This standard specifies the determination of particulate lead in ambient air by flame atomic absorption spectrophotometry. The method is simple, rapid and accurate. This method is applicable to the determination of particulate lead in ambient air. The detection limit of the method is 0.5μg/mL (1% absorption). When the sampling volume is 50m3, the minimum detection concentration is 5×10-4mg/m3. GB/T 15264-1994 Determination of lead in ambient air by flame atomic absorption spectrophotometry GB/T15264-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of lead in ambient air
Flame atomic absorption spectrophotometric method
Ambient air-- Determination of lead -Flameatomic ahsorption spectrophotometric method1 Subject content and scope of application
1.7 Subject content
CB/T15264-94
This standard specifies the determination of particulate lead in ambient air by flame atomic absorption spectrophotometry. The method is simple to operate, fast and accurate. 1.2 Scope of application
This method is applicable to the determination of particulate lead in ambient air. The detection limit of the method is 0.5g/tmL (1% absorption). When the sampling area is 50m3 for determination, the minimum detection concentration is 5×10-mg/m3.2 Definition
Lead in ambient air refers to acid-soluble lead and lead oxides. 3 Principle
The sample is collected by glass fiber filter membrane and diffused through nitric acid-hydrogen peroxide solution to prepare the sample solution. It is directly atomized in air-acetylene fast flame and the absorption of the characteristic radiation of the hollow cathode lamp by the ground state atom is measured at 283.3nm. Under certain conditions, the absorption light is proportional to the metal concentration in the sample to be tested.
4 Reagents
Unless otherwise specified, all reagents in this standard are lead-free analytical pure reagents and deionized water or water of equivalent purity. 4.1 Lead: content not less than 99.99%.
4.2 Nitric acid (HVO), 0m1.42g/ml+ premium pure. 4.3 Nitric acid (HNO,), p=1.42g/mL. Analytical pure. 4.4 Hydrogen peroxide (H2O,), about 30% (m/m). 4.5 Hydrofluoric acid (HF), about 10% (m/m) 4.6 Nitric acid solution, 13%: Prepare with nitric acid (4.2). 4.7 Nitric acid solution, 1+1: Prepare with nitric acid (4.2). 4.8 Nitric acid-chlorine peroxide mixture: Prepare with nitric acid (4.2) and chlorine peroxide (4.4). Control (1+1), temporarily prepare 4.9 Lead standard stock solution, c=1.000g/L: Weigh 1.000±0.001g lead (4.1) in 10 mL of liquid, add 15mL nitric acid (4.2), heat until completely dissolved, then dilute with water to 1000mL and mix. 4.10 Lead standard solution, c=0.100g/L: Use a wave shift tube to take 10.00mL of lead standard stock solution (1.9) into a 100mL volumetric flask, dilute to the mark with nitric acid solution (4.6), and mix. 4.11 Gas: Acetylene, purity not less than 99%. Use cylinder gas or acetylene generator. Approved by the State Environmental Protection Agency on October 26, 1994 and implemented on June 1, 1995. GB/T 15264-94. 4.12 Oxidant: Air, generally supplied by a gas compressor. Before entering the burner, it should be properly filtered to remove water, oil and other impurities. 4.13 Filter membrane: Ultrafine glass fiber filter membrane. The maximum lead content of the blank filter membrane should be significantly lower than the minimum detection concentration specified in this method (see 1.2). 5 Instruments General laboratory instruments and: 5.1 Atomic absorption spectrophotometer and corresponding auxiliary equipment: The light source is a hollow cathode lamp or an electrodeless discharge lamp. The operating parameters can be selected by referring to the instrument group manual.
5.24 porous glass filter,
5.3 General avoidance of floating particles sampler: mid-flow sampler. Note: The glassware used in the experiment should be washed with detergent and soaked in nitric acid solution (4.?). Before use, it should be thoroughly cleaned with white water and lead water. 6 Samples
6.1 Collection nest
mid-flow sampler, when the diameter of the glass fiber filter membrane is 8cm, the flow rate is 50~150L/min, and the sampling is 30~60m. When sampling, the filter membrane should be placed with the hair side facing up, put into the sampling clamp and tighten. After sampling, carefully remove the filter membrane with the dust side facing up, fold it twice into a fan shape, put it back into the paper bag, and record the sampling conditions in detail.
6.2 Test solution
6.2.1 Nitric acid·hydrogen peroxide solution slow method Take the sample filter, put it in a tall beaker, add 10mL nitric acid-hydrogen peroxide mixed solution (4.8) and soak for more than 2h, heat it on low heat until boiling, and keep it boiling for 10min. After cooling, add 10mL hydrogen peroxide (4.4), boil until it is slightly cold, add 20mL nitric acid solution (1.6). Boil for another 10min. The hot solution passes through a porous glass filter (5.2) and is collected in a beaker. Rinse the filter several times with a small amount of hot nitric acid solution (4.6). After the filtrate cools, transfer it to a 50mT volumetric flask and dilute it to the mark with nitric acid solution (4.6). This is the test solution. 6+2.2 Preparation of blank solution
Take a blank filter of the same batch number and area, and prepare a blank solution according to the operation in 6.2.1. 7 Steps
7.1 Interference and its elimination
For flame atomic absorption spectrometry, under experimental conditions, antimony has absorption interference at 217.0nm, but at 283.8nm, antimony does not interfere with the measurement.
7.2 Drawing of calibration curve
Refer to Table 1. Take 6 100mL volumetric flasks and add lead standard solution (4.10) respectively. Then dilute to the mark with caustic soda solution (4.6) to prepare working standard solution, the concentration range of which includes the measured lead concentration in the sample. Table 1
Lead standard solution (+.10) Volume added mL
Concentration of working standard solution, mg/1
Based on the selected atomic absorption spectrophotometer working conditions, measure the absorbance of the working standard solution. Concentration is measured by absorbance.Sampling volume, m\: S, --- total area of ​​sample membrane, cm\
S, --- area of ​​filter membrane taken during determination, cm°. 9 Precision and accuracy
9.1 Precision
Five laboratories used the flame method to determine the same sample containing 1.0mg/L and 5.0mg/L lead. 9. 1. Repeatability
The relative standard deviations of repeatability were 4.0% and 2.4% respectively. 9.1.2 Reproducibility
The relative standard deviations of reproducibility were 4.6% and 3.1% respectively. 9.2 Accuracywww.bzxz.net
The recovery percentage of the spiked sample of 0.6mgPh/L by the flame method for the experimental case was 95.5% to 105.0%. Addition period:
This standard was proposed by the Science and Technology Standardization Department of the State Environmental Protection Administration. This standard was drafted by the Chongqing Environmental Science Research Institute. The main drafters of this standard are Qin Changhua, Li Ming and Sheng Heming. The China National Environmental Monitoring Center is responsible for interpreting this standard.
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