Device and method for detecting ultraviolet light absorber based on solid-phase microextraction and normal-pressure mass spectrometry

Abstract

The invention discloses a device and method for detecting an ultraviolet light absorber based on solid-phase microextraction and normal-pressure mass spectrometry, and belongs to the technical field of environmental analysis and detection.The device comprises a normal-pressure mass spectrometer, a 3D-printed fixed base and a detachable bracket, the fixed base is provided with a limiting groove, a conductive copper sheet is embedded in the limiting groove, and the limiting groove is connected with the detachable bracket; a positioning hole is formed in one surface of the detachable bracket and is used for accurately fixing a C18 functionalized wooden probe, so that stable butt joint of the probe and a mass spectrum injection port is realized. According to the detection method, solid-phase microextraction and toothpick spray normal-pressure mass spectrometry are combined, an ultraviolet absorbent in a water sample is efficiently enriched by using a functionalized wood probe, and then direct ionization analysis of an enriched substance is realized through the device. According to the method, the sample pretreatment process is remarkably simplified, the analysis efficiency and the operation convenience are improved, and the method has the advantages of being rapid, environmentally friendly, low in cost, easy to deploy on site and the like and is suitable for quality control of skin care products and rapid screening and monitoring of ultraviolet light absorbers in environmental water bodies.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental analysis and detection, and in particular to a device and a detection method for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry. Background Art

[0002] Ultraviolet absorbers (OUVs) can be detected in cosmetics, environmental water samples, biological tissues, and food contact materials. Screening and quantitative detection methods for these absorbers include gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), and HPLC-MS / MS. These methods have high sensitivity and accuracy, but in practice, they require complex sample pretreatment steps such as solid-phase extraction (SPE), liquid-liquid extraction (LLE), and concentration. Currently, solid-phase extraction (SPE) requires a large sample volume and multiple elution steps, resulting in complex operations that are time-consuming and labor-intensive. The large amount of organic solvents used poses a risk of environmental pollution, making this method difficult to meet the needs of rapid on-site detection and high-throughput analysis.

[0003] In recent years, atmospheric pressure mass spectrometry techniques, such as direct analysis in real time mass spectrometry (DART-MS) and low temperature plasma mass spectrometry (LTP-MS), have been increasingly applied to the rapid screening of UV absorbers. These techniques have garnered widespread attention due to their lack of complex pretreatment, rapid response, and ability to detect non-volatile compounds. However, the use of atmospheric pressure mass spectrometry for UV absorber screening still faces several technical bottlenecks, such as insufficient sensitivity, poor adaptability to complex sample matrices (such as oily creams or powdered products), low analytical throughput, and limited quantitative capability, making it difficult to fully replace traditional chromatographic methods.

[0004] After searching, a method based on stir bar sorptive extraction-direct analysis in real-time mass spectrometry (SBSE-DART-MS) was discovered, which uses atmospheric pressure mass spectrometry to screen for UV absorbers. This method involves immersing a stir bar coated with polydimethylsiloxane (PDMS) into a water sample. The UV absorber in the water is adsorbed through contact between the stir bar surface and the water sample. After the adsorption process continues for a certain period of time, the stir bar is removed and inserted into the direct analysis in real-time mass spectrometry (DART-MS) ion source. Under the influence of the high-temperature gas flow of the DART source, the target substance on the stir bar surface is ionized, and the generated ions enter the mass spectrometer for analysis. To improve the accuracy of quantitative analysis, the internal standard phenylcinnamic acid (BC) is also added to the water sample. The adsorption and desorption process of stir bar sorptive extraction (SBSE) typically takes an hour or even longer, making it difficult to meet the requirements for rapid screening of high-frequency, large-volume samples. Furthermore, the poor applicability of the detection matrix is ​​mainly due to the fact that atmospheric pressure ion sources (such as DART and LTP) are easily affected by matrix effects in complex matrices. For example, when dealing with high-viscosity samples such as creams and lotions, the adsorption-desorption mechanism has a low extraction efficiency for the target substance. The complex matrix components will cause severe ion suppression effects during the ionization process, resulting in a decrease in the signal-to-noise ratio, affecting the stability and accuracy of quantitative analysis, thereby limiting the direct application of this method in non-aqueous or highly viscous samples.

[0005] The problem with the high cost of commercial ion source equipment is that most existing atmospheric pressure mass spectrometers are imported products, using a closed design and patented packaging. The core components are expensive, the maintenance costs are high, and there is a lack of open interfaces. It is difficult for users to carry out secondary development or parameter optimization according to specific needs, which greatly limits the promotion and popularization of this technology in grassroots laboratories or portable detection platforms.

