Inductively coupled plasma mass spectrometry for measuring rare earth elements in urine

Abstract

The invention provides an inductively coupled plasma mass spectrometry for urine rare earth element determination, which comprises the following steps: S1, sample collection and preservation: collecting a urine sample by a disposable urine cup, determining urine creatinine or specific gravity, and carrying out anti-corrosion or anti-adsorption treatment by 1% HNO3 (V / V); s2, preparing a standard solution: diluting the standard application solution into a rare earth element standard working solution with the concentration range of 0.0 mu g / L-10.0 mu g / L by using a 1% HNO3 solution; s3, preparing a standard curve solution, namely adjusting the tuning solution, injecting the standard working solution, introducing the internal standard solution, respectively measuring the ratio of the response value of the rare earth element of the standard working solution with each concentration to the response value of the internal standard element, and enabling the correlation coefficient to be greater than or equal to 0.999; s4, preparing a to-be-detected solution, namely adding 1mL of urine into 9mL of diluted solution, and uniformly mixing; s5, urine sample determination: sequentially injecting the blank solution and the to-be-determined sample solution to obtain a signal response value, and calculating the content of the to-be-determined rare earth element according to the standard curve; s6, rare earth element result calculation: performing result calculation on the rare earth element content in the urine according to a calculation formula.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth element determination, in particular to an inductively coupled plasma mass spectrometry method for determining rare earth elements in urine. Background Art

[0002] Rare earth is a collective name for 17 chemical elements in the III-group sub-group of the periodic table, including scandium, yttrium and lanthanide elements, also known as rare earth metals or rare earth elements. With the rapid development of high-tech and emerging industries around the world, rare earths are widely used in various fields such as renewable energy, electronics, health care, agriculture and national defense due to their special structure and excellent physical and chemical properties such as light, electricity and magnetism. They have long been regarded as strategic mineral resources by the world. In recent years, with the large-scale mining, smelting and application of rare earth resources, rare earth metals have been released into various environmental media in large quantities, including atmospheric particulate matter, soil, water and sediments, making rare earths a new type of pollutant in the earth's environment, and rare earth exposure has become one of the important environmental issues. Inhalation of rare earths through breathing, food and drinking water is the main way for human environmental exposure. After entering the body, rare earths are absorbed through the respiratory system, digestive system and other pathways, and reach the whole body with blood circulation and accumulate in hair, bones, tissues and organs. Over the past few decades, a large amount of animal and cell experimental evidence on rare earth toxicity has been accumulated, providing extensive background information on the harmful effects of rare earth environmental exposure, and 16 rare earth metals have been included in the priority list of hazardous substances of the U.S. Agency for Toxic Substances and Disease Registry (ATSDR), but further research is needed to clarify their potential health risks to humans. Currently, there is evidence that rare earth metals may have a variety of toxic effects on the body, such as neurotoxicity, reproductive and developmental toxicity, and organ damage. These health risks are mainly related to long-term or high-dose rare earth exposure.

[0004] The existing atomic absorption spectrometry (AAS) has a high detection limit and low sensitivity, and can only determine one metal element at a time; the microwave digestion method has complicated steps, low efficiency, and many steps, which can easily cause contamination during sample processing and is not suitable for pre-treatment operations of large quantities of samples.

[0005] A method for detecting rare earth elements in human blood based on scientific research applications, with the publication number of "CN117805216A", comprises the following steps: selecting standard solutions of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and thorium; diluting the standard solutions of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and thorium into 0.0, 0.1, 0.25, 0.5, 1.0, 1.5, 2, 5 ng and 1.5 ng respectively with a diluent; / mL; draw a standard curve; place the diluted standard solution in the instrument, perform detection, and generate a blood rare earth element detection and calculation formula; take the blood sample out of the -80°C refrigerator and place it in a 4°C refrigerator to thaw. After the sample is thawed, mix the blood sample, draw 200 microliters, add 3.8 milliliters of diluent and mix evenly to form a sample to be tested; introduce the above sample to be tested into the instrument to detect and calculate the rare earth elements in human blood using the blood rare earth element detection and calculation formula; generate the result.

