Detection method of bis (2, 4-dicumyl phenyl) pentaerythritol diphosphite and application of bis (2, 4-dicumyl phenyl) pentaerythritol diphosphite

Abstract

The invention discloses a detection method of bis (2, 4-dicumyl phenyl) pentaerythritol diphosphite and application thereof, and relates to the technical field of detection. The detection method comprises the following steps: carrying out reflux extraction on a plastic sample by using tetrahydrofuran to obtain a solution to be detected; and analyzing the bis (2, 4-dicumyl phenyl) pentaerythritol diphosphite in the solution to be detected by adopting a liquid chromatography-mass spectrometry method. According to the detection method, the sample pretreatment step is simple and convenient, quantitative analysis of trace bis (2, 4-dicumyl phenyl) pentaerythritol diphosphite in the plastic sample can be realized, the detection limit and the quantitation limit are low, the precision is good, the adding standard recovery rate is high, the effect of early peak appearance time can also be realized by adjusting the detection conditions, and the method is suitable for large-scale popularization and application. Meanwhile, the matrix interference is reduced, the response and separation effects are improved, and the method is particularly suitable for detecting the content of bis (2, 4-dicumyl phenyl) pentaerythritol diphosphite in a food contact material.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and in particular to a detection method for bis(2,4-dicumylphenyl)pentaerythritol diphosphite and application thereof. Background Art

[0002] Bis(2,4-dicumylphenyl)pentaerythritol diphosphite is a hydrolytically stable phosphite with high molecular weight, low volatility, and high phosphorus content. It exhibits high thermal stability and low volatility under prolonged high-temperature conditions, effectively preventing yellowing during high-temperature processing of various engineering plastics, particularly PC, PA, PP, and ABS, and providing high-temperature degradation protection. However, in the field of food contact materials, bis(2,4-dicumylphenyl)pentaerythritol diphosphite can migrate from packaging materials into food, and the degradation products of phosphites may be potentially toxic, threatening food safety. Therefore, for food contact materials, detecting the content of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastics is one of the important ways to assess their safety.

[0003] However, current research on bis(2,4-dicumylphenyl)pentaerythritol diphosphite is focused on synthesis methods and application processes. Spectroscopic methods are commonly used for content analysis. However, the solubility of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastics is low, and there is interference from other plastic additives. Furthermore, bis(2,4-dicumylphenyl)pentaerythritol diphosphite lacks strong absorption characteristics in the UV-visible region (maximum absorption wavelength <230nm). Direct UV detection results in a low signal-to-noise ratio (S / N), making it difficult to accurately analyze its content using spectroscopic methods. Mass spectrometry is also an important detection method, but its detection is susceptible to interference from oligomers co-extracted from the plastic matrix, resulting in matrix effects and similarly unsatisfactory detection results. Summary of the Invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention provides a method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite. By performing special pretreatment on plastic samples and combining liquid chromatography-mass spectrometry for detection, the present invention can achieve qualitative and quantitative analysis of bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0005] A second aspect of the present invention provides an application of a method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A first aspect of the present invention provides a method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite, comprising the following steps: reflux extraction of a plastic sample using tetrahydrofuran to obtain a test solution; and analyzing the bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the test solution using liquid chromatography-mass spectrometry.

[0008] The present invention uses a specific extractant tetrahydrofuran to perform reflux extraction on the sample to be tested. Compared with other organic solvents as extractants, tetrahydrofuran extraction can successfully produce the target parent ion ([M+H] + =855 m / z), thus avoiding the problem of target degradation or addition with other ions during the extraction process, resulting in the inability to produce target parent ions.

[0009] The target precursor ion is the intact charged ion selected by the primary mass analyzer in mass spectrometry analysis. It is subsequently fragmented through collision-induced dissociation and other methods to generate product ions, which can be used for quantitative analysis. In liquid chromatography-mass spectrometry, the inability to generate the target precursor ion or insufficient target precursor ions can result in missing target peaks or reduced signal intensity, making it impossible to meet the requirements of trace analysis.

[0010] In addition, the sample preparation steps for reflux extraction using tetrahydrofuran are relatively simple and the required sample preparation time is relatively short.