[0006] Based on this, there is an urgent need to develop a low-cost, highly compatible, integrated rapid analysis platform suitable for complex matrices to meet the demand for efficient, convenient and economical analytical methods in grassroots applications. Summary of the Invention

[0007] The purpose of the present invention is to solve the above technical problems and provide a device and a detection method for ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A device for detecting ultraviolet absorbers based on solid-phase microextraction and atmospheric-pressure mass spectrometry comprises an atmospheric-pressure mass spectrometer, a fixed base and a detachable bracket. A limiting groove is provided on the fixed base, a conductive copper sheet is provided in the limiting groove passing through the fixed base, the detachable bracket is connected to the contact surface of the conductive copper sheet, a positioning hole is provided on one side of the detachable bracket, a wooden probe is provided in the positioning hole, and the wooden probe is in contact with the sampling port of the atmospheric-pressure mass spectrometer.

[0010] Preferably, an annular limiting groove matching the mouth of the sample bottle is further provided on the periphery of the positioning hole of the detachable bracket, and the portion of the conductive copper sheet located outside the fixed base is connected to the high-voltage wire.

[0011] Preferably, the wooden probe has a length of 3 cm and a tip diameter of 0.15-0.2 mm.

[0012] Preferably, the wooden probe surface has C 18 Hydrophobic coating.

[0013] In addition, the present invention also provides a detection method for ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry. The above device is used for detection, and the specific steps are as follows:

[0014] (1) Use a 3D printer to print the required fixed base and detachable bracket;

[0015] (2) pretreating the wooden probe; functionally modifying the wooden probe; inserting the modified wooden probe into the positioning hole of the detachable bracket, and immersing the wooden probe in the sample for extraction;

[0016] (3) placing the detachable bracket containing the extracted wooden probe into the limiting groove of the fixed base and aligning it with the inlet of the atmospheric pressure mass spectrometer;

[0017] (4) Add spray solvent to the tip of the wooden probe and let it stand for a certain period of time to promote the desorption of the target;

[0018] (5) Add the spray solvent again and apply voltage to generate charged ions through the spray process;

[0019] (6) Ion atmospheric pressure mass spectrometry analysis to obtain qualitative and quantitative detection of ultraviolet absorbers.

[0020] Preferably, in step (2), the method for pre-treating the wooden probe is: cutting the wooden toothpick into probes with a length of 3 cm and a tip diameter of 0.15-0.2 mm, and ultrasonically cleaning with methanol to remove impurities and drying.

[0021] Preferably, in step (2), the method for functionalizing the wood probe is as follows: placing the pretreated wood probe in anhydrous DMF solution, adding DMOAP reagent, and reacting at 120° C. under nitrogen atmosphere for 12 hours to modify C on the surface of the wood probe. 18 The hydrophobic groups give the wood probe the ability to selectively adsorb hydrophobic OUVs.

[0022] Preferably, in step (3), the angle between the wooden probe and the injection port of the atmospheric pressure mass spectrometer is 90°, and the distance between them is 0.25 cm.

[0023] Preferably, in step (4), the spray solvent is methanol and acetonitrile in a volume ratio of 3:7, and the mixture is allowed to stand for 5 seconds to promote the desorption of the target substance.

[0024] Preferably, in step (5), the applied voltage is 4.5 kV.

[0025] The beneficial effects of the present invention compared to the prior art are:

[0026] 1. The present invention uses 3D printing technology to construct a detachable bracket and a fixed base. By inserting a wooden probe into each detachable bracket, multiple wooden probes can be used to simultaneously adsorb multiple different samples. During the detection process, different samples can be detected by simply replacing the detachable bracket. Combined with adjusting the positioning and stable electrical contact between the wooden probe and the inlet of the atmospheric pressure mass spectrometer, the problems of cumbersome probe replacement and inaccurate positioning in traditional AMS devices are overcome. In addition, the structure of the device can be flexibly adjusted according to needs, with low manufacturing cost, conducive to promotion and application, and a wide range of applications.

[0027] 2. The wooden probe of the present invention is subjected to C 18 After modification, it has good hydrophobic selectivity and chemical stability, and can efficiently enrich ultraviolet absorbers in complex matrices such as water and cosmetics. The material source of the wood probe is wide and the preparation process is simple. 18 The modified wood probe can efficiently enrich a variety of OUVs in complex matrices such as water and cosmetics.

[0028] 3. The present invention integrates a toothpick spray atmospheric pressure mass spectrometer, using C 18 The modified wood probe can achieve direct ionization analysis of the target object without the need for expensive instruments or complex gas systems, effectively reducing equipment costs and technical barriers. It is suitable for application scenarios such as rapid on-site screening, mobile monitoring needs, and resource-constrained environments.

