ICP-MS atomizer cleaning method

Abstract

The invention provides an ICP-MS (Inductively Coupled Plasma Mass Spectrometry) atomizer cleaning method, which combines stepped chemical cleaning with online atomization verification, and adopts two customized cleaning solutions (A and B) to clean different impurities respectively, the cleaning solution A is used for metal impurities such as Cu, Ag, Pb, Fe, Co, Ni and the like, and the cleaning solution B is used for cleaning the metal impurities such as Cu, Ag, Pb, Fe, Co, Ni and the like; the cleaning solution B is used for cleaning W deposition deep in a Pt capillary aiming at the micro-channel in the atomizer, and atomizing the cleaning solution in an instrument diagnosis mode in the cleaning process to thoroughly clean stubborn deposits in the micro-channel in the atomizer; finally, the internal standard recovery rate and the standard curve linearity serve as indexes, and it is ensured that the cleaning effect can be quantitatively verified. Results show that after the atomizer is cleaned by the method, the recovery rate of Rh (103) is 91-95%, and the linear correlation coefficient of W is R2gt; the problems that cleaning is not thorough, and devices are prone to being damaged in a traditional cleaning method are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of precision instrument maintenance, and relates to a systematic cleaning method for an atomizer in an inductively coupled plasma mass spectrometer (ICP-MS), which is a precision analytical instrument. BACKGROUND

[0002] The inductively coupled plasma mass spectrometer (ICP-MS) is a high-sensitivity analytical instrument widely used in environmental monitoring, food safety, geological exploration and material science. In the analysis and detection process of the inductively coupled plasma mass spectrometer (ICP-MS), the atomizer, as a key component, is responsible for converting liquid samples into aerosols and introducing them into the plasma for testing. However, in the long-term use process, the atomizer is prone to blockage or contamination due to sample residue. In particular, when analyzing metal samples (such as high-purity metals, alloys, etc.) using ICP-MS, the contamination and blockage of the atomizer are particularly evident. Metal samples usually contain high concentrations of matrix elements (such as Fe, Al, Cu, Ni) or difficult-to-dissolve oxides / carbides (such as Ti, W, Zr), which are prone to deposit inside the atomizer during atomization, leading to problems such as decreased instrument test sensitivity, abnormal internal standard recovery, memory effect, and poor standard curve linearity.

[0003] The current common atomizer cleaning methods are as follows: 1. Pure water / dilute acid flushing, which can only remove part of the soluble residue and is ineffective for stubborn deposits; 2. Simple ultrasonic cleaning, which is ineffective for refractory metals and may damage the platinum capillary of the concentric atomizer; 3. aqua regia immersion, which cannot simulate the actual atomization effect, making it difficult to evaluate the cleaning effect, and requires repeated disassembly and installation, increasing the risk of errors. In view of this, there is an urgent need for an efficient and quantifiable atomizer cleaning method to solve the above problems. SUMMARY

[0004] The present application provides an improved ICP-MS atomizer cleaning method based on the defects of existing ICP-MS atomizer cleaning methods. The method combines step-by-step chemical cleaning with online atomization verification, uses two custom cleaning solutions (A and B) to target different types of residues, ensuring comprehensive cleaning. The instrument diagnostic mode is used to atomize the cleaning solution, thoroughly removing stubborn deposits from the atomizer's internal microchannels. Finally, the internal standard recovery and standard curve linearity are used as indicators to ensure that the cleaning effect can be quantitatively verified. The method solves the problems of incomplete cleaning and device damage that exist in traditional cleaning methods.

[0005] Based on the above idea, the specific technical solutions of the present application are as follows:

[0006] The ICP-MS atomizer cleaning method provided by the present application includes the following steps:

[0007] A, ultrasonic cleaning

[0008] The disassembled atomizer to be cleaned is completely immersed in cleaning solution A composed of HNO3, HCl, H2O2, ensuring that all channels are filled with liquid, the ultrasonic power is 300 W, and ultrasonic cleaning is performed at room temperature for 2-5 hours (preferably 3 hours) ; after the ultrasonic cleaning is completed, the atomizer is rinsed with ultrapure water and the internal microchannels of the atomizer are dried with high-purity nitrogen.

[0009] Preferably, the concentration ratio among HNO3, HCl and H2O2 in cleaning solution A is 23:5:1. Nitric acid (23%) is used to oxidize metals such as Cu, Ag and Pb to prevent the presence of reduced states; hydrochloric acid (5%) can dissolve transition metal deposits such as Fe, Co and Ni; and hydrogen peroxide (1%) enhances the reducing ability and decomposes organic complexing agents.

[0010] The preparation method of cleaning solution A is as follows: 69% HNO3, 37% HCl and 30% H2O2 are mixed in a mass ratio of 2.47:1:2.47, and then ultrapure water is added to a predetermined volume.