[0011] Preferably, the reflux time is 1 to 3 hours.

[0012] More preferably, the reflux time is 2 to 3 hours.

[0013] The reflux time affects the extraction efficiency. A suitable reflux time can help improve the extraction efficiency.

[0014] Preferably, during the reflux process, the number of reflux cycles per hour is ≥10 times.

[0015] Further preferably, during the reflux process, the number of reflux cycles per hour is 10 to 20 times.

[0016] More preferably, during the reflux process, the number of reflux cycles per hour is 10 to 15 times.

[0017] The number of reflux cycles per hour refers to the number of reflux cycles completed within an hour. This number also affects the extraction efficiency. An appropriate number of cycles is conducive to improving the extraction efficiency.

[0018] Preferably, after the reflux extraction, the method further comprises the steps of volume fixing and filtering; the volume fixing step comprises using tetrahydrofuran to fix the volume of the extracted solution to 195-205 mL, taking 1-2 mL of the fixed volume solution and filtering it through a 0.2-0.3 μm filter membrane to obtain a solution to be tested.

[0019] Further preferably, the filter membrane is a 0.21-0.23 μm filter membrane.

[0020] Preferably, the reflux extraction is performed using a Soxhlet extractor.

[0021] Preferably, in the liquid chromatography-mass spectrometry method, the elution mode of the liquid chromatography is isocratic elution, and the mobile phase is at least one of acetonitrile, water and acetonitrile, ammonium acetate solution and acetonitrile.

[0022] Preferably, the elution mode of the liquid chromatography is isocratic elution, and the mobile phase is water and acetonitrile; the volume ratio of the water to the acetonitrile is 1:(6-10).

[0023] More preferably, the volume ratio of the water to the acetonitrile is 1:(8-10).

[0024] More preferably, the volume ratio of the water to the acetonitrile is 1:(8.5-9.5).

[0025] More preferably, the volume ratio of water to acetonitrile is 1:(8.8-9.2).

[0026] More preferably, the flow rate of the mobile phase is 0.2 to 0.4 mL / min.

[0027] More preferably, the flow rate of the mobile phase is 0.25 to 0.35 mL / min.

[0028] Preferably, in the liquid chromatography-mass spectrometry method, the specification of the liquid chromatography column is 2.1×100 mm, and the filler particle size is 2.5-3 μm.

[0029] Preferably, in the liquid chromatography-mass spectrometry method, the liquid chromatography column is a CORTECS C18 column.

[0030] Preferably, in the liquid chromatography-mass spectrometry method, the column temperature of the liquid chromatography is 35-45°C.

[0031] More preferably, the column temperature of the liquid chromatography column is 38-42°C.

[0032] Optimization of the chromatographic column and mobile phase can shorten the peak elution time.

[0033] Preferably, in the liquid chromatography-mass spectrometry method, the injection volume of the liquid chromatography is 1 to 2 μL.

[0034] Preferably, in the liquid chromatography-mass spectrometry method, during the mass spectrometry detection process, the desolvation temperature is 350-750°C.

[0035] More preferably, the desolvation temperature is 550-750°C

[0036] More preferably, the desolvation temperature is 600-700°C.

[0037] More preferably, the desolvation temperature is 630-670°C.

[0038] More preferably, the desolvation temperature is 645-655°C.

[0039] Preferably, in the liquid chromatography-mass spectrometry method, the mass spectrometry detection conditions further include at least one of the following: a) to g):

[0040] a) Ion source: electrospray ion source;

[0041] b) Capillary voltage: 3-4kV;

[0042] c) Desolventization gas flow rate: 700-900 L / Hr;

[0043] d) Cone hole air flow rate: 8~15L / Hr;

[0044] e) Cone voltage: 35~45V;

[0045] f) Mass spectrometry acquisition mode: positive ion mode, select 885-886 m / z ion monitoring;

[0046] g) Dwell time: 0.2~0.3s.

[0047] Further preferably, the capillary voltage is 3.2-3.8 kV.

[0048] More preferably, the desolvation gas flow rate is 750 to 850 L / Hr.

