Method for simultaneously detecting multiple fluoro lithium salts in environmental medium
The detection challenge of various fluorinated lithium salts in environmental media was solved by using high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). High-precision detection of 11 fluorinated lithium salts was achieved, which is applicable to samples from lithium battery dismantling workshops and provides a systematic detection method.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-29
- Publication Date
- 2026-04-10
AI Technical Summary
Existing technologies lack a systematic approach to simultaneously, rapidly, selectively, and sensitively detect multiple fluorinated lithium salts in environmental media, especially those released into the surrounding environment during lithium battery recycling.
High-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to process environmental media samples through extraction, centrifugation, concentration, and filtration to establish a standard working curve. The concentrations of various lithium fluoride salts were then detected using LC-MS/MS. The specific steps included extraction with a methanol solution containing 0.1 wt% ammonia, ultrasonication and centrifugation, and detection using an XBridge BEH C18 column and a Triple Quad 5500 mass spectrometer.
This method enables simultaneous qualitative and quantitative analysis of 11 fluorinated lithium salts in environmental media. The detection method is highly accurate and applicable to dust, soil, and black powder samples from lithium battery dismantling workshops. It can detect a wide variety of samples and is stable, which is beneficial for the subsequent research and development of fluorinated lithium salts.
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Figure CN121831014A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of detection, and particularly relates to a method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium. BACKGROUND
[0002] With the transformation of global energy structure to low carbonization, lithium ion batteries have become the core power source in the field of new energy vehicles, energy storage systems and electronics due to their high energy density, long cycle life and environmental friendliness. Electrolyte is usually composed of lithium salt, organic solvent and functional additive, in which lithium salt is the basis for providing lithium ions and ensuring ionic conductivity. At present, the most widely used lithium salt in commercial electrolyte is lithium hexafluorophosphate, but new fluorinated lithium salts represented by lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide are gradually attracting attention and being applied to new generation high-performance batteries or as additives due to their potential advantages in thermal stability, electrochemical window, aluminum foil corrosion resistance or interface film forming properties.
[0003] However, in the recycling process of waste lithium ion batteries, fluorinated lithium salts as physically added chemicals are inevitably released into the surrounding environment, posing potential risks to the environment, ecology and human health. They may have persistence, bioaccumulation and toxicity, and are considered as potential new pollutants. At present, there are few studies on fluorinated lithium salts, and there is no systematic qualitative and quantitative detection method for fluorinated lithium salts. Therefore, it is an urgent technical requirement in the current lithium battery technology and environmental analysis field to develop an analysis method that can simultaneously, rapidly, highly selectively and highly sensitively detect multiple fluorinated lithium salts in environmental media. SUMMARY
[0004] In order to overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium.
[0005] The purpose of the present application is achieved by the following scheme:
[0006] A method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium, comprising the following steps:
[0007] (1) Pretreatment: The environmental medium to be tested is extracted with an extraction solvent, then the solid-liquid phase is separated by centrifugation, the supernatant is taken, concentrated, and then filtered to obtain a sample solution to be tested;
[0008] (2) Standard curve setting: a plurality of standard samples of fluorinated lithium salts are respectively prepared into standard working solutions with different concentration gradients by using solvents, then the standard working solutions with different concentrations of each standard sample of fluorinated lithium salts are respectively detected by using high performance liquid chromatography-tandem mass spectrometry (LC-MS / MS), and the concentration of the corresponding standard sample of fluorinated lithium salts in the standard working solution is taken as the abscissa and the peak area of the corresponding standard sample of fluorinated lithium salts in the standard working solution is taken as the ordinate, so as to respectively establish standard working curves of a plurality of fluorinated lithium salts;
[0009] (3) The pretreated sample solution in step (1) is tested according to the operation of high performance liquid chromatography-tandem mass spectrometry in step (2), then the peak area of each fluorinated lithium salt is substituted into the standard working curve of the corresponding fluorinated lithium salt in step (2) to obtain the corresponding concentration, and then the obtained concentration is converted to obtain the concentration of each fluorinated lithium salt in the environmental medium to be detected.
