Liquid chromatography-mass spectrometry detection method and system for organic ultraviolet masking agent in seawater

Abstract

The invention belongs to the technical field of mass spectrum detection, and discloses a liquid chromatography-mass spectrum detection method for an organic ultraviolet masking agent in seawater, and the technical scheme provided by the invention can be used for synchronously analyzing various types of organic ultraviolet masking agents such as BP-UVFs, TA-UVFs, DTS and SC-UVFs. For example, specific solid phase extraction and chemical analysis processes are adopted for BP-UVFs, TA-UVFs and DTS; for the SC-UVFs, liquid-liquid extraction, purification and a corresponding gas chromatography-mass spectrometry analysis method are adopted. According to the multi-class synchronous analysis scheme, the analysis efficiency is greatly improved, the pollution condition of the organic ultraviolet masking agent in the marine environment can be known more comprehensively, and richer data support is provided for related research and environment monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of mass spectrometry detection, and in particular relates to a liquid chromatography-mass spectrometry detection method and system for organic ultraviolet light screening agents in seawater. Background Art

[0002] Organic UV-shielding agents are widely present in marine environments, but existing technologies primarily target a single class of compounds, lacking a multi-class, simultaneous analysis solution. Traditional methods also suffer from low recoveries (especially for compounds with widely varying polarity), insufficient detection limits, and a lack of standardized quality control procedures for seawater matrices.

[0003] Existing technologies often target a single class of compounds, lacking solutions for simultaneous analysis of multiple classes. Furthermore, traditional methods suffer from low recoveries (especially for compounds with significant polarity differences), insufficient detection limits, and a lack of standardized quality control procedures for seawater matrices.

[0004] Existing technologies often use gas chromatography-mass spectrometry (GC-MS) to detect hydroxylated benzophenone UV absorbers in seawater. For example, the "dispersive liquid-liquid microextraction (DLLME)-GC-MS" process proposed by López-Darias et al.: chloroform and ethyl acetate are added to 10 mL of seawater sample to form an emulsion system, which is then derivatized with HFIP-silylation and analyzed on the machine. It can simultaneously determine six target compounds including 2-OH-BP-3 with a detection limit of 32–50 ngL-1, an enrichment factor of 58–64, and a repeatability RSD of ≈6% ([researchgate.net][1]). Similar SPE-GC-MS / MS methods have also been reported to exhibit significant matrix suppression in domestic sewage samples, requiring online BSTFA derivatization or standard addition calibration to ensure linearity and accuracy.

[0005] However, this type of GC-MS scheme has two technical bottlenecks: first, the recovery rate of polar to medium-polarity UVFs (such as DTS and TA-UVFs) in the derivatization-dispersive extraction step is unstable, and even less than 60% in high organic matter matrices; second, the detection limit usually remains at the level of tens of ngL-1, which is difficult to meet the needs of monitoring sub-ngL-1 background concentrations and short-cycle fluctuations of tide level and passenger flow in nearshore seawater. At the same time, the signal suppression caused by the high chloride matrix requires repeated correction, which significantly slows down the sample throughput and increases the use of toxic solvents. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a liquid chromatography-mass spectrometry method for detecting organic ultraviolet shielding agents in seawater.

[0007] The present invention is achieved by a liquid chromatography-mass spectrometry method for detecting an organic ultraviolet light screening agent in seawater, comprising:

[0008] Step 1: The collected seawater samples were filtered through a known weight of pre-burned GF / F glass fiber filter and extracted by OUVF. For chemical analysis of BP-UVFs, TA-UVFs, and DTS:

[0009] Step 2: 1 L of filtered seawater sample was added with 1 ng of deuterated internal standards (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15), and solid-phase extraction was performed using an Oasis HLB solid-phase extraction cartridge (6 mL / 500 mg) at a trickle flow rate.

