Matrix Effect Correction Method and Application of High-salt Samples

Abstract

The present invention relates to a method for correcting matrix effect of high-salt samples, comprising the steps of: (1) adding hydride to a sample containing a high-salt matrix, removing mercury, arsenic, selenium and antimony elements in the sample by hydride reaction, and obtaining a first matrix solution; (2) adding filler to the first matrix solution, removing other metal ions in the first matrix solution by filler chelation, and obtaining a second matrix solution; (3) using the second matrix solution calibration curve to make the matrix of the curve solution consistent with the sample solution. The hydride is any one of hydrochloric acid + potassium borohydride, nitric acid + sodium borohydride, and sulfuric acid + potassium borohydride; the filler is ethylenediaminetriacetic acid grafted on a small ball of a PS-DVB matrix and iminodiacetic acid grafted on a small ball of a PS-DVB matrix, and the mixing ratio is 1% to 50%. The present invention avoids the defect of matrix effect interference, ensures the consistency of the standard curve and the matrix of the sample to be tested during the detection of high-salt samples, and minimizes the interference of matrix effect.

Description

Technical Field

[0001] The invention relates to a high-salt sample matrix correction method and also to the application of the method. Background Art

[0002] When detecting the elements to be measured in the sample, elements other than the elements to be measured are called matrices. For example, Cu, Zn, and Pb in seawater are the elements to be measured, while the main solutes Na, Mg, K, and Ca salts in seawater are matrices. The matrix will have different degrees of inhibition or enhancement on the signal of the element to be measured, which is called the matrix effect. For example, a pure solution of 1ppb U can produce 80,000 cps signals on ICP-MS, but a 1ppbU salt solution (containing 0.1wt% NaNO3) can only produce 60,000 cps signals--the NaNO3 matrix inhibits the excitation of the U element. For another example, adding a few drops of methanol or ethanol to the As and Se test solutions can enhance the test signal by 10%-30%--the organic matrix enhances the excitation of the As and Se elements.

[0003] When using instrumental analysis to detect the heavy metal content in a sample, the matrix effect interference caused by the inconsistency of the matrix between the standard solution and the sample solution must be eliminated. The matrix effect interference will cause errors in the measured elements of the sample. Therefore, when testing the elements of the sample, the consistency of the standard curve matrix and the sample to be tested should be ensured to reduce the errors caused by the matrix effect interference.

[0004] Reference material (RM) is a material with specific properties that are sufficiently uniform and stable. Its properties are suitable for its intended use in measurement or nominal property inspection. It can be used as a "gauge" in the analytical measurement industry. It plays an indispensable role in calibrating measuring instruments and devices, evaluating measurement and analysis methods, measuring the property values ​​of substances or materials, and assessing the operational technical level of analysts, as well as in the quality control of products during the production process.

[0005] Matrix matching between reference materials and samples to be tested is a prerequisite for ICP-MS to obtain accurate and reliable test results. In the prior art, simulated matrix is ​​the most commonly used matrix matching method, but the simulated matrix still has interfering ions, resulting in problems such as the detection limit cannot be lowered and the recovery rate is low. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for correcting the matrix effect of high-salt samples, which uses a filler chelation method to treat high-salt samples to obtain a matrix solution that is highly compatible with the sample matrix, avoiding the defect of matrix effect interference, ensuring the consistency of the standard curve and the matrix of the sample to be tested during the high-salt sample detection process, and minimizing the matrix effect interference.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A method for correcting matrix effects of high-salt samples, characterized by comprising the following steps:

[0009] (1) adding a hydride to a sample containing a high-salt matrix, removing mercury, arsenic, selenium, and antimony elements in the sample through a hydride reaction, and obtaining a first matrix solution;

[0010] (2) adding a filler to the first matrix solution, removing other metal ions (including copper, zinc, lead, etc.) in the first matrix solution by chelation of the filler, and obtaining a second matrix solution;

[0011] (3) Use the second matrix solution to calibrate the curve so that the matrix of the curve solution is consistent with the sample solution, thus completing the matrix correction.