[0049] More preferably, the desolvation gas flow rate is 780-820 L / Hr.

[0050] Preferably, the desolvation gas flow rate is 795-805 L / Hr.

[0051] Further preferably, the cone hole gas flow rate is 8 to 12 L / Hr.

[0052] More preferably, the cone hole gas flow rate is 9 to 11 L / Hr.

[0053] Further preferably, the cone voltage is 38-42V.

[0054] Further preferably, the mass spectrometry acquisition selects 885.5-885.7 m / z ions for monitoring.

[0055] More preferably, the residence time is 0.21 to 0.22 s.

[0056] Preferably, the detection method further comprises the following steps:

[0057] A standard working solution is prepared by dissolving bis(2,4-dicumylphenyl)pentaerythritol diphosphite; the standard working solution is subjected to liquid chromatography-mass spectrometry analysis to obtain a standard working curve with concentration as the horizontal axis and peak area as the vertical axis; the standard working curve is used for quantitative analysis of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the plastic sample.

[0058] Further preferably, the preparation of the standard working solution comprises the following steps:

[0059] Dissolve bis(2,4-dicumylphenyl)pentaerythritol diphosphite in tetrahydrofuran to prepare a standard stock solution; dilute the standard stock solution with tetrahydrofuran to obtain a 0.1-2 mg / L standard working solution.

[0060] Specifically, the concentration of the standard stock solution may be 1000 mg / L; the concentration of the standard working solution may be 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1 mg / L and 2 mg / L.

[0061] Preferably, the detection limit of the detection method of the bis(2,4-dicumylphenyl)pentaerythritol diphosphite is 0.6883 mg / kg; the quantification limit of the bis(2,4-dicumylphenyl)pentaerythritol diphosphite is 2.2943 mg / kg.

[0062] The second aspect of the present invention provides an application of the detection method described in the first aspect of the present invention in detecting the content of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in food contact materials.

[0063] Preferably, the food contact material is made of plastic.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] 1) The bis(2,4-dicumylphenyl)pentaerythritol diphosphite detection method of the present invention can perform qualitative and quantitative analysis of trace bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastics. The plastic sample is pretreated by tetrahydrofuran reflux extraction, and the target parent ion is successfully generated during mass spectrometry analysis. The pretreatment steps are relatively simple and do not require complicated operations or excessive processing time. The obtained test solution can serve as the basis for liquid chromatography-mass spectrometry analysis. In combination with liquid chromatography-mass spectrometry, quantitative analysis of trace bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastics can be achieved.

[0066] 2) The present invention further adjusts the conditions during reflux extraction to help improve the extraction efficiency, increase the concentration of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the test solution, and more accurately detect the content of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the plastic sample.

[0067] 3) By further adjusting the detection conditions, such as the mobile phase, chromatographic column, and desolvation temperature, the present invention can make the peak elution time earlier, no more than 3 minutes. A symmetrical chromatographic separation peak can be obtained as early as around 2.71 minutes, and there is no interference from other impurity peaks near the retention time. It is also beneficial to reduce the matrix interference received, improve the signal response intensity and separation effect.

[0068] 4) The detection method of the present invention can realize the quantitative analysis of trace amounts of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastic samples, and has low detection limits and quantification limits, good precision, and high spike recovery. It is particularly suitable for detecting the content of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in food contact materials and realizing trace detection of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in contact materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 The mass spectra obtained after extraction with different extraction solvents in Example 1 and Comparative Example 1 are shown; wherein, Figure 1 The extraction solvents corresponding to Figures a, b, and c are methanol, acetonitrile, and tetrahydrofuran, respectively.

[0070] Figure 2 This is a graph showing the change in extraction efficiency under different reflux cycle numbers in Example 2.

[0071] Figure 3 This is a graph showing the change in extraction efficiency at different reflux extraction times in Example 3.

[0072] Figure 4 This is the chromatogram obtained when the mobile phase is methanol in Example 4.

[0073] Figure 5 The chromatogram obtained when the mobile phase is acetonitrile in Example 4 is shown in FIG.

[0074] Figure 6 The chromatogram obtained when the mobile phase in Example 4 was water and acetonitrile.