[0011] When the present application is used for ultrasonic cleaning, the ultrasonic temperature is room temperature, which can avoid volatilization of the acid solution or deformation of the atomizer caused by high temperature.

[0012] B, online dynamic atomization cleaning

[0013] Preparation of cleaning solution B, connect the cleaned and dried atomizer with the atomization chamber, force the acid cleaning solution to flow through the internal microchannels of the atomizer by the instrument diagnosis mode, and remove the residual dead volume.

[0014] Preferably, cleaning solution B is composed of HNO3, H2O2 and HF, and the concentration ratio among the three is 5:1:1. Hydrofluoric acid (1%) is specifically used to dissolve refractory silicides and aluminum oxides; low-concentration HF avoids corrosion of the atomizer while ensuring that refractory metal residues are dissolved.

[0015] The preparation method of cleaning solution B is as follows: 69% HNO3, 30% H2O2 and 49% HF are mixed in a mass ratio of 3.55:1.63:1, and then ultrapure water is added to a predetermined volume.

[0016] Further, the operation method is as follows: connect the cleaned and dried atomizer with the atomization chamber, place the sample needle in cleaning solution B, and click the software interface to enter the diagnosis mode. The atomizer starts to work in the diagnosis mode, and the atomizer is determined to be blocked by observing the atomization state: normal atomization should produce uniform and fine aerosol, if the atomization is unstable, the atomizer should be checked for blockage; maintain this state for one night to remove W deposits in the Pt capillary.

[0017] C, verification of cleanliness

[0018] The cleaning degree of the atomizer is determined by taking the internal standard recovery rate and the standard curve linearity as indexes.

[0019] Preferably, when determining the internal standard recovery rate, Rh (103) is selected as the internal standard, and the recovery rate is required to be between 80-120%; when determining the standard curve linearity, a mixed metal standard solution of 1-10 ppb is tested, and R2 is required to be greater than 0.9995.

[0020] The beneficial guarantees and effects of the present application are as follows:

[0021] The present application combines the step-by-step chemical cleaning with the online atomization verification, and adopts two kinds of customized cleaning solutions (A and B) to clean different impurities: the cleaning solution A is used to clean Cu, Ag, Pb, Fe, Co, Ni and other metal impurities; the cleaning solution B is used to clean the internal microchannels of the atomizer, and is used to remove the W deposition in the deep Pt capillary, and in the cleaning process, the atomization cleaning solution is verified by the instrument diagnosis mode, so as to completely remove the stubborn deposits in the internal microchannels of the atomizer; finally, the internal standard recovery rate and the standard curve linearity are taken as indexes to ensure that the cleaning effect can be quantitatively verified. The results show that after the atomizer is cleaned by the method of the present application, the recovery rate of Rh (103) is between 91% and 95%, the linear correlation coefficient R of W is greater than 0.9995, and the problems of incomplete cleaning and easy damage to the device existing in the traditional cleaning method are solved. 2 BRIEF DESCRIPTION OF DRAWINGS

[0022] The present disclosure will be further described below in conjunction with the accompanying drawings, wherein these drawings only serve to illustrate the embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure.

[0023] Figure 1 The linear comparison results before and after cleaning and maintaining the atomizer are shown. DETAILED DESCRIPTION

[0024] The following examples and experimental examples further illustrate the present application, which should not be construed as limiting the present application. The examples do not include detailed descriptions of the conventional methods, which are well known to those skilled in the art and are described in many publications.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art. In addition, any method and material similar or equivalent to those described herein can be used in the present application, and the preferred methods and materials described herein are only used for demonstration.

[0026] I. Preparation of cleaning solution

[0027] ​Cleaning solution A: Take 333.3333 g of 69% HNO3 + 135.1351 g of 37% HC1 + 33.3333 g of 30% H2O2, and make up to 1000 mL with ultrapure water (18.2 ) ;

[0028] Cleaning solution B: Take 72.4638 g of 69% HNO3 + 33.3333 g of 30% H2O2 + 20.4082 g of 49% HF, and make up to 1000 mL with ultrapure water (18.2 ) ;

[0029] Use PFA material containers to avoid acid corrosion; prepare the solution in a fume hood, and the operator should wear acid and alkali resistant gloves and a special protective mask.

[0030] II. Ultrasonic cleaning

[0031] (1) Ultrasonic treatment: completely immerse the disassembled atomizer in cleaning solution A, ensuring that all channels are filled with liquid. Ultrasonic power 300 W, ultrasonic temperature room temperature (avoid high temperature causing acid volatilization or atomizer deformation), ultrasonic for three hours.

[0032] (2) Rinse the atomizer: after ultrasonic treatment, rinse the atomizer with ultrapure water to ensure that there is no residual acid. Use high-purity nitrogen gas (99.999%) to dry the internal microchannels of the atomizer.

