LY/T 3129-2019Determination of the total copper, zinc, iron and manganese in forest soils by Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard is proposed and managed by the State Forestry and Grassland Administration.

This standard was drafted. Forestry Research Institute of Chinese Academy of Forestry, Beijing Forestry University, Chinese Academy of Forestry Subtropical Forest Industry Research Institute, Beijing Huaxue North Testing Technology Co., Ltd.

1 Scope

This standard specifies the determination of the total amount of copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) in forest soils by inductively coupled plasma.

Emission Spectroscopy (ICP-OES).

This standard applies to the determination of copper, zinc, iron, and manganese in forest soils.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this article Pieces. For undated references, the latest version (including all amendments) applies to this document.

Preparation of preparations and products used in GB/T 603 chemical reagent test method GB/T 6682 Analytical laboratory water specifications and test methods GB/T 4842 Argon LY/T 1210 Collection and preparation of forest soil samples

3 Matters needing attention

Some of the reagents used in the experiment are toxic or corrosive. The operation of adding acid, digestion, and acid drive should be performed in a fume hood.

Protective equipment should be worn in accordance with regulations to avoid contact with skin and clothing. If accidentally splashed on the skin, immediately use spray facilities or clean water.

Contamination should be prevented during sampling and sample preparation. The vessel used in the sample analysis process should be soaked with 10 90 nitric acid solution for 24 h.

Then rinse with tap water and experimental water in order, and dry in a clean environment for later use.

The main source of errors in the determination of copper, zinc, iron, and manganese is whether the sample is completely digested. During the actual measurement, it can be based on the difference in soil organic matter.

Adjust the amount of nitric acid, hydrochloric acid and hydrofluoric acid appropriately.

During the digestion using a microwave digester, attention should be paid to the requirements of the corresponding instrument and the temperature and pressure limitations of the digestion tank to avoid Bursting can cause personal and instrument damage.

ICP-OES cannot open the rectangular chamber door or rectangular tube chamber after igniting the plasma to prevent high frequency radiation from causing harm to personnel.

Due to the differences in the manufacturer and model of the instrument used in each laboratory, the instrument safety and operating instructions are different. List all relevant the recommendations are beyond the scope of this method. You can refer to the relevant instrument manual, consult the manufacturer, or consult the literature on safe operation.

4 Method summary

Soil samples are mixed with acid, digested by electric hot plate, graphite digestion furnace, microwave digestion instrument or automatic digestion instrument, and then inductively coupled to plasma the daughter emission spectrometer (ICP-OES) was used for detection.

The digested sample enters the atomizer of the plasma emission spectrometer to be atomized, and is carried into the plasma torch by the argon carrier gas.

The element is vaporized, ionized, excited and radiates characteristic lines in the plasma torch. The intensity of the characteristic spectral line and the content of the test element in the sample it is proportional to a certain concentration range.

5 Reagents and materials

6 Instruments and equipment

6.1 Inductively coupled plasma emission spectrometer.

6.2 Electric heating plate. The temperature control accuracy is ± 2.5 °C.

6.3 Graphite digestion furnace. equipped with Teflon digestion tank.

6.4 Microwave Digestion Apparatus. The temperature accuracy is ± 2.5 ° C, equipped with a polytetrafluoroethylene digestion tank.

6.5 Acid drive. acid drive equipment for microwave digestion.

6.6 Automatic digestion instrument. equipped with PTFE digestion tank.

6.7 Balance. Accuracy is 0.0001 g.

6.8 PTFE crucible. 50 mL.

6.9 Soil sieve. non-metal sieve, 0.149 mm (100 mesh).

6.10 Platinum crucible tongs.

6.11 Protective gloves.

6.12 Common laboratory equipment.

7 Analysis steps

8 Add 0.5 mL nitric acid

9 Add 20 mL of water and make up to 50 mL with water

7.4 Preparation of blank sample the blank solution was prepared in the same manner as in 7.3 except that no soil sample was added.

7.5 Instrument reference conditions the best test conditions for different models of instruments are different. Optimize the measurement conditions according to the requirements of the instrument manual. And choose according to the sample matrix Appropriate analytical spectrum. Refer to Appendix B.2, B.3 for the reference measurement conditions and recommended wavelength of the instrument. After the instrument warms up until the indicators are stable, Line measurement.

7.6 Drawing calibration curve the standard series of solutions were sequentially extracted from the low concentration to the high concentration by a peristaltic pump and introduced into the inductively coupled plasma emission spectrometer.

Measure the intensity signal response value of the analytical spectral line of the element to be measured, with the mass concentration of the element to be measured as the abscissa, and the signal response value of the element to be measured Ordinate, draw the standard curve.

7.7 Determination

The blank solution and the sample solution were respectively extracted into the inductively coupled plasma emission spectrometer by an equal amount of the peristaltic pump, and the elements to be measured were measured.

The signal response value of the element was obtained according to the standard curve. In the process of sample measurement, if the concentration of the element to be measured Beyond the range of the calibration curve, the sample needs to be re-measured after dilution.