[0006] However, the above device still has the following problems during implementation:

[0007] The dilution solution for blood samples is not suitable for urine samples. The solvent in the dilution solution has a great influence on the dispersion of urine samples. Literature and actual cohort studies have found that the correlation between blood rare earth element concentration and environmental rare earth exposure concentration is lower than the correlation between urine rare earth elements and environmental rare earth exposure, and blood sampling is traumatic to the human body. Summary of the invention

[0008] The object of the present invention is to provide an inductively coupled plasma mass spectrometry method for determining rare earth elements in urine to solve the problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] An inductively coupled plasma mass spectrometry method for determining rare earth elements in urine comprises the following steps:

[0011] S1. Sample collection and storage: Collect urine samples with a sterile disposable urine cup, mix well, and measure urine creatinine or specific gravity as soon as possible. Add 1% HNO3 (V / V) to the urine sample for preservation or anti-adsorption treatment, and transport it on ice to the analytical laboratory for analysis within 24 hours or store the urine sample at -80°C;

[0012] S2. Prepare standard solution: take 5-10 volumetric flasks, dilute the standard application solution with 1% HNO3 solution to a rare earth element standard working solution with a concentration range of 0.0μg / L-10.0μg / L. The concentrations of the standard series solutions are 0, 0.5, 1.0, 2.0, 5.0, 10.0μg / L;

[0013] S3, prepare standard curve solution: adjust the inductively coupled plasma mass spectrometer to the optimal measurement state with a tuning solution, inject the rare earth element standard working solution into the inductively coupled plasma mass spectrometer, introduce the internal standard working solution through the online three-way connection at the same time, measure the signal response value of the corresponding solution, and respectively measure the ratio (R) of the response value of the rare earth element to be measured at each concentration of the standard working solution to the response value of the internal standard element, and draw a standard curve or calculate a regression equation based on the measured R value against the corresponding rare earth element concentration (μg / L) to be measured, and the correlation coefficient is ≥0.999;

[0014] S4. Prepare the test solution: add 1 mL of urine to 9 mL of dilution solution, mix well and set aside;

[0015] S5. Urine sample determination: Inject the urine sample blank solution and the sample solution to be tested into the inductively coupled plasma mass spectrometer in sequence to obtain the signal response value, obtain the concentration of the blank solution and the sample solution according to the standard curve, calculate the content of the rare earth element to be tested according to the standard curve, and the determination is completed;

[0016] S6. Calculation of rare earth element results: Calculate the rare earth element content in urine according to the rare earth element calculation formula to generate the result.

[0017] Preferably, the dilution solution in step S4 includes 0.1% HNO3, 0.1% TritonX-100 and 0.5% n-butanol. During preparation, 0.1 mL HNO3, 0.1 ml TritonX and 0.5 ml n-butanol are slowly added to ultrapure water to make a volume of 100 mL and mixed.

[0018] Preferably, the equipment used to prepare the standard curve in step S3 is preferably an inductively coupled plasma mass spectrometer, and the operating reference conditions are as follows:

[0019] Incident power: 1500W;

[0020] Cooling gas (argon) flow rate: 15L / min, argon (Ar) purity> 99.999%;

[0021] Carrier gas (argon) flow rate: 0.7L / min, argon (Ar) purity>99.999%;

[0022] Auxiliary gas (argon) flow rate: 0.2L / min, argon (Ar) purity> 99.999%;

[0023] Integration time: 0.1s;

[0024] Nickel sampling cone and nickel skimmer cone.

[0025] Preferably, after obtaining the rare earth element standard working solution, the inductively coupled plasma mass spectrometer is adjusted to the optimal measurement state with a tuning solution, and the tuning solution is a mixed solution of lithium, yttrium, cerium and thallium and is not limited to the above mixed solution.

