Method for detecting hexabromocyclododecane in petrochemical wastewater

Abstract

The invention discloses a method for detecting hexabromocyclododecane in petrochemical wastewater. The method comprises the steps of sample collection and preservation, sample pretreatment and LC-MS / MS detection. The magnetic solid phase extraction-high performance liquid chromatography-electrospray-tandem triple quadrupole mass spectrometer is adopted to perform trace detection on hexabromocyclododecane in the petrochemical wastewater, the more perfect and comprehensive LC-MS / MS detection method for hexabromocyclododecane in the petrochemical wastewater is provided, and on the premise that the recovery rate and the accuracy and precision of the detection result are guaranteed, the detection efficiency is improved, and the detection cost is reduced. The sample pretreatment mode and detection conditions are optimized and adjusted, the purification treatment capacity for high turbidity, high oil content, high salinity and the like in the petrochemical wastewater is enhanced, the experiment process is more convenient and faster, time and labor are saved, the experiment error is reduced, trace detection of hexabromocyclododecane in the petrochemical wastewater can be met, and the method is suitable for popularization and application. And data support is provided for quality supervision and risk early warning in petrochemical wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental detection, and particularly relates to a method for detecting hexabromocyclododecane in petrochemical wastewater. Background Art

[0002] Hexabromocyclododecane (HBCD), as an efficient brominated flame retardant, is widely used in fields such as polystyrene foam (EPS / XPS), textiles, and electronic devices, significantly improving the fire resistance of materials by inhibiting the combustion chain reaction. However, traditional HBCD has significant technical bottlenecks: its synthesis process relies on highly toxic solvents (such as carbon tetrachloride), with complex by-products and limited yields; at the same time, HBCD has the characteristics of persistent organic pollutants (POPs) and is prone to long-term residues in the environment.

[0003] Currently, the detection of HBCD in petrochemical wastewater faces multiple technical challenges, mainly due to its complex matrix characteristics and environmental behavior. Petrochemical wastewater usually contains co-existing pollutants such as high-concentration oils, polycyclic aromatic hydrocarbons (PAHs), surfactants, and heavy metals. These components not only interfere with the extraction and purification process of HBCD but also cause significant matrix effects in instrumental analysis, resulting in signal suppression or false positives of the target substance. HBCD itself has special physical and chemical properties - its high hydrophobicity makes it easily adsorbed on the surface of suspended particles or colloids, while its thermal instability limits the direct analysis by gas chromatography (GC), making it difficult to meet the measurement and detection requirements. Existing international standard methods (such as EPA 1614) or technical solutions, although providing a basic framework, are not fully designed for the multiphase and highly interfering characteristics of petrochemical wastewater, resulting in insufficient sensitivity and poor repeatability in practical applications. The existing liquid chromatography-tandem mass spectrometry (LC-MS / MS) method can be applied to the detection of conventional water environments, with advantages such as no need for derivatization treatment, high detection efficiency, and the ability to meet the quantitative analysis of trace pollutants. However, when this method is directly applied to the detection of fossil wastewater, it will be affected by factors such as background interference, and the detection results are inaccurate. Moreover, there is still room for optimization in terms of detection speed and sensitivity, and most can only meet the needs of basic laboratories and conventional water environments.

[0004] Therefore, it is very necessary to develop a method for detecting hexabromocyclododecane in petrochemical wastewater using LC-MS / MS, which is more convenient, faster, time-saving, labor-saving, consumable-saving, can ensure the recovery rate, and has higher accuracy and precision of the detection results. Summary of the Invention

[0005] To solve the above technical problems, the object of the present invention is to provide a method for detecting hexabromocyclododecane in petrochemical wastewater. The method of the present invention optimizes the sample pretreatment method and the detection conditions on the machine, making the treatment and operation process simple and convenient, with a short sample detection and analysis time, a low detection limit, and high detection precision and accuracy, and solving the interference problem of background factors such as high turbidity, high oil content, strong acid / alkali content, and high salinity in petrochemical wastewater on the trace detection of hexabromocyclododecane.

