Quantitative detection method for potassium perfluorobutanesulfonate in high polymer material and application of quantitative detection method

Abstract

The invention belongs to the technical field of high polymer material detection, and discloses a quantitative detection method for potassium perfluorobutanesulfonate in a high polymer material and application of the quantitative detection method. According to the method, trichloromethane reflux extraction and methanol precipitation are adopted as pretreatment, and specific liquid chromatography-tandem mass spectrometry detection conditions are matched, so that excellent recovery rate and extremely low limit of quantitation are obtained, and the determination requirement of potassium perfluorobutanesulfonate in a high polymer material is met. In addition, the invention further provides a detection method for simultaneously detecting the content of the potassium perfluorobutanesulfonate and the content of the polytetrafluoroethylene in the high polymer material, the content of perfluorine in a sample is detected firstly, then the content of the potassium perfluorobutanesulfonate is detected by adopting the quantitative detection method, and the content of the polytetrafluoroethylene is calculated through the content of the potassium perfluorobutanesulfonate and the content of the polytetrafluoroethylene. The method provided by the invention is simple and easy to implement, high in accuracy and good in reproducibility.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material detection, and in particular to a quantitative detection method of potassium perfluorobutanesulfonate in polymer materials and application thereof. Background Art

[0002] Polymer materials, such as polycarbonate (PC) and ABS, are widely used in various sectors of the national economy and play an irreplaceable role in my country's industry, agriculture, national defense, transportation, construction, packaging, electronics and electrical engineering, information networks, and biomedicine. Currently, flame retardant systems for polymer materials mainly include three major systems: inorganic flame retardants, organophosphorus flame retardants, and organohalogen flame retardants. It is worth noting that one type of inorganic flame retardants is sulfonate flame retardants, such as potassium perfluorobutylsulfonate (KPFBS), which belongs to the category of per- and polyfluoroalkyl substances (PFASs). Due to their extremely high thermal and chemical stability, PFASs have high bioaccumulation capacity and physiological toxicity, and have significant impacts on the environment, organisms, and human health. With the increasing environmental protection requirements, PFASs are facing increasingly stringent regulatory policies. Currently, many countries and regions around the world have successively promulgated relevant regulations to restrict or replace the production and application of PFASs. In view of this, accurate qualitative and quantitative analysis of PFASs in polymer materials is currently an urgent need.

[0003] Patent publication number CN111505146A discloses a method for detecting residual potassium perfluorobutanesulfonate in plastics. The method uses dichloromethane extraction, HLB solid-phase extraction cleanup, and liquid chromatography-tandem mass spectrometry to determine the residual potassium perfluorobutanesulfonate in plastics. However, the limit of quantification of this method is only 0.01 mg / kg, and the spike recovery rate at a spike concentration of 0.2 μg / mL is less than 90%.

[0004] The document "Establishment of a High-Performance Liquid Chromatography-Mass Spectrometry Method for the Determination of Perfluorobutanesulfonic Acid in Plastics" discloses a quantitative method for potassium perfluorobutanesulfonate in plastics. It uses methanol-tetrahydrofuran extraction, pure water purification, and liquid chromatography-tandem mass spectrometry to determine the content of potassium perfluorobutanesulfonate in plastics. However, the quantitative limit of the above method is only 0.04 μg / L.

[0005] The dissertation "Establishment of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Detection of Perfluoroalkyl Compounds in Bovine Tissues and Food Packaging Materials" disclosed a method for detecting the content of potassium perfluorobutanesulfonate in plastic packaging materials. It used methanol extraction, WAX solid-phase extraction cleanup, and liquid chromatography-tandem mass spectrometry to determine the content of potassium perfluorobutanesulfonate in plastic packaging materials. However, the quantitative limit of the above method was only 0.4-1.0 μg / kg.

[0006] The above existing technologies provide a quantitative detection method for potassium perfluorobutanesulfonate in polymer materials. However, the quantitative limit of the above method is insufficient and the recovery rate is low, which cannot meet the current detection needs of potassium perfluorobutanesulfonate in polymer materials. Summary of the Invention

[0007] In order to solve the above technical problems existing in the prior art, the present invention provides a method for quantitative detection of potassium perfluorobutanesulfonate in polymer materials.