[0075] Figure 7 This is the chromatogram obtained when the mobile phase in Example 4 is ammonium acetate and acetonitrile.

[0076] Figure 8 This is the chromatogram when the chromatographic column in Example 5 is a ZORBAX Eclipse XDB-C18 column.

[0077] Figure 9 This is the chromatogram when the chromatographic column in Example 5 is a Poroshell 120Aq-C18 column.

[0078] Figure 10 This is the chromatogram when the chromatographic column in Example 5 is a CORTECS C18 column.

[0079] Figure 11 The chromatograms obtained at different desolvation temperatures in Example 6 are shown; Figure 11 The desolvation temperatures corresponding to Figures a and b are 650°C and 350°C respectively. DETAILED DESCRIPTION

[0080] The present invention is further described in detail below using specific examples. Unless otherwise specified, the raw materials, reagents, and apparatus used in the examples and comparative examples are available from conventional commercial sources or by conventional methods. Unless otherwise specified, all experimental or testing methods are conventional in the art.

[0081] Instrument and reagent description

[0082] Liquid chromatography-mass spectrometry: ACQUITY SQD2.

[0083] Plastic sample: conventional commercially available PA66 sample, cut into pieces, with a size no larger than 2mm×2mm.

[0084] Standard working solution: Dissolve 10 mg of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in tetrahydrofuran and dilute to 10 mL to prepare a 1000 mg / L standard stock solution; gradually dilute the standard stock solution with tetrahydrofuran to obtain a series of standard working solutions of 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1 mg / L, and 2 mg / L, which are ready for use.

[0085] Example 1

[0086] A method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite comprises the following steps:

[0087] Weigh 1.0 mg of plastic sample (accurate to 0.1 mg) into a fiber sleeve and place it in a Soxhlet extractor. Add 1.5 times the volume of tetrahydrofuran (1.5 times the volume of the siphon) to the absorption flask, heat until the tetrahydrofuran boils, and reflux extract for 1 hour. The reflux cycle is 10 times per hour. The obtained extraction solution is diluted to 200 mL with the corresponding extraction solvent. Take 1 mL of the diluted solution and filter it through a 0.22 μm filter membrane to obtain the test solution. The test solution is analyzed by liquid chromatography-mass spectrometry using a liquid chromatography-mass spectrometer.

[0088] The liquid chromatography conditions were as follows: column: CORTECS C18 2.7 μm, 2.1 × 100 mm; injection volume: 1 μL; column temperature: 40°C; mobile phase: water and acetonitrile; flow rate: 0.3 mL / min; elution mode: isocratic elution, water:acetonitrile (volume ratio) = 10:90, hold time: 5 min;

[0089] The mass spectrometry conditions were as follows: ion source: electrospray ion source; capillary voltage: 3.5 kV; desolvation gas temperature: 650°C; desolvation gas flow rate: 800 L / Hr; cone gas flow rate: 10 L / Hr; cone voltage: 40.0 V; mass spectrometry acquisition mode: full ion scan; dwell time: 0.211 s.

[0090] Comparative Example 1

[0091] A method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite is different from that of Example 1 in that methanol and acetonitrile are used instead of tetrahydrofuran; the rest of the method is the same as that of Example 1.

[0092] Example 1 and Comparative Example 1 screened extraction solvents and compared the effects of different extraction solvents. Plastic samples were subjected to reflux extraction using methanol, acetonitrile, and tetrahydrofuran, respectively. Soxhlet extraction was performed for 1 hour, followed by liquid chromatography-mass spectrometry analysis using full ion scan acquisition mode. The results showed that methanol, acetonitrile, and tetrahydrofuran were unable to completely dissolve the plastic samples, while acetonitrile and tetrahydrofuran were able to completely dissolve the plastic samples. Figure 1 The mass spectrometry analysis of the samples after extraction with different extraction solvents shows that, except for tetrahydrofuran, the extraction solutions with other solvents do not have the target parent ion ([M+H] + =855 m / z). This may be because the target compound was degraded during the extraction process or was adducted with other ions, resulting in the inability to generate the target parent ion and the inability to analyze bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0093] It should be noted that in Soxhlet extraction, the solvent circulates to dissolve the solid sample, and even if the solid is eventually completely dissolved, the entire process is still considered extraction because the target substance is continuously extracted and enriched in the solvent.

