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HJ 687-2014Solid waste. Determination of Hexavalent Chromium. Alkaline digestion/flame atomic absorption spectrophotometic (English PDF)

固体废物六价铬的测定碱消解火焰原子吸收分光光度法

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Issued by

Ministry of Ecology and Environment

Level / Type

National · Mandatory

Issue date

January 1, 1970

Implementation date

January 1, 1970

Scope

HJ 687-2014 is the English-translated version of 固体废物六价铬的测定碱消解火焰原子吸收分光光度法.

HJ 687-2014 — This standard specifies the determination of solid waste hexavalent chromium in alkali digestion/flame atomic absorption spectrophotometry. This standard applies to the determination of hexavalent chromium in solid waste.

When the amount of solid waste sampling 2.5g, constant volume of 100ml, the method detection limit of 2mg/kg, detection limit of 8mg/kg, Determination of the range of 8mg/kg ~ 320mg/kg.

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Document preview — HJ 687-2014

National Standard of the People's Republic of China

ICS: 13.030.10
Classification: Z 13

Issued by: Ministry of Ecology and Environment

Preface .ii
1. Scope
2 Normative references
3 Principle of the method
4 And eliminate interference .1
5 Reagents and materials .1
6 .2 instruments and equipment
7 Sample .2
8 Analysis step
9 Results Calculation and representation
10 Precision and accuracy
11 Quality Assurance and Quality Control
12 Waste disposal

Foreword

To implement the "People's Republic of China Environmental Protection Law" and "People's Republic of China Solid Waste Pollution Prevention Law," to protect the ecological Environment, safeguarding human health, standardized measurement method of solid waste hexavalent chromium, the development of this standard.

This standard specifies the determination of solid waste hexavalent chromium in alkali digestion/flame atomic absorption spectrophotometry.

This standard applies to the determination of hexavalent chromium in solid waste.

This standard is the first release.

Drafting of this standard. Shanghai Environmental Monitoring Center.

The standard verification. Jiangsu Provincial Environment Monitoring Center, Nanjing Environmental Monitoring Center, Shanghai Textile energy saving center, on Mirage Environmental Sciences, Environmental Monitoring Station of Putuo District, Shanghai Pudong New Area Environmental Monitoring Station.

This standard MEP January 13, 2014 for approval.

This standard since April 1, 2014 implementation.

The standard explanation by the Ministry of Environmental Protection.

Solid waste - Determination of hexavalent chromium Alkaline Digestion/Flame atomic absorption spectrophotometry

1 Scope

This standard specifies the determination of solid waste hexavalent chromium in alkali digestion/flame atomic absorption spectrophotometry.

This standard applies to the determination of hexavalent chromium in solid waste.

When the amount of solid waste sampling 2.5g, constant volume of 100ml, the method detection limit of 2mg/kg, detection limit of 8mg/kg, Determination of the range of 8mg/kg ~ 320mg/kg.

2 Normative references

This standard refers to the contents of the following documents or the terms. For undated references, the effective version applies to this standard quasi.

HJ/T 20 industrial solid waste sampling sample preparation Technical Specifications HJ/T 298 Identification of Hazardous Waste Technical Specifications GB/T 6682 national laboratory use - Specification and test methods

3 PRINCIPLE OF THE METHOD

Samples in alkaline medium by adding magnesium chloride and potassium hydrogen phosphate - potassium dihydrogen phosphate buffer solution, digestion dissolution of hexavalent chromium, flame original Sub absorption spectrophotometry content of hexavalent chromium.

4 and elimination of interference Sample in an alkaline medium, the magnesium chloride and potassium hydrogen phosphate - potassium dihydrogen phosphate buffer solution inhibiting presence of trivalent chromium to hexavalent chromium Determination without interference.

5 Reagents and materials

Unless otherwise indicated, the use of line with national standards of analytical reagent analysis, laboratory water, deionized water, in line with GB/T 6682, three.

5.1 concentrated nitric acid. rho (HNO3) = 1.42g/ml, pure class distinctions.

