This standard specifies the hygienic standard for zinc chloride (fume) in workshop air and its monitoring and inspection methods. This standard is applicable to all types of enterprises that produce and use zinc chloride. GB 16247-1996 Hygienic standard for zinc chloride (fume) in workshop air GB16247-1996 Standard download decompression password: www.bzxz.net

GB16247-1996
This standard is formulated for the first time based on toxicological experiments, on-site labor hygiene surveys, epidemiological survey data and reference to foreign occupational exposure limits. It is a health standard used for workplace environmental monitoring and health supervision. This standard shall be implemented from September 1, 1996. Appendix A of this standard is the appendix of the standard. This standard is proposed by the Ministry of Health of the People's Republic of China. The drafting unit of this standard is Zhejiang Provincial Institute of Labor Hygiene and Occupational Disease Prevention and Control. The main drafters of this standard are: Shen Yunzhi, Yuan Xuehong, Le Junyi, Sun Jianxi, Yang Xiaohua. This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine, which is the technical unit entrusted by the Ministry of Health. 582
National Standard of the People's Republic of China
Health standard for zinc chloride (fume) in the air of workplace
This standard specifies the health standard for zinc chloride (fume) in the air of workplace and its monitoring and inspection methods. This standard is applicable to all types of enterprises that produce and use zinc chloride. Hygiene requirements
GB16247—1996
The maximum permissible concentration of zinc chloride (fume) in workshop air is 2 mg/m3; the time-weighted average concentration is 1 mg/m3. 3 Monitoring and inspection methods
The monitoring and inspection of this standard adopts flame atomic absorption spectrometry, see Appendix A (Appendix to the standard). Approved by the State Bureau of Technical Supervision on April 3, 1996 and implemented on September 1, 1996
A1 Principle
GB 16247—1996
Appendix A
(Appendix to the standard)
Flame atomic absorption spectrometry of zinc chloride in workshop air Zinc chloride (fume) is collected by microporous filter membrane, then dissolved in acidic solution, and the content of zinc chloride is quantitatively determined by acetylene-air flame atomic absorption method at a wavelength of 213.8 nm.
A2 Instrument
A2.1 Sampling clamp
A2.2 Filter material: microporous filter membrane, pore size 0.8μm, diameter 40mm. A2.3 Sampler, flow range 0~101./min. A2.4 Beaker, 50mlL.
A2.5 Stoppered colorimetric tube or test tube, 10mL. A2.6 Atomic absorption spectrophotometer, equipped with acetylene-air flame combustion device. A2.7
Zinc hollow cathode lamp.
A3 ReagentsWww.bzxZ.net
Deionized water: water with a resistivity greater than 500kQ·cm obtained by passing through an ion exchange resin column, or water redistilled with a full glass distiller.
A3.2 Hydrochloric acid. p20=1.18g/mL, high purity. A3.3 Hydrochloric acid solution, 1.2mol/L.
A3.4 Hydrochloric acid solution, 2+98.
A3.5 Zinc standard solution: Accurately weigh 0.1000g of metallic zinc (spectrally pure), dissolve it in 10mL of hydrochloric acid (A3.2), transfer it into a 100ml volumetric flask with water (A3.1), and dilute it to the mark. 1mL of this solution = 1.0mg zinc. Dilute it with hydrochloric acid solution (A3.4) to 1mL-10μg zinc standard solution before use.
A4 Sampling
Install the microporous filter membrane in the sampling clip and collect 40L of air sample at a rate of 5L/min. A5 Analysis steps
A5.1 Control test: Bring the microporous filter membrane to the sampling site, except that the air is not collected, and the rest of the operations are the same as the sample as a blank control. A5.2 Sample treatment: Put the sampled microporous filter membrane into a beaker, add 5mL of hydrochloric acid solution (A3.3), and heat it carefully for 2min. Avoid splashing and burning of the solution. After cooling, transfer the solution into a stoppered colorimetric tube, wash the beaker and filter membrane with water (A3.1), and add the washing solution into the colorimetric tube. Dilute to the scale for determination.
A5.3 Drawing of standard curve: Take 6 stoppered colorimetric tubes and prepare standard tubes according to Table A1. Table A1
Preparation of zinc standard tubes
Zinc standard solution (A3.5), ml
Hydrochloric acid solution (A3.4), ml
Zinc base, μg/ml
GB 16247--1996
Adjust the flame atomic absorption spectrophotometer to the optimal operating conditions, and measure the standard tubes respectively at a wavelength of 213.8nm using an acetylene-air flame (lean gas flame), and measure each for 3 times. After the absorbance value of the measured value is subtracted from the value of the tube 0, a standard curve is drawn with the average value as the ordinate and the zinc content (ug/mlL) as the abscissa. A5.4 Determination: Use the same instrument operating conditions as A5.3 to inhale the treated sample solution into the flame and perform the determination; after every 10 sample solutions are determined, the determination result is corrected once with a standard solution of medium concentration. After the absorbance value of the sample is subtracted from the absorbance value of the blank control, the zinc content (μug/mL) is obtained from the standard curve (or the content is automatically displayed). A6 Calculation
A6.1 Convert the sample volume to the volume under standard conditions according to formula (A1): 273
V×273+t
Wherein, V---converted to the volume under standard conditions, L; V--sampling volume, L;
t-air temperature at the time of sampling, C;
-atmospheric pressure at the time of sampling, kPa.
A6.2 Calculate the concentration of zinc chloride in the air according to formula (A2): X
Wherein: X is the concentration of zinc chloride (smoke) in the air, mg/m2; (—the content of zinc in the sample found on the standard curve, ug/mL; V. Sampling volume under standard conditions, L;
2.085—the coefficient for converting zinc into zinc chloride. A7 Explanation
(Al)
(A2)
A7.1 The detection limit of this method is 0.015μg/ml, the sensitivity is 0.012μg/mL/1% absorption, the measurement range is 0.1~2.0μg/mL, and the coefficient of variation is 5.26%.
A7.2 The sampling efficiency of this method is 96.67%. Contamination should be prevented during sampling. The filter membrane cannot be installed and removed at the production site with high concentration. Keep sampling tools such as sampling clamps and tweezers clean. During sampling, transportation and storage, prevent the loss of samples on the filter membrane.
A7.3 After sampling, use clean tweezers to remove the filter membrane sample from the sampling clamp, fold it inward twice, put it in a clean paper bag, and then store it in a plastic bag.
A7.4 The glassware used for determination must be soaked in 1+1 nitric acid overnight before use. Prevent contamination during the determination. A7.5 The sample contains 1000ppm Fe3+, Si3+ and Sn2+ may produce positive interference. If there is a white precipitate in the sample solution, it can be removed by centrifugation. A7.6 The sample can be digested with 1+9 perchloric acid-nitric acid, and the residue is dissolved in hydrochloric acid solution (A3.4) for determination. If a dust filter membrane is used instead of a microporous filter membrane for sampling, 10mL 1+9 perchloric acid-nitric acid is required for digestion. 585
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