[0010] Step 3: The target compound was eluted with 3 × 4 mL of a methanol / dichloromethane mixture (50:50, v:v). The eluate was concentrated to near dryness under a gentle stream of high-purity nitrogen, reconstituted with 200 μL of methanol, and 13C6-UV-329 was added as an internal standard.

[0011] Step 4, for SC-UVFs: Transfer another 1 L filtered seawater sample to a 2 L separatory funnel, add 1 ng of deuterated internal standard isopropyl salicylate-d7, and perform two liquid-liquid extractions with dichloromethane (50 mL each).

[0012] Step 5: The combined extracts were concentrated to approximately 2 mL by rotary evaporation and then purified by passing through a pretreated HLB column and eluted with 3 × 4 mL of a 50:50 (v:v) methanol:dichloromethane solution. The eluate was concentrated to near dryness under a stream of nitrogen, reconstituted with 200 μL of isooctane, and phenyl salicylate-d5 was added as an internal standard.

[0013] In step 6, the final extract was stored in 2 mL glass vials, stored at −20 °C, and transported to our laboratory for instrumental analysis.

[0014] Furthermore, it also includes:

[0015] The extracts containing BP-UVFs, TA-UVFs and DTS were analyzed using an Agilent 1290 InfinityII ultra-high performance liquid chromatography coupled to an Agilent 6470 triple quadrupole mass spectrometer; the mass spectrometer was equipped with an AJS-ESI source (Agilent Jet Stream electrospray ionization source) in positive ion mode.

[0016] Furthermore, it also includes:

[0017] The injection volume was 2 μL, and chromatographic separation was performed on an Agilent ZORBAXSB-Phenyl column (2.1 × 100 mm, 1.8 μm) with the column oven temperature set at 40°C. The mobile phase consisted of milli-Q water (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.30 mL / min. A gradient elution program was used: the initial methanol ratio was 30%, increasing to 60% at 3 minutes, 80% at 5 minutes, 90% at 10 minutes, and 100% methanol at 11 minutes (held for 5 minutes), and then returning to the initial conditions.

[0018] Furthermore, data acquisition adopted dynamic multiple reaction monitoring (dMRM) mode; SC-UVFs in water were determined using an Agilent 8890 gas chromatography system connected to an Agilent 7010B mass spectrometer, and the mass spectrometry adopted 70 eV electron bombardment (EI) mode, and separation was performed on an Agilent HP-5MSUI capillary column (30 m × 0.25 mm × 0.25 μm).

[0019] Furthermore, the column oven temperature was programmed to rise: 60°C for 1 minute, then to 120°C at 40°C / min, and finally to 300°C at 5°C / min (held for 7.5 minutes).

[0020] Furthermore, quantification of SC-UVFs was performed in dMRM mode;

[0021] Another object of the present invention is to provide a liquid chromatography-mass spectrometry detection system for organic ultraviolet screeners in seawater, comprising:

[0022] Acquisition module, used for filtering the collected seawater samples with a known weight of pre-ignited GF / F glass fiber filter and OUVF extraction; for chemical analysis of BP-UVFs, TA-UVFs and DTS:

[0023] An extraction module was used to take 1 L of filtered seawater sample, add 1 ng of deuterated internal standards (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15), and perform solid-phase extraction using an Oasis HLB solid-phase extraction cartridge (6 mL / 500 mg) at a trickle flow rate;

[0024] Elution module: eluted the target compound with 3 × 4 mL of a methanol / dichloromethane mixture (50:50, v:v). The eluate was concentrated to near dryness under a gentle stream of high-purity nitrogen, reconstituted with 200 μL of methanol, and 13C6-UV-329 was added as an internal standard for injection.

[0025] Filtration module for SC-UVFs: Transfer another 1 L filtered seawater sample to a 2 L separatory funnel, add 1 ng of deuterated internal standard isopropyl salicylate-d7, and perform two liquid-liquid extractions with dichloromethane (50 mL each).

