This standard specifies the maximum permissible concentration of monomethylhydrazine in drinking water source water and the monitoring and testing methods. This standard is applicable to drinking water source water from rivers, lakes, reservoirs, ponds (wells). GB 18062-2000 Hygienic Standard for Monomethylhydrazine in Water Source Water GB18062-2000 Standard download decompression password: www.bzxz.net

GB18062—2000
All technical contents of this standard are mandatory. Foreword
In order to implement the "Environmental Protection Law of the People's Republic of China" and the "Water Pollution Prevention and Control Law of the People's Republic of China", prevent and control the pollution of the water environment by the aerospace industry waste, and protect the health of the general public, this standard is formulated according to the principles of formulating water source water hygiene standards, referring to foreign research results, and based on the actual situation in my country.
This standard shall be implemented on January 1, 2001. This standard is proposed by the Ministry of Health of the People's Republic of China and the Ministry of Aerospace Industry. Appendix A of this standard is the appendix of the standard.
The responsible drafting unit of this standard is the Seventh Design Institute of the Ministry of Aerospace Industry; participating units are the Academy of Military Medical Sciences of the Chinese People's Liberation Army and the 165th Station of the Ministry of Aerospace.
The main drafters of this standard are Xu Zhitong, Xia Zhiqiao, Chen Qingyu, and Wang Lancui. This standard is entrusted by the Ministry of Health to the Institute of Environmental Health Monitoring of the Chinese Academy of Preventive Medicine for interpretation. 203
National Standard of the People's Republic of China
Hygienic standard for monomethyl hydrazine in water sources
Hygienic standard for monomethyl hydrazine in water sourcesGB18062- 2000
This standard specifies the maximum permissible concentration of monomethyl hydrazine in drinking water sources and the monitoring and inspection methods. This standard is applicable to drinking water sources from rivers, lakes, reservoirs, ponds (wells). 2 Standard content
The maximum permissible concentration of monomethyl hydrazine in drinking water sources is 0.04mg/L. 3 Monitoring and inspection methods
This standard adopts the "p-dimethylaminobenzaldehyde spectrophotometric method" to detect monomethylhydrazine in water, see Appendix A. Approved by the State Administration of Quality and Technical Supervision on April 10, 2000, 204
Implementation on January 1, 2001
A1 Method Overview
GB 18062-2000
Appendix A
(Appendix to the standard)
Determination of monomethylhydrazine in water
p-dimethylaminobenzaldehyde spectrophotometric method
In sulfuric acid ethanol medium, trace monomethylhydrazine reacts with dimethylaminobenzaldehyde to form a yellow condensation product. The depth of the yellow color in the determination range is proportional to the content of monomethylhydrazine, which conforms to the Lambert-Beer law. The maximum absorption wavelength of the yellow condensation product is 470 nm. Unsymmetrical dimethyl hydrazine, nitrate, phosphate, ammonia, urea, nitromethane, formaldehyde, hydroxylamine, fluoride and calcium and magnesium ions have no interference with the determination of methyl hydrazine content in water by this method. Hydrazine has serious interference. Nitrite shows negative interference with the increase of content. Ammonium aminosulfonate is selected as the masking agent. The determination range of methyl hydrazine is 0.02～0.80 mg/L. For monomethyl hydrazine greater than 0.80 mg/L, it can be diluted and determined according to this method. 42 Instruments and apparatus
A2. 1 Spectrophotometer: with 2 cm colorimetric resistor. A2.2 Colorimetric tube 25 ml., 10
A2.3 Volumetric flask 500mL, 1; 100ml., 2; 25mL, 10. A3 Reagents and preparation methods
A3.1 Sulfuric acid: u=1.84g/ml analytical grade. 43.2 Ethanol: more than 95%, analytical grade.
43.3 1.00mol/L sulfuric acid solution: analytical grade. A3.4 0.05mol/L sulfuric acid solution analytical grade. A3.5 p-Dimethylamino: benzaldehyde solution
Weigh 5.0g p-dimethylaminobenzaldehyde L(CH3), NC.HCH3()), add 20ml, 1.0mol/L sulfuric acid solution, mix well and add 100 1 ml ethanol reagent. Dissolve it.
A3.61% ammonium sulfamate or aminosulfonic acid solution Weigh 1.0 g of ammonium sulfamate (NH4SO4NH2) or aminosulfonic acid (NHS03H2O) and dissolve it in 100 ml of water. A3.7 Preparation of monomethyl hydrazine stock solution and standard solution -methyl hydrazine (CH4NH4H2O): 8-0.878 8 g/mL, purity above 98%. A3.7.1 Preparation of monomethyl hydrazine stock solution wwW.bzxz.Net
Absorb 5-10 ml 1.00 mol/L sulfuric acid solution into a 25 mL volumetric flask and weigh to one ten-thousandth of a gram. Use a syringe to absorb 0.3 ml of monomethyl hydrazine reagent and inject it into the above volumetric flask. Gently shake the bottle and weigh it again to one ten-thousandth of a gram. Dilute to the mark with 1.00 mol/L sulfuric acid solution. The concentration of monomethyl hydrazine in this solution is about 10 mg/mL. Absorb 2 ml of the above solution and transfer it into 100 mL volumetric flask, dilute to scale with 0.05 mol/L vegetable acid solution, the toluene concentration of this solution is 200ug/mL.
