HJ 540-2016 in English
VALIDStationary source emission - Determination of arsenic -Silver diethyldithiocarbamate spectrophotometric method
- Issued on:2016-07-26
- Implemented on:2016-10-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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本标准规定了测定固定污染源废气中以颗粒物形态存在的砷及其化合物的二乙基二硫代氨基甲酸银分光光度法。
本标准适用于固定污染源废气中以颗粒物形态存在的砷及其化合物的测定。 当采样体积为 0.4 m3（标准状态），定容体积为 50.0 ml 时，本方法检出限为 0.004 mg/m3，测定下限为 0.016 mg/m3（均以 As 计）。
Introduction
Background of Standard Revision and Technological Evolution
This standard is the first revision of the 2009 version of HJ 540. The main technical changes include:
| Revision Dimensions | 2009 Version | 2016 Version |
|---|---|---|
| Scope of Application | Ambient Air and Exhaust Gas | Limited to Exhaust Gas from Stationary Pollution Sources |
| Detection Limit | 0.9 μg/m³ | 0.004 mg/m³ |
| Quality Control | Basic requirements | New chapters on precision, accuracy and waste disposal |
Core method principle
Arsenic-containing particles are collected using a quartz fiber filter cartridge, and after acid digestion, AsH₃ gas is generated through an arsenic generator, which reacts with silver diethyldithiocarbamate to form a red complex, and the absorbance is measured at a wavelength of 510 nm using a visible spectrophotometer.
Key reaction equation
As³⁺ + 3Zn + 3H⁺ → AsH₃↑ + 3Zn²⁺
AsH₃ + 6Ag(DDTC) → 6Ag + As(DDTC)₃ + 3HDDTC
Instrument configuration requirements
| Instrument type | Technical parameters | Precautions |
|---|---|---|
| Smoke sampler | 5-80 L/min | Must comply with HJ/T 48 standard |
| Spectrophotometer | 10 mm cuvette | Regularly calibrate the wavelength |
| Arsenic hydrogen generator | Inner diameter of gas tube 8mm | Need to be cleaned with ethanol before use |
Key points of quality control
- Cartridge blank value: Arsenic content in digestion solution ≤1.3 μg
- Calibration curve: Correlation coefficient ≥0.999
- Precision control: RSD≤7.5% (15 μg/50ml concentration)
- Interference elimination: When antimony content is ＞50 μg, the amount of SnCl₂ needs to be increased
Implementation suggestions
Operational safety specifications
The experiment must be carried out in a fume hood, and the operator should wear a gas mask. The arsenic hydrogen generator needs to be filtered with lead acetate cotton, and the connection of the reaction bottle needs to be strictly leak-checked.
Sample processing points
- Digestion endpoint judgment: the liquid surface is calm and there is no brown smoke
- Temperature control: a cold water bath is required in summer to keep the reaction temperature ≤30℃
- Zinc particle selection: 10-20 mesh zinc particles with rough surface have the best effect
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