SN/T 5680-2024 in English
VALIDDetermination of Arsenic and Lead in Chromite by Atomic Fluorescence Spectrometry
- Issued on:2024-12-31
- Implemented on:2025-07-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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| Standard No: | SN/T 5680-2024 |
| Document status: | VALID |
| Title in English: | Determination of Arsenic and Lead in Chromite by Atomic Fluorescence Spectrometry |
| Title in Chinese: | 铬矿中砷和铅含量的测定 原子荧光光谱法 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2024-12-31 |
| Implemented on: | 2025-07-01 |
| ICS Classification: | 73.060.30-Chromium ores |
| Chinese Classification: | D33-Chrome ore |
| Professional Classification: | SN-Import&Export Inspection |
| Related Keywords: | atomic fluorescence spectrometry introduction technical background
atomic fluorescence spectrometer interference elimination measures arsenic combined determination pre-reduction lead |
Introduction
Technical background and significance of the standard
As the international control of heavy metal pollution becomes stricter, the General Administration of Customs of my country issued the SN/T 5680 standard in 2024, establishing the combined determination of arsenic and lead in chromium ore for the first time. This standard fills the technical gap of heavy metal detection in chromium ore trade, pushing the detection limit to 0.0002%, which is 10 times more sensitive than traditional methods.
Detailed explanation of the method principle
When using atomic fluorescence spectrometer for detection, the sample is melted with sodium peroxide and then in the hydride generator:
| Element | Reduction Reaction | Characteristic Wavelength (nm) | Interference Elimination Measures |
|---|---|---|---|
| Arsenic (As) | As³⁺ + BH₄⁻ → AsH₃↑ | 193.7 | Thiourea-ascorbic acid pre-reduction |
| Lead (Pb) | Pb²⁺ + BH₄⁻ → PbH₄↑ | 283.3 | Potassium ferrocyanide masking interference |
Key operation points
Sample treatment case
Verification by Lianyungang Customs Laboratory shows that 650℃ melting for 20 minutes can completely decompose chromium ore, and adjusting the pH to 4-10 can avoid the loss of heavy metal hydrolysis. In practical applications, when the sample contains high sulfur, it is recommended to add 5mL nitric acid to assist digestion.
Instrument parameter optimization
The standard recommended working parameters of the atomic fluorescence spectrometer have been verified by 11 laboratories:
- Negative high voltage: arsenic 275mV/lead 250mV
- Atomizer height: uniform 8mm
- Gas flow: auxiliary gas 400mL/min, shielding gas 800mL/min
Implementation suggestions
1. Quality control: Each batch of samples should be carried out with national standard materials (such as GBW07294) for parallel determination
2. Equipment maintenance: The quartz atomizer should be ultrasonically cleaned with 10% nitric acid every week
3. Safety protection: Sodium peroxide melting should be operated in an explosion-proof fume hood
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