HJ/T 42-1999
ActiveStationary source emission - Determination of nitrogen oxide - Ultraviolet spectrophotometric method
固定污染源排气中氮氧化物的测定 紫外分光光度法
Catalogue
1 适用范围 → 2 方法原理 → 3 引用标准 → 4 试剂与材料 → 5 仪器 → 6 样品采集和保存 1 Scope → 2 Principle of method → 3 Normative references → 4 Reagents and materials → 5 Apparatus → 6 Sample collection and preservation
Scope
1.1 This standard is applicable to the determination of nitrogen oxides in organized emissions from stationary sources. 1.2 When the sampling volume is 1 L, the detection limit of the method for nitrogen oxides is 10 mg/m³, the lower limit of quantitative determination is 34 mg/m³, and the upper limit of determination without dilution is 1730 mg/m³.
1.1 本标准适用于固定污染源有组织排放的氮氧化物测定。 1.2 当采样体积为1L时，方法的氮氧化物检出限为10 mg/m³，定量测定的浓度下限为34 mg/m³，在不作稀释的情况下，测定的浓度上限为1730 mg/m³。
Normative References
Keywords
Application Summary AI generated
Environmental monitoring agencies and industrial environmental departments use this standard to measure nitrogen oxide concentrations in stationary source emissions. It provides accurate quantitative analysis via ultraviolet spectrophotometry, helping to control air pollutant emissions and ensure compliance with national standards. Its importance lies in providing reliable data for enforcement and emission reduction.
环境监测机构、工业企业环保部门使用该标准来测定固定污染源排放的氮氧化物浓度。该标准通过紫外分光光度法提供准确的定量分析，帮助控制大气污染物排放，确保符合国家排放标准。其重要性在于为执法和减排提供可靠数据。
AI Summary AI generated
This standard specifies the ultraviolet spectrophotometric method for determining nitrogen oxides in stationary source emissions. The method is based on oxidizing and absorbing nitrogen oxides into nitrate ions, measuring absorbance at 210 nm. It applies to organized emissions with a detection limit of 10 mg/m³ and a determination range of 34-1730 mg/m³. The standard details sampling apparatus, reagent preparation, sampling procedures, and instrument requirements, referencing GB 16297 and GB 16157 for sampling points and frequency.
本标准规定了固定污染源排气中氮氧化物的紫外分光光度测定方法。方法基于将氮氧化物氧化吸收为硝酸根离子，在210 nm处测定吸光度。适用于有组织排放，检出限为10 mg/m³，测定范围34-1730 mg/m³。标准详细描述了采样装置、试剂配制、采样步骤和仪器要求，引用GB 16297和GB 16157作为采样点和频次的依据。
Key Sentences extracted from text
样品气体被收集在一个盛有稀硫酸-过氧化氢吸收液的瓶中，氮氧化物受到氧化和被吸收，成为NO₃⁻存在于吸收液中，于210 nm处测定NO₃⁻的光吸收。
当采样体积为1L时，方法的氮氧化物检出限为10 mg/m³，定量测定的浓度下限为34 mg/m³，在不作稀释的情况下，测定的浓度上限为1730 mg/m³。
将吸收瓶内的真空度抽至负70~90 kPa，旋转三通阀活塞使吸收瓶关闭，采样管抽取排气筒内的气体清洗管道约3 min，再旋转三通阀活塞，使采样管内的气体迅速进入吸收瓶内。
按GB 16157-1996中9.1.1和9.1.2设置采样位置和采样点。
按GB 16297-1996中8.2设置采样时间和采样频次。
The sample gas is collected in a bottle containing dilute sulfuric acid-hydrogen peroxide absorption solution; nitrogen oxides are oxidized and absorbed, becoming NO₃⁻ in the absorption solution, and the light absorption of NO₃⁻ is measured at 210 nm.
When the sampling volume is 1 L, the detection limit of the method for nitrogen oxides is 10 mg/m³, the lower limit of quantitative determination is 34 mg/m³, and the upper limit of determination without dilution is 1730 mg/m³.
Evacuate the absorption bottle to a vacuum of -70 to -90 kPa, rotate the three-way valve piston to close the absorption bottle, use the sampling tube to draw gas from the exhaust stack to purge the pipeline for about 3 min, then rotate the three-way valve piston to rapidly introduce the gas from the sampling tube into the absorption bottle.
Set the sampling position and sampling points according to sections 9.1.1 and 9.1.2 of GB 16157-1996.
Set the sampling time and sampling frequency according to section 8.2 of GB 16297-1996.