[0094] Example 2

[0095] This example investigates the effect of the number of reflux cycles on the extraction efficiency of bis(2,4-dicumylphenyl)pentaerythritol diphosphite during reflux extraction of plastic samples. The reflux extraction conditions differ from those in Example 1 in that the number of reflux cycles is controlled to 5, 10, and 15, respectively; all other conditions remain the same as in Example 1.

[0096] The effects of different reflux cycle times on the extraction efficiency in Example 2 are as follows: Figure 2 , where extraction efficiency = actual concentration of target compound in the extraction solution / theoretical concentration. It can be seen that within 5 to 10 cycles, the concentration of bis(2,4-dicumylphenyl)pentaerythritol diphosphite (target compound) in the extraction solution increases with the number of cycles. However, when the number of cycles exceeds 10, the concentration of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the extraction solution does not increase significantly.

[0097] Example 3

[0098] This example investigates the effect of reflux time on the extraction efficiency of bis(2,4-dicumylphenyl)pentaerythritol diphosphite during reflux extraction of plastic samples. The reflux extraction conditions differ from those in Example 1 in that the reflux times are 30 minutes, 1 hour, 1.5 hours, 2 hours, 2.5 hours, and 3 hours, respectively; all other conditions remain the same as in Example 1. It should be noted that the number of reflux cycles is 10 per hour, with the number halved at 30 minutes, i.e., 5 reflux cycles per 30 minutes.

[0099] The extraction efficiency of different reflux times in Example 3 is as follows: Figure 3 As shown in FIG. 1 , it can be seen that the extraction efficiency increases with the increase of the reflux time. However, when the reflux time reaches 2 h, the extraction efficiency does not increase significantly when the reflux time continues to increase. The calculation of the extraction efficiency is the same as in Example 2.

[0100] Example 4

[0101] This example studies the effect of different mobile phases on the detection results of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastics. The specific detection method differs from that in Example 1 in that: the reflux extraction time is 2 h, the mass spectrometry acquisition mode is positive ion mode, selected ion monitoring, ion: 885.6 m / z; different mobile phases are set; and the remaining detection conditions are the same as in Example 1.

[0102] In Example 4, water and 10 mmol / L ammonium acetate solution were used as the aqueous phase, methanol and acetonitrile were used as the organic phase, and the mobile phases were methanol, acetonitrile, water-acetonitrile, and ammonium acetate-acetonitrile. The liquid chromatography test results were as follows: Figures 4 to 7 shown. Figure 4 When the mobile phase is methanol, the peak width is wider and there are impurity peaks, while Figure 5 The mobile phase in the assay was acetonitrile, which had a narrow peak shape, high response, and no impurity peak interference near its retention time. Therefore, acetonitrile was selected as the organic phase for further optimization. Figure 6 、 Figure 7 The following are the liquid chromatograms when water-acetonitrile and ammonium acetate-acetonitrile are used as the mobile phases. It is not difficult to see that there is no impurity peak interference near the retention time when water-acetonitrile and ammonium acetate-acetonitrile are used as the mobile phases, and the peak elution time is also earlier. However, in comparison, when water and acetonitrile are used as the mobile phases, the response value of the chromatographic peak is higher than that using ammonium acetate solution and acetonitrile as the mobile phases, and the peak elution time is also earlier.

[0103] Example 5

[0104] This example studies the effects of different chromatographic columns on the detection results of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastics. The specific detection method differs from that in Example 1 in that: the reflux extraction time is 2 h, the mass spectrometry acquisition mode is positive ion mode, selected ion monitoring, ion: 885.6 m / z; different chromatographic columns are set; and the rest is the same as in Example 1.

