑AES, steel analysis, alloyed steel, molybdenum content.

Key topics and technical requirements

• Analytical principle: Dissolution of a 0.25 g test portion in hydrochloric, nitric and phosphoric acids; perchloric fuming; treatment with hydrofluoric acid; dilution and nebulization into ICP‑AES.
• Matrix matching and bracketing: Calibration solutions must closely match the sample matrix and bracket the sample concentration to compensate spectral and matrix interferences. If sample composition is unknown, a semi‑quantitative pre‑analysis is required.
• Instrument performance criteria:
  • Bandwidth (FWHM) for selected lines < 0.030 nm
  • Short‑term stability (RSD of 10 measurements) ≤ 0.4%
  • Background equivalent concentration (BEC) < 0.5 mg/L
  • Detection limit (DL) < 0.015 mg/L
  • Calibration linearity: correlation coefficient > 0.999
• Recommended analytical lines & interferences: examples include Mo 202.03 nm (Ta interference) and Mo 281.61 nm (Al, Hf interference); scandium 363.07 nm is recommended as an interference‑free internal standard line for many matrices.
• Reagents and apparatus: Analytical‑grade acids (HCl, HNO3, H3PO4, HClO4, HF), class A volumetric glassware, HF‑resistant nebulizer/spray system and PTFE beakers.

Applications and users

This technical specification is intended for:

• Steel producers and alloy manufacturers for quality control of Mo content
• Analytical and metallurgical laboratories performing compositional analysis of alloyed steels
• Third‑party testing and certification bodies requiring standardized Mo quantification
• R&D groups developing or validating ICP‑AES methods for high‑alloy steels

Practical applications include batch release testing, alloy verification, traceability in supply chains, and support for metallurgical process control where accurate Mo content is critical to material properties.

Related standards

• ISO/TS 13899 (Parts 2 & 3) - determination of Nb and W by ICP‑AES
• ISO 14284 - sampling and sample preparation for chemical composition
• ISO 3696 - water for analytical laboratory use
• ISO 648, ISO 1042 - calibrated pipettes and volumetric flasks
• ISO 5725 series - accuracy (trueness and precision) of measurement methods

Using ISO/TS 13899-1 helps ensure reproducible, accurate molybdenum determinations in alloyed steels and supports compliance with international analytical best practices.

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 13899-1
First edition
2004-04-01
Steel — Determination of Mo, Nb and W
contents in alloyed steel — Inductively
coupled plasma atomic emission
spectrometric method —
Part 1:
Determination of Mo content
Aciers — Dosage du Mo, du Nb et du W dans les aciers alliés —
Méthode par spectrométrie d'émission atomique avec plasma induit par
haute fréquence —
Partie 1: Dosage du Mo
Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
1 Scope. 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 2
5 Apparatus. 3
6 Sampling and samples . 4
7 Determination procedure . 4
7.1 Test portion . 4
7.2 Preparation of test solution, T . 4
n
7.3 Optimization of spectrometer . 4
7.4 Pre-determination of the test solution . 4
7.5 Preparation of calibration solutions for bracketing, K and K . 5
Ln Hn
7.6 Determination of test solutions . 5
8 Expression of results. 6
8.1 Method of calculation . 6
8.2 Precision . 6
9 Test report. 7
Annex A (informative) Suggested analytical lines together with possible spectral interferences in
determination of molybdenum in steel by ICP-AES . 8
Annex B (informative) Additional information on international cooperative tests. 9
Annex C (informative) Graphical representation of precision data. 11

Foreword
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(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 13899-1 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of
determination of chemical composition.
ISO/TS 13899 consists of the following parts, under the general title Steel — Determination of Mo, Nb and W
contents in alloyed steel — Inductively coupled plasma atomic emission spectrometric method:
 Part 1: Determination of Mo content
 Part 2: Determination of Nb content
 Part 3: Determination of W content
iv © ISO 2004 – All rights reserved

TECHNICAL SPECIFICATION ISO/TS 13899-1:2004(E)