[0012] Furthermore, the hydride in step (1) is any one of hydrochloric acid + potassium borohydride, nitric acid + sodium borohydride, and sulfuric acid + potassium borohydride; preferably hydrochloric acid + potassium borohydride; the concentration of the hydrochloric acid, nitric acid, and sulfuric acid is 1% to 10%, and the concentration of potassium borohydride and sodium borohydride is 1mmol / L to 1mol / L.

[0013] Furthermore, the filler in step (2) is a mixture of two fillers, wherein the mixing ratio of the two fillers is ethylenediaminetriacetic acid grafted on the beads of the PS-DVB matrix: iminodiacetic acid grafted on the beads of the PS-DVB matrix = 1: 1-100.

[0014] Furthermore, the amount of filler added in step (2) is 0.5 g to 5 g (the total amount added after the two fillers are mixed) in 1 L of sample solution.

[0015] The present invention also provides an ICP-MS matrix matching analysis method based on the above correction method, comprising:

[0016] The matrix matching solution required for the sample to be tested was prepared by the high-salt sample matrix effect correction method as described above, and the calibration curve was then tested in sequence using the ICP-MS multi-element full scan mode.

[0017] The filler functions to chelate metal ions in the sample solution. The matrix solution obtained after the metal ions in the sample solution are chelated and removed by the filler does not contain any metal ions, and the matrix (salinity, composition, etc.) is completely consistent with the sample.

[0018] The present invention also provides an ICP-MS matrix matching analysis method, which is characterized by: using the high-salt sample matrix effect correction method as described above to prepare the matrix matching solution required for the sample to be tested, and then calibrating the curve, and using the ICP-MS multi-element full scan mode to test the standard curve and the sample in sequence.

[0019] Beneficial effects: The high-salt matrix effect correction method provided by the present invention can ensure the consistency of the calibration curve or the standard solution matrix and the sample matrix to be tested to the greatest extent, reduce the error caused by matrix effect interference, and lower the detection limit. The matrix correction method improves the uniformity and stability of the standard substance in the sample through chelation, which can ensure the accuracy, comparability and traceability of the heavy metal content detection results of the relevant high-salt samples, and is of great significance to the quality detection of high-salt products. DETAILED DESCRIPTION

[0020] Example 1

[0021] Taking the detection of sample 1 in seawater as an example, the high-salt matrix calibration method provided in this embodiment includes the following steps:

[0022] (1) adding hydride 1% hydrochloric acid + 1mmol / L potassium borohydride to a sample containing a high salt matrix, removing mercury, arsenic, selenium and antimony elements in the sample through a hydride reaction to obtain a first matrix solution;

[0023] (2) adding ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix and iminodiacetic acid grafted on the beads of PS-DVB matrix to the first matrix solution, the mixing ratio of the two fillers being ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix:iminodiacetic acid grafted on the beads of PS-DVB matrix=1:100, removing other metal ions (copper, zinc, lead, etc.) in the first matrix solution by filler chelation, and obtaining a second matrix solution;

[0024] (3) Use the second matrix solution to calibrate the curve so that the matrix of the curve solution is consistent with the sample solution, thus completing the matrix correction.

[0025] The working conditions of HPLC are as follows:

[0026] Injection volume: 900ul;

[0027] The working conditions of ICP-MS are as follows:

[0028] Power: 1400W;

[0029] Nebulizer flow rate: 1.04ml / min;

[0030] Plasma torch auxiliary gas flow rate: 0.7ml / min;

[0031] Plasma torch cooling gas flow rate: 15ml / min;

[0032] Detector analog step voltage: -1787V;

[0033] Detection pulse step voltage: 900V.

[0034] The test results of sample 1 are shown in Table 1 below. The purification efficiency of each element is above 90%. If you want to get a higher purification efficiency, you can increase the number of purification times.