[0010] The environmental medium in step (1) is preferably at least one of dust in a lithium battery disassembly workshop, soil at the entrance of the workshop, and black powder in the workshop, wherein the black powder in the workshop refers to fine powder formed by grinding or high-temperature treatment of electrode materials (positive and negative active materials) after separating the shell, diaphragm, copper and aluminum foil after the pretreatment steps of disassembling, discharging, crushing and screening of waste lithium batteries.
[0011] The environmental medium in step (1) is preferably sieved to remove large impurities such as stones and leaves before pretreatment. The sieving is preferably through a 150 μm stainless steel screen.
[0012] The extraction solvent in step (1) is at least one of a methanol solution containing 0.1wt% ammonia, an acetonitrile solution containing 0.1wt% ammonia, and an ethyl acetate solution containing 0.1wt% ammonia, wherein the concentration of ammonia is ≥25wt%; preferably, the extraction solvent in step (1) is a methanol solution containing 0.1wt% ammonia.
[0013] The amount of the extraction solvent in step (1) satisfies: 0.5-3mL of the extraction solvent is used for every 20 mg of the environmental medium.
[0014] The extraction in step (1) is preferably vortexed at a speed of 2000 rpm for 6 min, and then ultrasonicated at a power of 300-500W for 20 min; the centrifugation in step (1) refers to centrifugation at 3800 rpm for 6 min.
[0015] In order to fully extract, the following solid can be repeatedly extracted after centrifugation, preferably 3 times, and then the supernatant is combined and concentrated to 500 μL under mild nitrogen.
[0016] The filtration membrane in step (1) refers to a 0.22 μm filtration membrane.
[0017] The fluorinated lithium salt in step (2) is at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(pentafluoroethylsulfonyl)imide, lithium (fluorosulfonyl)(trifluoromethylsulfonyl)imide, lithium [(nonafluorobutyl)sulfonyl][(trifluoromethyl)sulfonyl]imide, lithium bis(nonafiuorobutylsulfonyl)imide, lithium trifluoromethanesulfonate, lithium nonafluoro-1-butanesulfonate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoro(oxalato)borate.
[0018] The full name, abbreviation, CAS number, molecular formula, molecular weight and chemical structure of the 11 fluorinated lithium salts are shown in Table 1.
[0019] Table 1 Full name, abbreviation, CAS number, molecular formula, molecular weight and chemical structure of 11 fluorinated lithium salts
[0020]
[0021] The solvent in step (2) is at least one of methanol, acetonitrile and ethyl acetate, and is preferably methanol.
[0022] The concentration gradient in step (2) is preferably a concentration range of 1 ng / ml-100 ng / ml; more preferably, seven concentration gradients of standard working solutions are selected, i.e. 1 ng / ml, 2 ng / ml, 5 ng / ml, 10 ng / ml, 20 ng / ml, 50 ng / ml and 100 ng / ml. The concentration is calculated by the amount of the standard of the fluorinated lithium salt and the actual volume of the solvent.
[0023] In step (2), the standard working curve can also be prepared by the following method: a plurality of standard samples of fluorinated lithium salts are prepared into a mixed standard working solution with a solvent, a plurality of concentration gradients of the mixed standard working solution corresponding to each standard sample of the fluorinated lithium salt are set, and then the mixed standard working solution is detected by high performance liquid chromatography-tandem mass spectrometry (LC-MS / MS), the peak area of each standard sample of the fluorinated lithium salt in the mixed standard working solution is taken as the vertical coordinate, and the concentration of the corresponding standard sample of the fluorinated lithium salt in the mixed standard working solution is taken as the horizontal coordinate, and a plurality of corresponding standard working curves of the fluorinated lithium salts are established.
