This standard specifies the determination of lead in workshop air by graphite furnace atomic absorption spectrometry. This standard applies to the determination of lead smoke and lead dust generated in metal smelting, lead melting, plate casting and type casting in the printing industry, the manufacture of batteries, lead glass, enamel, pigments, and electric welding, melting and cutting in the shipbuilding industry. GB/T 16008-1995 Graphite furnace atomic absorption spectrometry method for the determination of lead in workshop air GB/T16008-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Workplace air --Determination of leadl-Graphite furnace atomic ahsorptinn spectrophotometric method1 Subject content and scope of application
Standard provisions "Determination of lead in workshop air by graphite furnace atomic absorption spectrophotometric method. GB/T 160081995
This standard is applicable to the determination of lead smoke and lead dust generated in the smelting of lead metals, the casting of plates and type in the printing industry, the manufacture of batteries, lead glass, porcelain and pigments, as well as welding and smelting in the shipbuilding industry. 2 Principle
Lead dust and lead smoke are collected on a microporous filter membrane. After the sample is digested with nitric acid-perchloric acid, the content is determined by the stone furnace atomic absorption method at a wavelength of 283.3rtl. bZxz.net
3 Instruments
3.1 Sampling clamp.
3.2 Filter material Microporous filter membrane, pore size 0.8 μm, diameter 40 nm. 3.3 Vacuum.
3.4 ​​Flow rate, 0~10 L/min.
3.5 High-type beaker, 50 ml.
3.6 Table or porcelain crucible cover, diameter about 5 ctl.3.7 Electric sand bath or electric heating plate.
3.8 Bottle. 50 mL.
3.9 Micro-injector. 10～25μl
3.10 Atomic absorption spectrophotometer, with graphite furnace device and equipment. 3.11 Lead hollow cathode lamp,
4 Reagents
4.1 Deionized water: The specific resistance obtained by passing through an ion exchange resin column is greater than 500kQ·cin, or the water obtained by re-distilling with a full glass distillation device. 4.2 Perchloric acid?02: -1.67g/mL, high purity 4.3 Nitric acid, 0m=1.42g/ml. High purity,
4.4 Perfluoric acid-nitric acid , 1+9.
4.5 Nitric acid solution. c(HN)）().1mol/I. 4.6 Nitric acid solution. c(HNO)=0.01Iol/L. 4.7 Lead standard solution Weigh 0.1598g lead nitrate [Pb(N0) (superior grade. Dry at 105℃ for 2h), deionized water State Technical Supervision Bureau 1995-12-15 Approved 1996-07-01 Implementation
GB/T160081995
(4.1) Dissolve, transfer to 10ml volumetric flask [t, Shenzhen people 1 ml. nitric acid (4.3), diluted to scale with deionized water (4.1). This solution is 1.0umg/ml.Pb. Before the clinical diagnosis, dilute it step by step with nitric acid solution (4.6) to a standard solution of 5.μg/ml.Fb 5 Sampling
Install the microporous filter membrane (3.2) in the sampling clip (3.1), and collect 50L of air sample at a speed of 5L/min. 6 Analysis steps
6.1 Control test
Use the microporous filter membrane (3.2) that has not been sampled to treat the sample according to the sample treatment operation as a blank control, 6.2 Sample treatment
Put the microporous filter membrane that has been sampled into a high-type beaker, add 5m perchloric acid-nitric acid (4.4), cover the surface III, and place it on the electric sand bath for heating and digestion, and the temperature is maintained between 150~180. After the solution becomes clear, continue heating for 3-5 minutes. Remove the surface blood and evaporate it below 150℃. Remove the beaker and add 5mL nitric acid solution (4.5). Heat slightly to dissolve the residual solution and transfer it to a 50ml volumetric flask. Wash the beaker several times with deionized water (4.1), add the washing solution to the flask, add water to the scale for measurement. 6.3 Drawing of standard curve
Collect 6 tall beakers. Put a microporous filter membrane (3.2) in each and prepare the standard tube. Follow the steps in 6.2. The lead content in the table is the concentration after dilution to 50ml.
Preparation of lead standard tubes
Lead standard solution (4.7).ml.
Nitric acid solution (4. 6),ml.
Lead content,ug
Adjust the graphite furnace atomic absorption spectrophotometer to the optimal operating conditions, use background calibration, and measure each standard tube at a wavelength of 283.31m1. Read the absorbance value or record the peak height and draw a standard curve. 6.4 Determination
Use the same instrument operating conditions as 6.3 to measure the samples from the processing shop. After measuring 19 samples, use the standard solution of medium concentration to correct the measurement results. After subtracting the absorbance value (or peak height) of the blank control from the absorbance value (or peak height) of the sample, the lead content can be obtained by the standard curve.
7 Calculation
7.1 Use formula (1) to convert the sample volume into the volume under standard conditions. Ve = V× 273 +7 *
Where: V, the sample volume under standard conditions. 1..V
Sample volume, I.
Temperature C;
Atmospheric pressure, kPa.
7.2 Use formula (2) to calculate the concentration of lead in the air. 101.3
comWhere: X—Concentration of lead in air, mg/m GB/T 16008-1995
C—Measured lead content in the sample solution, μg/V. —Converted to the sample volume under standard conditions, 1.8 Explanation
8.1 The detection limit of this method is 0.002μg/ml., the sensitivity is 0.002g/ml., the measurement range is 0.0~0.09g/ml. The total coefficient of variation is 5.5%.
8.2 The average sampling efficiency of this method for field sampling with a lead smoke concentration of 0.02~1.34mg/m2 and a lead dust concentration of 1.019~39.991g/m2 is 98.5%.
8.3 The filter membrane should be installed in an environment without lead pollution. The sampling clip and tweezers should be kept clean during use. 8.4 Take the filter membrane sample from the sampling shop, fold it in half with the face facing inwards, wrap it with a layer of clean filter paper, cover it in a small plastic bag, and put it in the sample box. After sampling, it can be stored for a long time. Prevent the filter membrane from falling off during transportation and storage. 8.5 After the sample is digested, the acid should be evaporated, otherwise the sample solution will be too acidic and affect the life of the glass tube: the temperature should not be too high when it is shaken dry, otherwise the residue is easy to carbonize.
8.6 When the concentration of Zn2+, Ca*+Cd\+, Mn\Cu*, Fe\A-Si+, Cr is less than 5g/ml, it will not interfere with the determination. 8.7 There is a white precipitate in the sample solution, which can be removed by centrifugation. 8.8 The glass tube should be soaked in 1+1 nitric acid overnight and then rinsed with deionized water. 8.9 If the dust filter is used instead of the microporous filter for sampling, 10 mL of pernitrogenous acid-nitric acid (4.4) should be added during digestion. If necessary, an appropriate amount of mixed acid can be added until the digestion is complete. 1+4 perchloric acid-nitric acid can also be used instead of 1+9 perchloric acid-nitric acid to accelerate digestion. Additional remarks:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Jiangsu Provincial Health Prevention and Control Station. The main drafters of this standard are Zheng Ling and Shi Guiyun. This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases, Chinese Academy of Preventive Medicine, the technical management unit entrusted by the Ministry of Health.
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