[0029] 4. The detection method of the present invention effectively solves the problems of cumbersome pretreatment steps and complex atmospheric pressure mass spectrometry operations in traditional OUVs analysis. Through the integrated device structure, it is compact, easy to operate, and environmentally friendly. It is suitable for OUVs quality control in skin care products and rapid screening and monitoring of OUVs in environmental water bodies. It has practical application potential and industrial prospects in multiple fields such as environmental monitoring, product quality control, and emergency response. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of a device for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to the present invention;

[0031] Figure 2Schematic diagram of the structure of the fixed base (a), the detachable bracket (b) and the overall assembly (c) of the present invention;

[0032] Figure 3 This is a flow chart of a detection method for ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to the present invention;

[0033] Figure 4 (a) The TIC image and (b) the MS / MS images of seven OUVs in Example 1;

[0034] Figure 5 is the enrichment factor of the wood probe for the seven OUVs in Example 1;

[0035] Figure 6 These are the mass spectrometry signals of the seven OUVs in Example 1 at different stirring speeds (a) and enrichment times (b);

[0036] Figure 7 Figures 1 and 2 are different angles between the wooden probe and the mass spectrometer injection port (a) and MS / MS images at different angles (b);

[0037] Figure 8 Mass spectrometry signals (d) of the seven OUVs in Example 1 at different optimized spray angles (a), distances between the probe and the mass spectrometer entrance (b), spray voltages (c), and spray solvents;

[0038] Figure 9 Figure 1 shows the standard curve, detection limit, quantification limit (a), and recovery rate (b) of the seven OUVs in Example 1.

[0039] Figure 10 is the content and composition of OUVs in the eight sunscreens in Example 2;

[0040] Figure 11 is the release amount of EHMC in the four sunscreens under different washing behaviors in Example 3;

[0041] Figure 2 、 Figure 3 In the figure, 1: atmospheric pressure mass spectrometer, 2: fixed base, 3: detachable bracket, 4: limiting groove, 5: conductive copper sheet, 6: annular limiting groove, 7: positioning hole, 8: wooden probe. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and by way of preferred embodiments. However, it should be noted that many of the details listed in this specification are merely provided to help the reader gain a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be practiced even without these specific details.

[0043] The present invention relates to experimental materials and reagents including: dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (C 18 , 60% purity) and anhydrous N,N-dimethylformamide (DMF, 99.8% purity) were purchased from J&K Scientific (Beijing, China). OUV standards including AVO (purity >99%), BP-1 (purity >99%), BP-3 (purity >99%), BP-8 (purity >99%), EHMC (purity >96%), and ODPABA (purity >98%) were purchased from TCL (Shanghai, China). In addition, 4-MBC (purity >99%) was purchased from AccuStandard (New Haven, CT, USA). Deuterated internal standard (IS): benzophenone-3-d5 (BP-3-d5, purity >99%) was purchased from Sigma-Aldrich (St. Louis, MO, USA). All of the above were standard products. Organic solvents methanol and acetonitrile (UPLC / LC-MS) were purchased from CNW (Germany). Ultrapure water was prepared using a Millipore Milli-Q water purification system (Bedford, MA, USA). Wooden toothpicks (Double Gun brand) were purchased from a local supermarket in Guangxi Zhuang Autonomous Region. A fixed base and removable bracket were 3D-printed. The fixed base was constructed from Sanlv brand polylactic acid filament (PLA, Zhuhai, China), and the removable bracket was constructed from aluminum alloy powder (AlSi10Mg, Dongguan, China). The conductive copper sheet for the fixed base was purchased locally and custom cut in the laboratory. The nitrogen-blown drying assembly was also 3D-printed from Sanlv brand polylactic acid filament (PLA, Zhuhai, China).

[0044] Instruments and models include: LTQ XL TM Linear ion trap mass spectrometer (Thermo Science, USA), 3D printer (Bambu Lab, Shenzhen Tuozhu Technology Co., Ltd., China, model: A1 mini; Suzhou Zhongrui Zhichuang 3D Technology Co., Ltd., China, model: AFS420), CNC ultrasonic cleaner (Kunshan Ultrasonic Instrument Co., Ltd., China, model: KQ-100DE), heating magnetic stirrer (Dalong Xingchuang Experimental Instrument Co., Ltd., China, model: MS-H-Pro M ), nitrogen blowdown apparatus (Tianjin Aotesense Instrument Co., Ltd., China, model: MTN-2800D), 1 / 10,000 analytical balance (Ohaus International Trade (Shanghai) Co., Ltd., China, model: PX124ZH), pipette (Germany, Eppendorf AG, model: Eppendorf plus), high-speed centrifuge (Germany, Sigma Laborzentrifugen, model: D-37520), and multi-function vortex mixer (USA, Scientific Industries, model: Vortex-Genie2).