[0024] Preferably, when the mixed standard working solution is prepared, the concentrations of the plurality of standard samples of the fluorinated lithium salts in the mixed standard working solution are the same, and the range of the uniform concentration is 1 ng / ml-100 ng / ml.
[0025] More preferably, when the mixed standard working solution is prepared, preferably seven concentration gradient mixed standard working solutions are prepared, which are a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 1 ng / ml, a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 2 ng / ml, a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 5 ng / ml, a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 10 ng / ml, a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 20 ng / ml, a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 50 ng / ml, and a mixed standard working solution with the concentration of each of the plurality of fluorinated lithium salt standards being 100 ng / ml.
[0026] In step (2), the fluorinated lithium salt is detected using Exion LC AC high performance liquid chromatography combined with Triple Quad 5500 mass spectrometer (LC-MS / MS).
[0027] In step (2), the mobile phase A in the high performance liquid chromatography is a water solution containing 0.1wt% ammonia water, and the mobile phase B is a methanol solution containing 0.1wt% ammonia water, wherein the ammonia water refers to ammonia water with a mass percentage of ≥25%.
[0028] The gradient elution parameters include:
[0029] At time 0 ~ 1.5 min, a mixed solution composed of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 is used as the mobile phase, and the flow rate is 0.3 mL / min;
[0030] At time 1.5 ~ 5 min, the mixed solution composed of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 is increased to a mixed solution composed of 0.1% ammonia water in water and 0.1% ammonia water in methanol with a volume ratio of 0:100 as the mobile phase, and the flow rate is 0.3 mL / min;
[0031] At time 5 ~ 9 min, a mixed solution composed of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 0:100 is used as the mobile phase, and the flow rate is 0.3 mL / min;
[0032] At time 9 ~ 11 min, the mixed solution composed of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 0:100 is decreased to a mixed solution composed of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 as the mobile phase, and the flow rate is 0.3 mL / min;
[0033] Time 11~12 min: the mixed solution of 0.1wt% ammonia water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 was used as the mobile phase, and the flow rate was 0.3 mL / min;
[0034] The post-run used the mixed solution of 0.1wt% ammonia water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 as the mobile phase, and the flow rate was 0.3 mL / min, and the post-run time was 5 min.
[0035] An XBridge BEH C18 column (2.1 mm×100 mm, 2.5 µm) was used, the column temperature was 40 ℃, the injection volume was 5 µL, and the flow rate was 0.3 mL / min.
[0036] The mass spectrometry parameters were as follows: the ion source was ESI (negative mode), the detection mode was multiple reaction monitoring mode (MRM), the ion spray voltage was-4500V, and the ion source temperature was 450 ℃. The mass spectrometry collection time was 0~12 min.
[0037] Compared with the prior art, the method has the following advantages and beneficial effects:
[0038] The method for simultaneously detecting a plurality of fluorinated lithium salts in an environmental medium of the application adopts LC-MS / MS, can simultaneously qualitatively and quantitatively analyze 11 fluorinated lithium salts, has a large number of detection types, high detection method accuracy and stability, and is beneficial to the subsequent research and development of fluorinated lithium salts. BRIEF DESCRIPTION OF DRAWINGS
[0039] Figure 1 It is the chromatogram of a single ion channel of 11 fluorinated lithium salts at a concentration of 100 ng / ml.
[0040] Figure 2 It is the MRM chromatogram obtained after the sample to be tested in Example 1 is detected by LC-MS / MS.
[0041] Figure 3 It is the MRM chromatogram obtained after the sample to be tested in Example 2 is detected by LC-MS / MS.
[0042] Figure 4 It is the MRM chromatogram obtained after the sample to be tested in Example 3 is detected by LC-MS / MS. DETAILED DESCRIPTION
[0043] The present application will be further described in conjunction with the examples and the accompanying drawings, but the embodiments of the present application are not limited thereto. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, but are conventional products that can be purchased on the market.
