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Ambient air. Determination of the fluoride. Lime-paper sampling followed by fluorine ion-selective electrode method
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HJ 481-2009
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| Standard ID | HJ 481-2009 (HJ481-2009) | | Description (Translated English) | Ambient air. Determination of the fluoride. Lime-paper sampling followed by fluorine ion-selective electrode method | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z15 | | Classification of International Standard | 13.040 | | Word Count Estimation | 12,140 | | Date of Issue | 2009-09-27 | | Date of Implementation | 2009-11-01 | | Older Standard (superseded by this standard) | GB/T 15433-1995 | | Quoted Standard | GB 7484 | | Drafting Organization | Shenyang Municipal Environmental Monitoring Center Station | | Administrative Organization | Ministry of Environment Protection | | Regulation (derived from) | Department of Environmental Protection Notice No. 47 of 2009 | | Summary | This standard specifies the determination of fluoride in ambient air collected lime paper fluoride ion selective electrode method (abbreviated LTP France). This standard applies to ambient air pollution levels of fluoride in the determination of long-term average. When the sampling time is one month, the method detection limit is 0. 18��g/(dm ^ 2 �� d). |
HJ 481-2009
Ambient air.Determination of the fluoride.Lime-paper sampling followed by fluorine ion-selective electrode method
HJ
National Environmental Protection Standard of the People's Republic
Replace GB/T 15433-1995
Determination of ambient air fluoride
Lime filter paper sampling fluoride ion selective electrode method
Ambient air-Determination of the fluoride-Lime-paper sampling followed
By fluorine ion-selective electrode method
Published on.2009-09-27
2009-11-01 Implementation
Ministry of Environmental Protection released
Ministry of Environmental Protection
announcement
No. 47 of.2009
In order to implement the "Environmental Protection Law of the People's Republic of China", protect the environment, and protect human health, we now approve the measurement of water quality polycyclic aromatic hydrocarbons.
Eighteen standards, such as fixed liquid extraction and solid phase extraction high performance liquid chromatography, are national environmental protection standards and are released.
The standard name and number are as follows.
I. Determination of Polycyclic Aromatic Hydrocarbons by Liquid-Liquid Extraction and Solid Phase Extraction High Performance Liquid Chromatography (HJ 478-2009);
2. Determination of nitrous oxides (nitrogen oxides and nitrogen dioxide) - Determination of naphthalene diamine hydrochloride spectrophotometric method (HJ 479-
2009);
III. Determination of Fluoride in Ambient Air Filtration of Fluoride Ion Selective Electrode Method (HJ 480-2009);
V. Determination of Sulfur Dioxide in Ambient Air - Formaldehyde Absorption - Pararosaniline Spectrophotometry (HJ 482-2009);
6. Determination of Sulfur Dioxide in Ambient Air - Tetrachloromercury Salt Absorption - Pararosaniline Spectrophotometry (HJ 483-2009);
VII. Determination of water content cyanide volumetric method and spectrophotometry (HJ 484-2009);
VIII. Determination of copper in water quality by diethyldithiocarbamate spectrophotometry (HJ 485-2009);
IX. Determination of copper in water quality 2,9-Dimethyl-1,10 phenanthroline spectrophotometry (HJ 486-2009);
X. Determination of Fluoride in Water Quality by Spectrophotometric Method of Zirconium Sulfate Sulfate (HJ 487-2009);
XI. Determination of Fluoride in Water Quality Fluorescence Spectrophotometry (HJ 488-2009);
XII. Determination of Silver in Water Quality 3,5-Br2-PADAP Spectrophotometry (HJ 489-2009);
XIII. Determination of Silver in Water Quality by Cadmium Reagent 2B Spectrophotometry (HJ 490-2009);
XIV. Determination of Total Chromium in Soils by Flame Atomic Absorption Spectrophotometry (HJ 491-2009);
15. Air Quality Vocabulary (HJ 492-2009);
XVI. Technical Regulations for the Preservation and Management of Water Quality Samples (HJ 493-2009);
17. Water Quality Sampling Technical Guidance (HJ 494-2009);
18. “Technical Guidance for the Design of Water Quality Sampling Plans” (HJ 495-2009).
The above standards have been implemented since November 1,.2009 and published by the China Environmental Science Press. The standard content can be found on the website of the Ministry of Environmental Protection.
From the date of implementation of the above standards, the following 20 national environmental protection standards approved and issued by the former National Environmental Protection Agency shall be abolished.
