HJ 766-2015Solid Waste. Determination of metals. Inductively coupled plasma mass spectrometry (ICP-MS) (English PDF)

4.1 Mass spectrum interference

Mass spectrometry interference mainly includes isotope interference, polyatomic ion interference, oxide and double charge interference. The same amount Isotope interference can be corrected using the interference correction equation or by chemical separation of the sample before analysis except. Commonly used mass count interference correction equation is shown in Appendix B-1.

Polyatomic ion interference is the most important source of interference for ICP-MS. It can use the interference correction equation, instrument optimization and Collision reaction pool technology to eliminate. Common polyatomic ion disturbances are given in Appendix B-2.

Oxide interference and double charge interference can reduce the degree of interference by adjusting the instrument parameters.

4.2 Non-mass spectral interference

Non-mass spectral interference mainly includes matrix suppression interference, space charge effect interference, physical effect interference and so on. Non-mass spectrometry the degree of interference is related to the nature of the sample matrix and can be eliminated by means of internal standard method, instrument condition optimization or standard addition method.

7.1 Acquisition and storage

The collection and storage of solid wastes are carried out in accordance with the relevant provisions of HJ/T 20 and HJ/T 298.

7.2 Sample preparation

7.2.1 Solid waste leachate

The preparation of the leachate was carried out according to the relevant provisions of HJ/T 299, HJ/T 300 and HJ 557.

7.2.2 Solid waste

The preparation of solid waste samples was carried out in accordance with the relevant provisions of HJ/T 20. For solid waste or dry semi-solid solids Waste sample, accurately weighed 10 g sample (m1, accurate to 0.01 g), natural air-dried or freeze-dried, weighing again (m2, Accurate to 0.01 g), grinding, all over 0.15 mm (100 mesh) nylon sieve (6.4) spare.

7.3 Preparation of samples

7.3.1 Solid waste leachate sample

Remove the solid waste leachate 25.0 ml, placed in the digestion tank, add 4 ml of nitric acid (5.2) and 1 ml of hydrochloric acid (5.1), Place the digestion tank in the microwave digestion device (6.2) for digestion. The recommended sample digestion procedure is given in Appendix B-3. Digest after cooling to the room temperature, carefully open the lid of the digestion tank, and then put the digestion tank on the acid analyzer (6.6), at 150 °C exposure to acid the internal solution was dried and cooled to room temperature. The inside solution was dissolved with deionized water and the solution was transferred to a 50 ml volumetric flask.

Deionized water to 50 ml. The filter (6.5) was filtered before filtration or the supernatant was used for the determination.

7.3.2 Solid waste samples

For solid samples or dry semi-solid samples, we sample 0.1 g to 0.2 g (m3) of sieved samples (7.2.2);

In liquid or non-dry solid samples, directly weighed the sample 0.2 g (m3), accurate to 0.0001 g. Place the sample in digestion (5.1), 4 ml of nitric acid (5.2), 1 ml of hydrofluoric acid (5.3) and 1 ml of hydrogen peroxide (5.4) were added to the mixture the digestion tank is placed in a microwave digestion device (6.2) for digestion. The recommended sample digestion procedure is given in Appendix B-3. After digestion to cool to at room temperature, carefully open the lid of the digestion tank and place the digestion tank in the acid reflux (6.6), at 150 ° C.

The internal solution was dried and cooled to room temperature. The inside solution was dissolved with deionized water and the solution was transferred to a 50 ml volumetric flask.

Deionized water to 50 ml. The filter (6.5) was filtered before filtration or the supernatant was used for the determination.

Note 2. For special matrix samples, if the digestion of the digestion solution is not complete, may be appropriate to increase the amount of acid.

Note 3. If other quality control and quality assurance requirements can be met by verification, other digestion methods such as hot plates can also be used.

7.4 Blank sample

Instead of the sample with deionized water, the same procedure and reagent preparation were used to prepare a blank sample.

8.1 Instrument operation reference conditions

Different models of the best working conditions of different instruments, the standard mode and the reaction pool mode should be in accordance with the instrument operating instructions operating.

8.2 Instrument tuning

After igniting the plasma, the instrument is warmed up for 30 minutes. Use the mass spectrometer to tune the solution (5.11) to the instrument's sensitivity, Oxide and double charge to adjust, in the instrument's sensitivity, oxide, double charge to meet the requirements of the conditions, the mass spectrometer to the relative standard deviation of the intensity of the elemental signal contained in the tuning solution is less than or equal to 5%. In the range of mass values covering the elements to be measured Line quality correction and resolution check if the quality correction result differs from the true value by more than ± 0.1 amu or the tuning element signal Resolution in the 10% peak height corresponding to the peak width of more than 0.6 amu ~ 0.8 amu range, should be in accordance with the instructions of the instrument Try to correct the quality to the correct value.