[0033] III. Online dynamic atomization cleaning

[0034] Connect the cleaned and dried atomizer to the atomization chamber, place the sample needle in cleaning solution B, and click "Syngistix" software interface System Tools → Nebulizer and Torch Gas → click diagnose. At this time, the atomizer starts to work, and the atomization state is observed. Normal should produce uniform and fine aerosol (if the atomization is unstable, check if the atomizer is blocked), and maintain this state for one night. Pay attention to monitor the liquid level of the waste liquid tank during cleaning to avoid overflow.

[0035] IV. Performance verification phase

[0036] 4.1 Click the power button in front of "Plasma" in the "control" interface of "Syngistix" software to ignite the plasma.

[0037] 4.2 After igniting the plasma, use the nitric acid solution within the shelf life (consistent with the acidity of the sample) to pump the sample, and continue for 5-10 minutes.

[0038] 4.3 Tuning, click "SmartTune", open the instrument tuning interface, click "[STD] performanceCheck" for performance test.

[0039] 4.4 Open the method, insert the sample tube into the standard blank solution after stabilization, and establish the standard curve.

[0040] V. Results

[0041] Table 1 shows the internal standard recovery rate after the maintenance of the atomizer. The results show that the internal standard recovery rate is between 80-120%, which meets the requirements.

[0042] Table 1 shows the internal standard recovery rate after the maintenance of the atomizer. The results show that the internal standard recovery rate is between 80-120%, which meets the requirements.

[0043]

[0044] Figure 1 The linear correlation coefficient R2 of W before cleaning the atomizer is <0.9995 (A), and the linear correlation coefficient R2 of W after cleaning the atomizer is >0.9995 (B). Figure 1 Figure 1 Figure 1

[0045] The data in Table 1 and Table 2 show that the method can effectively clean the atomizer and restore the normal use of the instrument. Figure 1

[0046] The unexplained parts involved in the present application are the same as the prior art or are realized by using the prior art. The applicant declares that the present application is illustrated by the above specific embodiments to explain the detailed method of the present application, but the present application is not limited to the above detailed method, that is, it does not mean that the present application must rely on the above detailed method to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.​​​​

Claims

1. A method for cleaning an ICP-MS atomizer, characterized in that, Includes the following steps: A. Ultrasonic cleaning The disassembled atomizer to be cleaned is completely immersed in cleaning solution A, which consists of HNO3, HCl, and H2O2. Ensure all channels are filled with liquid and sonicate at room temperature for 2-5 hours; after sonication, rinse the nebulizer with ultrapure water and dry the internal microchannels of the nebulizer with high-purity nitrogen; the concentration ratio of HNO3, HCl and H2O2 in cleaning solution A is 23:5:

1. B. Online dynamic atomization cleaning Prepare cleaning solution B, connect the cleaned and dried nebulizer to the nebulization chamber, and force it through the instrument diagnostic mode. The atomized pickling solution is allowed to flow fully through the microchannels inside the atomizer to remove dead volume residue; wherein, the cleaning solution B is composed of HNO3, H2O2 and HF, and the concentration ratio of the three is 5:1:1; C. Cleanliness Verification The cleanliness of the atomizer was judged by the internal standard recovery rate and the linearity of the standard curve.

2. The ICP-MS atomizer cleaning method according to claim 1, characterized in that: in, In step A, the preparation method of cleaning solution A is as follows: 69% HNO3, 37% HCl and 30% H2O2 are mixed in a mass ratio of 2.47:1:2.47, and then diluted to a predetermined volume with ultrapure water; In step B, the cleaning solution B is prepared as follows: 69% HNO3, 30% H2O2 and 49% HF are mixed in a mass ratio of 3.55 : 1.63 : 1, and then diluted to a predetermined volume with ultrapure water.

3. The ICP-MS atomizer cleaning method according to claim 1, characterized in that, Its features are: In step A, the ultrasonic power is 300W and the ultrasonic time is 3 hours.

4. The ICP-MS atomizer cleaning method according to claim 1, characterized in that: in, In step B, the atomizer starts working in diagnostic mode. By observing the atomization status, it is determined whether the atomizer is blocked: Normally, it should produce a uniform and fine aerosol. If the atomization is unstable, it is necessary to check whether the atomizer is blocked. Keep it in this state overnight to remove the W deposits deep in the Pt capillary.

5. The ICP-MS atomizer cleaning method according to claim 4, characterized in that: in, After cleaning and drying, connect the nebulizer to the nebulization chamber, place the injection needle into cleaning solution B, and click on the software interface to enter diagnostic mode.

6. The ICP-MS atomizer cleaning method according to claim 4, characterized in that: in, In step C, when determining the recovery rate of the internal standard, Rh(103) is selected as the internal standard, and the recovery rate is required to be between 80-120%. When determining the linearity of the standard curve, a metal mixed standard solution of 1-10 ppb is tested, and R2 is required to be >0.9995.

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