GB/T 15072.4-2025 Methods for chemical analysis of precious metal alloys—Part 4: Determination of palladium 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 15072.4-2025
Replaces GB/T 15072.4-2008
Methods for chemical analysis of precious metal alloys - Part 4: Determination of palladium 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: Dimethylglyoxime Gravimetry
5 Method 2: Potentiometric Titration with Potassium Iodide (KI)
6 Method 3: Fire Assay Gravimetry
Methods for chemical analysis of precious metal alloys - Part 4: Determination of palladium 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 methods for determining palladium content in precious metal alloys using:
Dimethylglyoxime gravimetry (Method 1)
Dimethylglyoxime precipitation with EDTA complexometric titration (Method 2)
Applicability: Palladium determination in precious metal alloys.
Range: 4.00%–95.00% (mass fraction).
2 Normative References
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 Method 1: Dimethylglyoxime Gravimetry
4.1 Principle
The sample is dissolved in nitric acid (or HCl-HNO₃ mixture for Au/Pt/Rh/Ir/W-containing alloys).
Gold is separated by sodium nitrite reduction, silver by AgCl precipitation, and tungsten by WO₃ precipitation.
Palladium is precipitated as dimethylglyoxime (DMG) in dilute HCl, and its content is determined gravimetrically.
4.2 Reagents and Materials
Analytical-grade reagents and distilled/deionized water must be used.
4.2.1 HCl (ρ = 1.19 g/mL).
4.2.3 Glacial acetic acid (ρ = 1.05 g/mL).
4.2.9 HCl-HNO₃ mixture (3:1, v/v). Prepare fresh before use.
4.2.15 Dimethylglyoxime (DMG) ethanol solution (10 g/L).
4.3 Apparatus
4.3.1 Balance with 0.01 mg sensitivity.
4.3.2 Grade 4 glass frit crucible (30 mL capacity).
4.3.3 Oven (≤300°C).
4.3.4 PTFE digestion vessel (25 mm ±2 mm wall thickness, 30 mL capacity).
4.4 Sample Preparation
Process into shreds (≤0.2 mm thick, ≤2.0 mm length/width).
Clean with glacial acetic acid (10 min) and anhydrous ethanol, then dry and mix thoroughly.
4.5 Procedure
4.5.1 Sample Portioning
Weigh sample according to Table 1, ±0.00001 g.
4.5.2 Parallel Tests
Perform two parallel tests and take the average.
4.5.3 Blank Test
Conduct a blank test simultaneously with the sample.
4.5.4 Determination
4.5.4.1 Sample Dissolution
4.5.4.1.1 Non-Au/Pt/Rh/Ir/W samples:
Dissolve in 10 mL HNO₃ on a hotplate, then cool.
4.5.4.1.2 Au/Pt/Rh/Ir/W-containing samples:
Dissolve in 20 mL HCl-HNO₃ mixture in a PTFE vessel at 150°C ±5°C for 12 h, then transfer to a beaker.
4.5.4.2 Solution Treatment
4.5.4.2.1 Non-W/Ag/Au solutions: Evaporate to ~1 mL on low heat.
4.5.4.3 Precipitation
Add 2 mL sodium chloride solution (4.2.11) to the test solution (4.5.4.2.2), and evaporate to a wet-salt state on low heat. Add 10 mL HCl (4.2.1), evaporate to a wet-salt state, and repeat this step twice. Add 10 mL HCl (4.2.1) and 200 mL water, then dropwise add 50 mL dimethylglyoxime ethanol solution (4.2.15) under stirring. Continue stirring for 3 minutes and let stand for 2 hours.
4.5.4.4 Filtration
Filter the precipitate (4.5.4.3) through a pre-cleaned, dried, and pre-weighed Grade 4 glass frit crucible using suction. Wash the beaker and precipitate 10 times each with HCl-HNO₃ mixture (4.2.9), and scrub the beaker edges with a rubber-tipped glass rod. Rinse the crucible and precipitate 3 times with 5 mL anhydrous ethanol (4.2.4).
Place the crucible in an oven at 110°C ±5°C and dry for 1.5 hours. Remove, cool in a desiccator for 30 minutes, and weigh. Repeat until constant mass is achieved.
4.5.4.5 Test Data Processing
4.7 Precision
4.7.1 Repeatability
Under repeatability conditions, the absolute difference between two independent test results shall not exceed the repeatability limit (r) when the average value falls within the range specified in Table 2. The probability of exceeding the repeatability limit (r) shall be ≤5%. The repeatability limit (r) is determined by linear interpolation or extrapolation based on the data in Table 2. Precision statistics are provided in Appendix A.
Standard
GB/T 15072.4-2025 Methods for chemical analysis of precious metal alloys—Part 4: Determination of palladium content (English Version)
Standard No.