[0008] Another object of the present invention is to provide a method for simultaneously detecting the contents of potassium perfluorobutanesulfonate and polytetrafluoroethylene in polymer materials.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0010] The present invention claims protection for a method for quantitative determination of potassium perfluorobutanesulfonate in a polymer material, comprising the following steps:

[0011] Pretreatment: Mixing a polymer material sample containing potassium perfluorobutanesulfonate with chloroform and subjecting it to reflux extraction to obtain an extract; cooling the extract, adding methanol for precipitation, filtering, and obtaining a test solution;

[0012] On-machine detection: The test solution is detected by liquid chromatography-tandem mass spectrometry. The liquid chromatography detection conditions include: the separation column is a C18 chromatographic column with an average particle size of less than or equal to 3 μm, the mobile phase A is a 1-5 mM ammonium acetate aqueous solution, and the mobile phase B is methanol;

[0013] The elution program is as follows:

[0014] Time point / min Mobile phase B volume / % 0 10-30 0.5-2 10-30 3-6 80-100 6.1-9 1-20。

[0015] The present invention first mixes the polymer material sample containing potassium perfluorobutane sulfonate with chloroform and carries out reflux extraction, then adopts methanol to precipitate, obtains liquid to be measured.Adopt chloroform extraction-methanol precipitation system and the mode of adopting reflux extraction, can effectively extract the potassium perfluorobutane sulfonate in polymer material, avoid the influence of impurities such as small molecule auxiliary agents (such as antioxidant, anti-dripping agent etc.) on potassium perfluorobutane sulfonate in polymer material, can effectively separate potassium perfluorobutane sulfonate from impurities, can better extract potassium perfluorobutane sulfonate.The detection conditions used by the present invention can effectively separate potassium perfluorobutane sulfonate from other impurities in polymer material, improve detection sensitivity, improve quantitative limit and recovery rate.

[0016] Preferably, the ratio of chloroform to polymer material sample is 20-120 mL: 0.3-0.8 g; more specifically, the ratio is 50-110 mL: 0.5-0.8 g; more specifically, the ratio is 80-100 mL: 0.5-0.6 g.

[0017] Preferably, the reflux extraction time is ≥2 h; more specifically, the reflux extraction time is 2-4.5 h; more specifically, the reflux extraction time is 3-4 h; more specifically, the reflux extraction time is 3.5-4 h.

[0018] Preferably, the ratio of methanol to polymer material sample is 40-120 mL:0.3 g; more specifically, the ratio is 60-110 mL:0.3 g; more specifically, the ratio is 80-100 mL:0.3 g.

[0019] Preferably, the polymer material sample is selected from at least one of PC, ABS, PP, PC / ABS, PBT, PA6, and PA66. More specifically, the polymer material sample is selected from at least one of PC, ABS, and PC / ABS.

[0020] Preferably, the average particle size of the C18 chromatographic column is 1.5-3 μm; more specifically, the average particle size of the C18 chromatographic column is 1.5-2.7 μm; more specifically, the average particle size of the C18 chromatographic column is 1.7-2.0 μm.

[0021] Preferably, the mobile phase A is a 1.5-3 mM ammonium acetate aqueous solution. Specifically, the concentration of the ammonium acetate aqueous solution is 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, etc., or a range formed by any of the above values.

[0022] Preferably, the elution procedure is as follows:

[0023] Time point / min Mobile phase B volume / % 0 15-25 0.5-2 15-25 3-6 85-95 6.1-9 5-15。

[0024] Further preferably, the elution procedure is as follows:

[0025] Time point / min Mobile phase B volume / % 0 20 1 20 4 90 6 90 6.1 10 8 10。

[0026] Preferably, the liquid chromatography detection conditions are selected from at least one of the following (a)-(c):

[0027] (a) a flow rate of 0.1-0.5 mL / min, preferably 0.3 mL / min;

[0028] (b) the column temperature is 30-50°C, preferably 40°C;

[0029] (c) The injection volume is 1-3 μL, preferably 1 μL.

