This method specifies the determination methods of trace elements such as barium, beryllium, cerium, cobalt, copper, lanthanum, lithium, manganese, nickel, scandium, strontium, vanadium, zinc and major elements such as calcium oxide, iron oxide, magnesium oxide and sodium oxide in geochemical samples.

This method is suitable for the determination of the above elements in river sediments and soil samples.

The detection limit (3S) and determination range of this method are shown in Table 1 and Table 2.

Table 1 detection limit and determination range of main elements

The detection limit and determination range of trace elements in Table 2

2 normative reference documents

In this part of this method, the clauses in the following documents become clauses of this part by reference.

The latest version of the following undated reference documents is applicable to this method.

Compilation rules of GB/T2000 1.4 Standard Part 4: Chemical analysis methods.

GB/T 14505 general rules for chemical analysis methods of rocks and ores.

Accuracy of GB6379 test method The repeatability and reproducibility of the standard test method are determined through inter-laboratory tests.

Gb/t 14496-93 geochemical exploration terms.

3 method summary

The samples were cold-dissolved overnight with hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid, and then decomposed by heating the next day until the white smoke of perchloric acid was discharged. After the hydrochloric acid is dissolved, it is transferred to a 10mL plastic pipe with a plug, and the volume is constant. The solution is introduced into a plasma torch, and the emission spectral intensity of each element ion and atom is measured at the selected wavelength. The instrument has its own computer to calculate the content of each element, correct the influence of matrix, and directly print out the analysis report of each element content.

4 reagent

Unless otherwise specified, only analytically pure reagents and distilled water (deionized water) or sub-boiling distilled water are used in the analysis. In the blank test, if the reagent used has been detected to contain more than the detection limit of each method listed in this method, and it is confirmed that it has affected the low-level determination of the element in the sample, the reagent should be purified.

4. 1 perchloric acid (ρ1.67g/ml)

Excellent purity.

4.2 Nitric acid (ρ1.40g/ml)

4.3 hydrochloric acid (ρ 1. 19g/mL)

4.4 hydrofluoric acid (ρ 1. 13g/mL)

Excellent purity.

4.5 hydrochloric acid (1+ 1)

4.6 hydrochloric acid (1+9)

4.7 Nitric acid (1+ 1)

4.8 sulfuric acid (ρ1.84g/ml)

Excellent purity.

4.9 sulfuric acid (1+ 1)

4. 10 barium standard solution [ρ (Ba) = 1.000 mg/ml]

Weigh1.5160g of spectrally pure anhydrous barium chloride dried at 105℃ for 2 hours, put it in a100ml beaker, add 50ml of water and10ml of hydrochloric acid (4.3) to dissolve it, and transfer it to/kloc-.

4. 1 1 cobalt standard solution [ρ (Co) = 100 μ g/ml]

Weigh 0. 1000g of metallic cobalt with the purity of [w (co) = 99.9%], put it in a 250mL beaker, add 20mL nitric acid (4.7), slightly dissolve it, move it into a 1000mL volumetric flask, dilute it to scale with water, and shake well for later use.

4. 12 copper standard solution [ρ (Cu) = 100 μ g/ml]

Weigh 0. 1000g of metallic copper with the purity of [w (Cu) = 99.95%], put it in a 100mL beaker, add 20mL of nitric acid (4.7) for slight heat dissolution, move it into a 1000mL volumetric flask, dilute it to scale with water, and shake well for use.

4. 13 lanthanum standard solution [ρ (La) = 100 μ g/ml]

0. 1 173g of spectrally pure lanthanum oxide calcined at 800℃ is weighed, placed in a 100mL beaker, wetted with water, slightly dissolved in 10mL hydrochloric acid (4.5), transferred into a 1000mL volumetric flask and diluted with water.

4. 14 manganese standard solution [ρ (Mn) = 1.000 mg/ml]

Weigh 1.000g of manganese metal with the purity of [w (Mn) = 99.95%], put it in a beaker of 100mL, add 20mL of nitric acid (4.7) to slightly dissolve it, move it into a volumetric flask of 1000mL, dilute it to scale with water, and shake well for later use.

