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HJ 803-2016: PDF in English

HJ 803-2016
HJ
NATIONAL ENVIRONMENTAL PROTECTION STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Soil and sediment - Determination of aqua regia extracts of
12 metal elements - Inductively coupled plasma mass
spectrometry
ISSUED ON: JUNE 24, 2016
IMPLEMENTED ON: AUGUST 01, 2016
Issued by: Ministry of Environmental Protection
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Method principle ... 5
4 Interference and elimination ... 5
5 Reagents and materials ... 6
6 Instruments and equipment ... 7
7 Sample ... 8
8 Analysis steps ... 9
9 Result calculation and presentation ... 11
10 Precision and accuracy ... 13
11 Quality assurance and quality control ... 13
12 Waste disposal ... 14
13 Precautions ... 14
Annex A (informative) Polyatomic ion interference and interference correction
equations ... 15
Annex B (informative) Method precision and accuracy summary data ... 17
Soil and sediment - Determination of aqua regia extracts of
12 metal elements - Inductively coupled plasma mass
spectrometry
WARNING: Nitric and hydrochloric acids are highly corrosive and oxidizing.
Wear protective equipment as required during operation. Avoid contact with skin
and clothing. Sample pretreatment shall be performed in a fume hood.
1 Scope
This Standard specifies the inductively coupled plasma mass spectrometry method for
the determination of 12 metal elements in aqua regia extracts of soil and sediment.
This Standard applies to the determination of 12 metal elements -- cadmium (Cd),
cobalt (Co), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), zinc
(Zn), vanadium (V), arsenic (As), molybdenum (Mo), and antimony (Sb) -- in soil and
sediment. If verified, this Standard can also be applied to the determination of other
metal elements.
When the sampling volume is 0.10g and the constant volume after digestion is 50ml,
the detection limits and lower determination limits of the 12 metal elements are shown
in Table 1.
Translator NOTE: In the table, A: cadmium B: cobalt C: copper D: chromium E: manganese F:
nickel G: lead H: zinc I: vanadium J: arsenic K: molybdenum L: antimony.
2 Normative references
This Standard refers to the following documents or their clauses. For undated references,
the latest edition of the referenced document applies.
HJ/T 166, Technical specification for soil environmental monitoring
HJ 613, Soil - Determination of dry matter and water content - Gravimetric method
GB 17378.3, The specification for marine monitoring - Part 3: Sample collection,
storage and transportation
GB 17378.5, The specification for marine monitoring - Part 5: Sediment analysis
3 Method principle
Soil and sediment samples are digested by a mixed solution of hydrochloric acid/nitric
acid (aqua regia) on an electric heating plate or microwave digestion apparatus. Use an
inductively coupled plasma mass spectrometer to test. Qualification is based on the
mass spectrum or characteristic ions of the element. Use internal standard method for
quantification.
The specimen is brought into the atomization system by the carrier gas for atomization.
The target element goes into the axial channel of the plasma in the form of aerosol. It
is fully evaporated, dissociated, atomized and ionized at high temperature and inert gas.
It is then converted into charged positive ion. It enters the mass spectrometer through
the ion acquisition system. The mass spectrometer separates and analyzes qualitatively
and quantitatively according to the mass-to-charge ratio of the ion. Within a certain
concentration range, the response value corresponding to the mass-to-charge ratio of an
ion is proportional to its concentration.
4 Interference and elimination
4.1 Mass spectrum interference
Mass spectrum interference mainly includes polyatomic ion interference, isobaric
interference, oxide and doubly charged ion interference.
Polyatomic ion interference is the most important source of interference in ICP-MS. It
can use interference correction equations, instrument optimization, and collision-
reaction cell techniques to resolve. See Table A.1 in Annex A for common polyatomic
ion interferences. Isobaric interferences can be corrected using the interference
correction equation. Or before the analysis, eliminate the sample by chemical separation
and other methods. See Table A.2 in Annex A for the main interference correction
equations. Oxide interference and double charge interference can be reduced by
adjusting the instrument parameters.
4.2 Non-mass spectrum interference
It can use high-purity metals (purity is greater than 99.99%) or metal salts (baseline or
high-purity reagents) to prepare. Commercially available certified reference materials
can also be purchased for preparation. The medium is nitric acid solution (5.4).