Steel — Determination of Mo, Nb and W contents in alloyed
steel — Inductively coupled plasma atomic emission
spectrometric method —
Part 1:
Determination of Mo content
1 Scope
This Technical Specification specifies an inductively coupled plasma atomic emission spectrometric method
for the determination of molybdenum content in steel.
The method is applicable to molybdenum contents between 0,03 % (mass fraction) and 8,5 % (mass fraction).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 648:1977, Laboratory glassware — One-mark pipettes
ISO 1042:1998, Laboratory glassware — One-mark volumetric flasks
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results — Part 1: General
principles and definitions
ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic
method for the determination of repeatability and reproducibility of a standard measurement method
ISO 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results — Part 3:
Intermediate measures of the precision of a standard measurement method
ISO 14284:1996, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition
3 Principle
Dissolution of a test portion in a mixture of hydrochloric, nitric and phosphoric acid and fuming with a mixture
of phosphoric and perchloric acids. Addition of hydrofluoric acid and, if necessary, an internal reference
element and dilution of the solution to known volume. Nebulization of the solution into an inductively coupled
plasma atomic emission spectrometer and measurement of the intensity of the emitted light from molybdenum,
or with emitted light from the internal reference element, simultaneously.
NOTE 1 The method uses a calibration graph based on a very close matrix matching of the calibration solutions to the
sample and close bracketing of the contents around the approximate concentration of molybdenum in the sample to be
analysed. The concentrations of all elements in the sample must, therefore, be approximately known. If the concentrations
are not known, the sample must be analysed by some semi-quantitative method.
NOTE 2 The advantage with this procedure is that all possible interferences from the matrix are automatically
compensated, which results in high accuracy. This is most important for spectral interferences, which can be severe in
very highly alloyed steels. However, all possible interferences must be kept on a minimum level. Therefore it is essential
that the spectrometer used meets the performance criteria specified in the method for the selected analytical lines.
Examples of the analytical lines are given in Table 1.
Table 1 — Examples of analytical lines together with interfering elements
Analytical line
Element Interferences
nm
202,03 Ta
Molybdenum
281,61 Al, Hf
NOTE 3 These lines have been carefully investigated (see Annex A). The strongest possible interferences are given in
Table 1. If other lines are used, they have to be carefully checked so that interferences are not higher than the values
given in Annex A. It is recommended to use scandium 363.07 nm. This line is interference-free for the elements and
concentrations given in Annex A.
4 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only
grade 2 water as specified in ISO 3696.
4.1 Hydrofluoric acid, HF, 40 % (mass fraction), ρ approximately 1,14 g/ml, or 50 % (mass fraction), ρ
approximately 1,17 g/ml.
4.2 Hydrochloric acid, HCl, ρ approximately 1,19 g/ml
4.3 Nitric acid, HNO , ρ approximately 1,40 g/ml
4.4 Phosphoric acid, H PO , ρ approximately 1,70 g/ml, diluted 1 + 1
3 4
4.5 Perchloric acid, HClO , ρ approximately 1,54 g/ml, diluted 1 + 1
4.6 Internal standard solution, 1 000 mg/l
Choose a suitable element to be added as internal reference and prepare a 1 000 mg/l solution.
4.7 Molybdenum stock standard solution, 1 000 mg/l
Weigh, to the nearest 0,000 5 g, 0,5 g of high purity molybdenum [minimum 99,95 % (mass fraction)] and
dissolve in a mixture of 25 ml hydrochloric acid (4.2) and 25 ml nitric acid (4.3). Keep the temperature of a
one-mark volumetric flask the same as that at which the volumetric flask was calibrated. Cool and transfer the
solution quantitatively to a calibrated 500 ml one-mark volumetric flask. Dilute to the mark with water and mix.
4.8 Molybdenum standard solution, 100 mg/l
Keep the temperature of a one-mark volumetric flask the same as that at which the volumetric flask was
calibrated. Using a calibrated pipette, transfer 100 ml of the molybdenum stock standard solution (4.7) into a
2 © ISO 2004 – All rights reserved

calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.2). Dilute to the mark with
water and mix.
4.9 Molybdenum standard solution, 10 mg/l
Keep the temperature of a one-mark volumetric flask the same as that at which the volumetric flask was
calibrated. Using a calibrated pipette, transfer 100 ml of the molybdenum standard solution (4.8) into a
calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.2). Dilute to the mark with
water and mix.
4.10 Standard solutions of interfering elements
Prepare standard solutions for each element of which more than 1 % by mass is contained in the test sample.
Use pure metal or chemical substances with molybdenum contents less
...