[0030] Preferably, the detection conditions of the tandem mass spectrometry are selected from at least one of the following (d)-(k):

[0031] (d) Ion source type: ESI;

[0032] (e) Working mode: multiple reaction detection negative ion mode;

[0033] (f) Capillary voltage: 2-3 kV, preferably 2.5 kV;

[0034] (g) cone voltage: 30-50 V, preferably 40 V;

[0035] (h) desolvation temperature: 300-550°C, preferably 450°C;

[0036] (i) desolvation flow rate: 800-1000 L / h, preferably 900 L / h;

[0037] (j) Low energy channel: 6 V, high energy channel: 20-60 V;

[0038] (k) The monitored ion pairs were: parent ion m / z 298.9, and product ions m / z 79.9 and m / z 298.9.

[0039] The present invention also claims protection for a method for simultaneously detecting the contents of potassium perfluorobutanesulfonate and polytetrafluoroethylene in a polymer material, comprising the following steps:

[0040] Detection of total fluorine content in polymer material samples containing potassium perfluorobutanesulfonate and polytetrafluoroethylene;

[0041] The above quantitative detection method is used to detect the content of potassium perfluorobutanesulfonate in the polymer material sample and convert it into the fluorine content in potassium perfluorobutanesulfonate;

[0042] The fluorine content in polytetrafluoroethylene is obtained by subtracting the fluorine content in potassium perfluorobutanesulfonate from the total fluorine content, which is then converted into polytetrafluoroethylene content.

[0043] Specifically, the total fluorine content can be detected by conventional methods in the art; more specifically, the detection method includes but is not limited to the alkali fusion method or the oxygen bottle combustion method.

[0044] Specifically, in some embodiments, the alkali fusion method is performed by mixing a polymer sample with an alkali, melting the mixture at 500-600°C, then heating the mixture to 600-700°C and continuing to melt the mixture, then removing the mixture and cooling it to room temperature. The frit is then mixed and dissolved with a solvent, followed by the addition of an alizarin S solution. The solution is neutralized with an acid until it just turns yellow, then adjusted with an alkali until it turns purple-red. A buffer solution is then added, the volume is fixed, and the fluoride ion selective electrode is used for measurement.

[0045] Specifically, the base can be any commonly used base in the art, including but not limited to sodium hydroxide and potassium hydroxide. Specifically, the melting time at 500-600°C is ≥ 3 minutes; preferably, the melting time is 3-10 minutes; more preferably, the melting time is 4-6 minutes. Specifically, the buffer solution can be any commonly used buffer solution in the art, including but not limited to sodium citrate-sodium chloride buffer solution.

[0046] Specifically, in some embodiments, the oxygen bottle combustion method is operated as follows: the polymer material sample is ignited and then placed in a buffer solution for full combustion, so that the buffer solution absorbs the fluorine-containing compound gas generated after the combustion of the polymer material standard sample, the volume is constant, and then the measurement is performed.

[0047] Specifically, in the alkali fusion method or the oxygen bottle combustion method, a fluoride ion selective electrode is used to test the potential in the solution, and a standard equation of the potential and the logarithm of the fluoride ion concentration is plotted. The sample potential is converted into fluoride ion concentration according to the standard equation, and then converted into total fluoride content.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The present invention provides a method for quantitatively detecting potassium perfluorobutanesulfonate in polymer materials. By using chloroform reflux extraction, methanol precipitation, and specific detection conditions, potassium perfluorobutanesulfonate in polymer materials is effectively extracted while avoiding the influence of other impurities in the sample matrix. The quantitative detection method provided by the present invention improves detection sensitivity, quantitative limit, and recovery rate.

[0050] (2) The present invention also provides a method for simultaneously detecting potassium perfluorobutanesulfonate and polytetrafluoroethylene in a polymer material. The method comprises first detecting the total fluorine content in the polymer material, then detecting the potassium perfluorobutanesulfonate content in the polymer material by the above method, and then calculating the polytetrafluoroethylene content based on the above two contents. The method is simple, easy to use, highly accurate, and reproducible. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The total ion current diagram of blank solvent and PC material extract containing potassium perfluorobutanesulfonate.

[0052] Figure 2 The parent ion (top) and product ion (bottom) mass spectra of potassium perfluorobutanesulfonate. DETAILED DESCRIPTION

[0053] The present invention is further described below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection claimed in the present invention.

[0054] The samples used in the present invention include the following types:

[0055] PC material, polycarbonate, PC-KPFBS / PTFE, Kingfa Science & Technology Co., Ltd. The PC material contains: 99.5 wt.% polycarbonate raw material, 0.1 wt.% antioxidant 1076, 0.1 wt.% antioxidant 168, 0.1 wt.% potassium perfluorobutanesulfonate, and 0.2 wt.% anti-drip agent (the anti-drip agent contains: 50 wt.% styrene-acrylonitrile copolymer, 50 wt.% polytetrafluoroethylene).

[0056] PC / ABS material, polycarbonate / acrylonitrile-butadiene-styrene copolymer, PC / ABS-KPFBS / PTFE, Kingfa Science & Technology Co., Ltd. The PC / ABS material contains: 79.5wt.% polycarbonate raw material, 20wt.% acrylonitrile-butadiene-styrene copolymer raw material, 0.1wt.% antioxidant 1076, 0.1wt.% antioxidant 168, 0.1wt.% potassium perfluorobutanesulfonate, 0.2wt.% anti-drip agent (the anti-drip agent contains: 50wt.% styrene-acrylonitrile copolymer, 50wt.% polytetrafluoroethylene).

[0057] ABS material, acrylonitrile-butadiene-styrene copolymer, ABS-KPFBS / PTFE, Kingfa Science & Technology Co., Ltd. ABS material contains: 99.5 wt.% acrylonitrile-butadiene-styrene copolymer, 0.1 wt.% antioxidant 1076, 0.1 wt.% antioxidant 168, 0.1 wt.% potassium perfluorobutanesulfonate, 0.2 wt.% anti-drip agent (the anti-drip agent contains: 50 wt.% styrene-acrylonitrile copolymer, 50 wt.% polytetrafluoroethylene).

[0058] Unless otherwise specified, the solution used in the present invention is prepared as follows:

[0059] 1. Prepare total ionic strength adjustment buffer (TISAB): weigh 50 g NaCl, 15 g sodium citrate dihydrate, and 50 mL glacial acetic acid respectively, stir and dissolve with about 500 mL deionized water, slowly add about 125 mL of 5 mol / L sodium hydroxide solution, adjust the pH to between 5.0 and 5.5, cool to room temperature, transfer to a 1000 mL volumetric flask, dilute to the mark with deionized water and shake well.

[0060] 2. Fluoride ion series standard solution (concentration of 100ug / mL): purchased from the National Nonferrous Metals and Electronic Materials Analysis and Testing Center. Accurately transfer the corresponding volume of fluorine standard stock solution into the sampling bottle according to the prepared concentration, and add TISAB to dilute to the following concentration points: 100ug / mL, 50ug / mL, 20ug / mL, 10ug / mL, 5ug / mL, 2ug / mL, and 1ug / mL.

[0061] 3. Prepare potassium perfluorobutanesulfonate series standard solutions: Accurately weigh 0.001g KPFBS standard, dissolve it in methanol and prepare 100mL of 10μg / mL standard solution stock solution. Use a pipette to dilute it in sequence to 0.01μg / mL, 0.02μg / mL, 0.05μg / mL, 0.1μg / mL, 0.2μg / mL, 0.5μg / mL and 1μg / mL standard solution. Transfer it to a sample vial through a 0.22μm organic filter membrane and then test it on the instrument.

[0062] Example 1 A quantitative method for potassium perfluorobutanesulfonate in polymer materials

[0063] (1) Weigh 0.3 g of the above-mentioned PC material sample and transfer it to a ground-mouth round-bottom flask. Add 20 mL of chloroform to the round-bottom flask, then place the round-bottom flask in a Soxhlet extractor with a condenser, heat at 100 ° C, reflux and extract for 4 hours, then take it out and let it stand for 5 minutes, then add 40 mL of methanol to precipitate the plastic matrix. After standing for 10 minutes, filter the precipitate in a funnel using a qualitative filter paper with a pore size of 30-50 μm and collect the filtrate. Use a hot plate to evaporate the chloroform / methanol solvent to about 1-2 mL of the collected filtrate at 100 ° C. After cooling, transfer the filtrate to a 25 mL volumetric flask, rinse the flask with methanol, and dilute to the scale to obtain the sample solution to be tested.

[0064] (2) The sample solution and KPFBS series standard solutions prepared in step (1) are injected into a liquid chromatography-tandem mass spectrometer for testing to obtain the target substance (KPFBS) concentration. The KPFBS content in the sample solution is calculated based on the target substance (KPFBS) concentration. The calculation formula for KPFBS content is shown in the following formula (1):

[0065]

[0066] Wherein, C represents the concentration of the target substance (KPFBS), in ug / mL; V represents the fixed volume, in mL; m represents the sample mass, in g; and KPFBS content represents the potassium perfluorobutanesulfonate content, in wt.%.

[0067] The detection conditions of liquid chromatography were as follows: mobile phase A was 2 mM ammonium acetate aqueous solution, mobile phase B was methanol, flow rate: 0.3 mL / min, column temperature: 40 °C, injection volume: 1 μL, separation column: ACQUITY BEH C18 column, column size is 2.1mm×50mm×1.7μm, elution procedure is as follows:

[0068] Time point / min Mobile phase B volume / % 0 20 1 20 4 90 6 90 6.1 10 8 10。

[0069] The detection conditions of tandem mass spectrometry were as follows: ion source type: ESI, operating mode: multiple reaction detection negative ion mode, capillary voltage: 2.5 kV, cone voltage: 40 V, desolvation temperature: 450 °C, desolvation flow rate: 900 L / h, low energy channel: 6 V, high energy channel: 20-60 V, and the monitoring ion pair parameters of KPFBS were parent ion m / z 298.9, daughter ion m / z 298.9, and m / z 79.9.

[0070] The total ion currents of blank solvent and PC material sample extract containing potassium perfluorobutanesulfonate, as well as the parent ion (upper) and daughter ion (lower) mass spectra of potassium perfluorobutanesulfonate are shown in Figure 2. Figure 1 and Figure 2 As shown ( Figure 1 The red box at 3.85 min is the retention time of potassium perfluorobutanesulfonate).

[0071] Example 2 A quantitative method for potassium perfluorobutanesulfonate in polymer materials

[0072] The difference between this embodiment and embodiment 1 is that the sample weighed in step (1) is PC / ABS material.

[0073] Example 3 A quantitative method for potassium perfluorobutanesulfonate in polymer materials

[0074] The difference between this embodiment and embodiment 1 is that the sample weighed in step (1) is ABS material.

[0075] Example 4 A method for simultaneously detecting the content of potassium perfluorobutanesulfonate and polytetrafluoroethylene in polymer materials

[0076] 1. Standard samples

[0077] PC material.

[0078] 2. Detection of perfluorinated content

[0079] (1) Sample melting: Accurately weigh 0.3 g of PC material and place it in a nickel crucible containing 2.5 g of sodium hydroxide. After mixing the PC material and sodium hydroxide, cover the surface with 1.5 g of sodium hydroxide and melt it in a muffle furnace at 550 °C for 5 min. Continue to heat it to 650 °C and continue melting. Take it out and cool it to room temperature.

[0080] (2) Fluoride sample transfer: Place the crucible in a 100 mL beaker, add 40 mL of hot water to soak the frit, add a few drops of ethanol, boil, wash out the crucible, cool to room temperature, transfer to a 50 mL volumetric flask, dilute with water to the mark, shake well, and dry filter using a 30-50 μm pore size qualitative filter paper in a funnel;

[0081] (3) Adjustment of alkalinity of sample solution: Take 5 mL of the filtrate and place it in a 25 mL volumetric flask. Add one drop of Alizarin S solution and neutralize with hydrochloric acid until the solution just turns yellow. Then use sodium hydroxide to adjust the solution to purple-red. Add 20 mL of sodium citrate-sodium chloride buffer solution and dilute with water to the mark and shake well to obtain the sample solution.

[0082] (4) Determination: The sample solution is poured into a beaker and placed on a magnetic stirrer for electromagnetic stirring. The potential of the sample solution and a series of fluoride ion standard solutions are measured in an ion activity meter using a fluoride ion selective electrode and a calomel reference electrode. After standing, the potential value on the ion meter is read and the standard equation of potential and logarithm of fluoride ion concentration E-lg c(F) is plotted. - ), the sample potential is converted into fluoride ion concentration according to the standard equation, and then converted into total fluorine content (F0 content (wt.%)) according to formula (2):

[0083]

[0084] Where C0 represents the concentration of the target substance (fluoride ion) in ug / mL; V0 represents the fixed volume in mL; m is the sample mass in g; F0 is the total fluorine content in wt.%.

[0085] 3. Determination of potassium perfluorobutanesulfonate

[0086] See step (2) of Example 1 to obtain.

[0087] 4. Determination of polytetrafluoroethylene

[0088] The fluorine content (F1 content (wt.%)) in potassium perfluorobutanesulfonate is calculated according to formula (3), which is as follows:

[0089] F1 content (wt.%) = KPFBS content (wt.%) × 0.51 (3).

[0090] The polytetrafluoroethylene content (PTFE content (wt.%)) was calculated according to formula (4):

[0091]

[0092] Example 5 A method for simultaneously detecting the content of potassium perfluorobutanesulfonate and polytetrafluoroethylene in polycarbonate materials

[0093] 1. Preparation of standard samples

[0094] PC material.

[0095] 2. Detection of perfluorinated content

[0096] (1) Accurately weigh 13 mg of polycarbonate powder sample containing potassium perfluorobutanesulfonate and polytetrafluoroethylene, wrap it with a small piece of ash-free filter paper, dip it in a small amount of anhydrous ethanol, ignite it, and quickly place it in a combustion bottle containing 20 mL of TISAB and filled with oxygen to fully burn (add a few drops of TISAB to the bottle mouth).

[0097] (2) Since the generated HF and other complex fluorine compound gases are highly reactive, they are completely absorbed by TISAB to generate fluoride ions after slight shaking and standing for about 20 minutes. After stirring evenly, transfer to a volumetric flask and dilute to the scale with buffer solution for later use.

[0098] (3) Determination: The sample solution was injected into a beaker and placed on a magnetic stirrer for electromagnetic stirring. The potential of the sample solution and each standard concentration point was measured in an ion activity meter using a fluoride ion selective electrode and a calomel reference electrode. After standing, the potential value on the ion meter was read. The standard equation of potential and logarithm of fluoride ion concentration, E-lg c(F-), was plotted. The sample potential was converted into fluoride ion concentration according to the standard equation, and then converted into total fluorine content according to formula (2) in Example 4.

[0099] 3. Determination of potassium perfluorobutanesulfonate

[0100] See Example 1.

[0101] 4. Determination of polytetrafluoroethylene

[0102] Calculated according to formulas (3) and (4) in Example 4.

[0103] Comparative Example 1

[0104] The difference between this comparative example and Example 1 is that the extraction solvent used in step (1) is dichloromethane, that is, dichloromethane is used instead of chloroform.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that the HLB solid phase extraction method is used for purification, and the specific steps are as follows:

[0107] In step (1) of Example 1, after heating and refluxing, the mixture was allowed to stand for 5 minutes and then centrifuged at 6000 r / min for 60 minutes. The supernatant was taken and nitrogen was blown to 1-2 mL. Methanol was added for redissolution to obtain the extract to be purified. The extract was passed through an HLB solid phase extraction column activated with methanol, and the solution washed with methanol was collected. The solution was then nitrogen blown to 1-2 mL, methanol solution was added for redissolution, and filtered through a 0.22 μm filter membrane to obtain the sample solution to be tested. The sample solution to be tested was tested according to step (2) of Example 1.

