GB/T 17140-1997 Determination of lead and cadmium in soil quality - KI-MIBK extraction flame atomic absorption spectrophotometry

GB/T 17140-1997 Determination of lead and cadmium in soil quality KI-MIBK extraction flame atomic absorption spectrophotometry GB/T17140-1997 Standard download decompression password: www.bzxz.net

ICX13.080
National Standard of the People's Republic of China
GB/T17140-1997
Soil quality Detcrmination of lead, cadmium-KI-MIBKExtractinn rlame atomic absorption spectrophotometry199712.08Published
National Technology Protection Bureau
1998-05-01Implementation
National Standard of the People's Republic of China
Soil quality-Dctermination of lead,GB/T17140-1997
cadmiumKI-MIBKExtraction flame atomic absorption spectrophotometry Spectropholometry Subject Content and Scope of Application
1.1 This standard specifies the determination of potassium iodide in soil and potash by flame atomic absorption spectrophotometry.
The detection limit of this standard (calculated by weighing the test solution and diluting to 5: ml) is: cobalt: = 1ug/kg, solution. 05mg/kgge1.2
When the content of zinc in the test solution is high, the iodine will be consumed, and the amount of the catalyst will be increased accordingly. 2 Principle
If the method of hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid is used for complete decomposition, the mineral lattice of the soil is completely destroyed, and all the elements to be measured in the sample enter the test solution. Then, in a salt medium of about %, add an appropriate amount of KI. P and Cd in the test solution form stable ion associations with radium, which can be extracted by methyl isobutyl ketone (MIBK). Spray the organic phase into the flame. Under the high temperature of the flame, lead and radium compounds dissociate into ground state atoms. The ground state atomic vapor selectively absorbs the characteristic spectral lines emitted by the corresponding hollow cathode lamp. Under the selected optimal determination conditions, the absorbance of lead and radium is determined. When the concentration of hydrochloric acid is 1%~2% and the concentration of molybdenum iodide is mal/L, the absorption rate of MIEBK to benzene or radium is 4% and more than 3% respectively. When the concentration of radium in the concentrated test solution is 0.5%, it can also achieve the separation of iron, aluminum, alkali metals and alkaline earth metals from the six coexisting components.
3 Reagents||tt || Unless otherwise specified, the trial preparations used in this standard are all analytical reagents and deionized water or salts of equivalent purity that meet national standards (HCl=
g/ml, premium grade pure).
Hydrochloric acid substitution
: 1: Prepare
salt slurry with 4.1, the long volume fraction is (2%; use 3, arsenic acid (HNO), 0=t,4g/ml, premium grade nitric acid,
1: Prepare with 3.4.
Hydrofluoric acid (HF), 0=1.49g/ml
Perfluoric acid (HCl0), e=1.60g/ml. Premium grade pure. Ascorbic acid (CT0) aqueous solution, mass fraction is%. Potassium iodide (KI).2mol/L: Weigh 33. 2g Kl ruthenium 1ml water methyl isobutyl ketone (MIBK, (CH.) CHCHCOCH), water saturated solution: put an equal volume of water and MIBK3.10
in a separatory bucket, strain, minutes. After standing for stratification (about 3 minutes), discard the cloudy water phase and use the upper MLBK file. c0% mg/ml: weigh
t6203g (the amount is confirmed to be 3.5032g) spectroscopic metal in a 0ml beaker lead standard reserve micron,
, add 20ml nitric acid drop liquid (35), warm to dissolve, transfer the entire amount to a 1300ml volumetric flask, cool, dilute to the mark with water, and shake.
National Environmental Protection Agency
Approved on July 30, 1997||t t||1998-05-01 implementation
CB/T171401997
3.12 Palladium standard stock solution, 1.000mg/ml: weigh 1.0030g (accurate to 5.00g) spectrally pure metal cadmium into a 50ml beaker, add 20ml nitric acid solution (3:5), dissolve in a heat insulation, transfer the entire amount to a 1090ml volumetric flask, and cool. Add water to the mark, shake the spoon
3.13 Feed, cadmium standard working solution, lead: mg/L, plate C25rmg/1: day hydrochloric acid solution (33) remote level release, silver standard half reserve wave (3) (preparation
General laboratory instruments and the following instruments.
Atomic absorption spectrophotometer (with background correction device). Lead hollow cathode lamp.