[0044] The mass spectrometry parameters of the 11 fluorinated lithium salts in the LC-MS / MS analysis of the examples are shown in Table 2.
[0045] Table 2 Mass spectrometry parameters of 11 fluorinated lithium salts
[0046]
[0047] Bold is the quantitative ion pair, and the other pair is the qualitative ion pair
[0048] Example 1
[0049] The present example provides a method for analyzing fluorinated lithium salts in environmental solid matrices based on LC-MS / MS technology; the sample to be analyzed in the present example is a lithium battery disassembly workshop dust sample, and the method comprises the following steps:
[0050] Collect dust from a lithium battery disassembly workshop, and transfer it from a paper sampling bag to a clean aluminum foil; after sieving through a stainless steel screen (150 μm), a dust sample is obtained, which is stored in an amber glass jar at a temperature of -20℃ until analysis.
[0051] (1) Pretreatment method:
[0052] Weigh 20 mg of dust sample into a glass centrifuge tube; then add 3 mL of methanol solution containing 0.1wt% ammonia, vortex at 2000 rpm for 6 min, then ultrasonic at 400 W for 20 min, then centrifuge at 3800 r / min for 6 min, transfer the supernatant to another centrifuge tube, repeat the extraction three times, and combine the supernatant. Concentrate to 500 μL under mild nitrogen, then pass through a 0.22 μm filter membrane for instrument analysis;
[0053] (2) LC-MS / MS detection:
[0054] LC-MS / MS detection: Exion LC AC high performance liquid chromatography combined with Triple Quad 5500 mass spectrometer (LC-MS / MS). Mobile phase A is a water solution containing 0.1wt% ammonia, and mobile phase B is a methanol solution containing 0.1wt% ammonia, wherein the ammonia refers to ammonia with a mass percentage of 25%.
[0055] The mobile phase gradient is as follows: at time 0 ~ 1.5 min, a mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 80:20 is used as the mobile phase, and the flow rate is 0.3 mL / min;
[0056] At time 1.5 ~ 5 min, the mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 80:20 is increased to a mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 0:100, and the flow rate is 0.3 mL / min;
[0057] At time 5 ~ 9 min, a mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 0:100 is used as the mobile phase, and the flow rate is 0.3 mL / min;
[0058] At time 9 ~ 11 min, the mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 0:100 is decreased to a mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 80:20, and the flow rate is 0.3 mL / min;
[0059] At time 11 ~ 12 min, a mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 80:20 is used as the mobile phase, and the flow rate is 0.3 mL / min;
[0060] The post-run uses a mixed solution of 0.1wt% ammonia aqueous solution and 0.1wt% ammonia methanol solution with a volume ratio of 80:20 as the mobile phase, and the flow rate is 0.3 mL / min, and the post-run time is 5 min.
[0061] An XBridge BEH C18 column (2.1 mm x 100 mm, 2.5 µm) is used, the column temperature is 40 ℃, the injection volume is 5 µL, and the flow rate is 0.3 mL / min. The ion source is ESI (negative mode), the detection mode is multiple reaction monitoring mode (MRM), the ion spray voltage is -4500V, and the ion source temperature is 450 ℃. The mass spectrometry acquisition time is 0 ~ 12 min.
[0062] Eleven fluorinated lithium salt standard samples are prepared into 100 ng / ml methanol solutions with methanol, and then detected according to the LC-MS / MS detection step of step (2) above. The chromatograms of the eleven fluorinated lithium salts at a concentration of 100 ng / ml in a single ion channel are as follows: Figure 1as shown.
