1 适用范围

1.1 本标准适用于固定污染源有组织排放和无组织排放的乙醛测定。

1.2 当采样体积为100L，进样体积为1μL时，乙醛的检出限为4×10^-2mg/m³，乙醛的定量测定浓度范围为0.14mg/m³-30mg/m³。

2 方法原理

用亚硫酸氢钠溶液采样，乙醛与亚硫酸氢钠发生亲核加成反应，在中性溶液中生成稳定的a-羟基磺酸盐，然后在稀碱溶液中共热释放出乙醛，经色谱柱分离，用氢火焰离子化检测器测定，以标准样品色谱峰的保留时间定性，峰高定量。

3 引用标准

      下列标准所包含的条文，通过在本标准中引用而构成为本标准的条文。

      GB 16297-1996 大气污染物综合排放标准

      GB 161157-1996 固定污染源排气中颗粒物测定和气态污染物采样方法

4 试剂和材料

      除非另有说明，分析时均使用符合国家标准的分析纯试剂和不含有机物的蒸馏水。

不含有机物蒸馏水的制备：加入少量高锰酸钾的碱性溶液于普通的蒸馏水或去离子水中使呈红紫色，再进行蒸馏即得（在整个蒸馏过程中水应始终保持红紫色，否则应随时补加高锰酸钾）。

4.1 丙酮(CH₃COCH₃)。

4.2 三聚乙醛(CH₃CHO)₃。

4.3 浓盐酸（HCI):ρ=1.19g/ml。

4.4 浓硫酸(H₂SO₄),ρ=1.84g/ml。

固定污染源排气中乙醛的测定填充柱  测试谱图：



Packed column for determination of acetaldehyde in exhaust of stationary pollution source
Packed column for determination of acetaldehyde in exhaust gas from stationary pollution source Details:

Name: Filled glass column
Specification: 2m*3mm (inner diameter)
Model: 20%PEG-20M/GCS880 AW DMCS (80-100 mesh)

HJ/T 35-1999 Determination of Acetaldehyde in Exhaust from Stationary Pollution Source Gas Chromatography
1 Scope of application

1.1 This standard is applicable to the determination of acetaldehyde from organized and unorganized emissions from stationary sources.

1.2 When the sampling volume is 100L and the injection volume is 1μL, the detection limit of acetaldehyde is 4×10-2mg/m3, and the quantitative measurement concentration range of acetaldehyde is 0.14mg/m3-30mg/m3.

2 Principle of the method

Sampling with sodium bisulfite solution, acetaldehyde and sodium bisulfite undergo a nucleophilic addition reaction to form a stable a-hydroxysulfonate in a neutral solution, and then co-thermally release acetaldehyde in a dilute alkali solution. The chromatographic column is separated and measured with a hydrogen flame ionization detector, qualitatively based on the retention time of the chromatographic peak of the standard sample, and the peak height is quantified.

       
3 Reference standards

      The provisions contained in the following standards constitute the provisions of this standard through quotation in this standard.

      GB 16297-1996 Comprehensive Emission Standard of Air Pollutants

      GB 161157-1996 Determination of particulate matter in exhaust gas from stationary sources and sampling method for gaseous pollutants

4 Reagents and materials

      Unless otherwise specified, analytical reagents that meet national standards and distilled water without organic substances are used for analysis.

Preparation of organic-free distilled water: add a small amount of alkaline solution of potassium permanganate to ordinary distilled water or deionized water to make it reddish purple, and then distill it to obtain (the water should always remain reddish purple during the entire distillation process, otherwise it should be Add potassium permanganate at any time).

4.1 Acetone (CH3COCH3).

4.2 Triacetaldehyde (CH3CHO)3.

4.3 Concentrated hydrochloric acid (HCI): ρ=1.19g/ml.

4.4 Concentrated sulfuric acid (H2SO4), ρ=1.84g/ml.

Determination of acetaldehyde in exhaust gas from stationary pollution sources. Packed column Test spectrum: