HJ 550-2009_English: PDF (HJ550-2009)
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Water quality. Determination of cobalt. 5-CI-PADAB spectrophotometry
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HJ 550-2009
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| HJ 550-2015 | English | 229 |
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Water quality. Determination of cobalt. 5-Cl-PADAB Spectrophotometry
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HJ 550-2015
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Newer version: HJ 550-2015 Standards related to: HJ 550-2015
| Standard ID | HJ 550-2009 (HJ550-2009) | | Description (Translated English) | Water quality. Determination of cobalt. 5-CI-PADAB spectrophotometry | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z16 | | Classification of International Standard | 13.060 | | Word Count Estimation | 9,984 | | Date of Issue | 2009-12-30 | | Date of Implementation | 2010-04-01 | | Drafting Organization | Beijing Municipal Environmental Monitoring Center | | Administrative Organization | Ministry of Environment Protection | | Regulation (derived from) | Department of Environmental Protection Notice No. 74 of 2009 | | Summary | This standard specifies the determination of total cobalt 5 chloro-2 (pyridine- azo) -1, 3 diaminobenzene spectrophotometry. This standard applies to surface water, groundwater, industrial wastewater and domestic sewage total of cobalt. | HJ 550-2009
Water quality.Determination of cobalt.5-CI-PADAB spectrophotometry
National Environmental Protection Standard of the People's Republic
Determination of total cobalt in water
Spectrophotometry (tentative)
Water quality-Determination of cobalt
-5-Cl-PADAB spectrophotometry
Released.2009-12-30
2010-04-01 Implementation
Ministry of Environmental Protection released
Ministry of Environmental Protection
announcement
No. 74 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 lead gas of fixed pollution sources.
The four standards, such as the determination of flame atomic absorption spectrophotometry (tentative), are national environmental protection standards and are released.
The standard name and number are as follows.
I. Determination of lead in fixed pollution sources - Flame atomic absorption spectrophotometry (tentative) (HJ 538-2009);
2. Determination of lead in ambient air by graphite furnace atomic absorption spectrophotometry (tentative) (HJ 539-2009);
III. Determination of arsenic in ambient air and exhaust gases - Spectrophotometric method of silver diethyldithiocarbamate (interim) (HJ 540-2009);
4. Determination of gaseous arsenic in the production of yellow phosphorus - Determination of silver diethyldithiocarbamate spectrophotometry (interim) (HJ 541-2009);
V. Determination of mercury in ambient air - Enrichment of sulfhydryl cotton - Cold atomic fluorescence spectrophotometry (interim) (HJ 542-2009);
6. Determination of mercury in fixed pollution sources - Cold atomic absorption spectrophotometry (provisional) (HJ 543-2009);
VII. Determination of Sulfuric Acid Fog of Fixed Pollution Sources by Ion Chromatography (Provisional) (HJ 544-2009);
VIII. Determination of gaseous total phosphorus in fixed pollution sources - Determination of quinolinol ketone capacity (provisional) (HJ 545-2009);
IX. Determination of Phosphorus Pentoxide in Ambient Air Ascorbic Acid Reduction - Molybdenum Blue Spectrophotometry (Provisional) (HJ 546-2009);
X. Determination of chlorine gas from fixed pollution sources, iodometric method (provisional) (HJ 547-2009);
XI. Determination of hydrogen chloride in fixed source pollution. Silver nitrate capacity method (provisional) (HJ 548-2009);
12. Determination of hydrogen chloride in ambient air and exhaust gas Ion chromatography (interim) (HJ 549-2009);
14. Determination of Chlorine Dioxide in Water Quality Iodometric Method (Provisional) (HJ 551-2009).
The above standards have been implemented since April 1,.2010 and published by the China Environmental Science Press. The standard content can be found on the website of the Ministry of Environmental Protection.
Special announcement.
December 30,.2009
Content
Foreword..iv
1 Scope..1
2 Method principle..1
3 interference and elimination.1
4 Reagents and materials.1
5 instruments and equipment. 2
6 samples.3
7 Analysis steps..3
8 result calculation..4
9 precision and accuracy..4
Foreword
To protect the environment and protect the human body 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 Water Pollution Prevention and Control
To develop and standardize the monitoring methods for cobalt in water.
This standard specifies the 5-chloro-2-(pyridylazo)-1,3-diaminobenzene spectrophotometric method for the determination of total cobalt in water.
This standard was formulated by the Science and Technology Standards Department of the Ministry of Environmental Protection.
This standard was drafted. Beijing Environmental Protection Monitoring Center.
This standard was approved by the Ministry of Environmental Protection on December 30,.2009.
This standard has been implemented since April 1,.2010.
This standard is explained by the Ministry of Environmental Protection.
Iv
Determination of total cobalt in water
5-Chloro-2-(pyridylazo)-1,3-diaminobenzene spectrophotometry (interim)
1 Scope of application
This standard specifies the 5-chloro-2-(pyridylazo)-1,3-diaminobenzene spectrophotometric method for the determination of total cobalt in water.
This standard applies to the determination of total cobalt in surface water, groundwater, industrial wastewater and domestic sewage.
Without pre-enrichment, when the sampling volume is 10 ml, the method detection limit is 0.007 mg/L, the lower limit of determination is 0.02 mg/L, and the upper limit of determination is
0.16 mg/L. After pre-enrichment, the method detection limit can be reduced by 50 times.
2 Principle of the method
Cobalt and 5-chloro-2-(pyridylazo)-1,3-diaminobenzene (5-Cl-PADAB) in a pH-to-sodium acetate-sodium acetate buffer medium
The reaction produces a purple-red complex, and its absorbance is measured by a spectrophotometer at a wavelength of 570 nm. The molar absorptivity is 1.03×105 L/
(mol·cm), the mass concentration of cobalt in the range of 0.02 to 0.16 mg/L in accordance with Lambert Beer's law.
When the cobalt content in water is less than 0.02 mg/L, it is pre-enriched with sulfhydryl cotton or XAD-2 macroporous reticulated resin, and then color measurement is carried out.
Its sensitivity can be increased by 5 to 50 times.
3 interference and elimination
Alkali metals and alkaline earth metals do not interfere with the determination without pre-enrichment treatment. When the Fe3 content is greater than 0.006 mg, the Cr3 content is greater than 0.001 mg
Positive interference occurs. The interference of Fe3 can be added to the sodium pyrophosphate solution at pH=5~6 until the iron brown disappears, then add 2.5 m1.
Masking; Cr3 interference can be removed by digestion with HNO3-HCl-HClO4. Some heavy metal ions and 5-Cl-PADAB coloration interfere with cobalt
Determination, but after the color development is completed, add HCl to strong acid to decompose and discolor to eliminate the interference, while the cobalt complex is very stable, not
Affected.
A large amount of Fe2 and Cr6 may cause negative interference, and may also be digested with HNO3-HCl-HClO4, respectively, by oxidation, masking and volatilization.
Remove.
SO42−, Cl−, PO43−, NO3−, Br−, ClO4−, tartarate, etc. do not interfere with the determination. The citrate makes the cobalt color incomplete.
If pre-enrichment is carried out with sulfhydryl cotton, adding appropriate amount of tartrate can prevent manganese and iron from hydrolyzing to form colloid at pH=9, and the remaining metal is separated.
The sub-series can be separated and removed without interference. Organic complexing agents such as citric acid and cysteine do not affect the adsorption of Co2.
If the XAD-2 type macroporous reticulated resin is pre-enriched, the interference and elimination methods are the same as those without pre-enrichment treatment.
4 reagents and materials
Unless otherwise stated, analytically pure reagents that meet national standards were used for the analysis. The experimental water is freshly prepared deionized water or distilled water.
4.1 Nitric acid. ρ (HNO3) = 1.42 g/ml, excellent grade pure.
4.2 Perchloric acid. ρ (HClO4) = 1.67 g/ml, excellent grade pure.
4.3 Hydrochloric acid. ρ (HCl) = 1.19 g/ml, excellent grade pure.
4.4 Sulfuric acid. ρ (H2SO4) = 1.84 g/ml, excellent grade pure.
4.5 thioglycolic acid.
4.6 Acetic anhydride.
4.7 36% acetic acid.
4.8 95% ethanol.
4.9 Ammonia. pH=10.
4.10 Hydrochloric acid solution. 1 1.
4.11 Hydrochloric acid solution. c (HCl) = 3 mol/L.
4.12 Hydrochloric acid solution. c (HCl) = 1 mol/L.
4.13 Sodium hydroxide. w (NaOH) = 20%.
Weigh 20.0 g of sodium hydroxide and dissolve in 100 ml of water.
4.14 Ammonium tartrate solution. w (C4H12N2O6) = 10%.
Weigh 10.0 g of ammonium tartrate, dissolve in water, and dilute to 100 ml.
4.15 sodium thiosulfate solution. w (Na2S2O7·5H2O) = 20%.
Weigh 20.0 g of sodium thiosulfate, dissolve in water, and dilute to 100 ml.