[0063] The MRM chromatogram obtained after LC-MS / MS detection of the solution to be tested in Example 1 is as shown. Figure 2
[0064] (3) Preparation of standard working curve:
[0065] Prepare 11 bottles of single fluorinated lithium salt standard solution with a concentration of 10 mg / mL using methanol, then mix equal volumes of single fluorinated lithium salt standard solution in the 11 bottles, and dilute with methanol to obtain 11 kinds of mixed standard working solution of single fluorinated lithium salt with concentrations of 1 ng / ml, 2 ng / ml, 5 ng / ml, 10 ng / ml, 20 ng / ml, 50 ng / ml and 100 ng / ml. Then detect the 11 kinds of mixed standard working solution with different concentration gradients by high performance liquid chromatography-tandem mass spectrometry (LC-MS / MS), take the peak area of fluorinated lithium salt in the mixed standard working solution as the vertical coordinate, and the concentration of the corresponding fluorinated lithium salt in the mixed standard working solution as the horizontal coordinate, and use the 11 points to obtain the standard working curve of each fluorinated lithium salt, and the corresponding linear equation and correlation coefficient are shown in Table 3.
[0066] (4) Matrix standard addition recovery rate: add 11 kinds of fluorinated lithium salt standard to 20 mg of dust without fluorinated lithium salt, and the addition amount of each fluorinated lithium salt standard is 1 ng, then repeat the pretreatment operation of step (1) to obtain solution 1; add 11 kinds of fluorinated lithium salt standards to methanol at the same time, each fluorinated lithium salt is 1 ng, and dilute to 500 µL to obtain solution 2; detect both solutions by LC-MS / MS according to the parameters of step (2) and compare, and the matrix standard addition recovery rate of each fluorinated lithium salt is obtained by the ratio of the peak area of solution 1 to solution 2. The specific values are shown in Table 3.
[0067] (5) Matrix effect: weigh 20 mg of dust without fluorinated lithium salt, then repeat the pretreatment operation of step (1) to obtain the matrix solvent. Add 11 kinds of fluorinated lithium salt standards to the matrix solvent at the same time, each fluorinated lithium salt is 1 ng, and dilute to 500 µL to obtain solution 1; at the same time, add 11 kinds of fluorinated lithium salt standards to methanol at the same time, each fluorinated lithium salt is 1 ng, and dilute to 500 µL to obtain solution 2; detect both solutions by LC-MS / MS according to the parameters of step (2) and compare, and the matrix effect of each fluorinated lithium salt is obtained by the ratio of the peak area of solution 1 to solution 2.
[0068] (6) Solvent blank and program blank:
[0069] Solvent blank refers to using the same pure solvent (methanol) as the sample pretreatment as "sample" for on-machine analysis. It does not contain any analyte or sample matrix, and is used to evaluate whether there is pollution or interference in the whole analysis system (from sample injection to detection).
[0070] Procedure blank refers to using high-purity solvent (methanol) instead of actual sample, then going through the same complete sample pretreatment process as the real sample, and finally analyzing on the machine. Monitor whether it is contaminated by the outside world during the experiment.
[0071] (7) Method detection limit
[0072] The method detection limit is calculated by 3 times the signal-to-noise ratio. Table 3 analyzes the sample with 1 ng of each fluorinated lithium salt standard added to the 20 mg dust sample matrix. The results are shown in Table 3.
[0073] Table 3 Quality assurance and quality control (QA / QC) data of 11 fluorinated lithium salts in dust samples
[0074]
[0075] ND means not detected
[0076] As can be seen from Table 3, the test method of the present application has good accuracy.
[0077] Example 2
[0078] The present embodiment provides a method for analyzing fluorinated lithium salts in environmental solid matrix based on LC-MS / MS technology; the analysis of the sample to be tested in this embodiment is a soil sample collected at the entrance of a lithium battery disassembly workshop, and this method comprises the following steps:
[0079] Soil is collected at the entrance of a lithium battery disassembly workshop and transferred from a paper sampling bag to a clean aluminum foil; after sieving through a stainless steel screen (150 μm), 20 mg of soil sample is obtained and stored in an amber glass jar at a temperature of -20 ℃ until analysis.
[0080] (1) Pretreatment method:
[0081] The same as Example 1.
[0082] (2) LC-MS / MS detection:
[0083] The same as Example 1.