5.7.5 Internal standard reference use solution: ρ = 100μg/L.
Use nitric acid solution (5.4) to dilute the internal standard reference stock solution
(5.7.4) and prepare the internal standard reference use solution. Due to the different
diameters of peristaltic pump tubes used in different instruments, when adding internal
standard online, the concentration added is also different. Therefore, when preparing
the internal standard reference use solution, the concentration of the internal standard
element in the specimen shall be 10~50μg/L.
5.7.6 Tuning solution: ρ = 10μg/L.
It is advisable to choose a solution containing Li, Be, Mg, Y, Co, In, Tl, Pb and Bi
elements as the tuning solution of the mass spectrometer. It can use high-purity metals
(purity is greater than 99.99%) or corresponding metal salts (baseline or high-purity
reagents) to prepare. Commercially available certified reference materials can also be
purchased
NOTE 1: Reference solutions of all elements shall be stored in sealed polyethylene or
polypropylene bottles after preparation.
5.8 Slow quantitative filter paper.
5.9 Carrier gas: Argon, purity ≥99.999%.
6 Instruments and equipment
6.1 Inductively coupled plasma mass spectrometer: The mass range that can be scanned
is 5~250u. The peak width at a resolution of 10% peak height shall be between 0.6~0.8u.
6.2 Temperature control electric heating plate: The control accuracy is ±0.2°C. The
maximum temperature can be set up to 250°C.
6.3 Microwave digester: The output power is 1000~1600W. It has programmable
control function. It can carry out full monitoring of temperature, pressure and time
(heating time and holding time). It has safety protection function.
6.4 Analytical balance: The accuracy is 0.0001g.
6.5 Teflon closed digestion vessel: It can resist pressure, acid and corrosion. It has the
function of pressure relief.
6.6 Erlenmeyer flask: 100ml.
6.7 Glass funnel.
6.8 Volumetric flask: 50ml.
6.9 Nylon sieve: 0.15mm (100 mesh).
6.10 General laboratory instruments and equipment.
7 Sample
7.1 Sample collection and storage
Collect and preserve soil samples in accordance with the relevant regulations of HJ/T
166. Collect and preserve sediment samples in accordance with the relevant provisions
of GB 17378.3. Contamination and loss of analyte elements shall be avoided during
sample collection, transportation and storage.
7.2 Determination of moisture
Determination of dry matter of soil samples is carried out in accordance with HJ 613.
The moisture content of sediment samples shall be carried out in accordance with GB
17378.5.
7.3 Sample preparation
Remove sticks, leaves, stones and other foreign objects in the sample. According to the
requirements of HJ/T 166 and GB 17378.5, the collected samples are air-dried, coarsely
ground, and finely ground to pass through a sieve (6.9) with an aperture of 0.15mm
(100 mesh). The sample preparation process shall avoid contamination and loss of
analyte elements.
7.4 Specimen preparation
7.4.1 Hot plate heating and digestion
Pipette 15ml of aqua regia (5.3) into a 100ml Erlenmeyer flask. Add 3 or 4 small glass
beads. Put on the glass funnel (6.7). Heat to a slight boil on a hot plate. Let the aqua
regia vapor infiltrate the inner wall of the Erlenmeyer flask for about 30min. Discard
after cooling. Use experimental water to wash the inner wall of the Erlenmeyer flask.
Let dry and set aside.
Weigh 0.1g of the sample to be tested (accurate to 0.0001g). Place in the 100ml
Erlenmeyer flask prepared above. Add 6ml of aqua regia solution (5.3). Put on the glass
funnel (6.7). Heat on the hot plate. Keep the aqua regia in a slightly boiling state for 2h
(keep the aqua regia vapor refluxing on the flask wall and glass funnel, but the reaction
shall not be so violent that the sample overflows). Place and cool to room temperature
after digestion. Use slow quantitative filter paper (5.8) to filter the extract. Collect it in
10 Precision and accuracy
10.1 Precision
6 laboratories use the electric hot plate digestion method and microwave digestion
method to measure 5 kinds of unified standard soil samples and sediment samples with
different content levels. For the precision and total data of the hot plate digestion
method, see Table B.1 in Annex B. See Table B.2 in Annex B for summary data on the
viscosity of the microwave digestion method.