[0108] Comparative Example 3

[0109] The difference between this comparative example and Example 1 is that the chromatographic column used in step (2) is a C18 chromatographic column of the XSelect CSH model, with a size of 50 mm×2.1 mm×3.5 μm.

[0110] Comparative Example 4

[0111] The difference between this comparative example and Example 1 is that the elution procedure in step (2) is different. The specific elution procedure is as follows:

[0112] Time point / min Mobile phase B volume / % 0 3 1 25 9 85 10 97 12 (isocratic wash for 2 minutes) 97 15 97

[0113] Comparative Example 5

[0114] The difference between this comparative example and Example 1 is that in step (1), after adding chloroform, ultrasonic extraction is used for extraction.

[0115] The process conditions for ultrasonic extraction are as follows: weigh 0.3 g of PC material sample, transfer it to a 40 mL brown screw-capped bottle, add 20 mL of chloroform to the bottle and seal it, then place it in a 50°C ultrasonic water bath for 6 hours, add distilled water to the ultrasonic bath so that the water level of the water bath is higher than the solvent level in the beaker. Then take it out of the ultrasonic bath and let it stand for 5 minutes, then add 40 mL of methanol to precipitate the plastic matrix. After standing for 10 minutes, filter the precipitate using a qualitative filter paper with a pore size of 30-50 μm, and collect the filtrate. Use a hot plate to evaporate the chloroform / methanol solvent to about 1-2 mL of the collected filtrate at 100°C. After cooling, transfer the filtrate to a 25 mL volumetric flask, rinse the flask with methanol, and dilute to the scale to obtain the sample solution to be tested.

[0116] Comparative Example 6

[0117] The difference between this comparative example and Example 1 is that in step (1), after adding chloroform, extraction is carried out by stirring and dissolving.

[0118] The process conditions for stirring and dissolving are as follows: weigh 0.3g of PC material sample, transfer it to a 100mL beaker, add 20mL of chloroform and a stirrer to the cup and seal it, then place it in a 50℃ magnetic stirrer for 6h, add distilled water to the stirrer, and make the water level of the water bath higher than the solvent level in the beaker. Then take out the beaker and let it stand for 5min, then add 40mL of methanol to precipitate the plastic matrix. After standing for 10min, filter the precipitate using a qualitative filter paper with a pore size of 30-50μm, and collect the filtrate. Use a hot plate to evaporate the chloroform / methanol solvent to about 1-2mL at 100℃. After cooling, transfer the filtrate to a 25mL volumetric flask, rinse the flask with methanol, and dilute to the scale to obtain the sample solution to be tested.

[0119] Test Case

[0120] The recovery rate and quantitative limit of potassium perfluorobutanesulfonate in each embodiment and comparative example are shown in Table 1 below.

[0121] The recovery rate was calculated as follows: recovery rate (%) = (test concentration / theoretical concentration) × 100%.

[0122] The limit of quantification is the lowest quantifiable concentration when the signal-to-noise ratio is ≥10. The limit of quantification can be obtained by continuously injecting the above-configured potassium perfluorobutanesulfonate standard solutions of various concentrations and calculating the ratio of baseline noise to target peak signal intensity.

[0123] Table 1

[0124] Recovery rate / % Limit of quantification / mg / kg Example 1 99.98 0.001 Example 2 99.87 0.001 Example 3 99.94 0.001 Example 4 99.96 0.001 Example 5 99.95 0.001 Comparative Example 1 91.41 0.008 Comparative Example 2 85.69 0.02 Comparative Example 3 82.78 0.04 Comparative Example 4 83.16 0.04 Comparative Example 5 75.24 0.08 Comparative Example 6 79.35 0.08

[0125] As shown in Table 1, the method provided by the present invention for quantitatively detecting potassium perfluorobutanesulfonate in polymer materials exhibits excellent recovery and limit of quantification (LOQ), with a recovery rate of ≥99.87% and a LOQ of 0.001 mg / kg. This demonstrates that the method provided by the present invention has excellent accuracy and sensitivity and is applicable to the quantitative detection of potassium perfluorobutanesulfonate and polytetrafluoroethylene in a variety of polymer materials.