8.3 Calibration curve is established

Respectively, take a certain volume of multi-element standard use of liquid (5.9) and the standard reserve solution (5.10) in the volumetric flask, Diluted with nitric acid solution (5.5) to prepare metal concentrations of 0 µg/L, 10.0 µg/L, 20.0 µg/L, 50.0 Mg/L, 100 µg/L, 500 µg/L calibration series. The internal standard stock solution (5.10) can be added directly to the calibration series , Can also be added online via the peristaltic pump before the sample is atomized. The concentration of the selected internal standard should be much higher than the internal standard contained in the sample itself Element concentration, the commonly used internal standard concentration range of 50.0 µg/L ~ 1000 µg/L. Determination by ICP-MS to each element the concentration of the abscissa, the response value and the internal standard response value of the ratio of the vertical axis, the establishment of calibration curve. Calibration curve concentration the range can be adjusted according to the measurement needs.

8.4 Specimen determination

Before each sample is measured, rinse the system with nitric acid solution (5.6) until the signal is minimized until the analytical signal is stabilized can begin to be measured. The prepared samples were added to the same standard of internal standard as the calibration curve. Under the same instrumental analysis conditions to be measured. If the concentration of the element to be measured in the sample exceeds the calibration curve, it needs to be re-measured by dilution, Acid solution (5.5).

8.5 Blank sample determination

The blank sample was measured according to the same measurement conditions as the sample.

9.2 Calculation of solid waste determination results

9.2.1 Solid and dry semi-solid solid waste

The content of metal elements to be measured in solid waste (mg/kg) is calculated according to formula (2).

A a) A

Where.

ohm - content of metal elements to be measured in solid waste, mg/kg;

Xrho - the concentration of the metal element to be measured in the test sample is calculated from the calibration curve, µg/L;

0rho - the concentration of metal elements to be measured in the blank sample, µg/L;

V - volume of the sample after digestion, ml;

1m - the amount of sample weighed, g;

2m - the mass of the dried sample, g;

3m - the quality of the sample after sieving, g.

9.2.2 Liquid and non-dry semi-solid solid waste

The content of metal elements in solid waste (mg/kg) is calculated according to formula (3).

Where.

ohm - the content of metal elements to be measured in solid waste, mg/kg;

Xrho - Calculate the concentration of the metal element to be measured in the sample by the calibration curve, µg/L;

0rho - the concentration of the metal element to be measured in the blank sample, µg/L;

V - volume of the sample after digestion, ml;

3m - Weigh the quality of the sample, g.

9.3 Calculation of determination results of solid waste leachate

The concentration rho (µg/L) of the metal element to be measured in the solid waste leaching solution is calculated according to the formula (4).

Where.

rho - content of metal element to be measured in solid waste leachate, µg/L;

Xrho - Calculate the concentration of the metal element to be measured in the sample by the calibration curve, µg/L;

0rho - the concentration of the metal element to be measured in the blank sample, µg/L;

1V - leachate sampling volume, ml;

2V - volume of the sample after digestion, ml.

9.4 The result is shown for solid waste, when the result is less than 10 mg/kg, one after the decimal point is retained; when the result is greater than or equal at 10 mg/kg, three valid digits are retained.

() 10x V

rho rhoomega - × = × () X V rho rhorho - × = () 10x V m Mm rho rhoomega - × = × × for solid waste leachate, when the determination is less than 10 µg/L, one after the decimal point is retained; when the result is greater than or equal to 10 µg/L, retain three significant digits.

10.1 Precision

Six laboratories were the actual solid waste samples were measured, the metal elements of the laboratory relative standard deviation 0.0% ~ 41%, the relative standard deviation between the laboratory is 3.5% ~ 44%, the repeatability r is 0.2 mg/kg ~ 66.1 mg/kg, the reproducibility limit was 0.4 mg/kg to 186 mg/kg.

Six laboratories were the actual solid waste leachate samples were measured, the elements of the laboratory relative standard deviation and the relative standard deviation was 2.3% ~ 30%, the repeatability r was 0.7 µg/L ~ 117 µg/L, Reproducibility R was 2.3 µg/L ~ 121 µg/L.

10.2 Accuracy

Six laboratories, respectively, solid waste, solid waste leaching solution of the actual sample spiked and certified standard substances were measured.

The recoveries of the spiked samples in the solid samples were 75.0% ~ 125%, and the recoveries were (85.0 ± 19) % ~ (111 ± 24)%. The relative error of the reference material in the laboratory was -6.7% ~ 5.7%, and the relative error between the (-2.7 ± 2.5)% ~ (1.6 ± 7.0)%.

The recovery rate of the solid waste leaching solution in the laboratory was 75.5% ~ 124%, and the recoveries were as follows. (84.2 ± 17)% ~ (111 ± 25)%. There is a relative error of -55% ~ 28% in laboratory, and the relative error between laboratories (-46 ± 20)% to (7.8 ± 30)%.

Details of the precision and accuracy of each metal element are given in Appendix C.