[0026] Preferably, if the content of the element to be measured in step S5 exceeds the linear range, the test solution can be diluted before measurement, and the measurement result can be multiplied by the dilution factor when calculating.

[0027] Preferably, the radio frequency power of the inductively coupled plasma mass spectrometer is 1500w; the sampling depth is 10.0mm; the nebulizer temperature is 3°C; the carrier gas is 0.7L / min; the plasma gas flow rate is 15L / min; the auxiliary gas flow rate is 1.5L / min; the scanning mode is peak skipping; and the number of repetitions is 3 times.

[0028] Preferably, the rare earth element content calculation formula is:

[0029] X = (C1-C0) × F;

[0030] Where X: rare earth element content in the sample, in micrograms per liter (μg / L);

[0031] C1: The measured concentration of rare earth elements in the sample digestion solution, in micrograms per liter (μg / L);

[0032] C0: The measured concentration of rare earth elements in the blank digestion solution of the sample, in micrograms per liter (μg / L);

[0033] F: dilution factor.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The inductively coupled plasma mass spectrometry method adopted in the present invention is to perform digestion pretreatment on the urine sample, fix the volume to a certain volume, introduce the urine sample solution into the inductively coupled plasma mass spectrometer, establish a standard curve of concentration and mass spectrometry signal in a certain range, compare it with the signal response value corresponding to the mass number of each element in the standard sample, and obtain the content of 15 rare earth elements or the total amount of rare earth in the sample solution through intensity comparison. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is an operation flow chart of the present invention; DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 1 , the present invention provides a technical solution:

[0039] An inductively coupled plasma mass spectrometry method for determining rare earth elements in urine comprises the following steps:

[0040] S1. Sample collection and storage: Collect urine samples with a sterile disposable urine cup, mix well, and measure urine creatinine or specific gravity as soon as possible. Add 1% HNO3 (V / V) to the urine sample for preservation or anti-adsorption treatment, and transport it on ice to the analytical laboratory for analysis within 24 hours or store the urine sample at -80°C;

[0041] S2. Prepare standard solution: take 5-10 volumetric flasks, dilute the standard application solution with 1% HNO3 solution to a rare earth element standard working solution with a concentration range of 0.0μg / L-10.0μg / L. The concentrations of the standard series solutions are 0, 0.5, 1.0, 2.0, 5.0, 10.0μg / L;

[0042] S3, prepare standard curve solution: adjust the inductively coupled plasma mass spectrometer to the optimal measurement state with a tuning solution, inject the rare earth element standard working solution into the inductively coupled plasma mass spectrometer, introduce the internal standard working solution through the online three-way connection at the same time, measure the signal response value of the corresponding solution, and respectively measure the ratio (R) of the response value of the rare earth element to be measured at each concentration of the standard working solution to the response value of the internal standard element, and draw a standard curve or calculate a regression equation based on the measured R value against the corresponding rare earth element concentration (μg / L) to be measured, and the correlation coefficient is ≥0.999;

[0043] S4. Prepare the test solution: add 1 mL of urine to 9 mL of dilution solution, mix well and set aside;

[0044] S5. Urine sample determination: Inject the urine sample blank solution and the sample solution to be tested into the inductively coupled plasma mass spectrometer in sequence to obtain the signal response value, obtain the concentration of the blank solution and the sample solution according to the standard curve, calculate the content of the rare earth element to be tested according to the standard curve, and the determination is completed;

[0045] S6. Calculation of rare earth element results: Calculate the rare earth element content in urine according to the rare earth element calculation formula to generate the result.

[0046] The dilution solution in step S4 includes 0.1% HNO3, 0.1% TritonX-100 and 0.5% n-butanol. When preparing, 0.1 mL HNO3, 0.1 ml TritonX and 0.5 ml n-butanol are slowly added to ultrapure water to make a volume of 100 mL and mixed.