[0126] It can be seen from Example 1, Comparative Example 1 and Comparative Example 2 that an excellent pretreatment effect can be achieved by using chloroform for reflux extraction and then using methanol for precipitation, while using dichloromethane as the extraction solvent or using HLB solid phase extraction for purification is difficult to achieve the technical effect of the present invention.

[0127] It can be seen from Example 1 and Comparative Example 3 that it is difficult to achieve the technical effect of the present invention when a chromatographic column with a larger average particle size is used. This is because a chromatographic column with a larger average particle size will bring about problems such as mass transfer resistance, eddy diffusion and decreased selectivity of potassium perfluorobutanesulfonate, thereby reducing the overall separation effect.

[0128] It can be seen from Example 1 and Comparative Example 4 that a specific elution procedure is required to achieve the technical effect of the present invention.

[0129] It can be seen from Example 1, Comparative Example 5 and Comparative Example 6 that it is difficult to achieve the technical effect of the present invention by extracting potassium perfluorobutanesulfonate using either ultrasonic extraction or stirring and dissolving.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for quantitative detection of potassium perfluorobutanesulfonate in polymer materials, characterized in that: The following steps are involved: Pretreatment: mixing a polymer material sample containing potassium perfluorobutanesulfonate with chloroform and performing reflux extraction to obtain an extract; After the extract is cooled, methanol is added for precipitation, and the extract is filtered to obtain a test solution; On-machine detection: The test solution is detected by liquid chromatography-tandem mass spectrometry. The liquid chromatography detection conditions include: the separation column is a C18 chromatographic column with an average particle size of less than or equal to 3 μm, the mobile phase A is a 1-5 mM ammonium acetate aqueous solution, and the mobile phase B is methanol; The elution program is as follows:

2. The quantitative detection method according to claim 1, characterized in that The ratio of chloroform to polymer material sample is 20-120 mL: 0.3-0.8 g.

3. The quantitative detection method according to claim 1, characterized in that The reflux extraction time is ≥2h.

4. The quantitative detection method according to claim 1, characterized in that The ratio of the methanol to the polymer material sample is 40-120 mL: 0.3 g.

5. The quantitative detection method according to claim 1, characterized in that The polymer material sample is selected from at least one of PC, ABS, PP, PC / ABS, PBT, PA6, and PA66.

6. The quantitative detection method according to claim 1, characterized in that The average particle size of the C18 chromatographic column is 1.5-3 μm.

7. The quantitative detection method according to claim 1, characterized in that The elution procedure is as follows:

8. The quantitative detection method according to claim 1, characterized in that The detection conditions of the liquid chromatography are selected from at least one of the following (a)-(c): (a) Flow rate 0.1-0.5 mL / min; (b) Column temperature is 30-50°C; (c) The injection volume is 1-3 μL.

9. The quantitative detection method according to claim 1 or 8, characterized in that The detection conditions of the tandem mass spectrometry are selected from at least one of the following (d)-(k): (d) Ion source type: ESI; (e) Working mode: multiple reaction detection negative ion mode; (f) Capillary voltage: 2-3 kV; (g) Cone voltage: 30-50V; (h) Desolvation temperature: 300-550°C; (i) Desolventization flow rate: 800-1000 L / h; (j) Low energy channel: 6 V, high energy channel: 20-60 V; (k) The monitored ion pairs were: parent ion m / z 298.9, and product ions m / z 79.9 and m / z 298.

9.

10. A method for simultaneously detecting the content of potassium perfluorobutanesulfonate and polytetrafluoroethylene in polymer materials, characterized in that: The following steps are involved: Detection of total fluorine content in polymer material samples containing potassium perfluorobutanesulfonate and polytetrafluoroethylene; The quantitative detection method according to any one of claims 1 to 9 is used to detect the content of potassium perfluorobutanesulfonate in a polymer material sample, and the content is converted into the fluorine content in potassium perfluorobutanesulfonate; The fluorine content in polytetrafluoroethylene is obtained by subtracting the fluorine content in potassium perfluorobutanesulfonate from the total fluorine content, which is then converted into polytetrafluoroethylene content.

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