4. 15 nickel standard solution [ρ (Ni) = 100 μ g/ml]

Weigh 0. 1000g of metallic nickel with the purity of [w (Ni) = 99.95%], put it in a 100mL beaker, add 20mL of nitric acid (4.7) for slight heat dissolution, move it into a 1000mL volumetric flask, dilute it to scale with water, and shake well for use.

4. 16 strontium standard solution [ρ (Sr) = 1.000 mg/ml]

Weigh 2.4 153g spectrally pure strontium nitrate that has been dried in the dryer for a day and night, put it in a 250mL beaker, add water to dissolve it, move it into a 1000mL volumetric flask, dilute it to scale with water, and shake it well for later use.

4. 17 vanadium standard solution [ρ (V) = 200 μ g/ml]

Weigh 0.4593g of spectrally pure ammonium metavanadate (NH4VO3) dried in a dryer for more than two days, put it in a 100mL beaker, add 20mL of nitric acid (4.7) for slight heat dissolution, transfer it to a 1000mL volumetric flask, dilute it to scale with water, and shake well for use.

4. 18 zinc standard solution [ρ (Zn) = 250 μ g/ml]

Weigh 0.2500g of metallic zinc with the purity of [w(Zn)=99.95%], put it in a beaker of 100mL, add 20mL of hydrochloric acid (4.5) for slight heat dissolution, move it into a volumetric flask of 1000mL, dilute it to scale with water, and shake well for use.

4. 19 beryllium standard solution [ρ (be) = 50μ g/ml]

Weigh 0. 1388g spectrally pure beryllium oxide calcined at 1000℃, put it in a 100mL beaker, add 100 ml sulfuric acid (4.9) for slight thermal dissolution, transfer it to a 1000mL volumetric flask, and use water.

4.20 cerium standard solution [ρ (Ce) = 100 μ g/ml]

Weigh 0. 1228g cerium oxide with the purity of [w (CEO 2) = 99.95%] into a 100mL beaker, add 20mL nitric acid (4.7) and a few drops of hydrogen peroxide, cover the surface, heat and dissolve, cool, and transfer to1000.

4.2 1 scandium standard solution [ρ (SC) = 1.00 mg/ml]

Weigh 0. 1534g scandium trioxide with the purity of [w (Sc2O3) = 99.95%] into a 100mL beaker, add 20mL hydrochloric acid (4.3), cover the dial, and heat it on a temperature-controlled electric heating plate until it dissolves. Wash the watch dish with a little water, steam it until the salt is wet, add 10mL hydrochloric acid (4.3), transfer it to a 100mL volumetric flask, dilute it with water to scale, and shake it well for use.

4.22 aluminum standard solution [ρ (Al2O3) = 10.0 mg/ml]

Weigh 5.2925g of metallic aluminum with the purity of [w (Al) = 99.95%] into a 250ml beaker, add100ml hydrochloric acid (4.3) and a small amount of nitric acid for dissolution, then add100ml hydrochloric acid (4.3) after dissolution, and transfer to 1000.

4.23 Iron standard solution [ρ (Fe2O3) = 5.00 mg/ml]

Weigh 5.000g of spectrally pure iron oxide, put it in a 250ml beaker, add100ml hydrochloric acid (4.3) to dissolve it, transfer it into a1000ml volumetric flask, dilute it to scale with water, and shake it evenly for later use.

4.24 Calcium oxide standard solution [ρ (Cao) = 5.00 mg/ml]

Weigh 8.9239g of spectrally pure calcium carbonate dried at 120℃ for 2h into a 250ml conical flask, add 50ml of water, cover it with watch glasses, add 50ml of hydrochloric acid (4.3) several times along the wall of the flask to dissolve all calcium carbonate, boil to remove carbon dioxide, cool, transfer to a1000ml volumetric flask, and dilute it to scale with water.