The exact name and number are as follows.
1. "Determination of six specific polycyclic aromatic hydrocarbons in water quality by high performance liquid chromatography" (GB 13198-91);
2. Determination of nitrogen oxides in air quality - Determination of naphthylethylenediamine hydrochloride (GB 8969-88);
3. "Saltzman method for determination of nitrogen oxides in ambient air" (GB/T 15436-1995);
4. Determination of the concentration of fluoride in ambient air, filter membrane and fluoride ion selective electrode method (GB/T 15434-1995);
V. Determination of Fluoride in Ambient Air Lime Filter Paper · Fluoride Ion Selective Electrode Method (GB/T 15433-1995);
6. Determination of Sulphur Dioxide in Ambient Air - Formaldehyde Absorption - Pararosaniline Spectrophotometry (GB/T 15262-94);
VII. Determination of Air Quality, Sulfur Dioxide, Tetrachloromercury Salt - Pararosaniline Hydrochloride Colorimetric Method (GB 8970-88);
VIII. Determination of Cyanide in Water Quality Part I Determination of Total Cyanide (GB 7486-87);
IX. Determination of Cyanide in Water Quality Part 2 Determination of Cyanide (GB 7487-87);
X. Determination of copper in water quality by diethyldithiocarbamate spectrophotometry (GB 7474-87);
XI. Determination of Copper in Water Quality 2,9-Dimethyl-1,10-phenanthroline Spectrophotometric Method (GB 7473-87);
Twelve, "Determination of Fluoride in Water Quality, Zirconium Sulfonic Acid Visual Colorimetric Method" (GB 7482-87);
XIII. Determination of Fluoride in Water Quality Fluorescence Spectrophotometry (GB 7483-87);
XIV. Determination of Silver in Water Quality, 3,5-Br2-PADAP Spectrophotometry (GB 11909-89);
Fifteen, "Measurement of mercury in water, cadmium reagent 2B spectrophotometry" (GB 11908-89);
XVI. Determination of Total Chromium in Soil Quality by Flame Atomic Absorption Spectrophotometry (GB/T 17137-1997);
17. Air Quality Vocabulary (GB 6919-86);
18. Technical Regulations for the Preservation and Management of Water Samples (GB 12999-91);
Nineteen, "Water Quality Sampling Technical Guidance" (GB 12998-91);
20. Technical Regulations for the Design of Water Quality Sampling Plans (GB 12997-91).
Special announcement.
September 27,.2009
Content
Foreword..iv
1 Scope..1
2 Normative references..1
3 method principle..1
4 Reagents and materials.1
5 instruments and equipment. 2
6 interference and elimination.3
7 samples.3
8 Analysis steps..3
9 results indicate ..4
10 Precision and Accuracy 4
11 Notes 4
Foreword
In order to implement the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on the Prevention and Control of Atmospheric Pollution
Human health, standardizing the monitoring methods for fluoride in the air, and developing this standard.
This standard specifies a sample of fluoride ion-selective electrode for the determination of fluoride in the ambient air.
This standard is for the determination of fluoride in ambient air, lime filter paper and fluoride ion selective electrode method (GB/T 15433-1995)
Line revision.
This standard was first published in.1995. The original standard drafting unit was Baotou Environmental Monitoring Station. This is the first revision.
The main revisions are as follows.
-- modified the name of the standard;
- In the reagents and materials, the purity of the reagents used is specified, and the detailed preparation process of sodium hydroxide is added; the total ions are added.
Method for preparing intensity adjustment buffer; simplifying the preparation process of standard solution;
- specifies the operating conditions of the fluoride ion selective electrode;
-- Added electrode cleaning method to the precautions.
The national environmental protection standard “Environmental Environment” approved and issued by the former National Environmental Protection Agency on March 25,.1995, from the date of implementation of this standard.
Determination of air fluoride Lime filter paper · fluoride ion selective electrode method (GB/T 15433-1995) abolished.
This standard was formulated by the Science and Technology Standards Department of the Ministry of Environmental Protection.
This standard was drafted. Shenyang Environmental Monitoring Center Station.
This standard was approved by the Ministry of Environmental Protection on September 27,.2009.
This standard has been implemented since November 1,.2009.
This standard is explained by the Ministry of Environmental Protection.
Iv
Determination of ambient air fluoride
Lime filter paper sampling fluoride ion selective electrode method
1 Scope of application
This standard specifies the fluoride ion selective electrode method (LTP method) for the determination of fluoride in the ambient air.