[0026] The combined extracts were concentrated by rotary concentrator to approximately 2 mL in a concentration module and then cleaned up by passing them through a pretreated HLB column and eluting with 3 × 4 mL of a 50:50 (v:v) methanol:dichloromethane solution. The eluate was concentrated to near dryness under a stream of nitrogen and reconstituted with 200 μL of isooctane, with phenyl salicylate-d5 added as an internal standard.

[0027] The analytical module was used to store the final extract in 2 mL glass vials, stored at −20 °C, and transported to our laboratory for instrumental analysis.

[0028] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the liquid chromatography-mass spectrometry detection method for organic ultraviolet screeners in seawater.

[0029] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the liquid chromatography-mass spectrometry detection method for organic ultraviolet screeners in seawater.

[0030] Another object of the present invention is to provide an information data processing terminal, which is used to implement a liquid chromatography-mass spectrometry detection system for the organic ultraviolet screener in seawater.

[0031] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0032] The collected seawater samples were filtered through a known weight of pre-ignited GF / F glass fiber filters and extracted using OUVF. For chemical analysis of BP-UVFs, TA-UVFs, and DTS, 1 liter of filtered seawater was spiked with 1 ng of deuterated internal standards (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15). Solid-phase extraction was performed using an Oasis HLB solid-phase extraction cartridge (6 mL / 500 mg) at a trickle flow rate. The target compounds were eluted with 3 × 4 mL of a methanol / dichloromethane mixture (50:50, v:v). The eluate was concentrated to near dryness under a gentle stream of high-purity nitrogen, reconstituted with 200 μL of methanol, and spiked with 13C6-UV-329 as an injection internal standard. For SC-UVFs: A separate 1-liter filtered seawater sample was transferred to a 2-liter separatory funnel, 1 ng of the deuterated internal standard, isopropyl salicylate-d7, was added, and two liquid-liquid extractions were performed with dichloromethane (50 mL each). The combined extracts were concentrated by rotary centrifugation to approximately 2 mL and then cleaned up by passage through a pretreated HLB column, eluting with 3 × 4 mL of a 50:50 (v:v) methanol:dichloromethane solution. The eluate was concentrated to near dryness under a stream of nitrogen, reconstituted with 200 μL of isooctane, and phenyl salicylate-d5 was added as an internal standard. The final extract was stored in 2-mL glass vials at −20°C and shipped to our laboratory for instrumental analysis.

[0033] Extracts containing BP-UVFs, TA-UVFs, and DTS were analyzed using an Agilent 1290 Infinity II ultra-high performance liquid chromatograph coupled to an Agilent 6470 triple quadrupole mass spectrometer. The mass spectrometer was equipped with an AJS-ESI source (Agilent Jet Stream electrospray ionization) in positive ion mode. The injection volume was 2 μL, and chromatographic separation was performed on an Agilent ZORBAX SB-Phenyl column (2.1 × 100 mm, 1.8 μm) with a column oven temperature set at 40°C. The mobile phase consisted of milli-Q water (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.30 mL / min. A gradient elution program was used: starting with 30% methanol, increasing to 60% at 3 minutes, 80% at 5 minutes, 90% at 10 minutes, and 100% methanol at 11 minutes (held for 5 minutes), followed by a return to the starting conditions. Data were acquired in dynamic multiple reaction monitoring (dMRM) mode. SC-UVFs in water were determined using an Agilent 8890 gas chromatography system coupled to an Agilent 7010B mass spectrometer. Mass spectrometry was performed in 70 eV electron impact (EI) mode, with separation on an Agilent HP-5MSUI capillary column (30 m × 0.25 mm × 0.25 μm). The column oven temperature was programmed as follows: 60°C for 1 minute, then increased to 120°C at 40°C / min, and finally to 300°C (held for 7.5 minutes) at 5°C / min. Quantification of SC-UVFs was performed in dMRM mode.

[0034] The technical solution provided by this invention enables simultaneous analysis of multiple categories of organic UV-shielding agents, including BP-UVFs, TA-UVFs, DTS, and SC-UVFs. For example, for BP-UVFs, TA-UVFs, and DTS, a specific solid-phase extraction and chemical analysis process is employed; for SC-UVFs, liquid-liquid extraction, cleanup, and corresponding gas chromatography-mass spectrometry analysis methods are employed. This multi-category simultaneous analysis approach significantly improves analytical efficiency, enabling a more comprehensive understanding of the contamination status of organic UV-shielding agents in the marine environment and providing richer data support for related research and environmental monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention provides a flow chart of a method for detecting organic ultraviolet light shielding agents in seawater using liquid chromatography-mass spectrometry.

[0036] Figure 2 This is a structural block diagram of a liquid chromatography-mass spectrometry detection system for organic ultraviolet shielding agents in seawater provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] like Figure 1 As shown, a liquid chromatography-mass spectrometry method for detecting organic ultraviolet shielding agents in seawater provided by an embodiment of the present invention comprises the following steps:

[0039] S101, the collected seawater samples were filtered through a known weight of pre-burned GF / F glass fiber filter and extracted by OUVF; for chemical analysis of BP-UVFs, TA-UVFs and DTS:

[0040] S102: 1 L of filtered seawater sample was added with 1 ng of deuterated internal standards (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15), and solid-phase extraction was performed using an Oasis HLB solid-phase extraction cartridge (6 mL / 500 mg) at a trickle flow rate.

[0041] S103, the target compound was eluted with a methanol / dichloromethane mixture (50:50, v:v) (3 × 4 mL). The eluate was concentrated to near dryness under a gentle stream of high-purity nitrogen, reconstituted with 200 μL of methanol, and 13C6-UV-329 was added as an internal standard for injection.

[0042] S104, for SC-UVFs: Transfer another 1 L filtered seawater sample to a 2 L separatory funnel, add 1 ng of deuterated internal standard isopropyl salicylate-d7, and perform two liquid-liquid extractions with dichloromethane (50 mL each).

[0043] S105, the combined extracts were concentrated by rotary evaporation to approximately 2 mL, then purified by passing through a pretreated HLB column and eluted with 3 × 4 mL of a 50:50 (v:v) methanol:dichloromethane solution; the eluate was concentrated to near dryness under a stream of nitrogen, reconstituted with 200 μL of isooctane, and phenyl salicylate-d5 was added as an internal standard;

[0044] S106, the final extract was stored in 2 mL glass vials, stored at −20°C, and shipped to our laboratory for instrumental analysis.

[0045] Extracts containing BP-UVFs, TA-UVFs, and DTS were analyzed using an Agilent 1290 Infinity II ultra-high performance liquid chromatograph coupled to an Agilent 6470 triple quadrupole mass spectrometer. The mass spectrometer was equipped with an AJS-ESI source (Agilent Jet Stream electrospray ionization) in positive ion mode. The injection volume was 2 μL, and chromatographic separation was performed on an Agilent ZORBAX SB-Phenyl column (2.1 × 100 mm, 1.8 μm) with a column oven temperature set at 40°C. The mobile phase consisted of milli-Q water (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.30 mL / min. A gradient elution program was used: starting with 30% methanol, increasing to 60% at 3 minutes, 80% at 5 minutes, 90% at 10 minutes, and 100% methanol at 11 minutes (held for 5 minutes), followed by a return to the starting conditions. Data were acquired in dynamic multiple reaction monitoring (dMRM) mode. SC-UVFs in water were determined using an Agilent 8890 gas chromatography system coupled to an Agilent 7010B mass spectrometer. Mass spectrometry was performed in 70 eV electron impact (EI) mode, with separation on an Agilent HP-5MSUI capillary column (30 m × 0.25 mm × 0.25 μm). The column oven temperature was programmed as follows: 60°C for 1 minute, then increased to 120°C at 40°C / min, and finally to 300°C (held for 7.5 minutes) at 5°C / min. Quantification of SC-UVFs was performed in dMRM mode.

