Silver Content of Silver Jewellery Alloys— Potentiometric Titration Method

The REX Ti-50 Automatic Potential Titrator allows quick and simple determinations of the silver content of silver jewellery alloys.

Standard Reference

ISO 11427 : 2024 Jewellery — Determination of silver in silver jewellery alloys — Volumetric (potentiometric) method using potassium bromide

This document specifies a volumetric method for the determination of silver on a material considered homogeneous. The silver content of the sample lies preferably between (100 and 999,0) parts per thousand (‰) by mass. Fineness above 999,0 ‰ can be determined using a spectroscopy method by difference (e.g. ISO 15096).

The Principle

The sample is dissolved in dilute nitric acid. The silver content of the resulting solution is determined by titration with standard potassium bromide solution using a potentiometric indication of the equivalence point. Palladium can interfere with the measurement and is precipitated before commencing titration, other elements do not interfere with this method of determination.

Motor-driven plunger or piston-type burette, linked to a potentiometer or automatic titrator and capable of delivering increments of 0,05 ml at the equivalence point. 6.3 Titration apparatus, with combination silver electrode coated with silver bromide and Hg/Hg2SO4 or other suitable reference electrode.

Add, via the plunger-burette under continuous stirring, sufficient potassium bromide solution to precipitate about 95 % of the silver in the solution. Titrate the remaining silver in such a manner that the equivalence point can be interpolated from 0,05 ml additions of the potassium bromide solution.

Recommended Configuration

1. Ti-50 Automatic Potential Titrator 

• Range：(-2000.00~2000.00) mV
• mV Accuracy：±0.03% or ±0.2mV
• Support acid-base titration, non-aqueous aqueous phase titration, constant titration, REDOX titration, precipitation titration, complexation titration
• Support the following titration modes: DET (dynamic equivalence point titration), MET (monotone equivalence point titration), SET (Preset Endpoint Titration) and MAT (manual titration).
• Titration methods, curves and results are displayed in detail.

2. Electrodes

•  
• 216-01 Silver electrode

4. Titration Setting

• Precipitation titration
• Sample: DET (dynamic equivalence point titration)
• Blank Sample: MET (monotone equivalence point titration)