5.2 Sodium carbonate (Na2CO3).

5.3 Sodium hydroxide (NaOH).

5.4 Magnesium chloride (MgCl2).

Hydrogen 5.5 dipotassium phosphate (K2HPO4) - potassium dihydrogen phosphate (of KH2PO4) buffer solution. (pH = 7).

Weigh 87.1g and 68.0g potassium hydrogen phosphate potassium dihydrogen phosphate dissolved in deionized water and dilute the volume to 1L.

5.6 Sodium carbonate (Na2CO3)/sodium hydroxide (NaOH) mixed solution of Weigh 20.0g of sodium hydroxide and 30.0g of sodium carbonate dissolved in deionized water, diluted to 1L. Stored in a sealed polyethylene bottle. use Before measuring the pH value, if less than 11.5 to be re-formulated.

5.7 potassium dichromate (K2Cr2O7). reference reagent or pure class distinctions.

Weigh 5.0g potassium dichromate in a magnetic crucible and bake in oven at 105 °C for 2h, cooled to room temperature and stored in a dryer set aside.

5.8 Potassium dichromate stock solution. rho (Cr6) = 1000mg/L.

Accurately weigh 2.829g potassium dichromate (5.7) dissolved in deionized water and dilute the volume to 1000ml. It can also be purchased directly commercially certified Reference materials or certified reference solution. Storage at room temperature for 6 months.

5.9 Potassium dichromate standard solution. rho (Cr6) = 100mg/L.

Take 10.00ml potassium dichromate stock solution (5.8) transferred to a 100ml volumetric flask, diluted with deionized water to the mark, shake. Room temperature Stored for 6 months.

6 Instruments and equipment

Unless otherwise indicated, all using the national standard of Class A Glass Container analysis.

6.1 Flame atomic absorption spectrophotometer.

6.2 chromium hollow cathode lamp.

6.3 and heated with stirring apparatus. a heating magnetic stirrer, temperature control device (NIST with scale), and heated to 100 °C.

6.4 vacuum filtration apparatus.

6.5 pH meter. accuracy 0.01pH units.

6.6 Balance. accuracy 0.0001g.

6.7 membrane (0.45µm). fiber material or polycarbonate membrane.

6.8 round-bottomed flask. 250ml, silicate glass or quartz material.

6.9 polyethylene film.

6.10 General common laboratory instruments.

7 Sample

Samples collected 7.1 Sampling and preservation of samples of solid waste in accordance with HJ/T 20, the relevant provisions of HJ/T 298's. Sample collection and preservation should use plastic or glass device and the container can not use metal reservoir.

7.2 Preparation and storage of samples

After the sample collection of solid waste, according to HJ/T 20, HJ/T 298 of the relevant provisions of preparation and preservation.

Preparation 7.3 sample of Accurately weighed sample of solid waste (7.2) 2.50g (m) (accurate to 0.0001g) set 250ml round-bottomed flask (6.8), and 50.0ml of sodium carbonate/sodium hydroxide solution (5.6), plus magnesium chloride 400mg (5.4) and dipotassium hydrogen 50.0ml - dihydrogen phosphate buffer Red solution (5.5). Stir into the polyethylene film (6.9) and sealed in a stirring heating apparatus (6.3) on. It was stirred at room temperature sample After 5 minutes, turn the heating means is heated with stirring to 90-95 deg.] C, 60 minutes digestion. Digestion is complete, remove the round bottom flask was cooled to room temperature. With 0.45µm filter membrane (6.7) filtration, the filtrate was placed in 250ml beaker, pH of the solution is adjusted with concentrated nitric acid (5.1) to 9.0 ± 0.2. The solution was transferred to a 100ml volumetric flask, diluted with deionized water to volume (V), shake test.

Note 1. When adjusting the pH of the sample, if there is flocculent precipitate, need and then 0.45µm membrane filter.

Note 2. If the solid waste samples higher hexavalent chromium, may be appropriate to reduce the sample is measured after digestion or dilution measurement.

Note 3. After digestion of the sample, if it can not be analyzed immediately, at 0 ~ 4 °C sealed, shelf life of 30 days.