[0045] The present invention is based on the device for detecting ultraviolet absorbers by solid phase microextraction and atmospheric pressure mass spectrometry. Figure 1 As shown, a 3D printer is used to make a detachable bracket 3 and a fixed base 2. First, a fixed base 2 with a limiting groove 4 and a detachable bracket 3 with a positioning hole 7 are designed in Solidworks software. The design size and shape are as follows: Figure 2 As shown. After the fixed base design is completed, the model is imported into Bambu Studio software, the model is selected and sliced, and then the print task is sent to the 3D printer. The fixed base is printed using PLA material. The specific 3D printing parameters are: nozzle temperature 220°C, hot bed temperature 65°C, print speed 50-100MM / s, nozzle diameter 0.44mm, and print accuracy ±0.2mm. After the detachable bracket design is completed, the print task is sent to the metal 3D printer. The detachable bracket is sintered using AlSi10Mg powder. The specific 3D printing parameters are: laser IPG, laser power 500W, print layer 0.04mm, and print accuracy ±0.1mm.

[0046] The size of the limiting groove 4 of the fixed base 2 is consistent with the size of the detachable bracket 3, and the locating hole 7 can embed the wooden probe 8 made of toothpicks therein, the first is to play the effect of preventing loosening, and the second is to make the wooden probe tip in a fixed position at every turn. The bottom of the limiting groove 4 of the fixed base 2 is inserted with a conductive copper sheet 5, which extends from the fixed base 2 sidewalls and is connected to the crocodile clip one end connected with the high-voltage wire to ensure that the detachable bracket 3 obtains stable high voltage during use. The lifting platform and the fixed base 2 can also be set to be bonded by double-sided tape, which is convenient and flexible to adjust the distance between the ion source and the mass spectrometer injection port. In addition, an annular limiting groove 6 (for example, a width of 2.6mm is designed at the periphery of the locating hole 7 of the detachable bracket 3, and this annular limiting groove 6 is accurately matched with the standard 4mL glass sample bottle bottle mouth. Of course, the width of the annular limiting groove 6 can also be designed according to the diameter of the glass sample bottle) can be substituted in the enrichment process to effectively fix the position of the wooden probe.

[0047] The wooden probe 8 is made of wooden toothpicks. In order to better remove the impurities carried by the toothpicks and reduce the matrix interference during the mass spectrometry analysis, the toothpicks are C 18Before modification, the toothpicks were ultrasonically cleaned with methanol. The purchased wooden toothpicks were sharpened to a tip diameter of 0.15-0.2 mm using a tool and cut to a length of 3 cm. The sharpened and cut toothpicks were ultrasonically cleaned in methanol for 10 minutes and then dried with nitrogen. The treated toothpicks were then dispersed in 40 mL of anhydrous DMF and 2 mL of C was added under vigorous stirring. 18 The mixture was protected by nitrogen and then refluxed at 120°C for 12 hours to carry out the silanization reaction. 18- The SPME wooden probe was ultrasonically cleaned with methanol and dried with nitrogen before storage.

[0048] The detection method process is as follows Figure 3 As shown, before enriching OUVs in the sample, the blunt end of the wooden probe was inserted into the positioning hole 7 of the removable bracket 3 and secured in place. Before enrichment, the wooden probe was rinsed with methanol for 30 seconds. For all experiments, 4 mL of sample was used for enrichment. The tip of the wooden probe was inserted into the sample, maintaining an immersion depth of 1 cm. OUVs were enriched at a fixed rotation speed and enrichment time. After enrichment, the wooden probe 8 was rinsed with ultrapure water for 10 seconds to remove interfering matrix and then dried with nitrogen. Before mass spectrometry analysis, the removable bracket 3 was mounted on the fixed base 2. The wooden probe 8 was connected to the mass spectrometer inlet in a fixed orientation using a three-dimensional motion platform. The tip of the wooden probe 8 was adjusted to a fixed position relative to the mass spectrometer inlet. To detect target compounds, 20 μL of spray solvent (IS: BP-3-d5, concentration 1 mg / L) was added to the surface of the enriched wooden probe 8 using a pipette and held for 5 seconds to ensure effective desorption of the target compound into the solvent. After high voltage was applied, 30 μL of spray solvent was added to the wooden probe 8 to ensure that the signal duration of each analysis was longer than 0.5 min.

[0049] The mass spectrometer inlet temperature was set at 275°C. For tandem mass spectrometry (MS / MS), high-purity helium was used as the collision gas. The collision-induced dissociation (CID) energy was set to 30% for all six OUVs except EHMC, which was set to 50%. The activation time was 30 ms, and the separation width was set to m / z 1.0. The signal acquisition duration was set to 1 min per acquisition. All other mass spectrometer parameters used in the experiment were default values. The resulting mass spectra were processed using Xcalibur Qual Browser software.

[0050] The specific detection methods are as follows:

[0051] Example 1

[0052] In this example, seven OUVs, including 4-MBC, AVO, BP-1, BP-3, BP-8, EHMC, and ODPABA, were used as target compounds. The reliability and performance of the proposed atmospheric pressure mass spectrometry device and its analytical detection method were verified through experiments.