[0105] In Example 5, the detection effects of three chromatographic columns, CORTECS C18, ZORBAX Eclipse XDB-C18, and Poroshell 120SB-Aq, on bis(2,4-dicumylphenyl)pentaerythritol diphosphite were specifically compared. Figures 8-10 As shown, Figures 8-10The corresponding columns are ZORBAX Eclipse XDB-C18, Poroshell 120Aq-C18, and CORTECS C18, respectively. It can be seen that when using the ZORBAX Eclipse XDB-C18 column, the peak of bis(2,4-dicumylphenyl)pentaerythritol diphosphite is broad and has a later elution time, at 4.33 minutes. When using the Poroshell 120Aq-C18 column, the peak of bis(2,4-dicumylphenyl)pentaerythritol diphosphite is also broad and has a later elution time, at 3.48 minutes. When using the CORTECS C18 column, bis(2,4-dicumylphenyl)pentaerythritol diphosphite has a high response, a narrow and symmetrical peak shape, and an early elution time, at 2.71 minutes. At this time, the chromatographic peak of the compound is sharp and symmetrical, and there is no interference from impurity peaks near its retention time.

[0106] Example 6

[0107] This example studies the effects of different desolvation temperatures during mass spectrometry analysis. The specific detection method differs from that of Example 1 in that: the reflux extraction time is 2 h, the mass spectrometry acquisition mode is positive ion mode, selected ion monitoring, ion: 885.6 m / z; and the desolvation temperatures are set to 650°C and 350°C, respectively.

[0108] In Example 5, the effects of different desolvation temperatures were compared, and the results were as follows: Figure 11 As shown, Figure 11 The desolvation temperatures of Figure a and Figure b are 650℃ and 350℃ respectively. Figure 11 The results show that when the desolvation temperature is 650℃, the chromatogram obtained has a higher signal intensity than that obtained at 350℃.

[0109] Example 7

[0110] This embodiment provides a method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite, comprising the following steps:

[0111] Weigh 1.0 mg of plastic sample (accurate to 0.1 mg) into a fiber sleeve and place it in a Soxhlet extractor. Add 1.5 times the volume of tetrahydrofuran (1.5 times the volume of the siphon) to the absorption flask, heat until the tetrahydrofuran boils, and reflux extract for 1 hour. The reflux cycle is 10 times per hour. The obtained extraction solution is diluted to 200 mL with the corresponding extraction solvent. Take 1 mL of the diluted solution and filter it through a 0.22 μm filter membrane to obtain the test solution. The test solution is analyzed by liquid chromatography-mass spectrometry using a liquid chromatography-mass spectrometer.

[0112] The liquid chromatography conditions were as follows: column: CORTECS C18 2.7 μm, 2.1 × 100 mm; injection volume: 1 μL; column temperature: 40°C; mobile phase: water and acetonitrile; flow rate: 0.3 mL / min; elution mode: isocratic elution, water:acetonitrile (volume ratio) = 10:90, hold time: 5 min;

[0113] The mass spectrometry conditions were as follows: ion source: electrospray ion source; capillary voltage: 3.5 kV; desolvation gas temperature: 650°C; desolvation gas flow rate: 800 L / Hr; cone gas flow rate: 10 L / Hr; cone voltage: 40.0 V; mass spectrometry acquisition mode: positive ion mode, selected ion monitoring, ion: 885.6 m / z; dwell time: 0.211 s.

[0114] Verification Example 1

[0115] The same detection conditions as in Example 6 were used to perform liquid chromatography-mass spectrometry analysis on a series of standard working solutions of 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1 mg / L, and 2 mg / L. The standard working curve was plotted with the mass concentration X (mg / L) of the standard working solution as the abscissa and the peak area Y as the ordinate, thereby obtaining the linear equation and correlation coefficient of bis(2,4-dicumylphenyl)pentaerythritol diphosphite, as shown in Table 1. As can be seen from the data in Table 1, within the linear range of 0.1 mg / L to 2 mg / L, bis(2,4-dicumylphenyl)pentaerythritol diphosphite exhibited a good linear relationship with a correlation coefficient of 0.9998. On this basis, the limit of detection (LOD) and limit of quantification (LOQ) of the standard substance were determined using 3 times and 10 times the signal-to-noise ratio (S / N), and the detection limit of the detection method of the present invention was 0.6883 mg / kg and the limit of quantification was 2.2943 mg / kg. It can be seen that the detection method of the present invention can be used for the quantitative analysis of bis(2,4-dicumylphenyl)pentaerythritol diphosphite, and can be used to analyze trace amounts of bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0116] Table 1 Linear equation, correlation coefficient, detection limit and quantification limit