[0084] The MRM chromatogram obtained after LC-MS / MS detection of the solution to be tested in Example 2 is shown in Figure 3 .
[0085] (3) Drawing of standard working curve:
[0086] The same as Example 1.
[0087] (4) Matrix spike recovery rate: 11 kinds of fluorinated lithium salt standards were added to 20 mg of soil without fluorinated lithium salt, and the addition amount of each fluorinated lithium salt standard was 1 ng. Then the pretreatment operation of step (1) was repeated to obtain solution 1. 11 kinds of fluorinated lithium salt standards were simultaneously added to methanol, and each fluorinated lithium salt was 1 ng, and the volume was made to 500 µL to obtain solution 2. The two solutions were detected by LC-MS / MS according to the parameters of step (2) and compared. Through the peak area ratio of solution 1 and solution 2, the matrix spike recovery rate of each fluorinated lithium salt was obtained.
[0088] (5) Matrix effect: 20 mg of soil without fluorinated lithium salt was weighed, and then the pretreatment operation of step (1) was repeated to obtain a matrix solvent. 11 kinds of fluorinated lithium salt standards were simultaneously added to the matrix solvent, and each fluorinated lithium salt was 1 ng, and the volume was made to 500 µL to obtain solution 1. At the same time, 11 kinds of fluorinated lithium salt standards were simultaneously added to methanol, and each fluorinated lithium salt was 1 ng, and the volume was made to 500 µL to obtain solution 2. The two solutions were detected by LC-MS / MS according to the parameters of step (2) and compared. Through the peak area ratio of solution 1 and solution 2, the matrix effect of each fluorinated lithium salt was obtained.
[0089] (6) Solvent blank and program blank:
[0090] The same as Example 1.
[0091] (7) Method detection limit
[0092] The method detection limit is calculated by 3 times the signal-to-noise ratio. Table 4 analyzes the standard sample in which 1 ng of each fluorinated lithium salt standard is added to 20 mg of soil. See Table 4 for details.
[0093] Table 4 Quality assurance and quality control (QA / QC) data of 11 kinds of fluorinated lithium salts in soil samples
[0094]
[0095] ND indicates not detected
[0096] Example 3
[0097] The present embodiment provides a method for analyzing fluorinated lithium salts in environmental media based on LC-MS / MS technology. The analysis sample of the present embodiment is black powder in a lithium battery disassembly workshop. The method comprises the following steps:
[0098] The black powder was collected from the raw materials in the lithium battery disassembly workshop, and was transferred from the paper sample bag to a clean aluminum foil. After sieving through a stainless steel filter screen (150 μm), a 20 mg sample of the black powder was obtained and stored in an amber glass jar at a temperature of -20 ℃ until analysis.
[0099] (1) Pretreatment method:
[0100] The same as in Example 1.
[0101] The MRM chromatogram obtained after LC-MS / MS detection of the test solution in Example 3 is shown in Figure 4 .
[0102] (2) LC-MS / MS detection:
[0103] The same as in Example 1.
[0104] (3) Preparation of standard working curve:
[0105] The same as in Example 1.
[0106] (4) Matrix spike recovery: 11 kinds of fluorinated lithium salt standards were added to 20 mg of black powder not containing fluorinated lithium salts, with each fluorinated lithium salt standard having an addition amount of 1 ng. Then, the pretreatment operation of step (1) was repeated to obtain solution 1. The 11 kinds of fluorinated lithium salt standards were simultaneously added to methanol, with each fluorinated lithium salt being 1 ng, and the volume was made up to 500 μL to obtain solution 2. Both solutions were subjected to LC-MS / MS detection according to the parameters of step (2) and compared. Through the peak area ratio of solution 1 and solution 2, the matrix spike recovery of each fluorinated lithium salt was obtained.