[0053] All experiments used 1 mg / L OUVs mixed aqueous solution as the test sample. Figure 3 The experiment was carried out at room temperature. Three parallel experiments were conducted for each condition to ensure the reliability and accuracy of the results. Among them, the optimization of ionization conditions mainly considered the following four aspects: spray voltage (3.5kV, 4kV, 4.5kV, 5kV), the connection direction of the toothpick probe and the mass spectrometer injection port (parallel configuration (0°), orthogonal configuration (90°), oblique upward 45° configuration), C 18 -The distance between the SPME toothpick probe tip and the mass spectrometer inlet (0.1 cm, 0.25 cm, 0.5 cm, 0.75 cm, 1 cm) and the collision energy (an automatic program was used to select the energy with the highest peak intensity). The enrichment condition optimization mainly considered the following two aspects: enrichment time (1 min, 10 min, 30 min, 50 min) and stirring speed (0 rpm, 200 rpm, 500 rpm, 800 rpm). The desorption condition optimization mainly considered the different ratios of the spray solvents. Five volume ratios of methanol and acetonitrile were set: 1:0, 3:7, 1:1, 7:3, and 0:1.

[0054] Experimental results:

[0055] This analytical method can generate a stable signal for more than 0.5 min. Figure 4 As shown in a, the total ion current (TIC) curve shows high stability in the first 0.6 min and gradually decreases as the solvent is exhausted. This is because the spray solvent evaporates slowly during the ionization process, causing the TIC to gradually decrease. In the qualitative analysis of the 7 OUVs, the standards of the 7 OUVs were first analyzed by ESI-MS to determine their MS / MS spectra, as shown in Figure 1. Figure 4 b. Subsequent experiments will perform characteristic fragment ion matching based on the MS / MS spectra to achieve qualitative analysis. For quantitative analysis, the strongest secondary characteristic fragment ion in the MS / MS spectrum of each OUVs is selected as the quantitative ion, and the peak height is used as the quantitative basis. Specifically, the quantitative ions of BP-1, BP-3, BP-8, ODPABA, 4-MBC, AVO and EHMC are m / z 137, 151, 121, 166, 161, 237 and 179, respectively. These characteristic fragment ions can be used to ensure the specificity and sensitivity of compound identification and quantification.

[0056] In order to accurately evaluate the enrichment performance of wood probes for seven OUVs, this study used C 18 The surface modified wood probe and the unmodified toothpick probe were compared. The enrichment factor (EF) concept was introduced to quantitatively analyze C 18 In the experiment, 1 mg / L OUVs mixed solution was used as the analysis object, and the surface modified wood probe was used to collect the OUVs. 18 Surface modified wood probes and unmodified toothpick probes were used for enrichment experiments and the Figure 3 Perform mass spectrometry detection and analyze the mass spectrum intensity after IS correction.

[0057] The calculation formula is as follows:

[0058]

[0059] in, I was measured using three C18 surface-modified wood probes. OUVs / I Is Average value, I 未修饰牙签探针 : I measured using three unmodified toothpicks OUVs / I Is average value.

[0060] like Figure 5 As shown, after C 18 The surface-modified wood probes showed enrichment ability for all seven OUVs, with significant differences in EFs ranging from 2.0 (4-MBC) to 48.9 (BP-1). This difference may be due to the differences in the physicochemical properties of OUVs, such as hydrophobicity, steric hindrance, π-π interaction, and molecular weight. 18 synergy between them.

[0061] The effect of stirring speed on SPME enrichment is mainly related to mass transfer kinetics and matrix interference. In this study, four stirring speeds of 0 rpm, 200 rpm, 500 rpm and 800 rpm were set to investigate the enrichment effect of the wooden probe on the mixed aqueous solution of 7 OUVs at different stirring speeds. The results were compared and analyzed by comparing the characteristic peak intensities after IS correction. Figure 6 As shown in Figure a, the experiments showed that the mass spectrometry response intensity of the seven OUVs initially increased and then decreased with increasing stirring speed. At 500 rpm, the responses of all seven OUVs reached their highest values, demonstrating that this speed improves mass transfer efficiency while maintaining probe adsorption stability, thereby achieving optimal enrichment. Based on this analysis, 500 rpm was selected as the optimal stirring speed for subsequent experiments.

[0062] The enrichment time has an important influence on the enrichment effect of SPME, which is mainly limited by the adsorption kinetics and the degree of matrix interference. In this study, four time gradients of 1 min, 10 min, 30 min and 50 min were set to explore the enrichment effect of the wood probe on 7 OUVs at different enrichment times, and compare the characteristic peak intensities after IS correction, such as Figure 6 b. The experimental results showed that BP-1, BP-3, BP-8, AVO, and EHMC achieved the strongest mass spectrometry signals at 30 minutes, while 4-MBC and ODPABA reached their peaks at 10 minutes. 30 minutes was determined to be the optimal enrichment time for the wood probes for subsequent analysis.