GB/T 15072.4-2025
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 15072.4-2025
Standard No.
GB/T 15072.4-2025
English Name
Methods for chemical analysis of precious metal alloys—Part 4: Determination of palladium content
GB/T 15072.4-2025 Methods for chemical analysis of precious metal alloys—Part 4: Determination of palladium 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 15072.4-2025
Replaces GB/T 15072.4-2008
Methods for chemical analysis of precious metal alloys - Part 4: Determination of palladium 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: Dimethylglyoxime Gravimetry
5 Method 2: Potentiometric Titration with Potassium Iodide (KI)
6 Method 3: Fire Assay Gravimetry
Methods for chemical analysis of precious metal alloys - Part 4: Determination of palladium 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 methods for determining palladium content in precious metal alloys using:
Dimethylglyoxime gravimetry (Method 1)
Dimethylglyoxime precipitation with EDTA complexometric titration (Method 2)
Applicability: Palladium determination in precious metal alloys.
Range: 4.00%–95.00% (mass fraction).
2 Normative References
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 Method 1: Dimethylglyoxime Gravimetry
4.1 Principle
The sample is dissolved in nitric acid (or HCl-HNO₃ mixture for Au/Pt/Rh/Ir/W-containing alloys).
Gold is separated by sodium nitrite reduction, silver by AgCl precipitation, and tungsten by WO₃ precipitation.
Palladium is precipitated as dimethylglyoxime (DMG) in dilute HCl, and its content is determined gravimetrically.
4.2 Reagents and Materials
Analytical-grade reagents and distilled/deionized water must be used.
4.2.1 HCl (ρ = 1.19 g/mL).
4.2.3 Glacial acetic acid (ρ = 1.05 g/mL).
4.2.9 HCl-HNO₃ mixture (3:1, v/v). Prepare fresh before use.
4.2.15 Dimethylglyoxime (DMG) ethanol solution (10 g/L).
4.3 Apparatus
4.3.1 Balance with 0.01 mg sensitivity.
4.3.2 Grade 4 glass frit crucible (30 mL capacity).
4.3.3 Oven (≤300°C).
4.3.4 PTFE digestion vessel (25 mm ±2 mm wall thickness, 30 mL capacity).
4.4 Sample Preparation
Process into shreds (≤0.2 mm thick, ≤2.0 mm length/width).
Clean with glacial acetic acid (10 min) and anhydrous ethanol, then dry and mix thoroughly.
4.5 Procedure
4.5.1 Sample Portioning
Weigh sample according to Table 1, ±0.00001 g.
4.5.2 Parallel Tests
Perform two parallel tests and take the average.
4.5.3 Blank Test
Conduct a blank test simultaneously with the sample.
4.5.4 Determination
4.5.4.1 Sample Dissolution
4.5.4.1.1 Non-Au/Pt/Rh/Ir/W samples:
Dissolve in 10 mL HNO₃ on a hotplate, then cool.
4.5.4.1.2 Au/Pt/Rh/Ir/W-containing samples:
Dissolve in 20 mL HCl-HNO₃ mixture in a PTFE vessel at 150°C ±5°C for 12 h, then transfer to a beaker.
4.5.4.2 Solution Treatment
4.5.4.2.1 Non-W/Ag/Au solutions: Evaporate to ~1 mL on low heat.
4.5.4.3 Precipitation
Add 2 mL sodium chloride solution (4.2.11) to the test solution (4.5.4.2.2), and evaporate to a wet-salt state on low heat. Add 10 mL HCl (4.2.1), evaporate to a wet-salt state, and repeat this step twice. Add 10 mL HCl (4.2.1) and 200 mL water, then dropwise add 50 mL dimethylglyoxime ethanol solution (4.2.15) under stirring. Continue stirring for 3 minutes and let stand for 2 hours.
4.5.4.4 Filtration
Filter the precipitate (4.5.4.3) through a pre-cleaned, dried, and pre-weighed Grade 4 glass frit crucible using suction. Wash the beaker and precipitate 10 times each with HCl-HNO₃ mixture (4.2.9), and scrub the beaker edges with a rubber-tipped glass rod. Rinse the crucible and precipitate 3 times with 5 mL anhydrous ethanol (4.2.4).
Place the crucible in an oven at 110°C ±5°C and dry for 1.5 hours. Remove, cool in a desiccator for 30 minutes, and weigh. Repeat until constant mass is achieved.
4.5.4.5 Test Data Processing
4.7 Precision
4.7.1 Repeatability
Under repeatability conditions, the absolute difference between two independent test results shall not exceed the repeatability limit (r) when the average value falls within the range specified in Table 2. The probability of exceeding the repeatability limit (r) shall be ≤5%. The repeatability limit (r) is determined by linear interpolation or extrapolation based on the data in Table 2. Precision statistics are provided in Appendix A.
