my country's sanitation industry started late, and there is no monitoring method for total chromium in urban domestic waste in China. The monitoring method of soil is generally used, but the characteristics of soil and domestic waste are different. In order to standardize the determination method of total chromium in urban domestic waste, this standard is specially formulated. This standard specifies the principle, instrument, reagent and operation steps for the determination of mercury by cold atomic absorption spectrophotometry. This standard is applicable to the determination of mercury in urban domestic waste. CJ/T 98-1999 Determination of mercury in urban domestic waste by cold atomic absorption spectrophotometry CJ/T98-1999 Standard download decompression password: www.bzxz.net

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City Construction Industry Standard of the People's Republic of China CJ/T98——1999
Determination of mercury in municipal domestic refuse
Cold atomic absorption spectrophotometric method
Municipal domestic refuseDetermination of mercury-Cold atomic absorption spectrophotometric methodStandard Construction
Published on 1999-11-24
Implemented on 2000-06-01
Ministry of Construction of the People's Republic of China
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CJ/T98—1999
my country's environmental sanitation industry started late, and the monitoring method of mercury in municipal domestic refuse is a blank. At present, the monitoring methods of domestic waste are not unified across the country. In order to meet the needs of my country's environmental sanitation work and to standardize the monitoring methods of mercury in municipal domestic waste, this standard has been formulated.
This standard was proposed by the Standard and Quota Research Institute of the Ministry of Construction. This standard is under the jurisdiction of the Shanghai Municipal Environmental Sanitation Administration, the technical unit responsible for urban environmental sanitation standards of the Ministry of Construction.
This standard was drafted by the Tianjin Environmental Sanitation Engineering Design Institute. The main drafters of this standard are Zheng Wen and Zhang Fan. This standard is entrusted to the Tianjin Environmental Sanitation Engineering Design Institute for interpretation. Engineering Construction Standards Full-text Information System
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Urban Construction Industry Standards of the People's Republic of ChinaMunicipal domestic refuseDeterminatlon of mercuryCold atomic absorption spectrophotometric method1Scope
CJ/T98—1999
This standard specifies the principle, instrument, reagent and operating procedures for the determination of mercury by cold atomic absorption spectrophotometric method.
This standard applies to the determination of mercury in municipal solid waste. Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. CJ/T3039—1995 Sampling and physical analysis methods for municipal solid waste. Sample collection and preparation
The collection and preparation of municipal solid waste samples, the determination of moisture content and the preservation of samples shall be carried out in accordance with the provisions of CJ/T3039.
4 Principle
Mercury vapor has a strong absorption effect on ultraviolet light with a wavelength of 253.7nm. Approved by the Ministry of Construction of the People's Republic of China on November 24, 1999, and implemented on June 1, 2000. The sample is digested/oxidized to convert all organic and inorganic mercury into mercury ions, and then the mercury ions are reduced to elemental mercury with stannous chloride, and the mercury atoms are carried into the absorption cell of the mercury analyzer by carrier gas for determination. Under certain conditions, the mercury concentration is proportional to the absorption value. 5 Reagents Unless otherwise specified, the reagents used in this standard are analytically pure reagents, and the water used is distilled water.
5.1 Concentrated nitric acid (HNOg), p=1.40g/mL. 5.2 Concentrated sulfuric acid (H,SO,), p=1.84g/mL. 5.3 Concentrated hydrochloric acid (HCI), p=1.19g/mL. 5.41mol/L nitric acid.
5.56% potassium permanganate (KMnO,) solution (m/V). 310% hydroxylamine hydrochloride (HONHa) solution (m/V). 5.6
5.75% potassium persulfate (K,S,0g) solution (m/V). 5.85% nitric acid-0.05% potassium dichromate solution: weigh 0.5g potassium dichromate (K,Cr,0,) and dissolve it in distilled water, add 50mL concentrated nitric acid, and dilute to 1000mL. 5.940% stannous chloride solution: weigh 40g stannous chloride (SnClz·2H,O), dissolve it in 40mL concentrated hydrochloric acid, dissolve it with slight heat, and dilute it to 100mL with water after clarification. 5.10 Mercury standard stock solution: Accurately weigh 0.1354g mercuric chloride (HgCl) into a beaker, dissolve it with 5% nitric acid-0.05% potassium dichromate solution, transfer it into a 1000mL volumetric flask, dilute it to the mark with 5% nitric acid-0.05% potassium dichromate solution, and shake well. The mercury concentration of this solution is 100ug/mL.