4.16 Ammonium chloride-ammonia (NH4Cl-NH4OH) buffer solution. pH = 10.
Weigh 20.0 g of ammonium chloride (NH4Cl), dissolve it in 100 ml of concentrated ammonia water, close it, and store it in the refrigerator.
4.17 Acetic acid-sodium acetate (HAC-NaAC) buffer solution. pH = 5-6.
Weigh 21.0 g of anhydrous sodium acetate, dissolve in a small amount of water, add acetic acid to adjust the pH to 5-6, and dilute with water to 1 000 ml.
4.18 5-Cl-PADAB Ethanol solution. w(5-Cl-PADAB) = 0.1%.
0.10 g of 5-Cl-PADAB was weighed, dissolved in a 95% ethanol solution, and diluted to 100 ml. Store in brown bottles.
4.19 Sodium pyrophosphate solution. w(Na4P2O7·10H2O) = 5%.
Weigh 5.0 g of sodium pyrophosphate, dissolve in water, and dilute to 100 ml.
4.20 Cobalt standard stock solution. ρ (Co) = 100 μg/ml.
Weigh 0.035 15 g of the reference reagent cobalt dioxide, add 2.5 ml of hydrochloric acid (4.3) to dissolve, transfer to a 250 ml volumetric flask, and use water.
Dilute to the mark.
4.21 Cobalt standard use solution. ρ (Co) = 2 μg/ml.
Pipette 10.00 ml of cobalt standard stock solution (4.20), transfer to a 500 ml volumetric flask, and dilute to the mark with water.
4.22 p-Nitrophenol solution. w(C6H5NO3) = 0.2%.
Weigh 0.20 g of p-nitrophenol, dissolve in water, and dilute to 100 ml.
4.23 巯 base cotton
4.23.1 Add 100 ml of analytically pure thioglycolic acid (4.5), 60 ml of acetic anhydride (4.6), 40 ml of 36% acetic acid (4.7), and then to the grinding bottle.
0.3 ml of sulfuric acid (4.4), mix well. After cooling to room temperature, add 30 g of absorbent cotton, completely submerge, capped, and baked at 40 ° C
Remove in the box for 2 to 4 days, filter by suction, wash with distilled water until neutral, and dry at 30 °C. Put it into the grinding bottle, cover it in the dark and store it at low temperature.
Save for 3 months.
4.23.2 Sulfhydryl cotton can also be prepared by adding 70 ml of thioglycolic acid (4.5), 0.4 ml of sulfuric acid (4.4), and shaking in a small jar.
uniform. Add 10 g of cotton wool to completely submerge, cover and leave at room temperature for 24 h. The following steps are the same as 4.23.1.
4.24 XAD-2 Macroporous Resin
The XAD-2 resin was soaked in methanol (submerged resin) for 24 h, then filtered and washed several times with 3 mol/L hydrochloric acid (4.11) solution.
Rinse several times with ammonia water (4.9) and finally wash with distilled water until neutral.
5 Instruments and equipment
Unless otherwise stated, the analysis uses a Class A glass gauge that complies with national standards.
5.1 Visible spectrophotometer. equipped with a cuvette with an optical path of 20 mm.
5.2 Enrichment unit. A solid phase extraction column with a diameter of 1 cm is filled with 0.25 g of sulfhydryl cotton (4.23) or 0.5 g of resin (4.24).
6 samples
6.1 Sample collection and preservation
Depending on the amount of cobalt in the water sample, 250 ml to 2 L of water is collected. After sample collection, add sulfuric acid or hydrochloric acid to pH< 2, complex on the substrate
The mixed wastewater sample should have an acidity of about 1% and be stored at 0 to 4 °C.
6.2 Preparation of samples
6.2.1 Nitric acid-perchloric acid digestion
For surface water and sewage containing high quality, take 2-20 ml of water sample (depending on the cobalt content in the water sample) in a 100 ml beaker.
Add 2 ml of nitric acid (4.1), cover with a watch glass, heat and boil on a hot plate for 1 to 5 minutes, remove slightly cold, add 1 to 2 ml of perchloric acid (4.2)
(Depending on the amount of organic matter), continue to heat until thick white smoke, and continue until the solution is free of black residue. After taking off the cooling, turn
Move to a 25 ml plug colorimetric tube, add 1 to 2 drops of p-nitrophenol indicator (4.22), add 20% sodium hydroxide solution (4.13) to the solution.
Rendered yellow, to be tested.
6.2.2 Pre-enrichment
6.2.2.1 For samples containing less than 0.02 mg/L of cobalt, pre-enrichment is required. If the water sample contains organic matter or other impurities, it should be
Digestion is performed and pre-enrichment is performed.
