GB/T 5121.19-2008Methods for chemical analysis of copper and copper alloys - Part 19:Determination of silver content (English PDF)

3.1

nitrate (rho1.42g/mL) pure class distinctions.

3.2

hydrochloric acid (rho1.18g/mL) pure class distinctions.

3.3

nitric acid (1 + 1).

3.4

nitrate [Ba (HNO3) = 0.8mol/L].

3.5

ammonium thiocyanate solution [Ba (NH4SCN) = 0.5mol/L].

3.6 copper solution (10g/L)

Weigh 5.000g of pure copper (mass fraction of copper >=99.99%, silver content is not more than 0.0005%)

Placed in 500mL beaker, add 40mL of nitric acid (3.1), dissolved by heating, removal of nitrogen oxides was boiled and cooled. Moved 500mL Capacity

Dilution bottle with water to volume, and mix.

3.7 silver standard stock solution

Weigh 1.0000g Silver (mass fraction of silver >=99.95%) placed in 150mL beaker, add 10mL

Nitric acid (3.1), dissolved by heating, removal of nitrogen oxides was boiled and cooled. Moved into 1000mL volumetric flask, dilute with water to volume, and mix.

1mL solution containing 1mg silver.

Standard 3.8 Silver Solution A. Pipette 20.00mL standard silver stock solution (3.7) was placed in 500mL volumetric flask, 10mL of nitric acid was added (3.1), dilute to the mark and mix. This solution 1mL containing 40µg silver.

3.9 Silver standard solution B

Pipette 5.00mL standard silver stock solution (3.7) was placed in 500mL volumetric flask, 50mL of nitric acid was added (3.3), dilute with water to volume, and mix. This solution 1mL containing 10µg silver.

3.10 sulfhydryl cotton

Take 20mL thioglycolic acid (rho1.32g/mL) 14mL and acetic anhydride (rho1.08g/mL) placed in 250mL grinding mouth

Bottle, mix, add two drops of sulfuric acid (rho1.84g/mL), mix well, cool. 4g of cotton wool soaked it all, capped at

24h Place about 25 °C. Remove squeezed, washed with water until the washings were neutral, squeezed and placed in an oven at 37 °C ~ 38 °C drying (about 9h).

After cooling placed in a brown bottle grinding mouth, in a desiccator stored.

4.1 Instrument

4.1.1 flame atomic absorption spectrometer

a silver hollow-cathode lamp.

4.1.2

The following indicators were in optimum working conditions, who can be used to achieve

--- Sensitivity. the substrate solution consistent with the measurement solution, features silver concentration should not exceed 0.03µg/mL;