[0063] The potential contamination of the mass spectrometry inlet is one of the common problems in atmospheric pressure mass spectrometry technology. This type of contamination may not only weaken the mass spectrometry response of the target compound, but also introduce background interference, affecting the accuracy of qualitative and quantitative results. In order to reduce or eliminate this type of contamination, the study adjusted the configuration direction between the tip of the wooden probe and the mass spectrometry inlet to explore its effect on signal interference and analytical performance. This study explored the effects of three different configuration directions on the mass spectrometry signals (characteristic peak intensity) of seven OUVs, namely parallel (0°), oblique upward (45°), and orthogonal (90°). The experimental diagrams of the three directions are shown in Figure 2. Figure 7 The experiment found that there are four OUVs that are seriously interfered with, namely BP-1, ODPABA, AVO, and EHMC. The MS / MS spectra of these four OUVs are shown in Figure 1. Figure 7 As shown in b, when the spectrum is parallel or obliquely at 45°, the background interference is large, the characteristic fragment ions are not clear, and it is not conducive to the accurate characterization of low-concentration samples. In the orthogonal configuration, the spectrum background is clean, the fragment ions are obvious, and the analysis effect is the best. At the same time, Figure 8 As shown in a, all seven OUVs exhibited the highest characteristic peak intensity in the orthogonal (90°) direction. In summary, the orthogonal (90°) direction was selected as the optimal configuration and applied to subsequent analysis experiments.

[0064] The distance between the tip of the wood probe and the mass spectrometer inlet directly affects the ion transmission efficiency and the ionization efficiency of the analyzed compounds. In order to obtain a stable electrospray signal, this study systematically evaluated the influence of seven OUVs mass spectrometry signals (characteristic peak intensity) at different distances. The results are shown in Figure 2. Figure 8As shown in Figure b, as the distance between the probe and the injection port increases from 0.1 cm to 1.0 cm, the characteristic peak intensities of the seven OUVs all show a trend of first increasing and then decreasing, reaching a maximum at 0.25 cm. During the experiment, it was also found that when the distance was 0.1 cm and the amount of solvent on the wooden probe exceeded 10 μL, electric sparking was likely to occur. When the distance exceeded 0.5 cm, the mass spectrometer signal showed significant fluctuations. Therefore, 0.25 cm was selected as the optimal injection distance to ensure method signal strength, system stability, and analytical accuracy.

[0065] Toothpick spray mass spectrometry is a type of electrospray. In order to obtain better quality mass spectrometry signals, it is necessary to precisely control the applied spray voltage. This study investigated the effect of different spray voltages on the intensity of the characteristic peaks of seven OUVs. The results are as follows: Figure 8 As shown in Figure c. As the voltage applied to the wooden probe increases, the characteristic peak intensities of the seven OUVs show a trend of first increasing and then decreasing. When the spray voltage is 3.5 kV, the characteristic peak signal is weak, which may be due to insufficient voltage and low ionization efficiency of the target compound, resulting in a decrease in sensitivity. When the voltage is increased to 4.5 kV, the characteristic peak intensities of all targets reach the peak value, and the ionization efficiency is optimal at this voltage. If it is further increased to 5.0 kV, a decrease will occur instead. It is speculated that the excessive voltage may cause the ion source to discharge, resulting in unstable signal. Taking into account the signal intensity, stability and instrument safety, 4.5 kV was finally selected as the optimal spray voltage for subsequent analysis to ensure the accuracy of the method detection results and the reliability of the system operation.

[0066] Selecting a spray solvent that matches the properties of the target compound is a key step in improving the desorption efficiency of OUVs and the overall extraction performance. Based on the fact that the seven OUVs generally have weak polarity characteristics, this study selected a binary mixture of methanol and acetonitrile as the spray solvent. On the one hand, methanol and acetonitrile are both medium polar solvents, which conform to the principle of "like dissolves like". They can be adjusted by polarity to meet the solubility requirements of different OUVs and take into account the elution effect of multiple components. On the other hand, both can effectively destroy the interaction between OUVs and C 18 Hydrophobic interactions between stationary phases lead to efficient desorption. To screen the optimal solvent ratio, a series of volume fractions of methanol and acetonitrile ranging from 1:0 to 0:1 were set up in the experiment. The wood probe enriched with 7 OUVs was desorbed and sprayed, and the mass spectrometry signals (characteristic peak intensity after IS correction) generated under different ratios were systematically evaluated. The results are shown in Figure 2. Figure 8d. The data show that at a methanol-acetonitrile volume ratio of 3:7, BP-1, BP-3, BP-8, and 4-MBC achieved the highest signal intensities, followed by ODPABA, AVO, and EHMC. To balance the desorption efficiency of most OUVs and achieve optimal extraction performance, methanol:acetonitrile (3:7, v:v) was selected as the spray solvent to improve both the recovery and selectivity of OUVs.

