| HIRANUMA APPLICATION DATA | Automatic Titrator | Data No. | E11 | Apr. 5, 2019 |
| PLATING & ETCHING SOLUTION | Determination of copper in copper sulfate plating solution |
1.Abstract
Copper sulfate plating is widely used in plating industries such as ornament, basic plating of anticorrosion plating, and plating for printed circuit board etc. This report introduces an example for determination of copper in copper sulfate plating solution with redox titration as follows: add potassium iodide to acidic sample to oxidize iodide by copper ion and generate free iodine (reaction 1). Titrate this free iodine with sodium thiosulfate to determine copper concentration (reaction 2) by redox titration.
| 2Cu²+ + 4I- → 2CuI + I₂ | ・・・(1) |
| I₂ + 2Na₂S₂O₃ → 2NaI + Na₂S₄O₆ | ・・・(2) |
2. Configuration of instruments and Reagents
| (1) | Configuration of instruments | ||
| Main unit | : | Hiranuma Automatic Titrator COM Series | |
| Electrode | : | Platinum electrode PT-301 Reference electrode RE-201Z *The following electrode is also usable instead of the above electrode. ・PR-701BZ (Platinum reference electrode) ・Combination of PT-301 (Platinum electrode ) and GR-501BZ (Glass-reference electrode) |
|
| (2) | Reagents | ||
| Titrant | : | 0.1 mol/L Sodium thiosulfate standard solution | |
| Additive reagent | : | Potassium iodide | |
3. Measurement procedure
| (1) | Dispense 1 mL of sample into a 100 mL beaker with volumetric pipette. |
| (2) | Add 50 mL of DI water. |
| (3) | Add about 2 g of potassium iodide. |
| (4) | Immerse electrodes to start titration with 0.1 mol/L sodium thiosulfate standard solution. |
4. Measurement conditions and results
Examples of titration conditions
Measurement results
| Number of measurement |
Size (mL) |
Titrant volume(mL) |
Copper Concentration (g/L) |
|---|---|---|---|
| 1 | 1 | 9.623 | 61.456 |
| 2 | 1 | 9.622 | 61.450 |
| 3 | 1 | 9.632 | 61.514 |
| Statistic calculation |
Avg. | 61.5 g/L | |
| SD | 0.0353 g/L | ||
| RSD | 0.06 % | ||
Example of titration curve
5. Note
| ・ | Successive titration of sulfuric acid and copper |
| Copper concentration was determined with redox titration in this report. Regarding another analyte in copper sulfate plating solution, there is determination method for sulfuric acid. Sulfuric acid can be determined by neutralization titration with sodium hydroxide standard solution. The addition of one optional buret and two peristaltic pump dispensers allows to successively perform the neutralization titration for sulfuric acid (buret I, included in standard configuration), dispensing sulfuric acid and potassium iodide solution (peristaltic pump dispenser I and II, options), and the redox titration for copper (buret II, option). Glass-reference electrode GR-501BZ and platinum electrode PT-301 are required for this successive titration. |
| Keywords： | Copper sulfate plating solution, Copper, Potassium iodide, Sodium thiosulfate, Redox titration |
*Some measurement would not be possible depending on optional configuration of system.