[0047] In this embodiment, the equipment used to prepare the standard curve is preferably an inductively coupled plasma mass spectrometer, and the operating reference conditions are as follows:

[0048] Incident power: 1500W;

[0049] Cooling gas (argon) flow rate: 15L / min, argon (Ar) purity> 99.999%;

[0050] Carrier gas (argon) flow rate: 0.7L / min, argon (Ar) purity>99.999%;

[0051] Auxiliary gas (argon) flow rate: 0.2L / min, argon (Ar) purity> 99.999%;

[0052] Integration time: 0.1s;

[0053] Nickel sampling cone and nickel skimmer cone.

[0054] After obtaining the rare earth element standard working solution, the inductively coupled plasma mass spectrometer is adjusted to the optimal measurement state with a tuning solution, wherein the tuning solution is a mixed solution of lithium, yttrium, cerium and thallium and is not limited to the above mixed solution.

[0055] In this embodiment, the experimental water is ultrapure water, the acid is of high purity, and HNO3 is preferably electronic grade. The preparation of reagents and solutions used in the standards adapted in the determination method shall be in accordance with the provisions of HG / T2843 when the specifications and preparation methods are not specified.

[0056] It should be noted that if the content of the element to be measured in step S5 exceeds the linear range, the test solution can be diluted before measurement, and the measurement result can be multiplied by the dilution factor when calculating.

[0057] The inductively coupled plasma mass spectrometer operating parameters include:

[0058] RF power: 1500w;

[0059] Sampling depth 10.0 mm;

[0060] Nebulizer temperature 3°C; carrier gas 0.7L / min;

[0061] Plasma gas flow rate 15L / min; auxiliary gas flow rate 1.5L / min;

[0062] Scan mode: peak skipping; repeat 3 times.

[0063] It should be noted that the rare earth element content calculation formula is:

[0064] X = (C1-C0) × F;

[0065] Where X: rare earth element content in the sample, in micrograms per liter (μg / L);

[0066] C1: The measured concentration of rare earth elements in the sample digestion solution, in micrograms per liter (μg / L);

[0067] C0: The measured concentration of rare earth elements in the blank digestion solution of the sample, in micrograms per liter (μg / L);

[0068] F: dilution factor.

[0069] It should be noted that the standard solution in this embodiment refers to a single element or mixed standard solution of a rare earth element standard solution prepared into a 10.0 mg / L mixed standard stock solution and a 100 μg / L temporary mixed standard stock solution (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu).

[0070] The internal standard solution in this embodiment is recommended to be configured as a 500 μg / L online internal standard solution using a single element standard solution or a mixed standard solution of indium (In), rhodium (Rh), or rhenium (Re). The internal standard concentration may be appropriately adjusted depending on the situation and may be prepared using certified standard substances.

[0071] It should be noted that the above calculation results are corrected for the sample results using urine creatinine or urine specific gravity correction method.

[0072] The formula for calculating the total amount of rare earths is:

[0073]

[0074] ∑REE S : Total rare earth concentration (μg / L);

[0075] X i : The content of rare earth elements Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in the sample after correction (μg / L);

[0076] Determination of precision value in this embodiment:

[0077] The rare earth element content in urine samples is greater than 10 μg / L, and the absolute difference between two independent determination results obtained repeatedly shall not exceed 10% of the arithmetic mean;

[0078] When the rare earth element content in the urine sample is less than 10 μg / L, the absolute value of two independent measurement results obtained under repeatability conditions shall not exceed 20% of the arithmetic mean.