Hollow cathode lamp
Copper bottle
Air layer shrink bar, water, oil and dust removal devices should be prepared. Instrument parameters
The best test conditions for different types of instruments are different, and can be selected according to the instrument's instructions. Usually the measurement conditions adopted in this standard are shown in Table 1
Measurement wavelength (nm)
Band width (nm)
Lamp current (ma)
Flame properties
5Sample
Only instrument measurement conditions
OxidizingwwW.bzxz.Net
Oxidizing
Mix the collected soil fill sample (generally not less than 50g) and use the quartering method to reduce it to about 100g. After the shrunk, the ten samples are air-dried (natural air drying or cold drying), and the large particles and animal and plant residues are removed. Then they are ground with wood spirit (or macadamia stick), and mixed with 2mm thick solution (remove sand above am). Grind the soil sample that has passed the 2mm nylon sieve until it passes through the c (aperture 19) nylon sieve, and set it aside for later use: 6 Analysis Steps
6.1 Preparation of test solution
6.1.1 Digestion
Accurately weigh 0.2~0.5g (accurate to 0.0632g) of the sample into a 50ml polytetrafluoroethylene pot, moisten it with water, add 0ml of hydrochloric acid (31), and heat it at low temperature on the hot plate in the fume hood to decompose the sample initially. When it evaporates to about 3ml, remove the box from the cooler, and then add 5ml nitric acid (a.4), 5ml hydrofluoric acid (36), and 3ml perchloric acid (37): Cover and heat at medium temperature on the hot plate for about "15 minutes". , then cover and continue heating. In order to achieve a good effect, shake the product frequently. When heated to high oxygen, cover to make the black organic matter fully separated. After the black organic matter on the wall disappears, open the lid, drive the self-adjustment and steam until the contents become sticky. After the digestion, add ml hydrochloric acid (3-), 1 ml hydrofluoric acid (3.6), 1 ml perchloric acid (3.7), and repeat the above digestion process. When the white smoke disappears again and the contents become sticky, remove the cover and the inner wall of the village with cold water, and add 1 ml of hydrochloric acid solution (3.2) to dissolve the residue warm. Then transfer the whole amount to a 100 ml separatory funnel and add water to about 50 ml. ||tt| |CB/T171401997
Due to the large number of soil types and the large differences in organic matter content, care should be taken during digestion, and the amount of various acids can be increased according to the digestion situation. The digestion solution should be yellow or light yellow (soil with high iron content), and there should be no obvious precipitation. Note: The electrolyte should not be too high, otherwise it will cause the formation of polychlorinated substances. 6.1.2 Take a
distilled water funnel, add 27ml of cyclopentane solution (3.), 3Eml of potassium iodide solution (3), and remove the spoon. Then, accurately add 1m methyl iodide to the mixture (.13), simmer for 1~2 minutes, and let the layers stand. Take the organic analyte for analysis: the specific gravity of MBK Smaller than water, the layers can be directly introduced into the mixture, and it is not necessary to separate them at the same level. In the actual separation, a colorimetric tube can be used to replace the separation end.
6.2 Determination
According to the instrument manual, adjust the instrument to the best working conditions and measure the absorbance of the organic phase test solution (MIBK). 6.3 Vacuum test
Use deionized water instead of the test partner, use the same steps and reagents as (6.1), prepare the whole process of vacuum test, and then proceed to step (6.2) for determination. Prepare at least 100 samples per batch. 6.4 Calibration
Reference table Add the main separation solution to the actual concentration of the mixed layer. Then add m!Hydrochloric acid solution (22), thank you for your help, its packaging is usually sold in the test car, with the conditions of low to high temperature spray in the standard micro-determination will be used to subtract the absorbance of the air and the corresponding element content (mg/L) to prepare a calibration curve. Bag
flower standard liquid batch m
MIBK Ph concentration, mg/
MIBK Ca concentration, mg/
results expressed
calibration curve liquid concentration
soil sample aluminum, antimony content W (Pb (ca) mg/kg) sensitive calculated by the following formula: W
In the formula: c
m (tf)
According to the steps ():
The absorbance of the test solution minus the absorbance of the blank test, then the total amount of lead and cadmium is found on the calibration curve, mg/l; the volume of the test solution (organic phase), ml:
The weight of the test solution or the flow rate, ":
One test is selected to calculate the content, 5.
Precision and Accuracy
Multiple laboratories used this method to analyze the precision and accuracy of aluminum and radium in ESS series products. Table
Guaranteed value
144±6-2
Precision and accuracy of the method
Total mean
Relative standard sieve error in room
Relative standard deviation in space
Random error
Appendix A (Standard Appendix) (Record)
Determination of moisture content of soil samples
Weigh 5 to 19 air-dried soil samples (accurate to 0.10°g) that have passed through a 103-mesh sieve, place them in an aluminum box or a measuring bottle, and dry them in a drying oven at 135°C for 4 to 5 hours. Dry to constant weight, and calculate the main peak moisture content of the air-dried soil sample expressed as a percentage according to the following formula: A2
W—weight of soil sample before drying, g:
W—weight of soil sample after drying.
Additional instructions:
This standard is issued by the Science and Technology Standards Department of the State Environmental Protection Administration. This standard was drafted by the China Environmental Monitoring Center. The main drafters of this standard are Qi Wenqi and Liu Jing. This standard is interpreted by the China Environmental Monitoring Center.
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