[0046] like Figure 2 As shown, a liquid chromatography-mass spectrometry detection system for organic ultraviolet shielding agents in seawater provided by an embodiment of the present invention includes:

[0047] Acquisition module, used for filtering the collected seawater samples with a known weight of pre-ignited GF / F glass fiber filter and OUVF extraction; for chemical analysis of BP-UVFs, TA-UVFs and DTS:

[0048] An extraction module was used to take 1 L of filtered seawater sample, add 1 ng of deuterated internal standards (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15), and perform solid-phase extraction using an Oasis HLB solid-phase extraction cartridge (6 mL / 500 mg) at a trickle flow rate;

[0049] Elution module: eluted the target compound with 3 × 4 mL of a methanol / dichloromethane mixture (50:50, v:v). The eluate was concentrated to near dryness under a gentle stream of high-purity nitrogen, reconstituted with 200 μL of methanol, and 13C6-UV-329 was added as an internal standard for injection.

[0050] Filtration module for SC-UVFs: Transfer another 1 L filtered seawater sample to a 2 L separatory funnel, add 1 ng of deuterated internal standard isopropyl salicylate-d7, and perform two liquid-liquid extractions with dichloromethane (50 mL each).

[0051] The combined extracts were concentrated by rotary concentrator to approximately 2 mL in a concentration module and then cleaned up by passing them through a pretreated HLB column and eluting with 3 × 4 mL of a 50:50 (v:v) methanol:dichloromethane solution. The eluate was concentrated to near dryness under a stream of nitrogen and reconstituted with 200 μL of isooctane, with phenyl salicylate-d5 added as an internal standard.

[0052] The analytical module was used to store the final extract in 2 mL glass vials, stored at −20 °C, and transported to our laboratory for instrumental analysis.

[0053] After the monitoring vessel docked, seawater samples collected daily were immediately sent to the local environmental monitoring station for filtration (using pre-ignited GF / F glass fiber filters of known weight, Whatman, Maidstone, UK) and OUVF extraction. Studies have shown that the use of HLB solid-phase extraction (SPE) cartridges can achieve satisfactory recoveries of OUVFs with a wide range of polarities. For chemical analysis of BP-UVFs, TA-UVFs, and DTS, 1 liter of filtered seawater sample was spiked with 1 ng of deuterated internal standards (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15). SPE was performed using Oasis HLB SPE cartridges (6 mL / 500 mg) at a trickle flow rate. The target compounds were eluted with 3 × 4 mL of a methanol / dichloromethane mixture (50:50, v:v). The eluate was concentrated to near dryness under a gentle stream of high-purity nitrogen, reconstituted with 200 μL of methanol, and spiked with 13C6-UV-329 as an internal standard. For SC-UVFs, a separate 1 L sample of filtered seawater was transferred to a 2 L separatory funnel, 1 ng of the deuterated internal standard, isopropyl salicylate-d7, was added, and two liquid-liquid extractions were performed with dichloromethane (50 mL each). The combined extracts were concentrated by rotary centrifugation to approximately 2 mL, then cleaned up by passage through a pretreated HLB column and eluted with 3 × 4 mL of a 50:50 (v:v) methanol:dichloromethane solution. The eluate was concentrated to near dryness under a stream of nitrogen, reconstituted with 200 μL of isooctane, and spiked with phenyl salicylate-d5 as an internal standard. The final extract was stored in 2 mL glass vials at −20°C and shipped to our laboratory for instrumental analysis.

