1. Method Overview
After the sample is digested with aqua regia, the determination is carried out using an air-acetylene flame at an instrument wavelength of 324.7 nm.
2. Instruments and Reagents
2.1 Instruments and Equipment
2.1.1 Testing Instruments
| Serial No. | Name | Quantity | Technical Requirements | Accessories |
|---|---|---|---|---|
| 1 | Flame Atomic Absorption Spectrophotometer | 1 set | – | Copper Hollow Cathode Lamp |
| 2 | Acetylene Gas | 1 cylinder | Purity ≥ 99.99% | – |
| 3 | Air Compressor | 1 set | Rated discharge pressure: 0.3 MPa | – |
2.1.2 Sample Pretreatment Equipment
| Serial No. | Name | Quantity | Technical Requirements | Accessories |
|---|---|---|---|---|
| 1 | Temperature-Controlled Hot Plate | 1 set | Rated temperature: Room temperature ~ 300℃ | – |
| 2 | Electronic Balance | 1 set | Sensitivity: 0.1 mg | – |
| 3 | Ultrapure Water System | 1 set | – | – |
| 4 | Micropipette | 1 each | Ranges: 20 μL~200 μL, 100 μL~1000 μL | – |
| 5 | Volumetric Flask | Several | Volume: 100 mL | – |
| 6 | Test Tube | Several | Volume: 25 mL | – |
2.2 Reagents
2.2.1 Raw Reagents
| Serial No. | Name | Technical Requirements | Remarks |
|---|---|---|---|
| 1 | Nitric Acid | MOS Grade | – |
| 2 | Hydrochloric Acid | Guaranteed Reagent (GR) | – |
2.2.2 Prepared Reagents
| Serial No. | Name | Preparation Method | Remarks |
|---|---|---|---|
| 1 | Nitric Acid Solution (1+99) | Measure 10 mL of nitric acid, slowly add it to 990 mL of deionized water, and mix well. | – |
2.3 Reference Standards
2.3.1 Stock Solution
| Serial No. | No. | Name | Technical Requirements | Remarks |
|---|---|---|---|---|
| 1 | GBW 08615 | Copper Single-Element Standard Solution | Concentration: 1000 μg/mL | National Institute of Metrology, China |
3. Result Calculation
The copper content in the sample is calculated using the following formula:
Where:
- X = Copper content in the sample, unit: milligram per kilogram (mg/kg);
- ρ= Mass concentration of copper in the sample test solution, unit: microgram per milliliter (μg/mL);
- ρ0= Mass concentration of copper in the blank solution, unit: microgram per milliliter (μg/mL);
- f = Dilution factor of the digested sample solution;
- V = Total volume of the digested sample solution, unit: milliliter (mL);
- m = Mass of the sample, unit: gram (g).