[0067] In this analytical method, the standard curve, limit of detection (LOD), and limit of quantification (LOQ) are key parameters for evaluating the sensitivity and accuracy of the analytical method. In this study, under optimal experimental conditions, a mixed aqueous solution of seven OUVs with a concentration range of 0.01-1 mg / L was prepared according to a gradient, and 1 mg / L of BP-3-d5 was added to the spray solvent as an IS. The characteristic peak intensity was calibrated to construct a standard curve. The results are shown in Figure 2. Figure 9 As shown in a, in the range of 0.01-1 mg / L, all seven OUVs showed good linear relationships (R 2 >0.95). This indicates that within this concentration range, the analytical method has reliable accuracy for the quantitative analysis of the seven OUVs and can be effectively used for the quantitative detection of water samples. To evaluate the sensitivity and limit of quantification of the method, the LOD and LOQ were calculated based on the blank sample measurement results. The LOD was defined as 3 times the standard deviation of the signal obtained by 10 blank sample measurements, and the LOQ was defined as 10 times the standard deviation of the signal obtained by 10 blank sample measurements. The results are shown in Figure 2. Figure 9 As shown in a, the LOD range of the seven OUVs is 0.18-8.73 μg / L, and the LOQ range is 0.61-29.12 μg / L, both of which meet the requirements for trace analysis in environmental samples. The analytical method has good linear response, low detection limit and quantification limit for the seven OUVs in the range of 0.01-1 mg / L, which verifies the feasibility and practicality of this method for trace quantitative analysis of OUVs in complex matrices, and can provide reliable technical support for the efficient screening and detection of OUVs in environmental water samples. In order to evaluate the stability of the analytical method in different matrices, two representative media were used to carry out spike recovery studies: ultrapure water (simulating environmental samples) and facial cleanser cleaning wastewater (representing cosmetic matrices). OUVs of known concentrations were added to each matrix, and the spike recovery was evaluated accordingly. The results are shown in Figure 9 As shown in Figure b, the average recovery rates in ultrapure water ranged from 81.3% to 119.6%, and the average recovery rates in facial cleanser wastewater ranged from 81.4% to 119.5%, verifying the reliability of the analytical method and the stability of the system.

[0068] Example 2

[0069] In this study, eight commercially available sunscreen products were selected for analysis. Using a proposed method for detecting OUVs using SPME and AMS, the composition and content of OUVs in these products were systematically analyzed, and their quality was evaluated. All eight sunscreen products were purchased through Taobao (Alibaba Group, China).

[0070] The study selected eight top-selling sunscreens from the e-commerce platform during a shopping spree. Ultrasonic extraction was used to extract OUVs from the sunscreen samples. Approximately 0.1 g of the sunscreen sample was weighed into a 15 mL glass vial. 10 mL of methanol was added and vortexed to ensure thorough homogenization, followed by 30 minutes of ultrasonic extraction. Finally, 5 mL of the resulting OUVs extract was diluted with 45 mL of ultrapure water and brought to a volume of 50 mL. Prior to enrichment, a wooden probe was rinsed with methanol for 30 seconds to activate the adsorption surface. For OUVs enrichment, 4 mL of the aqueous sunscreen extract solution was directly immersed in the wooden probe under constant stirring at 500 rpm for 30 minutes. The wooden probe was then rinsed with ultrapure water for 10 seconds to remove interfering matrix and dried with nitrogen before mass spectrometry analysis. Methanol:acetonitrile (3:7, v:v) was used as the spray solvent for mass spectrometry detection, and IS was BP-3-d5 (1 mg / L). To reduce contamination interference caused by reagents and operation processes, a blank sample with the same reagents and procedures was added.

[0071] By applying this analytical method, 7 targeted OUVs of 8 commercially available sunscreens were quantitatively analyzed. Figure 10 As shown, EHMC was detected in 100% of the eight sunscreen products, while AVO was only detected in seven products. These results are consistent with the ingredient information published by the manufacturers. Regarding dosage, the EHMC content in the eight sunscreens ranged from 0.09 to 86.73 mg / g, while AVO was 0.59 mg / g. The measured concentrations of all detected OUVs were within the maximum permissible limits under current regulations, confirming the accuracy and suitability of this method for product quality control and regulatory monitoring.

[0072] Example 3

[0073] In Example 2, four different brands of sunscreen and one common facial cleanser were selected to simulate the washing process after daily activities. Two cleaning wastewater samples (facial cleanser wastewater and clean water wastewater) were analyzed using the proposed SPME and AMS-based OUVs detection method. The facial cleanser (brand: Hanshu, Shanghai Shangmei Cosmetics Co., Ltd., China) was purchased from a local supermarket in Guangxi Zhuang Autonomous Region.