7.8 Calculation

The content omega (mg/kg) of each metal element in the soil sample is calculated according to formula (1).

tV s

omega 0Mn) Fe, Zn, (Cu, ...(1) ts = ... (2) in the formula.

omega- soil total element mass fraction, mg/kg;

rho- mass concentration of measured element in test sample, mg/L;

rho0- mass concentration of measured element in blank sample, mg/L;

V- constant volume of sample, mL;

ts-divided multiples;

V1-Separate the volume of test solution, mL;

V2-Determine the volume of the test solution after fractionation, mL;

m-weigh the mass of the air-dried sample after screening, g;

k-Moisture conversion factor for air-dried sample mass converted to dry sample mass.

7.9 Representation of results the calculation result retains three significant figures and is expressed in scientific notation.

7.10 Allowable deviation

Table 3 Control of the maximum allowable relative deviation of parallel double samples

Content range

(mg/kg)

Allowable maximum relative deviation (%) > 100 5 10 ~ 100 10 < 10 20

8 Quality assurance and quality control

8.1 Blank experiment the result of the blank test should be less than the detection limit of the method.

8.2 Calibration

A calibration curve must be drawn for each batch of sample analysis, and the correlation coefficient of the calibration curve should be greater than or equal to 0.999.

Every 20 samples must be calibrated and checked with a standard solution at the middle point of the calibration curve.

The relative deviation of concentration at this point of the quasi-curve should be <=10%, otherwise the calibration curve should be redrawn.

8.3 Accuracy Control Every 20 samples should be tested for a certified soil standard sample or certified reference material, and the measured value should be within the guaranteed value range.

Appendix A

(Informative appendix) Standard solution series mass concentration See Table A.1 for the mass concentration of element standard solutions in the ICP-OES method.

Table A.1 Mass concentration of standard solution series

Ordinal element

Standard series mass concentration (mg/L) Series 1 Series 2 Series 3 Series 4 Series 5 Series 6

1 Cu 0 0.05 0.50 1.00 5.00 10.0

2 Zn 0 0.05 0.50 1.00 5.00 10.0

3 Fe 0 0.50 5.00 10.0 50.0 100

4 Mn 0 0.05 0.50 1.00 5.00 10.0 Appendix B (Informative appendix) Reference conditions for instrument operation B.1 Reference conditions for operation of microwave digestion apparatus

Table B.1 Reference heating program of microwave digestion instrument

B.2 Instrument parameters of inductively coupled plasma emission spectrometer

Table B.2 Reference conditions for ICP operation

power

Observation method

Plasma

air flow volume

(L/min)

Auxiliary

air flow volume

(L/min)

rinse

Pump speed

(rpm/min)

analysis

Pump speed

(rpm/min)

Nebulizer pressure

(kPa)

Clean

time

1.15

Copper, zinc and manganese levels Survey, iron vertical observation 12 0.5 100 50.200 28 B.3 Recommended wavelength for elemental determination and interfering elements

Table B.3 Recommended wavelengths for elemental determination and interfering elements

No. Determination Element Recommended Wavelength (nm) Interfering Element

1 Cu 324.752/327.393 Fe, Al, Ti, Mo

2 Zn

202.548

206.200

213.856

Co, Mg

Ni, La, Bi

Ni, Cu, Fe, Ti

3 Fe

238.204

239.924

240.488

259.940

261.762

Cr, W

Mo, Co, Ni

Mo, W

Mg, Cu, Be, Mn

4 Mn

257.610

259.372

293.306

Fe, Mg, Al, Ce

Al, Fe

Step temperature (°C) Heating time (min) Holding time (min) 4.200 5 5 references EPA 3052 Microwave assisted acid digestion of siliceous and organically based matrices.

ISO 14869-2017 Soil quality-dissolution for the determination of total element content-Part 3.

Dissolution with hydrofluoric, hydrochloric and nitric acids using pressurised microwave technique.

GB 5009.268-2016 National Food Safety Standard Determination of Multi-Elements in Foods.

HJ 777-2015 Determination of metal elements in air and waste particles. Inductively coupled plasma emission spectrometry.

HJ 781-2016 Determination of 22 metal elements in solid waste by inductively coupled plasma emission spectrometry.

HJ 803-2016 Determination of 12 metal elements in soil and sediments Aqua regia extraction-inductively coupled plasma mass spectrometry.

HJ 832-2017 Microwave digestion method for total metal elements in soil and sediment.

Lu Rukun. Chemical analysis method of soil agriculture. Beijing. China Agricultural Science and Technology Press..1999.

Yang Hua, Zhang Yonggang. Determination of six heavy metal elements in aqueous sediments by inductively coupled plasma atomic emission spectrometry (ICP-OES).

Chinese Inorganic Analytical Chemistry, 2014, 4 (1). 22-24.

Zheng Hongyan, Guo Xueqin, Zhu Zhixun, et al. Comparison of different pretreatment and analysis methods for determination of heavy metals in soil and sediment. Guangdong Chemical Engineering, 2017, (16). 242-245.