6.2.2.2 Pre-enrichment of sulphur-based cotton method
Take 500 ml of water (depending on the amount of cobalt in the water sample), add 2.5 ml of 10% ammonium tartrate solution (4.14), 2.5 ml of 20% thiosulfate
Sodium (4.15), adjust the pH to 8.5-9.5, add 10 ml ammonium chloride-ammonia buffer solution (4.16), pass at a flow rate of 1-4 ml/min
The adsorption device is enriched. After the water sample is finished, it is eluted twice with 4 ml of 1 mol/L hydrochloric acid (4.12) at a flow rate of 1-4 ml/min.
The eluate was taken up in a 25 ml plug colorimetric tube, and 1 to 2 drops of p-nitrophenol (4.22) was added to the eluent, and 20% sodium hydroxide solution (4.13) was added dropwise.
The solution appears yellow and is to be tested.
6.2.2.3 XAD-2 type resin pre-enrichment
Take 500 ml of water (depending on the amount of cobalt in the water sample), adjust the pH to 5-6, and add 10 ml of acetic acid-sodium acetate buffer solution (4.17).
1.5 ml of 5-Cl-PADAB solution (4.18), heated on a boiling water bath (or directly heated to near boiling) for 5 min. Dissolve with 20% NaOH after cooling
The liquid (4.13) is adjusted to pH 10 and is enriched by an adsorption device at a flow rate of 1 to 2 ml/min using 10 ml of 95% ethanol (4.8) solution.
The elution was performed in two portions, and the eluate was taken up in a 50 ml beaker. After elution, place it on a water bath or a low temperature electric heating plate and evaporate to about 5 ml.
Remove the cooling. Add 10 ml (1 1) HCl solution (4.10), transfer to a 25 ml plug colorimetric tube, dilute to the mark with water, shake well.
To be tested.
7 Analysis steps
7.1 Drawing of the calibration curve
Absorb cobalt standard solution (4.21) 0.00, 0.25, 0.50, 1.00, 1.50, 2.00 ml in 25 ml plug color tube, cobalt
The contents are in order. 0.00, 0.50, 1.00, 2.00, 3.00, 4.00 μg. Add 5.0 ml of acetic acid-sodium acetate buffer solution (4.17),
0.50 ml sodium pyrophosphate solution (4.19), 1.0 ml 5-Cl-PADAB solution (4.18), dilute with water to about 10 ml, shake well. Placed
Heat on a boiling water bath for 5 min, remove, cool to room temperature, add 10 ml (1 1) HCl solution (4.10), dilute to the mark with water.
Shake well. The absorbance was measured with a 20 mm cuvette at a wavelength of 570 nm using water as a reference. Absorbing cobalt corresponding to the reagent blank
The content is plotted against a calibration curve.
7.2 Sample Analysis
7.2.1 Pipette 2 to 10 ml of clean water (depending on the amount of cobalt in the water sample) in a 25 ml plug colorimetric tube. The following steps are the same as (7.1).
7.2.2 Using the digested sample (6.2.1) or the sample pre-enriched with the sulphur-based cotton method (6.2.2.2), the following procedure is the same as (7.1).
Note. If the iron content in the water sample is high, the sodium pyrophosphate solution should be added as appropriate. When preparing the calibration curve, the amount of sodium pyrophosphate solution should be the same as that of the measured water sample.
7.2.3 Samples pre-enriched with XAD-2 resin (6.2.2.3), directly with the colorimetric conditions of the calibration curve for absorbance determination.
7.3 Blank test
The sample was replaced with 10 ml of water and the absorbance was measured in the same manner as in the sample measurement (7.2).
8 Calculation of results
The total cobalt content ρ in the sample is calculated according to formula (1).
0(Co)
AA a
bV
ρ − −= (1)
Where. ρ (Co)--the total cobalt content in the water sample, mg/L;
A--the absorbance of the water sample;
A0--the absorbance of the blank test;
A--the intercept of the calibration curve;
B--the slope of the calibration curve;
V--water sample volume, ml.
9 Precision and accuracy
9.1 precision
Six laboratories use different pre-treatment methods for groundwater, surface water and industrial waste with a cobalt concentration of 0.001 to 0.130 mg/L.
The water uniform sample was measured, and the relative standard deviation between the laboratories was 0.2% to 23.0%.
9.2 Accuracy
Six laboratories use different pre-treatment methods for groundwater, surface water and industrial waste with a cobalt concentration of 0.001 to 0.130 mg/L.
The unified sample of water was spiked and the recovery rate was 90%-120%.
Six laboratories measured a cobalt concentration of 0.099 mg/L of reference material with a relative error of −5% to 2%.
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