Some standard content:
Coal Industry Standard of the People's Republic of China
Determination of copper in coal mine water
Atomic absorption spectrophotometry
1 Subject content and scope of application
This standard specifies the determination of copper in coal mine water by atomic absorption spectrophotometry. MT/T361-94
This standard is applicable to the determination of copper in surface water and groundwater in coal mines. Its determination range is 0.5-5 mg/L, and the determination range can be expanded by enrichment or dilution of water samples.
2 Method Summary
After the sample is treated according to the prescribed steps, the copper content is determined by atomic absorption spectrophotometry (using air-acetylene flame). 3 Reagents
3.1 Water: deionized water without metal ions or double distilled water of equal purity. 3.2 Concentrated nitric acid: high-grade pure nitric acid with a relative density of 1.4 (GB626). 3.3 (1+1) nitric acid solution: Prepare with concentrated nitric acid (3.2). 3.4 0.5% nitric acid solution: Prepare with concentrated nitric acid (3.2). 3.5 Perchloric acid: High-grade pure perchloric acid (GB623) with a relative density of 1.75. 3.6 Copper standard stock solution (1mL contains 1.00mgCu): Accurately weigh 0.2500±0.0002g of high-grade pure metallic copper, add a small amount of water, then add 5ml (1+1) nitric acid solution (3.3) to dissolve, transfer to a 250mL volumetric flask, dilute to scale with water, and shake well. Store in a polyethylene bottle.
3.7 Copper standard solution (1mL contains 0.10mgCu): Accurately pipette 10mL of copper standard stock solution (3.6) into a 100mL volumetric flask, dilute to scale with 0.5% nitric acid solution (3.4), and shake well (this solution can be stable for 24h). 4 Instruments and equipment
4.1 Analytical balance: sensitivity 0.2mg.
4.2 Atomic absorption spectrophotometer: qualified product certified by the national metrology department. 4.3 Light source: copper hollow cathode lamp.
4.4 Pipette: 10mL, accuracy ±0.04mL; 50mL, accuracy ±0.08mL; 100mL, accuracy ±0.16mL. 4.5 Burette: 10ml, graduation value 0.05mL. 4.6 Volumetric flask: 100mL; 250mL.
5 Water sample pretreatment
5.1 When the water sample is not turbid, take 100mL of the sample into a 100mL volumetric flask, add 0.5mL of concentrated nitric acid (3.2), and shake well. Set aside. 5.2 When the water sample contains suspended matter, take 100mL of the sample in a 150mL beaker, add 2mL of concentrated nitric acid (3.2), heat to dissolve, evaporate a small volume, transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. Set aside. Approved by the Ministry of Coal Industry of the People's Republic of China on August 31, 1994, implemented on May 1, 1995. MT/T 361—94 5.3 When the water sample is turbid or contains a lot of organic matter, take 100mL of the sample in a 150mL beaker, add 5mL of concentrated nitric acid (3.2), 2mL of perfluoric acid (3.5), heat to dissolve until smoke appears, remove and cool to room temperature, transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. Set aside.
6 Determination steps
6.1 Adjustment of instrument working conditions
Adjust the wavelength to 324.7nm. According to the instrument manual, adjust the relevant parameters of the instrument (lamp current, passband width, burner height and angle, combustion-supporting ratio, etc.) to the optimal values of the instrument. 6.2 Drawing of working curve
Accurately pipette 0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0mL of copper standard solution (3.7) into 100mL volumetric flasks respectively, dilute to scale with 0.5% nitric acid solution (3.4), and shake well. Adjust the zero point with the reagent blank, and measure the absorbance of the standard solution series. Draw the working curve with the concentration of the standard solution series as the horizontal axis and the absorbance as the vertical axis. 6.3 Determination of sample
Adjust the zero point with the reagent blank, measure the absorbance of the pretreated sample, and check the copper content on the working curve according to the absorbance. 7 Expression of determination results
The copper content is calculated according to the following formula:
Formula t: Cu-
Copper content, mg/L;www.bzxz.net
m—Copper content in the sample obtained on the working curve, mg; VSample volume, mL.