This standard applies to the determination of the long-term average pollution level of fluoride in ambient air.
When the sampling time is one month, the lower limit of the method is 0.18 μg/(dm2 · d).
2 Normative references
The contents of this standard refer to the terms in the following documents. For undated references, the latest valid version applies to this standard.
quasi.
GB 7484 Determination of fluoride in water quality - Ion selective electrode method
3 Principle of the method
Fluoride (hydrogen fluoride, silicon tetrafluoride, etc.) in the air is reacted with calcium hydroxide immersed in the filter paper to be fixed. Total ionic strength
After adjusting the buffer leaching, the content of fluoride on the lime filter paper was determined by a fluoride ion selective electrode method. The measurement results reflect the placement
The average level of fluoride in the air during the period.
4 reagents and materials
The reagents used in this standard are analyzed using analytical analytical reagents in accordance with national standards, unless otherwise stated.
Deionized water or distilled water.
4.1 Perchloric acid. 72%, excellent grade pure.
4.2 Sodium hydroxide solution c (NaOH) = 2.5 mol/L. Weigh 100.0 g of pure grade sodium hydroxide, dissolved in water, and then diluted to 1 000 ml after cooling.
4.3 Sodium hydroxide solution c (NaOH) = 5.0 mol/L. Weigh 100.0 g of excellent grade pure sodium hydroxide, dissolved in water, and then diluted to 500 ml after cooling.
4.4 Preparation of lime suspension. Weigh 56 g of calcium oxide, add 250 ml of water, slowly add perchloric acid (4.1) 250 ml with stirring, add
Heat to produce white smoke. After cooling, add.200 ml of water and heat to evaporate until white fumes are produced. Repeat three times. If there is sediment, use glass sand core to leak.
Bucket (G3) filtration. To the resulting transparent filtrate, a sodium hydroxide solution (4.2) of 1 000 ml was added under stirring to obtain a calcium hydroxide suspension. Static
After settling, the supernatant is decanted, and washed repeatedly 5 to 6 times with water. Finally, water is added to 5 000 ml, the mass fraction is about 1%, and it is kept in a sealed state.
Shake well when using.
4.5 Total ionic strength adjustment buffer solution (TISAB)
4.5.1 Total ionic strength adjustment buffer solution (TISABI). Weigh 58.0 g of sodium chloride, 10.0 g of sodium citrate, and measure 50 ml of glacial acetic acid.
Add 500 ml of water. After dissolving, add 135 ml of sodium hydroxide solution (4.3), adjust the pH of the solution to 5.2, and bring up to 1 000 ml with water.
Shake well.
4.5.2 Total ionic strength adjustment buffer solution (TISABII). weigh 142 g hexamethylenetetramine ((CH2)6N4), 85 g potassium nitrate (KNO3)
And 9.97 g of ferrotitanium reagent (C6H4Na2O8S2·H2O), add appropriate amount of water to dissolve, adjust the pH to 5-6, transfer to a 1 000 ml volumetric flask,
Dilute to the mark with water and shake well.
The preparation of the solution is not limited thereto, and the preparation method of the total ionic strength adjusting buffer solution in GB 7484 can also be referred to.
Note. When the sample composition is complex, acid (pH ≈ 2) or alkaline (pH ≈ 12), TISABII formula can be used.
4.6 Sodium fluoride standard stock solution ρ (NaF)=1 000 μg/ml. Weigh 0.221 0 g sodium fluoride (excellent grade, dry at 110 °C for 2 h)
Cool to room temperature in a desiccator, dissolve in water, and transfer to a 100 ml volumetric flask. Make up to the mark with water and shake well. Stored in a polyethylene bottle,
Save in the refrigerator. Take it out when it is ready and put it at room temperature for later use.
4.7 Sodium Fluoride Standard Solution. Dilute sodium fluoride standard stock solution (4.6) with water to 2.5, 5.0, 10.0, 25.0, 50.0, 100.0 μg/ml
The standard solution is ready for use. The above reagent solutions should be stored in polyethylene plastic bottles.
4.8 Qualitative filter paper. 12.5 cm in diameter.
4.9 Lime filter paper. Put a small amount of lime suspension with two large petri dishes (about 15 cm in diameter) and make a 12.5 cm diameter qualitative filter paper (4.8)
Into the first dish, soaked, drained, and then soaked in a second dish, drained (immersed 5 to 6 sheets of filter paper, replaced with new stone
Gray suspension), then spread on a large piece of clean, fluorine-free qualitative filter paper, dried at 60 ~ 70 ° C, into a plastic box (bag), sealed
Put it in the desiccator (no desiccant in the dryer).