5.11 Mercury standard intermediate solution: Accurately pipette 1.00mL of mercury standard stock solution into a 100mL volumetric flask, dilute it to the mark with 5% nitric acid-0.05% potassium dichromate solution, and shake well. The mercury concentration of this solution is 1.0μg/mL.
5.12 Mercury standard working solution: Accurately pipette 1.00mL of mercury standard intermediate solution into a 100mL volumetric flask, dilute it to the mark with 5% nitric acid-0.05% potassium dichromate solution, and shake well. The mercury concentration of this solution is 0.01ug/mL. This solution is prepared when used. 2
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Glass has an adsorption effect on mercury. Glassware such as conical flasks, volumetric flasks, and reaction bottles need to be soaked in 10% nitric acid solution after each use, and then washed with water for use. 6Instruments
a) Mercury analyzer;
b) Electric constant temperature water bath;
c) Analytical balance.
7 Operation steps
7.1 Drawing of standard curve
After adjusting the instrument according to the instrument manual, accurately pipette 0.00, 1.00, 2.00, 3.00, 4.00, 5.00, 7.00, 8.00, 10.00mL of mercury standard solution into the reaction bottle, dilute to 10mL with 1mol/L nitric acid, add 1mL of 40% stannous chloride and immediately measure, and draw the curve with the measured value minus the zero concentration as the ordinate and the corresponding mercury content as the abscissa.
7.2 Determination of sample
7.2.1 Digestion of sample
Weigh about 1g of sample (accurate to 0.0001g) into a 150mL conical flask, add 10mL of concentrated nitric acid, put a small funnel on the bottle mouth and let it stand overnight. Then add 10mL of concentrated sulfuric acid, and after cooling, add 2m concentrated hydrochloric acid and cover the small funnel. Place the conical flask in a constant temperature water bath at 65-75℃ (high temperature may cause mercury volatilization) and digest until the suspension is clear (usually 45h). Take out the conical flask from the water bath and place it in a cold water bath. After cooling, slowly add 10mL of 6% potassium permanganate solution, stirring slowly, and let it stand for 15min. Then slowly add 6% potassium permanganate solution dropwise and stir slowly until the purple color of permanganate ions lasts for at least 15min, then add 5mL of 5% potassium persulfate solution to ensure that the organic mercury compound is completely oxidized, and the mixture is left to stand for 4h or overnight. Add 10% hydroxylamine hydrochloride solution dropwise, shaking while dropping until the purple and brown colors fade away, then transfer to a 100mL volumetric flask, dilute to volume with water, and retain the supernatant A for the determination of (7.2.2).
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7.2.2 Determination of Sample
Pull 10.00mL of supernatant A obtained from (7.2.1) into a reaction bottle, add 1mL of 40% stannous chloride solution, and immediately perform the determination, and subtract the value of the blank experiment (7.3).
7.3 Blank Experiment
The blank experiment is carried out simultaneously with the sample determination. Except for not adding the sample, the reagents and amounts used are the same as those for the sample determination.
Note: The entire experiment must be carried out in a fume hood or a well-ventilated place. 8
Expression of analysis results
The mercury content c (mg/kg) is calculated as follows:
Wherein: m is the mercury content in the sample obtained from the curve, g; V is the volume of the sample, mL,
V is the volume of the digestion fluid absorbed, mL;
mm—sample weight, g.
The results are expressed in four decimal places.
Precision and accuracy
Two samples were measured, and four parallel samples were made for each sample. A total of three batches of experiments were conducted. The content was 0.04~0.45mg/kg, and the relative standard deviation was 2.2%~～5.6%. When 0.04~0.2ug of standard mercury was added to 1g of sample, the recovery rate was 82.3%~99.8%.
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