[0079] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An inductively coupled plasma mass spectrometry method for the determination of rare earth elements in urine, characterized in that: The steps include: S1. Sample collection and storage: Collect urine samples with a sterile disposable urine cup, mix well, and measure urine creatinine or specific gravity as soon as possible. Add 1% HNO3 (V / V) to the urine sample for preservation or anti-adsorption treatment, and transport it on ice to the analytical laboratory for analysis within 24 hours or store the urine sample at -80°C; S2. Prepare standard solution: take 5-10 volumetric flasks, dilute the standard application solution with 1% HNO3 solution to a rare earth element standard working solution with a concentration range of 0.0μg / L-10.0μg / L. The concentrations of the standard series solutions are 0, 0.5, 1.0, 2.0, 5.0, 10.0μg / L; S3, prepare standard curve solution: adjust the inductively coupled plasma mass spectrometer to the optimal measurement state with a tuning solution, inject the rare earth element standard working solution into the inductively coupled plasma mass spectrometer, introduce the internal standard working solution through the online three-way connection at the same time, measure the signal response value of the corresponding solution, and respectively measure the ratio (R) of the response value of the rare earth element to be measured at each concentration of the standard working solution to the response value of the internal standard element, and draw a standard curve or calculate a regression equation based on the measured R value against the corresponding rare earth element concentration to be measured (μg / L), and the correlation coefficient is ≥0.999; S4. Prepare the test solution: add 1 mL of urine to 9 mL of dilution solution, mix well and set aside; S5. Urine sample determination: Inject the urine sample blank solution and the sample solution to be tested into the inductively coupled plasma mass spectrometer in sequence to obtain the signal response value, obtain the concentration of the blank solution and the sample solution according to the standard curve, calculate the content of the rare earth element to be tested according to the standard curve, and the determination is completed; S6. Calculation of rare earth element results: Calculate the rare earth element content in urine according to the rare earth element calculation formula to generate the result.

2. The inductively coupled plasma mass spectrometry method for determining rare earth elements in urine according to claim 1, characterized in that: The dilution solution in step S4 includes 0.1% HNO3, 0.1% TritonX-100 and 0.5% n-butanol. When preparing, 0.1 mL HNO3, 0.1 ml TritonX and 0.5 ml n-butanol are slowly added to ultrapure water to make a volume of 100 mL and mixed.

3. The inductively coupled plasma mass spectrometry method for determining rare earth elements in urine according to claim 1, characterized in that: The equipment used to prepare the standard curve in step S3 is preferably an inductively coupled plasma mass spectrometer, and the operating reference conditions are as follows: Incident power: 1500W; Cooling gas (argon) flow rate: 15L / min, argon (Ar) purity> 99.999%; Carrier gas (argon) flow rate: 0.7L / min, argon (Ar) purity>99.999%; Auxiliary gas (argon) flow rate: 0.2L / min, argon (Ar) purity> 99.999%; Integration time: 0.1s; Nickel sampling cone and nickel skimmer cone.

4. The inductively coupled plasma mass spectrometry method for determining rare earth elements in urine according to claim 3, characterized in that: After obtaining the rare earth element standard working solution, the inductively coupled plasma mass spectrometer is adjusted to the optimal measurement state with a tuning solution, wherein the tuning solution is a mixed solution of lithium, yttrium, cerium and thallium and is not limited to the above mixed solution.

5. The inductively coupled plasma mass spectrometry method for determining rare earth elements in urine according to claim 1, characterized in that: If the content of the element to be measured in step S5 exceeds the linear range, the test solution can be diluted before measurement, and the measurement result can be multiplied by the dilution factor when calculating.

6. The inductively coupled plasma mass spectrometry method for determining rare earth elements in urine according to claim 3, characterized in that: The inductively coupled plasma mass spectrometer has a radio frequency power of 1500w, a sampling depth of 10.0mm, a nebulizer temperature of 3°C, a carrier gas of 0.7L / min, a plasma gas flow rate of 15L / min, an auxiliary gas flow rate of 1.5L / min, a scanning mode of peak skipping, and a number of repetitions of 3 times.

7. The inductively coupled plasma mass spectrometry method for determining rare earth elements in urine according to claim 1, characterized in that: The rare earth element content calculation formula is: X = (C1-C0) × F; Where X: rare earth element content in the sample, in micrograms per liter (μg / L); C1: measured concentration of rare earth elements in the sample digestion solution, in micrograms per liter (μg / L); C0: The measured concentration of rare earth elements in the blank digestion solution of the sample, in micrograms per liter (μg / L); F: dilution factor.

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