HJ 700-2014Water quality. Determination of 65 elements. Inductively coupled plasma-mass spectrometry (English PDF)

3.1 Soluble elements

Refers to the element content measured after filtration through a 0.45 µm filter on a sample that has not been acidified.

3.2 Total amount of elements

Refers to the unmeasured sample, the element content measured after digestion.

5.1 Mass Spectral Interference

Mass spectrometry interference mainly includes polyatomic ion interference, isobaric interference, oxide and double charge interference. Multiple original Sub-ion interference is the most important source of interference for ICP-MS, and can be used for interference correction equations, instrument optimization, and collision reactions.

Pool technology to solve, common polyatomic ion interference see Appendix Table B.1. Isobaric interference can use interference correction the equation is corrected, or the sample is chemically separated before analysis, and the main interference correction equation is attached.

Record B.2. Oxide interference and double charge interference can reduce the effects by adjusting instrument parameters.

5.2 Non-mass speculative interference

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

6.8 Standard solution

6.8.1 Single element standard stock solution. rho = 1.00 mg/mL.

Available in spectrally pure metals (purity greater than 99.99%) or other standard materials to a concentration of 1.00 mg/mL Stock solution, select the appropriate medium according to the nature of each element (see Appendix Table B.3 Mixed Standard Stock Solution Group Recommendation Save media). A certified standard solution can also be purchased.

6.8.2 Mixed standard stock solution

Can purchase certified mixed standard solution, depending on the interference between elements, the nature of the standard solution and the test the content of the elements, the elements are grouped into a mixed standard stock solution (see Appendix B.3 recommended mixed standard stock solution) Liquid grouping and storage medium).

Note 1. Standard stock solutions for all elements should be stored in sealed polyethylene or polypropylene bottles after preparation.

Note 2. The solution containing the element Ag needs to be stored in the dark.

6.8.3 Mixed standard use solution

Can purchase certified mixed standard solution, depending on the interference between elements, the nature of the standard solution and the test the content of the element, the elemental standard stock solution (6.8.1 or 6.8.2) is diluted with a nitric acid solution (6.5), and the elements are grouped and formulated.

Into a mixed standard use solution, potassium, sodium, calcium, magnesium stock solution is the use of its solution, the concentration is 100 mg/L; the rest the element mixing solution concentration was 1 mg/L.

6.9 Internal standard storage solution. rho=100µg/L.

6Li, 45Sc, 74Ge, 89Y, 103Rh, 115In, 185Re, 209Bi should be selected as the internal standard elements (the selection of internal standard elements) refer to Appendix Table B.4) for details. The certified standard solution can be purchased directly and diluted to 100 µg/L with a nitric acid solution (6.4).

6.10 Internal standard use solution

The internal standard stock solution (6.9) was diluted with a nitric acid solution (6.4) to prepare an internal standard use solution. Due to different instruments Different internal diameter peristaltic pump tubes are added to the internal standard online, resulting in different concentrations of internal standard into the sample, so the internal concentration of the liquid is used.

The concentration of the internal standard element in the sample solution should be considered to be about 5 µg/L to 50 µg/L.

6.11 Mass spectrometer tuning solution. rho = 10 µg/L.

A tuning solution containing Li, Y, Be, Mg, Co, In, Tl, Pb, and Bi elements as a mass spectrometer should be used. Directly Purchase a certified standard solution and dilute to 10 µg/L with a nitric acid solution (6.4).

6.12 Argon. The purity is not less than 99.99%.

8.1 Sample collection

Sample collection is performed in accordance with the relevant provisions of HJ/T 91 and HJ/T 164. Soluble element samples and total element samples are divided.

Do not collect.

8.2 Preservation of samples

Soluble element samples were collected immediately after collection with a 0.45 µm filter (7.4), and the initial filtrate was discarded.

The filtrate is cleaned of the sampling bottle, and the required volume of the filtrate is collected in a sampling bottle, and an appropriate amount of nitric acid (6.6) is added to adjust the acidity to pH9 Analysis steps

9.1 Instrument Commissioning

9.1.1 Reference operating conditions of the instrument

Different types of instruments have different optimal working conditions. Standard mode, collision/reaction cell mode, etc. should be used according to the instrument.

Instructions for operation.

9.1.2 Instrument Tuning

After igniting the plasma, the instrument needs to be preheated for 30 minutes. First use the mass spectrometer to tune the solution (6.11) to the instrument Sensitivity, oxide and double charge are tuned, under the condition that the sensitivity, oxide and double charge of the instrument meet the requirements.

The relative standard deviation of the signal intensity of the elements contained in the tuning solution is <= 5%. Then proceed within the mass range covering the elements to be tested Quality correction and resolution check, such as the difference between the quality correction result and the true value exceeds ±0.1 amu or the resolution of the tuned element signal the ratio of the peak width corresponding to the peak height of 10% exceeds 0.6-0.8 amu, and the mass spectrometer should be used according to the requirements of the instrument manual.

Make corrections.

9.2 Drawing of the calibration curve

A series of standard solutions of the elements to be tested are sequentially prepared, and the concentration range of the calibration curve can be adjusted according to the measurement needs. In capacity Take a certain volume of the standard use solution (6.8.3) in the bottle, and prepare a series of standard curve using the nitric acid solution (6.4).

