GB/T 15072.3-2025 Methods for chemical analysis of precious metal alloys―Part 3: Determination of platinum content English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 97.120.99
CCS H 57
National Standard of the People's Republic of China
GB/T 15072.3-2025
Replaces GB/T 15072.3-2008
Methods for chemical analysis of precious metal alloys - Part 3 : Determination of platinum content
Issue date: 2025-08-29 Implementation date: 2026-03-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
Introduction
1 Scope
2 Normative References
3 Terms and Definitions
4 Method 1: Potentiometric Titration with Sodium Chloride (NaCl)
5 Method 2: Potentiometric Titration with Potassium Iodide (KI)
6 Method 3: Fire Assay Gravimetry
Methods for chemical analysis of precious metal alloys Part 3 :Determination of platinum content
Warning—Personnel using this document should have practical laboratory experience. This document does not address all potential safety issues. Users are responsible for implementing appropriate safety and health measures and ensuring compliance with national regulatory requirements.
1 Scope
This document describes a method for determining platinum content in precious metal alloys using potentiometric titration with potassium permanganate (KMnO₄).
Applicability: Platinum determination in precious metal alloys.
Range: 5.00%–95.00% (mass fraction).
2 Normative References
The following documents are indispensable for the application of this document. For dated references, only the edition corresponding to the date applies; for undated references, the latest edition (including all amendments) applies.
GB/T 8170 Rules for Rounding off Numerical Values and Representation of Limit Values (latest version applies).
3 Terms and Definitions
No terms require definition in this document.
4 Principle
The sample is dissolved in hydrochloric acid (HCl) and hydrogen peroxide (H₂O₂) in a polytetrafluoroethylene (PTFE) digestion vessel at 150°C ±5°C.
Platinum (IV) is reduced to platinum (II) using cuprous chloride (CuCl) in dilute HCl.
Potassium permanganate (KMnO₄) standard solution titrates platinum(II), with potentiometric endpoint detection.
5 Reagents and Materials
Analytical-grade reagents and distilled/deionized water (or equivalent purity) must be used.
5.1 Hydrochloric acid (HCl) (ρ = 1.19 g/mL).
5.4 Cuprous chloride solution (40 g/L)
Preparation: Dissolve 4.0 g CuCl in 40 mL HCl (5.1) and dilute to 100 mL with water. Prepare fresh before use.
5.5 Potassium permanganate (KMnO₄) standard titrant
(a) Preparation:
Dissolve 0.7 g KMnO₄ in 4 L water, boil for 1.5 h, and let stand overnight.
Filter through a Grade 3 glass frit funnel, dilute to 5 L, and store in a brown bottle in the dark.
(b) Standardization:
10.00 mL platinum standard solution (5.6) is titrated with KMnO₄ under potentiometric control.
Endpoint: Determined from ** titration curve or dE/dV curve**.
Acceptance criteria: ≤ 0.05 mL difference between 3 parallel titrations.
Actual concentration (c) calculated using Equation
c = actual KMnO₄ concentration (mol/mL)
ρ₀ = platinum standard solution concentration (mg/mL)
V₁ = volume of platinum standard solution (mL)
195.08 = molar mass of platinum (g/mol)
V₂ = volume of KMnO₄ consumed (mL)
5.6 Platinum standard solution
Preparation:
Dissolve 0.5000 g platinum (wPt ≥ 99.99%, ±0.00001 g) in 20 mL HCl + 5 mL H₂O₂ in a PTFE digestion vessel at 150°C ±5°C for 48 h.
Dilute to 500 mL with 200 mL HCl.
Concentration: 1 mg Pt per mL.
6 Apparatus
6.1 Balance with 0.01 mg sensitivity.
6.2 Potentiometric titrator (see Appendix A for parameters).
6.3 PTFE digestion vessel (25 mm ±2 mm wall thickness, 30 mL capacity).
6.4 Oven (≤300°C).
6.5 Purge apparatus (as per Figure 1).
7 Sample
The sample is processed into shreds with the following specifications:
Thickness: ≤ 0.2 mm
Length & width: ≤ 2.0 mm
Cleaning:
Soak in glacial acetic acid for 10 minutes.
Rinse with anhydrous ethanol, dry, and mix thoroughly.
8 Procedure
8.1 Sample Portioning
Weigh the sample according to Table 1, ±0.00001 g.
8.2 Parallel Tests
Perform two parallel tests and take the average value.
8.3 Blank Test
Carry out a blank test simultaneously with the sample.
Standard
GB/T 15072.3-2025 Methods for chemical analysis of precious metal alloys―Part 3: Determination of platinum content (English Version)
Standard No.