[0054] Extracts containing BP-UVFs, TA-UVFs, and DTS were analyzed using an Agilent 1290 Infinity II Ultra Performance Liquid Chromatography coupled to an Agilent 6470 Triple Quadrupole Mass Spectrometer (Agilent Technologies, Santa Clara, CA, USA). The mass spectrometer was equipped with an AJS-ESI source (Agilent Jet Stream Electrospray Ionization Source) in positive ion mode. The injection volume was 2 μL, and chromatographic separation was performed on an Agilent ZORBAX SB-Phenyl column (2.1 × 100 mm, 1.8 μm) with a column oven temperature set at 40°C. The mobile phase consisted of milli-Q water (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.30 mL / min. A gradient elution program was used: starting with 30% methanol, increasing to 60% at 3 minutes, 80% at 5 minutes, 90% at 10 minutes, and 100% methanol at 11 minutes (hold for 5 minutes), followed by a return to the initial conditions. Data acquisition was performed in dynamic multiple reaction monitoring (dMRM) mode. SC-UVFs in water were determined using an Agilent 8890 gas chromatography system coupled to an Agilent 7010B mass spectrometer. Mass spectrometry was performed in 70 eV electron impact (EI) mode, with separation performed on an Agilent HP-5MSUI capillary column (30 m × 0.25 mm × 0.25 μm). The column oven temperature was programmed as follows: 60°C for 1 minute, then increased to 120°C at 40°C / min, and finally increased to 300°C at 5°C / min (held for 7.5 minutes). Quantification of SC-UVFs was performed in dMRM mode.

[0055] Highly sensitive quantitative analysis of organic UV filters (UVFs) in seawater samples plays an indispensable supporting role in assessing the cumulative risk of cosmetic and sunscreen emissions to nearshore ecosystems, tracking increasingly stringent emission limits, and providing a basis for decision-making in coral reef protection, blue carbon project site selection, and beach water quality grading management. The liquid chromatography-mass spectrometry detection method disclosed in this invention can be directly integrated into the routine project lists of coastal monitoring stations, joint shore-based observation systems of scientific research vessels, and third-party environmental testing laboratories. It is compatible with existing heavy metal and persistent organic pollutant monitoring procedures, reducing additional personnel training and equipment modification costs.

[0056] At the product level, the method elements have been packaged into an "all-in-one SPE-LC-MS analysis kit": pre-ignited GF / F membrane filters and pre-activated OasisHLB solid-phase extraction cartridges are assembled into a disposable kit; deuterated and 13C isotope internal standard solutions are dispensed into low-adsorption glass ampoules at factory-prepared concentrations; and an instrument method file containing optimized gradients and multiple reaction monitoring (MRM) ion pairs is included, allowing for plug-and-play operation on most triple quadrupole and high-resolution mass spectrometry platforms. This kit has been validated at several domestic marine environmental monitoring centers and is being used by several daily chemical companies for raw liquid discharge audits and product eco-label certification.

[0057] To demonstrate the effectiveness of this technique, the research team conducted blind spiking experiments on 42 field samples collected near the shore of Xugong Island in the East China Sea and in the warm current confluence zone near Taiwan Island. The average recoveries for 11 representative UVFs, including BP-3, UV-328, EHT, and DTS, were 86%–95%, with method detection limits (MDLs) ranging from 0.3–1.2 ng / L⁻¹. The relative standard deviations (RSDs) of peak areas for replicate samples (n=6) were all below 5%. Compared to the National Marine Standard Method (GB / T37810-2019), this method shortened sample preparation time by approximately 40% under identical instrumental conditions and significantly reduced matrix suppression (average signal enhancement rate ≈10%).

[0058] Further field applications demonstrated that during the peak tourist season of August, when weekly sampling was conducted at three typical swimming areas near the Xiamen coast, peak total UVF concentrations measured using the present method were significantly correlated with concurrent changes in tourist flow, tidal exchange coefficients, and sea surface temperature (Pearson r = 0.82, p < 0.01). Conventional solid-liquid partitioning-GC / MS methods yielded only fragmentary results for the same sample batches. Storage stability experiments also revealed that the loss of all target compounds was less than 4% within seven days of storage at -20°C, providing ample time buffer for centralized batch analysis. These data fully demonstrate the combined advantages of the present method in terms of sensitivity, throughput, and reliable results.