[0107] (5) Matrix effect: 20 mg of black powder not containing fluorinated lithium salts was weighed, and then the pretreatment operation of step (1) was repeated to obtain a matrix solvent. The 11 kinds of fluorinated lithium salt standards were simultaneously added to the matrix solvent, with each fluorinated lithium salt being 1 ng, and the volume was made up to 500 μL to obtain solution 1. At the same time, the 11 kinds of fluorinated lithium salt standards were simultaneously added to methanol, with each fluorinated lithium salt standard being 1 ng, and the volume was made up to 500 μL to obtain solution 2. Both solutions were subjected to LC-MS / MS detection according to the parameters of step (2) and compared. Through the peak area ratio of solution 1 and solution 2, the matrix effect of each fluorinated lithium salt was obtained.
[0108] (6) Solvent blank and procedural blank:
[0109] The same as in Example 1.
[0110] (7) Method detection limit
[0111] The 3-fold signal-to-noise ratio calculation method was used to detect the limit of the sample in Table 5. The sample was prepared by adding 1 ng of each fluorinated lithium salt standard to 20 mg of black powder matrix. See Table 5 for details.
[0112] Table 5. Quality assurance and quality control (QA / QC) data of 11 fluorinated lithium salts in black powder samples
[0113]
[0114] ND indicates not detected
[0115] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are included in the protection scope of the present application.
Claims
1. A method for the simultaneous detection of a plurality of fluoro-lithium salts in an environmental medium, characterized in that The method comprises the following steps: (1) Pretreatment: The environmental medium to be tested is extracted with an extraction solvent, and then the solid-liquid phases are separated by centrifugation, the supernatant is taken, concentrated, and then filtered to obtain a sample solution to be tested; (2) Standard curve setting: A plurality of standard samples of fluorinated lithium salts are respectively prepared into standard working solutions with different concentration gradients by using a solvent, and then the standard working solutions with different concentrations of each fluorinated lithium salt standard sample are detected by using high performance liquid chromatography-tandem mass spectrometry, the concentration of the corresponding fluorinated lithium salt standard sample in the standard working solution is taken as the abscissa, and the peak area of the corresponding fluorinated lithium salt standard sample in the standard working solution is taken as the ordinate, and then a standard working curve of the plurality of fluorinated lithium salts is respectively established; (3) The sample solution to be tested after pretreatment in step (1) is tested according to the operation of high performance liquid chromatography-tandem mass spectrometry in step (2), then the peak area of each fluorinated lithium salt is substituted into the standard working curve of the corresponding fluorinated lithium salt in step (2) to obtain the corresponding concentration, and then the obtained concentration is converted to obtain the concentration of each fluorinated lithium salt in the environmental medium to be tested.
2. The method for simultaneously detecting a plurality of fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: The fluorinated lithium salt in step (2) is at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(pentafluoroethylsulfonyl)imide, lithium (fluorosulfonyl)(trifluoromethylsulfonyl)imide, lithium [(nonafluorobutyl)sulfonyl][(trifluoromethyl)sulfonyl]imide, lithium bis(nonafiuorobutylsulfonyl)imide, lithium trifluoromethanesulfonate, lithium nonafluoro-1-butanesulfonate, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate.
3. The method for simultaneously detecting a plurality of fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: The environmental medium in step (1) is at least one of dust in a lithium battery disassembly workshop, soil at the entrance of the workshop, and black powder in the workshop, wherein the black powder in the workshop refers to fine powder formed by grinding or high-temperature treatment of positive and negative active materials after the shell, separator, and copper-aluminum foil are separated from the waste lithium battery after pretreatment such as discharging, disassembly, crushing, and screening; The environmental medium in step (1) is sieved to remove large impurities before pretreatment, wherein the sieving is performed through a 150 μm stainless steel sieve; In step (1), the solid is repeatedly extracted after centrifugation to ensure sufficient extraction, and then the supernatants are combined and concentrated to 500 μL under mild nitrogen; and the filter membrane in step (1) refers to a 0.22 μm filter membrane.