The prepared stock solution should be stored at low temperature.
A3.7.2 Preparation of methyl thiocyanate standard solution
Pipette 5 mL of 200 μg/mL methyl thiocyanate stock solution and transfer it to a 500 mL volumetric flask. Dilute to scale with 0.05 mol/L vegetable acid solution and mix well. The methyl thiocyanate content of this standard solution is 2μg/ml. A4 Analysis steps
A4.1 Drawing of standard curve
GB18062·-2000
A4.1. 1 Drawing of standard curve when nitrite is not presentA4.1.1.1 Take 0.00, 0.02, 0.04, 0.08, 0.20, 0.400.80mL monomethylhydrazine standard solution respectively, inject into a set of 25mL volumetric flasks, add 4.5mL ethanol reagent, add 5ml. color developer [A3.5], dilute to the scale with 0.05mol/L sulfuric acid solution, and shake the spoon.
A4. 1. 1. 2 After 40 minutes of kidney placement, measure the absorbance at 470 nm in a spectrophotometer with a reagent blank as the reference solution and a 2 cm pathlength colorimetric blood.
A4.1.1.3 Draw a standard curve based on the measured absorbance and the corresponding monomethyl content, and find the regression equation. A4.1.2 Draw the standard curve when nitrite is present: After taking the monomethyl standard solution according to A4.1.1.1, add 0.2mL of 1% ammonium sulfamate solution, and the rest of the steps are the same as A4.1.1. A4.2 Sample analysis
A4.2.1 Sampling and sample treatment
A4.2.1.1 Sampling is carried out in accordance with national standards and special suggestions are made according to the type of water sample to be tested. A4.2.1.2 Sample treatment: Measure 500mL of water sample and adjust the pH of the water sample to about 1.0 with concentrated sulfuric acid. This solution is the sample test solution. A4.2.2 Determination method when there is no nitrite and other nitrites in the water sample A4.2.2. 1 Pipette 15 mL of the test solution into a 25 mL colorimetric tube, add 4.5 ml of ethanol reagent, 5.0 ml of p-methylaminobenzaldehyde solution, shake and dilute to the mark with 0.05 mol/l sulfuric acid solution, and let stand for 40 min. A4.2.2.2 Spectrophotometric determination: At a wavelength of 470 nm, use a colorimetric blood with a 2 cm optical path, use distilled water as the reference solution, measure the absorbance of the solution, deduct the reagent blank absorbance, and obtain the corresponding monomethyl nitrite mass (g) in the solution from the standard curve or calculate it according to the regression equation. A4.2.3 Determination method when nitrites are present in the water Pipette 15 ml of the test solution into a 25 ml colorimetric tube, add 0.2 ml of 1% ammonium sulfamate, and perform the remaining steps according to A4.2.2. In a fixed volume of 25 mL, if the total amount of NO exceeds 20, the recovery rate should be measured at the same time, and the measured value divided by the recovery rate is the content of monomethylhydrazine. The relative error of the quotient of the average release should not exceed 10%.
A4.2.4 Determination method when unsymmetrical dimethylhydrazine exists in water A4. 2. 4. 1 When the content of unsymmetrical dimethylhydrazine in the water sample is higher than that of monomethylhydrazine, the unsymmetrical dimethylhydrazine content should be measured according to the unsymmetrical dimethylhydrazine determination method.
A4.2.4.2 Prepare an unsymmetrical dimethylhydrazine calibration curve according to A4.1.1 or A4.1.2, and find the absorbance AI corresponding to the unsymmetrical dimethylhydrazine content on the curve
A4.2.4.3 Operate according to A4.2.2 or A4.2.3, and record the absorbance A. A4.2.4.4 A: - A, - A: Use the A, value to find the mass of monomethylhydrazine contained in the water sample on the standard curve or calculate it by the regression equation.
A5 Calculation
The mass of monomethyl argon in the water sample is calculated by the formula (AI):
× 1000 X n
W——the mass of monomethyl argon in the water sample obtained from the standard curve or calculated by the regression equation, μg: V——the constant volume,25 mL;
V Sample volume, mL;
Sample dilution factor;
10--converted to per liter of sample.
Take the arithmetic mean of the parallel determination results as the determination result. 206
A6 Determination error
GB180622000
When the concentration of monomethyl thiocyanate is lower than 0.10 mg/L, the relative standard deviation shall not exceed 15%; when it is 0.10~0.80 mg/L, the relative standard deviation shall not exceed 3.6%.
A7 Precautions
A7.1 The sensitivity of this method decreases with increasing temperature. The determination of the amount of monomethyl thiocyanate contained in the water sample should be carried out simultaneously with the preparation of the standard curve. A7.2 The temperature adaptability range of this method is 15~30℃. If the temperature exceeds the range, the color should be developed in a constant temperature water bath. 207
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