4.25 magnesium oxide standard solution [ρ (MgO) = 5.00 mg/ml]

Weigh 5.000g of magnesium oxide burnt at 800℃ for 65438±0h, put it in a 250ml beaker, add 65438 000 ml hydrochloric acid (4.5) for slight heat dissolution, transfer it to a 65438 0000 ml volumetric flask, dilute it to scale with water, and shake it well for later use.

4.26 Titanium standard solution [ρ (Ti) = 1.00 mg/ml]

Weigh 1.6680g of spectrally pure titanium dioxide calcined at 1000℃, put it into a 30mL porcelain crucible, add 15g of potassium pyrosulfate, cover the porcelain crucible, put it into a high-temperature furnace, heat it to 700℃ and melt it for about 30min until it is completely melted, take it out and cool it with/kloc-. Clean the crucible, heat it until the solution is clear, and then cool it. Transfer to a 1000mL volumetric flask, add 100mL hydrochloric acid (4.5), dilute to scale with water, and shake well for later use.

4.27 Lithium standard solution [ρ (Li) = 100 μ g/ml]

Weigh 0.5323g of spectrally pure lithium carbonate dried at 105℃ for 2 hours, put it into a 150mL triangular beaker, cover the dial, and add 10mL hydrochloric acid (4.5) along the cup wall to dissolve it. Heat to a slight boiling point, remove carbon dioxide, cool, transfer to a 1000mL volumetric flask, dilute to scale with water, and shake well for later use.

4.28 Sodium oxide standard solution [ρ (Na2O) = 1.00 mg/ml]

Weigh 1.8859 g of spectrally pure sodium chloride calcined at 500℃ for 30 minutes, dissolve it in 100 ml beaker, transfer it into 1000 ml volumetric flask, dilute it to scale with water, and shake well for use.

4.29 Mixed standard working solution

See table 3.

Table 3 Element combination and concentration of mixed standard working solution

4.29. 1 ρ (cobalt) = 1.0 μ g/ml, ρ (copper) =2.0 μ g/ml, ρ (nickel) =2.0 μ g/ml, ρ (vanadium) =4.0 μ g/ml and ρ (zinc) =5.0. Divided into 50.00mL barium standard solution (4. 10), 10.00mL cobalt standard solution (4. 1 1), 20.00mL copper standard solution (4. 12) and 20.00mL lanthanum.

4.29.2 ρ(Be)=0.25μg/mL, divide 5.00mL of beryllium standard solution (4. 19) into 1000mL volumetric flask, dilute it to scale with hydrochloric acid (4.6), and shake well.

4.29.3 ρ(Ti)=60 μ g/ml, ρ(MgO)=250 μ g/ml, ρ(CaO)=500 μ g/ml, ρ(Fe2O3)= 1000 μ g/ml, and ρ (Al2O3) =1. Minute 15.00mL alumina standard solution (4.22), 20.00mL iron oxide standard solution (4.23), 10.00mL calcium oxide standard solution (4.24), 5.00mL magnesium oxide standard solution (4.25) and 6.00mL titanium standard solution (4.26).

4.29.4 ρ(Li)=5.0 μ g/ml, ρ(Na2O)=250 μ g/ml. Take 5.00mL lithium standard solution (4.27) and 25.00mL sodium oxide standard solution (4.28), put them in a 100mL volumetric flask and dilute them with hydrochloric acid (4.6).

4.29.5 ρ(Ce)=2.0μg/mL, ρ(Sc)=20μg/mL. Divide 20.00mL of cerium standard solution (4.20) and 20.00mL of scandium standard solution (4.2 1) into 1000mL volumetric flask.

5 Instruments and materials

5. 1 inductively coupled plasma atomic emission spectrometer

See appendix a for working conditions. Other models of inductively coupled plasma atomic emission spectrometer can be used, which conforms to the index of clause A.3 in Appendix A. ..

5.2 Photomultiplier tube

Wavelength range: 190 nm to 7800 nm.