4. The method for simultaneously detecting a plurality of fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: The extraction solvent in step (1) is at least one of a methanol solution containing 0.1wt% ammonia, an acetonitrile solution containing 0.1wt% ammonia, and an ethyl acetate solution containing 0.1wt% ammonia, wherein the concentration of ammonia is ≥25wt%; The amount of the extraction solvent used in step (1) satisfies: 0.5-3 mL of the extraction solvent is used for every 20 mg of the environmental medium. The extraction in step (1) is vortexed for 6 min at a rotation speed of 2000 rpm, and then ultrasonicated for 20 min at a power of 300-500 W; the centrifugation in step (1) is performed at a rotation speed of 3800 rpm for 6 min.
5. The method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: The solvent in step (2) is at least one of methanol, acetonitrile, and ethyl acetate; The concentration gradient in step (2) is in the range of 1 ng / ml-100 ng / ml.
6. The method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: In step (2), the standard working curve is also prepared by the following method: a plurality of standard samples of fluorinated lithium salts are prepared into a mixed standard working solution with a solvent, a plurality of concentration gradients of the mixed standard working solution are set for each standard sample of fluorinated lithium salt, and then the mixed standard working solution is detected by high performance liquid chromatography-tandem mass spectrometry, the peak area of each standard sample of fluorinated lithium salt in the mixed standard working solution is taken as the vertical coordinate, and the concentration of the corresponding standard sample of fluorinated lithium salt in the mixed standard working solution is taken as the horizontal coordinate, and the corresponding standard working curve of each fluorinated lithium salt is established.
7. The method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium according to claim 1 or 6, characterized in that: The solvent in step (2) is at least one of methanol, acetonitrile, and ethyl acetate; The concentration gradient in step (2) is in the range of 1 ng / ml-100 ng / ml.
8. The method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: In step (2), the mobile phase A in the high performance liquid chromatography is a water solution containing 0.1wt% ammonia water, the mobile phase B is a methanol solution containing 0.1wt% ammonia water, the ammonia water refers to ammonia water with a mass percentage of ≥25%, an XBridge BEH C18 chromatographic column is used, the column temperature is 40 ℃, the injection amount is 5 µL, and the flow rate is 0.3 mL / min.
9. The method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium according to claim 8, characterized in that: The gradient elution parameters include: At time 0-1.5 min, a mixed solution of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 is used as the mobile phase, and the flow rate is 0.3 mL / min; At time 1.5-5 min, the mixed solution of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 80:20 is changed to a mixed solution of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 0:100 as the mobile phase, and the flow rate is 0.3 mL / min; At time 5-9 min, a mixed solution of 0.1wt% ammonia water in water and 0.1wt% ammonia water in methanol with a volume ratio of 0:100 is used as the mobile phase, and the flow rate is 0.3 mL / min; Time 9 ~ 11 min: the mixed solution consisting of 0.1wt% ammonia water aqueous solution and 0.1wt% ammonia water methanol solution with a volume ratio of 0:100 to 80:20 is used as the mobile phase, and the flow rate is 0.3 mL / min; Time 11 ~ 12 min: the mixed solution consisting of 0.1wt% ammonia water aqueous solution and 0.1wt% ammonia water methanol solution with a volume ratio of 80:20 is used as the mobile phase, and the flow rate is 0.3 mL / min; The post-run uses the mixed solution consisting of 0.1wt% ammonia water aqueous solution and 0.1wt% ammonia water methanol solution with a volume ratio of 80:20 as the mobile phase, and the flow rate is 0.3 mL / min, and the post-run time is 5 min.
10. The method for simultaneously detecting multiple fluorinated lithium salts in an environmental medium according to claim 1, characterized in that: The mass spectrometry parameters are: the ion source is ESI negative mode, the detection mode is multiple reaction monitoring mode, the ion spray voltage is -4500V, the ion source temperature is 450℃; and the mass spectrometry collection time is 0 ~ 12min.