[0059] Example 1 - Field measurement and verification of the coastal waters affected by tourists

[0060] In July 2025, we collected 1 L of surface seawater from the main swimming area of ​​Weizhou Island in the Beibu Gulf, 200 m offshore, 1 hour before high tide. The samples were immediately filtered through a 0.7 μm pre-calcined GF / F filter and spiked with 1 ng of a deuterated mixed internal standard (BP-d10, BP-12-d7, UV-328-d12, and EHT-d15). The samples were returned to the laboratory that day and extracted using a 6 mL / 500 mg Oasis HLB column using the method described in this invention. Elution was performed using 3 × 4 mL of 50:50 (v / v) methanol / dichloromethane. After nitrogen purging to near dryness, the samples were reconstituted in 200 μL of methanol and injected with 13C6-UV-329 as the internal standard. Using triple quadrupole LC-MS / MS (positive and negative ionization switching, MRM mode) analysis, the concentrations of BP-3, UV-328 and DTS in 11 target UVFs were 63, 27 and 14 ngL-1, respectively; the average recovery rate was 92% (RSD 4.3%) when a blind sample was added with 50 ngL-1 mixed standard and measured in parallel.

[0061] Example 2 - High Salinity / High Suspended Particles Laboratory Simulation Verification

[0062] To evaluate the method's applicability in extreme matrices, 3.8% salinity seawater from the Bohai Sea in winter was adjusted to 150 mg / L using powdered quartz sand. Four representative UVFs (n=3)—BP-3, UV-329, EHT, and isopropyl salicylate (ISA)—were spiked at concentrations of 5, 25, and 100 ng / L, respectively. After filtration through GF / F, the BP / TA-UVF fraction was processed using a solid-phase extraction (SPE) protocol. The SC-UVF fraction was extracted twice with 50 mL of dichloromethane and cleaned up by HLB. The final extract was reconstituted with 200 μL of isooctane and spiked with ISA-d5 as an internal standard. Analysis by high-resolution Orbitrap LC-MS (60000FWHM) showed average recoveries of 88%–95% across three spike levels, with signal suppression of <8% after matrix correction. Limits of detection (LODs) ranged from 0.4 to 1.0 ng / L.

[0063] Two sets of examples, spanning both natural high-organic matter / low-suspended-particle water and laboratory-fortified salinity-particulate matrices, achieved replicate RSDs of <5% and recoveries >85%, demonstrating consistent quantitative accuracy for both the SPE-LC-MS and LLE-clean-LC-MS workflows across diverse UVF structural classes and complex matrices. Compared to parallel tests (n=8) using the GB / T37810-2019 GC / MS method, this method can additionally detect polar to moderately polar components, including benzotriazines (TA-UVF) and silanols (DTS), while also reducing sample preparation time by 35% and nitrogen purging by approximately 40%.

[0064] The method demonstrated in the examples demonstrates excellent sensitivity, accuracy, and throughput in both real and simulated challenging matrices, with no significant target loss during the sample storage-transport-analysis chain (<4% loss in a 7-day stability test at -20°C). Therefore, this method can be used in both conventional coastal monitoring networks and is also suitable for simultaneous detection of high-salt, high-particle, and diverse UVF concentrations in daily chemical industry emissions audits and scientific research activities. It provides a reliable technical solution with potential for industrialization for marine ecological risk assessment and pollution source tracking.

[0065] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for detecting organic ultraviolet screeners in seawater, characterized in that: Follow these steps in order: a. Take one liter of seawater sample and filter through a GF / F glass fiber filter membrane to obtain the filtrate; b. Add one nanogram of each of the internal standards BP-d10, BP-12-d7, UV-328-d12, and EHT-d15 to the filtrate; c. Solid phase extraction was performed using a 6 ml 500 mg Oasis HLB solid phase extraction cartridge in a drip flow mode; d. Elute the target compound with a 1:1 volume ratio of methanol to dichloromethane in three portions of 4 ml each; e. The eluate was concentrated to near dryness under a stream of high-purity nitrogen, reconstituted by adding 200 μl of methanol, and 13C6-UV-329 was added as an internal standard for injection; f. Quantitative analysis was performed using triple quadrupole liquid chromatography-mass spectrometry in positive ion dynamic multiple reaction monitoring mode.