GB/T 15072.3-2025
Status
to be valid
Language
English
File Format
PDF
Word Count
9000 words
Price(USD)
270.0
Implemented on
2026-3-1
Delivery
via email in 1~3 business day
Detail of GB/T 15072.3-2025
Standard No.
GB/T 15072.3-2025
English Name
Methods for chemical analysis of precious metal alloys―Part 3: Determination of platinum content
GB/T 15072.3-2025 Methods for chemical analysis of precious metal alloys―Part 3: Determination of platinum content English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 97.120.99
CCS H 57
National Standard of the People's Republic of China
GB/T 15072.3-2025
Replaces GB/T 15072.3-2008
Methods for chemical analysis of precious metal alloys - Part 3 : Determination of platinum content
Issue date: 2025-08-29 Implementation date: 2026-03-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
Introduction
1 Scope
2 Normative References
3 Terms and Definitions
4 Method 1: Potentiometric Titration with Sodium Chloride (NaCl)
5 Method 2: Potentiometric Titration with Potassium Iodide (KI)
6 Method 3: Fire Assay Gravimetry
Methods for chemical analysis of precious metal alloys Part 3 :Determination of platinum content
Warning—Personnel using this document should have practical laboratory experience. This document does not address all potential safety issues. Users are responsible for implementing appropriate safety and health measures and ensuring compliance with national regulatory requirements.
1 Scope
This document describes a method for determining platinum content in precious metal alloys using potentiometric titration with potassium permanganate (KMnO₄).
Applicability: Platinum determination in precious metal alloys.
Range: 5.00%–95.00% (mass fraction).
2 Normative References
The following documents are indispensable for the application of this document. For dated references, only the edition corresponding to the date applies; for undated references, the latest edition (including all amendments) applies.
GB/T 8170 Rules for Rounding off Numerical Values and Representation of Limit Values (latest version applies).
3 Terms and Definitions
No terms require definition in this document.
4 Principle
The sample is dissolved in hydrochloric acid (HCl) and hydrogen peroxide (H₂O₂) in a polytetrafluoroethylene (PTFE) digestion vessel at 150°C ±5°C.
Platinum (IV) is reduced to platinum (II) using cuprous chloride (CuCl) in dilute HCl.
Potassium permanganate (KMnO₄) standard solution titrates platinum(II), with potentiometric endpoint detection.
5 Reagents and Materials
Analytical-grade reagents and distilled/deionized water (or equivalent purity) must be used.
5.1 Hydrochloric acid (HCl) (ρ = 1.19 g/mL).
5.4 Cuprous chloride solution (40 g/L)
Preparation: Dissolve 4.0 g CuCl in 40 mL HCl (5.1) and dilute to 100 mL with water. Prepare fresh before use.
5.5 Potassium permanganate (KMnO₄) standard titrant
(a) Preparation:
Dissolve 0.7 g KMnO₄ in 4 L water, boil for 1.5 h, and let stand overnight.
Filter through a Grade 3 glass frit funnel, dilute to 5 L, and store in a brown bottle in the dark.
(b) Standardization:
10.00 mL platinum standard solution (5.6) is titrated with KMnO₄ under potentiometric control.
Endpoint: Determined from ** titration curve or dE/dV curve**.
Acceptance criteria: ≤ 0.05 mL difference between 3 parallel titrations.
Actual concentration (c) calculated using Equation
c = actual KMnO₄ concentration (mol/mL)
ρ₀ = platinum standard solution concentration (mg/mL)
V₁ = volume of platinum standard solution (mL)
195.08 = molar mass of platinum (g/mol)
V₂ = volume of KMnO₄ consumed (mL)
5.6 Platinum standard solution
Preparation:
Dissolve 0.5000 g platinum (wPt ≥ 99.99%, ±0.00001 g) in 20 mL HCl + 5 mL H₂O₂ in a PTFE digestion vessel at 150°C ±5°C for 48 h.
Dilute to 500 mL with 200 mL HCl.
Concentration: 1 mg Pt per mL.
6 Apparatus
6.1 Balance with 0.01 mg sensitivity.
6.2 Potentiometric titrator (see Appendix A for parameters).
6.3 PTFE digestion vessel (25 mm ±2 mm wall thickness, 30 mL capacity).
6.4 Oven (≤300°C).
6.5 Purge apparatus (as per Figure 1).
7 Sample
The sample is processed into shreds with the following specifications:
Thickness: ≤ 0.2 mm
Length & width: ≤ 2.0 mm
Cleaning:
Soak in glacial acetic acid for 10 minutes.
Rinse with anhydrous ethanol, dry, and mix thoroughly.
8 Procedure
8.1 Sample Portioning
Weigh the sample according to Table 1, ±0.00001 g.
8.2 Parallel Tests
Perform two parallel tests and take the average value.
8.3 Blank Test
Carry out a blank test simultaneously with the sample.