10.2 Accuracy
6 laboratories use electric heating plate digestion method and microwave digestion
method to measure 2 kinds of unified standard soil samples and sediment samples with
different content levels. See Table B.3 in Annex B for summary data on the accuracy of
the hot plate digestion method. See Table B.4 in Annex B for summary data on the
accuracy of the microwave digestion method.
11 Quality assurance and quality control
11.1 Make at least 2 laboratory blank samples for each batch of samples. The
determination results shall be lower than the lower limit of determination.
11.2 A standard curve shall be established for each analysis. Its correlation coefficient
shall be greater than 0.999. For every 20 samples or every batch (at least 20
samples/batch) of samples, a middle concentration point of the standard curve shall be
analyzed. The relative deviation between the determination result and the actual
concentration shall not exceed 10%. Otherwise, find out the reason or reestablish the
standard curve. After every 20 samples or each batch (less than 20 samples/batch)
samples are analyzed, a zero-point analysis of the standard curve shall be performed.
The relative deviation between the measurement result and the actual concentration
value shall not exceed 30%.
11.3 At least 10% of each batch of double samples shall be tested in parallel. When the
number of samples is less than 10, at least one parallel double sample shall be
determined. In the parallel double-sample determination results, the relative deviation
of cobalt (Co), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb),
zinc (Zn), vanadium (V), arsenic (As) determined by hot plate digestion shall be less
than 30%. The relative deviation of cadmium (Cd), molybdenum (Mo) and antimony
(Sb) shall be less than 40%. The relative deviation of the 12 metal elements determined
by microwave digestion shall be less than 30%.
11.4 For each batch of samples, analyze at least 10% of spiked recovery samples. When
the number of samples is less than 10, at least one spiked recovery sample shall be made.
In the determination results of the spiked recovered samples, the spiked recovery rate
of cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), manganese (Mn), nickel
(Ni), lead (Pb), zinc (Zn), vanadium (CV) and arsenic (As) determined by the electric
hot plate digestion shall be controlled between 70%~125%. The spiked recovery rate
of molybdenum (Mo) and antimony (Sb) shall be controlled between 50%~125%. The
spiked recovery rate of 12 metal elements determined by microwave digestion shall be
controlled between 70%~125%.
11.5 ICP-MS requires high purity of reagents. Reagents with high purity shall be used.
Each batch of reagents must pass the blank test. The reagent blank value shall not
exceed the detection limit of the method. The same batch of samples shall use the same
batch of experimental water. Experimental water shall be used for blank experiments.
The blank value shall not exceed the detection limit of the method.
11.6 The intensity of the response to the internal standard shall be determined for each
analysis. The response value of the internal standard in the specimen shall be between
70%~130% of the response value of the standard curve. Otherwise, it means that the
instrument drifts or there is interference. The cause shall be found and reanalyzed. If
matrix interference is found, the specimen must be diluted for determination. If it is
found that the specimen contains internal standard elements, the internal standard must
be replaced, or the concentration of internal standard elements must be increased.
12 Waste disposal
Waste liquid and waste generated during the experiment shall be stored in airtight
containers. Entrust qualified agencies to handle.
13 Precautions
13.1 The glassware used in the experiment must be soaked in nitric acid solution (5.6)
for 24h. Wash with tap water and experimental water in turn before use.
13.2 To ensure the stability of the instrument and the accuracy of the experiment, refer
to the instrument manual. Clean the atomizer, torch, sampling cone and extraction cone
of the instrument periodically or after measuring a certain number of samples.
13.3 When using microwaves to digest samples, be aware of the temperature and
pressure limitations of the digestion vessel used. Check the tightness of the digestion
vessel before and after digestion. The check method is: When the digestion vessel is
filled with sample and digestion solution, cover the digestion vessel tightly and weigh
it (accurate to 0.01g). After the sample is digested, wait for the digestion vessel to cool
down to room temperature, then weigh again. Record the weight of each vessel. If the
post-digestion weight decreases by more than 10% from the pre-digestion weight,
discard the sample and investigate the cause.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.