[0035] Table 1

[0036]

[0037] Example 2

[0038] Taking the detection of sample 2 in seawater as an example, the high-salt matrix calibration method provided in this embodiment includes the following steps:

[0039] (1) adding 5% nitric acid + 100 mmol / L sodium borohydride to a sample containing a high salt matrix, removing mercury, arsenic, selenium and antimony elements in the sample through a hydride reaction to obtain a first matrix solution;

[0040] (2) adding ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix and iminodiacetic acid grafted on the beads of PS-DVB matrix to the first matrix solution, the mixing ratio of the two fillers being ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix:iminodiacetic acid grafted on the beads of PS-DVB matrix=1:50, removing other metal ions (copper, zinc, lead, etc.) in the first matrix solution by filler chelation, and obtaining a second matrix solution;

[0041] (3) Use the second matrix solution to calibrate the curve so that the matrix of the curve solution is consistent with the sample solution, thus completing the matrix correction.

[0042] The working conditions of HPLC and ICP-MS were the same as those in Example 1.

[0043] The test results of sample 2 are shown in Table 2. The purification efficiency of each element is above 90%. If you want to get a higher purification efficiency, you can increase the number of purification times.

[0044] Table 2

[0045]

[0046] Example 3

[0047] Taking the detection of sample 3 in seawater as an example, the high-salt matrix calibration method provided in this embodiment is adopted, comprising the following steps:

[0048] (1) adding 10% sulfuric acid + 1 mol / L potassium borohydride to a sample containing a high salt matrix, removing mercury, arsenic, selenium and antimony elements in the sample through a hydride reaction to obtain a first matrix solution;

[0049] (2) adding ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix and iminodiacetic acid grafted on the beads of PS-DVB matrix to the first matrix solution, the mixing ratio of the two fillers being ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix:iminodiacetic acid grafted on the beads of PS-DVB matrix=1:1, removing other metal ions (copper, zinc, lead, etc.) in the first matrix solution by filler chelation, and obtaining a second matrix solution;

[0050] (3) Use the second matrix solution to calibrate the curve so that the matrix of the curve solution is consistent with the sample solution, thus completing the matrix correction.

[0051] The working conditions of HPLC and ICP-MS were the same as those in Example 1.

[0052] The test results of sample 3 are shown in Table 3. The purification efficiency of each element is above 90%. If you want to get a higher purification efficiency, you can increase the number of purification times.

[0053] Table 3

[0054]

Claims

1. A method for correcting matrix effects of high-salt samples, characterized in that The following steps are involved: (1) adding a hydride to a sample containing a high-salt matrix, removing mercury, arsenic, selenium, and antimony elements in the sample through a hydride reaction, and obtaining a first matrix solution; (2) adding a filler to the first matrix solution, removing other metal ions in the first matrix solution by chelation of the filler, and obtaining a second matrix solution; (3) using a second matrix solution to calibrate the curve so that the matrix of the curve solution is consistent with the sample solution, thus completing the matrix calibration; The hydride in step (1) is any one of hydrochloric acid + potassium borohydride, nitric acid + sodium borohydride and sulfuric acid + potassium borohydride; The concentration of the hydrochloric acid, nitric acid or sulfuric acid is 1% to 10%; The filler in step (2) is a mixture of two fillers, namely: ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix and iminodiacetic acid grafted on the beads of PS-DVB matrix; The mixing ratio of the two fillers is ethylenediaminetriacetic acid grafted on the beads of PS-DVB matrix: iminodiacetic acid grafted on the beads of PS-DVB matrix = 1:1-100; The amount of filler added is 0.5 g to 5 g in 1 L of sample solution.

2. The method for correcting matrix effect of high-salt samples according to claim 1, characterized in that: The concentration of the potassium borohydride or sodium borohydride is 1 mmol / L to 1 mol / L.

3. An ICP-MS analysis method based on the correction method according to claim 2, comprising: The matrix matching solution required for the sample to be tested is prepared by the high-salt sample matrix effect correction method and then calibrated. The standard curve and samples were tested in sequence using ICP-MS multi-element full scan mode.

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