5.3 Plasma torch (three-axis concentric time torch)

5.4 Glass Coaxial Atomizer

5.5 Double glass atomizing chamber

5.6 PTFE crucible

Specification: 30mL.

5.7 graduated plastic test tube with stopper

Specification: 10mL.

Six analysis steps

6. 1 sample

The sample size should be less than 0.097mm, dried at room temperature, and put into a small ground glass bottle for later use.

Number of samples. Weigh 0. 1g sample to the nearest 0.0002g

6.2 Blank test

Double blank test was carried out in the whole process of sample analysis.

6.3 Quality control

Select 2 ~ 4 samples of the same type of river sediments or soil first-class reference materials and analyze them at the same time.

6.4 decision

6.4. 1 Weigh 0. 1000g sample (6. 1) and put it in a 30mL PTFE crucible (5.6) and add a few drops of water for wetting. Add 2mL perchloric acid (4. 1), 2mL nitric acid (4.2), 3mL hydrochloric acid (4.3) and 3mL hydrofluoric acid (4.4). Put it on a temperature-controlled electric heating plate, cover the crucible and leave it overnight. The next day, the temperature was raised to 1 10℃ and kept at 1.5 ~ 2h. Remove the cover, raise the temperature to 240℃ until the white smoke of perchloric acid is discharged, add 2mL hydrochloric acid (4.5), leach while it is hot, and cool. Move it into a graduated 10mL plastic tube with a plug (5.7), dilute it to scale with water, and shake it well for later use.

6.4.2 Preheat the instrument for 30 minutes. On ICP-AES, according to the working conditions of the instrument in Appendix A (A. 1), the intensity value of the sample solution and the concentration of each element in the working curve are simultaneously measured at the wavelength set by each element. The computer attached to the instrument gives the direct reading results of the concentration according to the correction matrix in Appendix B, and prints out the analysis report.

6.5 Drawing of Working Curve

Standardization of high and low working solutions is adopted. The low point is hydrochloric acid solution (4.6) containing no elements to be detected; Gaodian is a manually prepared mixed standard working solution (4.29. 1 to 4.29.5). See Table 3 for the element combinations and concentrations of the five high-point working solutions. According to the procedure of 6.4.2, it is determined and stored in the computer, and calculated by the system software to calculate the concentration value of each element in the sample.

7 Calculation of analysis results

The matrix of measured elements is corrected by computer (see Appendix B), and the content of each element is calculated according to the following formula:

Analysis method of regional geochemical exploration samples

Where: mi—— the amount of measured element I in the sample solution after matrix correction (see Appendix B) is found from the working curve, μ g; M0—— The amount of the element to be measured in the blank test solution is found from the working curve, and it is μ g; M-sample mass, g

8 accuracy

See Table 4 to Table 20 for the precision of macro, micro and trace elements.

Table 4 Accuracy [W (BA), 10-6]

Table 5 Accuracy [w (be), 10-6]

Table 6 Accuracy [W (CE), 10-6]

Table 7 Accuracy [W (CO), 10-6]

Table 8 Accuracy [W (Cu), 10-6]

Table 9 Accuracy [W (La), 10-6]

Table 10 accuracy [W (Li), 10-6]

Table 1 1 accuracy [W (Mn), 10-6]

Table 12 accuracy [W (Ni), 10-6]

Table 13 accuracy [W (SC), 10-6]

Table 14 accuracy [W (Sr), 10-6]

Table 15 accuracy [W (V), 10-6]

Table 16 accuracy [W (Zn), 10-6]

Table 17 Accuracy [W (Cao), 10-2]

Table 18 accuracy [w (TF2O3), 10-2]

Table 19 accuracy [W (MgO), 10-2]

Table 20 Accuracy [W (Na2O), 10-2]

Annex a

(Information Appendix)

A. 1 instrument working conditions

Table A. 1 instrument working conditions

A.2 wavelength of analytical elements

Table A.2 Wavelengths of Analytical Elements

A.3 instrument parameters

A.3. 1 instrument resolution ≤0.04 nm

A.3.2 Accuracy: After the instrument is preheated for 40 minutes, measure 10 times with a standard solution with a concentration of 1μg/mL, and its relative standard deviation shall be ≤ 1.5%.