[0074] The experiment involved five volunteers applying 0.1-0.2g of sunscreen to their left and right forearms. After a uniform film formed on the skin, the volunteers engaged in normal outdoor activities under natural conditions. The exposure time was uniformly set from 11:00 AM to 6:00 PM, for a total of 7 hours, to ensure sufficient exposure to the actual UV environment. Two types of cleaning wastewater samples were collected: facial wash wastewater was collected from the left arms of the five volunteers, using 0.1-0.2g of facial cleanser to remove the sunscreen from the skin; and water wash wastewater was collected from the right arms, using ultrapure water to remove the sunscreen without using facial cleanser. The volume of ultrapure water used was 1L, and the washing time was the same. All wastewater from the washing process was collected in a polypropylene container and immediately subjected to in situ enrichment using a wooden probe. A blank control was also established, using an equal amount of facial cleanser to wash the skin without sunscreen, and a blank wash sample was collected following the same procedure. Prior to enrichment, the wooden probe was rinsed with methanol for 30 seconds. To enrich OUVs, a wooden probe was immersed directly in 4 mL of the wash water with constant stirring at 500 rpm for 30 minutes. The probe was then rinsed with ultrapure water for 10 seconds to remove interfering matrix and dried with nitrogen before mass spectrometry. For mass spectrometry, methanol:acetonitrile (3:7, v:v) was used as the spray solvent, and BP-3-d5 (1 mg / L) was used as the IS.

[0075] Test results such as Figure 11 As shown, EHMC was detected in all four types of cleaning wastewater, and the concentration of OUVs in facial cleanser wastewater was 1.6 to 2.3 times higher than when washing with water alone, with statistical significance (p < 0.05, analysis of variance). These results are consistent with the composition of the ingredients detected in the original sunscreen sample, verifying the reliability of the analytical method and confirming its applicability in exploring the environmental migration patterns of OUVs.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A device for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry, characterized in that: The invention comprises an atmospheric pressure mass spectrometer, a fixed base and a detachable bracket. A limiting groove is provided on the fixed base, a conductive copper sheet is provided in the limiting groove penetrating the fixed base, the detachable bracket is connected to the contact surface of the conductive copper sheet, a positioning hole is provided on one side of the detachable bracket, a wooden probe is provided in the positioning hole, and the wooden probe is in contact with the sampling port of the atmospheric pressure mass spectrometer.

2. The device for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 1, characterized in that: An annular limiting groove matching the mouth of the sample bottle is also provided on the periphery of the positioning hole of the detachable bracket, and the portion of the conductive copper sheet located outside the fixed base is connected to the high-voltage wire.

3. The device for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 1, characterized in that: The wooden probe has a length of 3 cm and a tip diameter of 0.15-0.2 mm.

4. The device for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 1, characterized in that: The wooden probe surface has C 18 Hydrophobic coating.

5. A detection method for ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry, characterized in that: The detection is performed using the device according to any one of claims 1 to 4, and the specific steps are as follows: (1) Use a 3D printer to print the required fixed base and detachable bracket; (2) pretreating the wooden probe; functionally modifying the wooden probe; inserting the modified wooden probe into the positioning hole of the detachable bracket, and immersing the wooden probe in the sample for extraction; (3) placing the detachable bracket containing the extracted wooden probe into the limiting groove of the fixed base and aligning it with the inlet of the atmospheric pressure mass spectrometer; (4) Add spray solvent to the tip of the wooden probe and let it stand for a certain period of time to promote the desorption of the target; (5) Add the spray solvent again and apply voltage to generate charged ions through the spray process; (6) Ion atmospheric pressure mass spectrometry analysis to obtain qualitative and quantitative detection of ultraviolet absorbers.

6. The method for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 5, characterized in that: In step (2), the wooden probe is pretreated by cutting the wooden toothpick into probes with a length of 3 cm and a tip diameter of 0.15-0.2 mm, ultrasonically cleaning the probe with methanol to remove impurities, and drying the probe.

7. The method for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 5 or 6, characterized in that: In step (2), the method for functionalizing the wood probe is as follows: the pretreated wood probe is placed in anhydrous DMF solution, DMOAP reagent is added, and the reaction is refluxed at 120°C for 12 hours under a nitrogen atmosphere to modify C on the surface of the wood probe. 18 The hydrophobic groups give the wood probe the ability to selectively adsorb hydrophobic OUVs.

8. The method for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 5, characterized in that: In step (3), the angle between the wooden probe and the injection port of the atmospheric pressure mass spectrometer is 90°, and the distance between them is 0.25 cm.

9. The method for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 5, characterized in that: In step (4), the spray solvent is methanol and acetonitrile in a volume ratio of 3:7, and the mixture is allowed to stand for 5 seconds to promote the desorption of the target substance.

10. The method for detecting ultraviolet absorbers based on solid phase microextraction and atmospheric pressure mass spectrometry according to claim 5, characterized in that: In step (5), the applied voltage was 4.5 kV.

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