As follows. aluminum, boron, antimony, cobalt, copper, iron, manganese, titanium, zinc concentrations of 0µg/L, 10.0µg/L, 50.0µg/L, 100 µg/L, 200 µg/L, 300 µg/L, 400 µg/L, 500 µg/L; silver, arsenic, gold, antimony, bismuth, cadmium, antimony, chromium, antimony, bismuth, antimony, Bismuth, gallium, germanium, antimony, bismuth, antimony, indium, antimony, bismuth, antimony, molybdenum, antimony, bismuth, nickel, phosphorus, lead, palladium, rhodium, platinum, rhodium, 浓度, , , , , selenium, bismuth, tin, antimony, bismuth, antimony, bismuth, antimony, uranium, vanadium, tungsten, antimony, bismuth, zirconium 0µg/L, 0.5µg/L, 1.0µg/L, 5.0µg/L, 10.0µg/L, 20.0 µg/L, 40.0 µg/L, 50.0µg/L; potassium, sodium, Calcium and magnesium concentrations were 0 mg/L, 5.0 mg/L, 10.0 mg/L, 20.0 mg/L, 40.0 mg/L, 60.0 mg/L, 80.0 mg/L, 100mg/L; lithium and strontium concentrations are 0 mg/L, 0.1 mg/L, 0.5 mg/L, 1.0 mg/L, 2.0 mg/L, 3.00 mg/L, 4.0 mg/L, Standard series of 5.0mg/L. The internal standard element standard solution (6.10) can be directly added to the working solution or in the sample.

It is automatically added by a peristaltic pump before atomization. The concentration of the internal standard should be much higher than the concentration of the internal standard element contained in the sample itself.

The internal standard elements and concentration range are given in 6.10.

The standard solution is determined by ICP-MS, and the ratio of the sample signal to the internal standard signal is taken as the abscissa of the standard solution concentration.

A calibration curve is established on the ordinate. The slope was determined by linear regression analysis method for sample content calculation.

9.4 Determination

9.4.1 Determination of samples

Before each sample is measured, flush the system with nitric acid solution (6.5) until the signal is at a minimum, and the signal to be analyzed is stable.

The measurement can only be started afterwards. The same amount of internal standard element standard use solution should be added to the sample when measuring the calibration curve.

(6.10). If the concentration of the element to be tested in the sample exceeds the calibration curve, it should be diluted with nitric acid solution (6.4) and then re-measured.

The dilution factor is f. The sample solution matrix is complex, and when the polyatomic ion interference is serious, the calibration method listed in Appendix B.2 can be used.

The calibration is performed, and can also be corrected by the collision/reaction cell mode technique according to the conditions recommended by each instrument manufacturer.

9.4.2 Determination of laboratory blank samples

Laboratory blank samples were determined according to the same measurement conditions as the samples.

10.1 Calculation of results

The element content in the sample is calculated according to formula (1).

( )1 2 frho rho rho= - × (1) where. rho -- the concentration of the element in the sample, µg/L or mg/L;

1rho - the mass concentration of the elements in the sample after dilution, µg/L or mg/L;

2rho -- mass concentration of elements in laboratory blank samples after dilution, µg/L or mg/L;

f -- dilution factor.

10.2 Results are expressed

The number of decimal places of the measurement is consistent with the method detection limit, and up to three significant digits are reserved.

11.1 Precision

Six laboratories performed standard solutions with potassium, sodium, calcium and magnesium concentrations of 5.0 mg/L, 25.0 mg/L and 50.0 mg/L.

Direct measurement.

The relative standard deviations in the experimental room were 2.90% to 12.8%, 1.27% to 7.93%, and 1.46% to 6.85%, respectively.

The relative standard deviations between laboratories were. 2.83% to 7.71%, 3.99% to 5.70%, and 1.41 to 3.53%.

The repeatability limits ranged from 0.99 mg/L to 1.26 mg/L, from 1.78 mg/L to 3.42 mg/L, and from 3.56 mg/L to 5.67 mg/L.

The reproducibility limits range from 1.01 mg/L to 1.53 mg/L, from 3.06 mg/L to 4.60 mg/L, and from 4.85 mg/L to 7.58 mg/L.

6 laboratories for the remaining 61 elements with concentrations of 0.10~20.0µg/L, 20.0~50.0µg/L and 50.0~100µg/L the quasi-solution was directly measured.

The relative standard deviations in the experimental room were. 2.01% to 14.1%, 1.27% to 10.1%, and 1.15% to 7.84%, respectively.

The relative standard deviations between laboratories were 0.86% to 10.4%, 1.00% to 9.81%, and 0.85 to 4.80%, respectively.

The repeatability range is from 0.02 µg/L to 3.31 µg/L, from 0.08 µg/L to 7.38 µg/L, and from 3.47 µg/L to 11.9 µg/L.

The reproducibility limit ranges from 0.02 µg/L to 4.37 µg/L, from 0.08 µg/L to 8.24 µg/L, and from 3.82 µg/L to 16.9 µg/L.

11.2 Accuracy

Six laboratories carried out the spiked recovery test of soluble elements on surface water samples, and added back to the soluble elements of surface water.

The yield ranged from 86.8% to 102%, and the final recovery of the spiked standard was 86.8%±8.6%~102%±7.7%.

6 laboratories carried out the spiked recovery test of soluble elements in wastewater samples, and the recovery rate of soluble elements in wastewater was increased.

The circumference is. 85.7%~109%, and the final recovery rate is 85.7%±7.6%~109%±9.9%.

6 laboratories carried out spiked recovery experiments on surface water samples, and spiked recovery of total surface water elements the range is 91.3%~110%, and the final recovery of spiked standard is 91.3%±14.4%~110%±13.2%.

6 laboratories carried out spiked recovery experiments on total amount of waste water samples, and spiked recovery range of total waste water elements for. 92.1% to 108%, the final recovery of the spiked standard is 92.0% ± 11.4% ~ 108% ± 3.6%.

See Appendix C for statistics on precision and accuracy results.