A.3.3 Stability: After the instrument is preheated for 40min, it shall be measured every 65438±00min with a standard solution with a concentration of 65438 0 μ g/ml within 2 hours, with a total of 65438 02 times, and the relative standard deviation shall be ≤3%.

A.3.4 Linearity of working curve: linear correlation coefficient of working curve ≥0.999.

Additional record b

(Information Appendix)

B. 1 matrix element interference correction

In order to deduct the interference of matrix elements on each analytical element, matrix correction method is adopted. That is, the multiplicative interference coefficient KMj and additive interference coefficient KAj of matrix elements to each analysis element are obtained, and KMj and KAj are filled into the analysis program, and the computer automatically corrects the analysis results according to the system software as follows:

Analysis method of regional geochemical exploration samples

Where: ci-the analysis result of the modified analysis element I; CCI-analysis result of uncorrected analysis element I; KMJ-Multiplicative interference coefficient of interference element J; CJ- concentration of interfering element J; Kaj- additional interference coefficient of interference element j.

In the formula, Ci, Cci and Cj are the main elements, and when measured by oxide stoichiometry, the unit of measurement is%; When trace elements are measured in elemental state, the measurement unit is μ g/g/g. Because of the use of interference coefficients KMj and KAj, the matrix effect and spectral line interference are basically eliminated.

B.2 JY38/48 inductively coupled plasma atomic emission spectrometer of JY company in France is adopted.

See table B. 1 for the interference coefficient.

Table B. 1 interference coefficient

sequential

Annex c

(Information Appendix)

C1statistical data and other data obtained from the results of inter-laboratory tests.

See table C. 1 to table C. 17.

The precision cooperation data of this method is obtained by statistical analysis of the results provided by the cooperative research of methods in several laboratories.

Tables C. 1 to C. 17 do not need to list all the data of each concentration, but at least three or more parameters are listed according to the concentration statistics.

C. 1. 1 lists the number of laboratories with acceptable test results (that is, the laboratory data out of bounds after the mean and variance tests).

C. 1.2 lists the relative error parameters of the method, and the calculation formula is. In the formula, it is the average value measured in several laboratories, and x0 is the standard value of a class of reference materials.

C1.3 lists the precision parameters of the method, and the calculation formula is, where Sr is the repeated standard deviation; SR is the standard deviation of reproducibility. In order to be consistent with the naming of the parameters listed in GB/T2000 1.4, the precision tables of this method are named as "repeated coefficient of variation" and "repeated coefficient of variation".

C. 1.4 lists the relative accuracy parameters of this method. Relative accuracy refers to the percentage of the measured value (average value) to the true value.

Table C. 1 Ba statistical results table

Table C.2 Be statistical results table

Table C.3 Ce statistical results table

Table C.4 Table of Statistical Results of Carbon Monoxide

Table C.5 Table of Statistical Results of Cu

Table C.6 Statistics Results of Los Angeles

Table C.7 Table of Li Statistics Results

Table C.8 Mn Statistics Results Table

Table C.9 Table of Statistical Results of Ni

Table C. 10 Sc statistical results table

Table C. 1 1 Sr Statistical Results Table

Table C. 12 V statistical results table

Table C. 13 Zn statistical results table

Table C. 14 CaO statistical results table

Table C.15tef2o3 statistical results table

Table C.16mo statistical results table

Table C.17 statistical results of Na2O

additional information

This method was put forward by China Geological Survey.

This method is under the technical centralized control of Wuhan Rock and Mineral Comprehensive Testing Center.

This method was drafted by Wuhan Rock and Mineral Comprehensive Testing Center.

The main drafter of this method: Xiong.

The precision collaborative test of this method was organized and implemented by Jiang Baolin and Ye Jiayu of Wuhan Rock and Mineral Comprehensive Testing Center.