GB/T 7731.7-2008Ferrotungsten - Determination of tin content - Phenylfluorone photometric method and inductively coupled plasma-atomic emission spectrometry (English PDF)

3.1 Principle

Sample with nitric acid - hydrofluoric acid dissolution, white smoke sulfuric acid, tartaric acid containing sulfuric acid solution, hydrogen sulfide tin and copper,

Arsenic and other co-precipitation, separation. Nitric acid and sulfuric acid dissolved in sulfuric acid and potassium permanganate and manganese tin and manganese dioxide coprecipitation separation. use

Hydrochloric acid and hydrogen peroxide dissolved by adding tartaric acid, oxalic acid, polyvinyl alcohol masking interfering elements to adjust the pH value of the aqueous ammonia was added Phenylfluorone

Tin tin generation - Phenylfluorone complex, measuring the absorbance.

3.2 Reagents and materials

Unless otherwise indicated in the analysis using only recognized as analytical grade reagents and distilled water or its equivalent purity water.

3.2.1

tartaric, solid.

3.2.2

ascorbic acid, solid.

3.2.3

hydrofluoric acid, rho1.15g/mL.

3.2.4

nitrate, rho1.42g/mL.

3.2.5

sulfate, rho1.84g/mL.

3.2.6

hydrogen peroxide, rho1.10g/mL.

3.2.7

hydrochloric acid, 1 + 1.

3.2.8

nitric acid, 1 + 1.

3.2.9

sulfate, 1 + 1.

3.2.10

ammonia, rho0.90g/mL.

3.2.11

ammonia, 1 + 8.

3.2.12

hydrogen sulfide.

3.2.13

tartaric acid washing liquid, take 1g of tartaric acid were dissolved in 100mL saturated hydrogen sulfide sulfuric acid (1 + 100).

3.2.14

manganese sulfate solution, 20g/L, manganese sulfate weighed 20g [MnSO4 · (4 ~ 6) H2O) was dissolved in water and diluted to 1000mL,

Mix well.

3.2.15

potassium permanganate solution, 30g/L.