5 Instruments and equipment
5.1 Sampling device.
a. Sample box. Flat-bottomed plastic case with an outer diameter of 130 mm, an inner diameter of 126 mm and a height of 25 mm (excluding the cover), with a cover. Inside the box
Plastic ring gasket (outer diameter 125 mm, inner diameter 110 mm) and plastic welding rod (or spring ring) for fixing filter paper.
b. Rain cover. rain cover with a diameter of 300 mm and a height of 90 mm. The bottom of the basin is welded with a diameter of 130 mm and a height of 35 mm.
Circle for mounting the sample box.
The sampling device is shown in Figure 1. The dimensions in the figure are in mm.
Φ130 rain cover
Φ300
1-metal ring with fixed sampling box (130 mm diameter)
a. rain cover side view b. rain cover bottom view
Φ125
Thick 1~2
Φ110
Φ125
Thick 5~6
Φ125
1- plastic box bottom; 2-filter paper; 3- fixed filter paper plastic pressure ring;
4-spring clamp ring for fixing plastic pressure ring;
5-reed pin; 6-plastic cover
c. plastic pressure ring d. circlip (spring up) e. assembled sample box profile
Figure 1 sampling device diagram
5.2 Ion activity meter or precision acidity meter. resolution is 0.1 mV.
5.3 Fluoride ion selective electrode.
(1) Measurement of fluoride ion concentration range. 10−5～10−1 mol/L.
(2) Determination of the slope of the curve. at t ° C, (54 0.2 t) mV.
5.4 Calomel electrode. The salt bridge solution is saturated potassium chloride.
5.5 Magnetic stirrer. stirrer with polyethylene wrap.
5.6 Small ultrasonic cleaner.
5.7 Polyethylene plastic cup. 100 ml.
5.8 Polyethylene plastic bottles. 100, 1 000 ml.
6 interference and elimination
There are Si4, Fe3, and Al3 in the immersion liquid. When the mass concentration does not exceed 20 mg/L, the interference generated can be added to the total ion intensity.
Adjust the buffer to eliminate it.
7 samples
Take a piece of lime filter paper, tiling it on the bottom of the flat-bottomed plastic sample box, press the filter paper edge with a ring-shaped plastic collar, and use elastic plastic
The electrode or the circlip is pressed along the edge of the box (the rivet can be installed on the box to catch the electrode). Secure the filter paper firmly, cover it, and carry it to the sampling point.
The distance between sampling points is generally about 1 km. When the source is near, the distance between sampling points can be reduced, and the sampling point away from the pollution source.
The distance between them can be increased. Sampling points should be located in relatively empty areas, avoiding local small sources of pollution (such as chimneys, etc.). The sampling device can be fixed at
On the sampling rack of 3.5~4 m on the ground; in the densely populated area, it can be installed on the roof, and the height relative to the base surface should be more than 1.5 m.
When sampling, remove the lid of the sample box containing the lime filter paper, put it into the bottom iron ring of the sampling rain cover, fix it, and make the lime filter.
The paper is facing down and exposed to the air for a period of 7 d to one month. Do a good sampling record [record the sample location, sample number and put
Sample, sampling time (month, day, hour), etc.]. When taking the sample, take out the sample box from the rain cover, seal it, and bring it back to the lab.
The collected samples were stored in a laboratory air dryer and analyzed within 40 days.
8 Analysis steps
8.1 Drawing of the calibration curve
8.1.1 Take 6 100 ml polyethylene plastic cups and add them to the prepared standard series according to Table 1. They can also be prepared according to the actual sample concentration. may not
Less than 6 points. Take 2.00 ml of six standard use solutions (4.7), and add TISAB solution 25.00 ml, water 23.00 ml, and fluoride.
The ion content was 5.0, 10, 20, 50, 100,.200 μg in order.
8.1.2 Turn on the ion activity meter and insert the cleaned fluoride ion selective electrode and calomel electrode into the prepared liquid to be tested as required.
Do not stir the solution before inserting the electrode to avoid air bubbles on the electrode surface and affect the accuracy of the measurement. Measure from low to high concentration one by one
get on. Stir for a few minutes on a magnetic stirrer, the magnetic stirring time should be consistent, and the stirring speed should be moderate and stable. After the reading is stable
(ie, the electrode potential change is less than 0.2 mV per minute) Stop stirring, read the millivolt value after standing, and record the temperature at the time of measurement.