2. The method according to claim 1, characterized in that Liquid chromatography used a phenyl bonded silica gel column with a filler particle size of 1.8 μm and a size of 2.1 by 100 mm. The column temperature was 40 degrees Celsius, the flow rate was 0.3 ml per minute, and the gradient program was: starting with 30% methanol, increasing to 60% in three minutes, 80% in five minutes, 90% in ten minutes, and 100% in eleven minutes and maintaining for five minutes, then returning to the initial conditions and equilibrating for three minutes.

3. The method according to claim 1, characterized in that The concentrated solution obtained after elution in step d was immediately stored at -20 degrees Celsius after nitrogen purge and instrument detection was completed within 48 hours.

4. The method according to claim 1, wherein The ion spray voltage of the triple quadrupole mass spectrometer was set to 3500 V, the liner gas temperature to 350°C, and the nitrogen flow rate to 13 liters per minute.

5. A liquid chromatography-mass spectrometry method for detecting salicylate ultraviolet screeners in seawater, characterized in that: One liter of filtered seawater was added with one nanogram of isopropyl salicylate-d7 as an internal standard. Liquid-liquid extraction was then performed with dichloromethane (50 ml each time) twice. The combined extracts were rotary evaporated to 2 ml. The extracts were pretreated and purified on an Oasis HLB column. Elute was performed with a mixture of methanol and dichloromethane (1:1 by volume) three times with 4 ml each. After nitrogen purging until nearly dry, 200 μl of isooctane was added for redissolution, and phenyl salicylate-d5 as an internal standard was added. Quantitative analysis was finally performed using a gas chromatography-mass spectrometer operating in electron impact mode.

6. The method according to claim 5, characterized in that The gas chromatography capillary column is 30 meters long, with an inner diameter of 0.25 mm and a film thickness of 0.25 microns. The injection port temperature is 280 degrees Celsius. The heating program is: 60 degrees Celsius for one minute, increase to 120 degrees Celsius at 40 degrees Celsius per minute, and then increase to 300 degrees Celsius at 5 degrees Celsius per minute and maintain for seven and a half minutes.

7. A detection system for organic ultraviolet screeners in seawater, comprising a collection module, an extraction module, an elution module, a concentration module, and an analysis module, characterized in that: The collection module is equipped with a cauterized GF / F filter assembly and a one-liter quantitative sampler; The extraction module includes an OasisHLB solid phase extraction unit and a flow control unit; The elution module includes a methanol and dichloromethane mixed solvent supply unit in a ratio of one to one; The concentration module includes a rotary evaporator and a nitrogen blower; The analysis module is equipped with a triple quadrupole liquid chromatography-mass spectrometer and a gas chromatography-mass spectrometer. The central controller switches different analysis channels according to the preset program to complete the quantitative detection of BP-UVFs, TA-UVFs, DTS and SC-UVFs.

8. The system according to claim 7, characterized in that: The central controller uses barcode recognition technology to automatically track sample bottles and record each flow rate, temperature and pressure parameters to ensure traceability.

9. A seawater sample pretreatment kit comprising: A set of GF / F filtration device; At least two 500 mg OasisHLB extraction cartridges; 100 ml each of methanol, dichloromethane, and isooctane high-purity solvents; internal standard mixed solution containing BP-d10, BP-12-d7, UV-328-d12, EHT-d15, isopropyl salicylate-d7, phenyl salicylate-d5, and 13C6-UV-329; and operating instructions.

10. The kit according to claim 9, characterized in that The mass concentration of each isotope-labeled compound in the internal standard mixed solution was 1 μg / mL, methanol was used as the solvent and the solution was dispensed into 2 mL brown ampoules.

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