ISO/DTS 4188

FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 4188
ISO/TC 79/SC 5
Magnesium and magnesium
Secretariat: SAC
alloys — Determination of arsenic —
Voting begins on:
2023-07-25 Inductively coupled plasma optical
emission spectrometric method
Voting terminates on:
2023-09-19
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NATIONAL REGULATIONS. © ISO 2023

FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 4188
ISO/TC 79/SC 5
Magnesium and magnesium
Secretariat: SAC
alloys — Determination of arsenic —
Voting begins on:
Inductively coupled plasma optical
emission spectrometric method
Voting terminates on:
© ISO 2023
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ii
NATIONAL REGULATIONS. © ISO 2023

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
6.1 Inductively coupled plasma optical emission spectrometer . 2
6.1.1 General . 2
6.1.2 Wavelength . 2
6.1.3 Limit of detection . 3
6.1.4 Linearity of the calibration curve . 3
7 Sampling and sample preparation . 3
8 Procedure .3
8.1 General . 3
8.2 Test sample . 3
8.3 Preparation of the test solution . 3
8.4 Preparation of the calibration solutions . 3
8.5 Adjustment of the apparatus . 4
8.6 Measurement of the calibration solutions . 4
8.7 Calibration curve . 4
8.8 Measurement of the test solution . 4
9 Expression of results . 4
9.1 Method of calculation . 4
9.2 Precision . . . 5
10 Test report . 5
Annex A (normative) Limit of detection .6
Annex B (informative) Information on the precision test . 7
Annex C (informative) Graphical representation of precision data . 8
Bibliography . 9
iii
Foreword
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Subcommittee SC 5, Magnesium and alloys of cast or wrought magnesium.
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iv
Introduction
Magnesium and magnesium alloys are one kind of light metallic materials and show several
advantageous properties, such as low density, high specific stiffness and strength, good damping
capacity, castability, weldability and machinability, etc. Arsenic as one of the hazardous impurities has
negative effects on the environment and health, and needs to be strictly controlled. The sum of the
mass contents of cadmium (Cd), mercury (Hg), arsenic (As) and chromium (Cr) given in ISO 8287 is
defined to be less than 0,01 % in magnesium and its alloys, which needs to be inspected if used in food
and medicine fields.
v
TECHNICAL SPECIFICATION ISO/DTS 4188:2023(E)
Magnesium and magnesium alloys — Determination of
arsenic — Inductively coupled plasma optical emission
spectrometric method
1 Scope
This document specifies an inductively coupled plasma optical emission spectrometric method (ICP-
OES) for the determination of arsenic contents between 0,001 0 % (mass fraction) and 0,050 % (mass
fraction) in magnesium and magnesium alloys.
The method is limited to magnesium alloys containing less than 0,6 % (mass fraction) of cerium,
0,1 % (mass fraction) of gadolinium, 0,2 % (mass fraction) of neodymium and 0,8 % (mass fraction) of
zirconium.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
After dissolution of a test sample with nitric acid and hydrochloric acid, the solution is nebulized into
an inductively coupled plasma optical emission spectrometer and the intensity of the arsenic emitted
light is measured. The concentrations of arsenic in the test solutions are derived from a magnesium­
based calibration curve.
5 Reagents
During the analysis, use only reagents of recognized analytical grade and only grade 2 water as
specified in ISO 3696, or water of equivalent purity.
5.1 Pure magnesium, purity > 99,99 % (mass fraction), free from arsenic.
5.2 Pure arsenic, purity > 99,99 % (mass fraction).
5.3 Hydrochloric acid, ρ about 1,19 g/ml.
5.4 Nitric acid, ρ about 1,14 g/ml.
5.5 Hydrochloric acid solution 1 + 1
Add 500 ml of hydrochloric acid (5.3) to 500 ml of water and mix.
5.6 Nitric acid solution 1 + 1
Add 500 ml of nitric acid (5.4) to 500 ml of water and mix.
5.7 Arsenic standard solution, 1 g/l.
Weigh to the nearest 0,001 g, 0,5 g of pure arsenic (5.2) and transfer into a 250 ml beaker. Add 20 ml
of nitric acid solution (5.6) and cover with a watch glass. Heat gently until the metal is dissolved. After
cooling to room temperature, transfer the solution quantitatively into a 500 ml one-mark volumetric
flask, dilute to the mark with water and mix.
1 ml
...