8 Precision of copper determination
The relative allowable difference of repeated determinations should not exceed 15%. 60-1
Yunzhu Chuanshe
Standards for Hailai Free
Additional remarks:
MT/T361-94
This standard is proposed by the National Technical Committee for Coal Standardization. This standard is under the jurisdiction and drafted by the Sichuan Coalfield Geology Research Institute. The main drafters of this standard are Wu Fuxian, Chen Suize and Xu Ling. This standard is entrusted to the Sichuan Coalfield Geology Research Institute for interpretation. Free download of various labeling industry materials on Aw.bo
|Determination of copper, lead, zinc, cadmium and manganese in coal mine water (atomic absorption spectrophotometry) (MT/T 361～365--94) Preparation instructions
(Sichuan Coalfield Geology Research Institute)
In natural water such as groundwater and surface water, the content of copper, lead, zinc, cadmium, manganese, etc. is generally very low. Under certain special geological and geographical environments, some of these elements may also have higher content (especially some mine acidic water). Among these elements, some are beneficial to human health and are trace elements required by the human body, such as zinc and copper (under certain limited conditions), while others are harmful to human health and cause human poisoning, such as cadmium and lead. Therefore, determining the content of these elements in water is of great practical significance for both human health and environmental protection. 1. About the selection of determination methods
To determine copper, lead, zinc, cadmium, manganese and other elements in water, spectrophotometry and atomic absorption spectrophotometry are currently widely used at home and abroad (such as international standards, the United States, Japan and other countries, as well as relevant domestic standards). Spectrophotometry includes the determination of copper, lead, zinc and cadmium after extraction with dithiothiochloride-carbon tetrachloride; the determination of copper after extraction with diethyl dithiocarbamic acid, and the determination of manganese by formaldehyde method, periodic acid oxidation method, persulfate method, etc. These methods have their own characteristics and are relatively mature methods. However, in these determination methods, most of them use organic reagents for extraction and enrichment before determination, and the organic reagents used are often toxic and volatile, which brings adverse effects to the human body and pollutes the environment, and may cause the measured values to be unstable. In addition, the determination of different elements still requires the preparation of test solutions separately, which makes the operation more complicated and the analysis process longer. Atomic absorption spectrophotometry, in the absence of a large number of interfering substances, can use the same test solution to determine steel, lead, zinc, cadmium, manganese and other elements in water, and it is sensitive, accurate, simple and fast. Therefore, it is more appropriate to choose atomic absorption spectrophotometry as the standard for determining copper, lead, zinc, cadmium and manganese in coal mine water. 2 About the debugging of the instrument
The measurement conditions of the atomic absorption spectrophotometer, that is, the selection of relevant parameters of the instrument, such as wavelength, lamp current, negative high voltage, slit width, gas (acetylene) and auxiliary gas flow ratio, as well as burner height and angle, etc., are directly related to the sensitivity, accuracy and stability of the measurement. Therefore, it is very important to optimize the measurement conditions of the instrument. Since the performance of the instruments used by the testing units varies, it is difficult to uniformly stipulate the measurement conditions. Therefore, before the measurement, the instruments used must be repeatedly tested with test solutions and debugged to select and determine the best conditions for the determination of each element.
3 Test of relevant conditions
In order to examine the effect of the acidity of the test solution on the determination, the test solution was adjusted to different acidities with nitric acid solution (because if sulfate ions exist in large quantities, they will have positive interference on the determination of some elements, so it is not appropriate to use sulfuric acid solution to adjust the acidity of the test solution). Comparative tests were carried out according to the determination conditions. The test results show that when the acidity of the test solution is 0.2%～2% (V/V) has no effect on the determination. In order to observe the stability of the test solution, the test solution was prepared for determination and then placed for 24 hours before determination. The absorbance was measured without obvious change, which indicates that the test solution is stable within 24 hours.
Regarding whether the substances commonly present in natural water interfere with the determination, different water samples were tested. The test results show that the common components in water samples have basically no effect on the determination. In addition, in order to investigate whether copper, lead, zinc, cadmium, manganese, etc. interfere with the determination when they coexist, different amounts of copper, lead, zinc, cadmium, and manganese standard solutions were added to the known water samples, and then the determination was carried out. The determination results show that in the presence of the above elements, there is no obvious effect on the determination of each element. 4 Spiked recovery test
Using water samples with known content of the measured elements, different amounts of standard solutions of the relevant elements were added, and spiked recovery tests were carried out on copper, lead, zinc, cadmium, manganese, etc. The test results show that the average recovery rate of the above elements determined by atomic absorption spectrophotometry is above 95%. 675
Free download of industry data
5 In order to investigate the precision of atomic absorption spectrophotometry in determining copper, lead, zinc, cadmium, manganese and other elements in water, 30 spiked samples were used to repeat the determination of these elements. The determination results were statistically calculated, and the standard deviations of repeated determinations of copper, lead, zinc, cadmium and manganese were 12.5μg/L, 12.6pμg/1., 7.2μg/L, 5.2μg/L., and 4.9μg/L, respectively. Combined with the specific circumstances of daily analysis, considering that the content of these elements in general water samples is very small, it is recommended that the repeatability of the determination of copper, lead, zinc, cadmium and manganese in coal mine water be set to: the relative allowable difference shall not exceed 10%. 676
Standard search
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.