[0117]

[0118]

[0119] Verification Example 2

[0120] The purpose of this validation example was to verify the recovery and precision of the detection method described in Example 6. A blank matrix (PA66 plastic sample without bis(2,4-dicumylphenyl)pentaerythritol diphosphite) was spiked at three different spike concentrations: 0.1 mg / L, 0.5 mg / L, and 2 mg / L. Each spike concentration was tested in triplicate (n=3) for precision. The results showed that the recoveries of bis(2,4-dicumylphenyl)pentaerythritol diphosphite were 94.6-99.2% at all three spike levels, with relative standard deviations of no more than 1.3%. This demonstrates that the detection method of the present invention is highly accurate and meets the test requirements.

[0121] In summary, the method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite provided by the present invention has a simple sample pretreatment step and a short required time. It can achieve quantitative analysis of trace amounts of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in plastic samples, and has low limits of detection and quantification, good precision, and high spiked recovery. By further adjusting the detection conditions, it is also possible to achieve an early peak elution time, while reducing matrix interference and improving response and separation efficiency.

[0122] The detection method of the present invention shows a good linear relationship (r 2 >0.999), with low limits of detection and quantification (LOQ) of 0.6883 mg / kg, 2.2943 mg / kg, relative standard deviation of less than 1.3%, and recovery of spiked samples of 94.6-99.2%. It is suitable for the detection of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in food contact materials.

[0123] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for detecting bis(2,4-dicumylphenyl)pentaerythritol diphosphite, characterized in that: The following steps are involved: The plastic sample is subjected to reflux extraction using tetrahydrofuran to obtain a test solution; and the bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the test solution is analyzed by liquid chromatography-mass spectrometry.

2. The detection method according to claim 1, characterized in that The reflux time is 1 to 3 hours.

3. The detection method according to claim 1 or 2, characterized in that During the reflux process, the number of reflux cycles per hour is ≥10 times.

4. The detection method according to claim 1, wherein In the liquid chromatography-mass spectrometry method, the elution mode of the liquid chromatography is isocratic elution, and the mobile phase is at least one of acetonitrile, water and acetonitrile, ammonium acetate solution and acetonitrile.

5. The detection method according to claim 1, wherein In the liquid chromatography-mass spectrometry method, the chromatographic column of the liquid chromatography is a CORTECS C18 chromatographic column.

6. The detection method according to claim 1 or 5, characterized in that In the liquid chromatography-mass spectrometry method, the column temperature of the liquid chromatography is 35 to 45°C; And / or, in the liquid chromatography-mass spectrometry method, the injection volume of the liquid chromatography is 1 to 2 μL.

7. The detection method according to claim 1, characterized in that In the liquid chromatography-mass spectrometry method, during the mass spectrometry detection process, the desolvation temperature is 350-750°C.

8. The detection method according to claim 7, characterized in that In the liquid chromatography-mass spectrometry method, the mass spectrometry detection conditions further include at least one of the following: a) to g): a) Ion source: electrospray ion source; b) Capillary voltage: 3-4kV; c) Desolventization gas flow rate: 700-900 L / Hr; d) Cone hole air flow rate: 8~15L / Hr; e) Cone voltage: 35~45V; f) Mass spectrometry acquisition mode: positive ion mode, select 885-886 m / z ion detection; g) Dwell time: 0.2~0.3s.

9. The detection method according to claim 1, wherein The detection method further comprises the following steps: A standard working solution is prepared by dissolving bis(2,4-dicumylphenyl)pentaerythritol diphosphite; the standard working solution is subjected to liquid chromatography-mass spectrometry analysis to obtain a standard working curve with concentration as the horizontal axis and peak area as the vertical axis; the standard working curve is used for quantitative analysis of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in the plastic sample.

10. Use of the detection method according to any one of claims 1 to 10 in detecting the content of bis(2,4-dicumylphenyl)pentaerythritol diphosphite in food contact materials.

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