Analysis Step 8

8.1 Instrument Reference conditions

Different optimum conditions different models of atomic absorption spectrophotometer, you can choose according to the instrument manual. Recommended Instrument

Table 1 Condition measurements.

Table 1 Instrument Reference conditions

Elements Cr

Measurement Wavelength (nm) 357.9 Passband width (nm) 0.7 Flame reductive nature Subsensitive line (nm) 359.0; 360.5; 425.4 Burner height 8mm (the hollow cathode lights bright blue spot part by a flame)

8.2 Draw a calibration curve

Pipette accurately hexavalent chromium standard solution (5.9) 0.00,0.20,0.80,2.00,4.00, 8.00ml to 100ml volumetric flask, Deionized water volume to the mark, shake, concentration of hexavalent chromium were 0.00,0.20,0.80,2.00,4.00,8.00µg/ml. press from low to high concentrations of the order of successively measured absorbance of standard solution. Zero concentration calibration absorbance as ordinate, the corresponding chromium concentration Degree (µg/ml) as abscissa, the calibration curve.

8.3 Determination of the sample

The prepared sample (7.3) with the same instrument calibration curve analysis conditions were determined.

8.4 Blank test

Step 7.3 Preparation of blank samples, blank measurement by 8.2 steps.

9 Results Calculation and representation

9.1 Solid waste concentration of hexavalent chromium

Solid waste samples of hexavalent chromium content of omega (mg/kg) is calculated as follows.

fV ×× = rhoomega

Where. rho-- sample absorbance Richard hexavalent chromium concentrations (µg/ml) on the calibration curve;

m-- solid waste weighed sample weight, g;

f-- dilution;

V-- tolerance test was convinced volume, ml;

9.2 The results are shown Hexavalent chromium test results is less than 1mg/kg after two decimal places, greater than or equal to 1mg/kg when reserved three significant figures.

10 Precision and accuracy

10.1 Precision

Six laboratories respectively containing hexavalent chromium concentration of about 2.50mg/kg, 1.00 × 103mg/kg, 1.60 × 104mg/kg three solid waste, etc.

Was unified samples were measured. the laboratory relative standard deviations were. 3.4% to 14%; 1.6% ~ 4.7%; 0.9% ~ 5.7%;

Interlaboratory relative standard deviations were. 9.5%, 8.3%, 7.6%;

Repeatability limit. 0.852mg/kg; 79.8 mg/kg; 1.52 × 103 mg/kg;

Reproducibility limit. 1.06 mg/kg; 225 mg/kg; 3.54 × 103 mg/kg;

10.2 Accuracy

Six laboratories containing hexavalent chromium at a concentration of 175mg/kg (Uncertainty. 44.4-217mg/kg) standards were relatively solid material Error analysis, and the concentrations of 2.50mg/kg, 1.00 × 103mg/kg, 1.60 × 104mg/kg of solid waste unified the three samples Determination of recoveries.

Relative error. 0.7% ~ 47%; P = 22% ± 31% .. Recoveries were 94.2%, 104%, 88.5%;

Recoveries final value. 94.2 ± 19.0%; 104 ± 31.8%; 88.5 ± 17.6%;

11 Quality Assurance and Quality Control

An analytical sample shall be 11.1 per calibration curve, the correlation coefficient should be greater than or equal 0.999.

11.2 Sample blank

Each digestion batch of samples (up to 20) to do at least two blank samples, measured the Cr (VI) concentration must be lower than the method test limit.

11.3 Samples parallel

Analysis per batch (up to 20) samples do 10 to 20 percent of the parallel determination of at least relative deviation <=20%.

11.4 Spiked recovery

Analysis per batch (up to 20) samples should be 10 to 20% of the spiked recovery was measured. Recoveries should be between 70-130%.

11.5 Certified reference materials

Determination of each batch of samples to do at least one certified reference materials/certified reference samples.

12 Waste disposal

Hexavalent chromium solution or waste collection evacuation experiments produced a qualified hazardous waste disposal center for disposal.

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 7 pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 6682Water for analytical laboratory use - Specification and test methods

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