Note. The temperature of the solution is controlled at 15~35 °C to ensure the normal operation of the fluoride ion selective electrode.
Table 1 Standard solution preparation series
Cup number 1 2 3 4 5 6
F− standard solution/(μg/ml) 2.50 5.00 10.0 25.0 50.0 100.0
Standard solution amount/ml 2.00 2.00 2.00 2.00 2.00 2.00
TISAB solution/ml 25.00 25.00 25.00 25.00 25.00 25.00
Water/ml 23.00 23.00 23.00 23.00 23.00 23.00
F−content/μg 5.00 10.0 20.0 50.0 100.200
8.1.3 Linear regression with the logarithm of the fluorine content and its corresponding millivolt value, the absolute value of the correlation coefficient r is required to be greater than 0.999, the slope character
(54 0.2t) mV; or on semi-logarithmic paper, the fluorine content (μg) is expressed in logarithmic coordinates, and the millivolt value is expressed in equidistant coordinates.
Calibration curve.
8.2 Blank test
The instability of the blank value will directly affect the accuracy of the measurement results. Each batch of lime filter paper should be tested blank.
Draw 4 to 5 unsampled lime filter paper, cut into small pieces (approx. 5 mm × 5 mm), and place in a 100 ml polyethylene plastic cup.
Add 0.50 ml of 10.0 μg/ml sodium fluoride standard solution, add 25.00 ml of TISAB solution, 24.50 ml of water, and read millivolts according to 8.1.2.
Value, calculate the fluorine content according to the regression equation or find the fluorine content from the standard curve. The fluorine content of the blank lime filter paper is the measured value (μg) minus
The standard fluorine content to be added is 5 μg. Take the average value of the fluorine content of the blank lime filter paper (the fluorine content of each blank lime filter paper should not exceed
Over 1 μg).
8.3 Preparation of samples
Remove the lime filter paper sample, cut into small pieces (approx. 5 mm × 5 mm), place in a 100 ml polyethylene plastic cup, add 25.00 ml
TISAB buffer (4.5) and 25.00 ml water were extracted in an ultrasonic cleaner for 30 min and taken out overnight (capped to prevent placement)
Time pollution), to be tested.
8.4 Sample determination
The processed sample is measured in the same way as the calibration curve. After reading the millivolt value, calculate the fluorine content according to the regression equation or from calibration
The fluorine content was found on the curve.
The sample measurement should be performed simultaneously with the calibration curve. The difference between the temperature at which the sample is measured and the temperature at which the calibration curve is drawn should not exceed
±2 °C.
9 results indicate
The content of fluoride in the air ρ (F−) is calculated according to formula (1).
0(F )
WW
S n
ρ − −= × (1)
Where. ρ (F−)--the content of fluoride in the air, μg/(dm2 · d);
W--the fluorine content of the lime filter paper sample measured according to 8.3, μg;
W0--the average fluorine content of the blank lime filter paper measured according to 8.2, μg;
S--the area of the sample filter paper exposed to the air, dm2;
n--The number of days in which the sample filter paper is placed in the air, d, should be accurate to 0.1 d.
The results are expressed in 3 significant digits.
10 Precision and accuracy
10.1 Precision
Five laboratories collected atmospheric environmental samples at different locations, and each laboratory collected 5 parallel samples per batch, and obtained 31 batches of samples.
The mean value ranged from 2.81 to 192 μg/(dm2·d), with an average coefficient of variation of 5.5% and a maximum of 16.6%.
10.2 Accuracy
Five laboratories measured uniformly prepared fluorine-containing 50.0 μg lime filter paper samples with a relative error of 0.23%.
11 Precautions
Do not touch the surface of the electrode with a finger. To protect the electrode, the measured concentration of fluorine in the sample should not exceed 40 mg/L. If the electrode
The surface of the membrane is contaminated with organic matter and must be cleaned before use. The organic reagents such as methanol and acetone may be used for washing, and detergents may also be used.
For example, the electrode can be immersed in a warm, dilute detergent (1 part detergent plus 9 parts water) for 3 to 5 minutes. Can be placed in another diluted detergent
in. It was then rinsed with water, immersed in (1 1) hydrochloric acid for 30 s, and finally rinsed with water, and the water was removed by a filter paper.
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