[0006] The object of the present invention is achieved as follows, including the following steps: S1. Sample collection and preservation: Collect the petrochemical wastewater water sample, seal it in the dark and store it refrigerated, with a storage time not exceeding 7 days; the extracted sample is sealed in the dark and stored refrigerated, with a storage time not exceeding 40 days; S2. Sample pretreatment: Filter the water sample using a three-stage series filtration system, add the internal standard working solution and n-hexane containing formic acid, after vortex extraction, add magnetic particles, separate with a magnet, wash with a mixed solution of n-hexane - ethyl acetate, elute with a mixed solution of ethyl acetate - acetone, filter, and then use a nitrogen blower to slowly blow to near dryness, and make up the volume to with a mixed solution of formic acid - methanol, and ultrasonically mix evenly and wait for detection on the machine; S3. LC-MS / MS detection: Use ultra-high performance liquid chromatography - tandem mass spectrometry to determine hexabromocyclododecane in petrochemical wastewater, and obtain the concentration of hexabromocyclododecane in the sample according to the standard curve; Liquid chromatography conditions: Chromatographic column: Shim-pack GIST C18-AQ, specification 2.1mm×100mm, 3μm; Mobile phase: Phase A: 0.1% formic acid + 5mM ammonium acetate aqueous solution, Phase B: A mixture of acetonitrile and methanol in a volume ratio of 1:1; Flow rate: 0.3mL / min; Column temperature: 45°C; Injection volume: 10μL; Elution method: Gradient elution; Among them, the ratio of the two mobile phases is changed at different times. Under the comparison of interference, while shortening the sample measurement time, as much as possible ensure that hexabromocyclododecane is eluted and separated, with a short peak shape retention time, stable, symmetrical and no tailing; Triple quadrupole mass spectrometer mass conditions: Ion source scan mode: Electrospray negative ion mode; Monitoring mode: MRM; Nitrogen is used as the carrier gas; Dry gas temperature: 300°C; Dry gas flow rate: 10.0L / min; Sheath gas temperature: 350°C; Sheath gas flow rate: 12L / min; Capillary voltage: -3200V.

[0007] In step S1, a pre-washed and dried sampling bottle is used for water sample collection. Before sampling, note that the sampling bottle cannot be pre-washed with the water sample to prevent contamination or adsorption of the sample.

[0008] In step S3, the chromatographic column has high separation efficiency, enhanced anti-salt crystallization ability, increased response intensity in the negative ion mode, suppresses humic acid signals, achieves synchronous removal of multiple types of interfering substances, controls green costs, compresses the single-sample detection cycle to 8 minutes, breaks through 120 sample runs per day, improves the recovery rate and precision, and realizes trace, highly accurate, and fast-response detection of hexabromocyclododecane in petrochemical wastewater. It is the preferred technology for detecting hexabromocyclododecane in petrochemical wastewater.

[0009] Preferably, when collecting petrochemical wastewater in step S1, the sampling container is completely filled without leaving air bubbles. Add 1 mL of 10% ascorbic acid solution to the water sample, add 80 mg of sodium thiosulfate per liter of water to remove chlorine, and collect a blank control sample simultaneously during on-site sampling.

[0010] Preferably, the three-stage series filtration system in step S2 sequentially passes through a 5 μm stainless steel sieve, 1.0 μm glass fiber, and 0.22 μm lipophilic PTFE membrane at a flow rate of 12 mL / min.

[0011] Preferably, when adding the internal standard working solution in step S2, specifically add 50 μL of 100 ng / mL internal standard working solution to 1 L of water sample; add 30 mL to 50 mL of n-hexane containing 0.1% formic acid, and vortex extract for 6 min to 8 min at 1600 rpm to 2000 rpm; add 70 mg to 90 mg Magnetic particles are adsorbed for 15 min to 25 min; quickly separate with a 0.8 T neodymium iron boron magnet for 2 min; use 6 mL to 10 mL of a n-hexane-ethyl acetate mixed solution with a volume ratio of n-hexane to ethyl acetate of 95:5 to elute and remove non-polar interfering substances at a flow rate of 2.0 mL / min to 4.0 mL / min; use 4 mL to 8 mL of an ethyl acetate-acetone mixed solution with a volume ratio of ethyl acetate to acetone of 8:2 to elute HBCD at a flow rate of 1.0 mL / min to 1.5 mL / min; after the eluate is purified by a 0.22 μm PTFE syringe filter; slowly blow to nearly dry with a nitrogen blower at 45 °C; make up the volume to 1.0 mL with a formic acid-methanol mixed solution with a volume ratio of formic acid to methanol of 0.1:99.9, and ultrasonically mix for 30 s; the sample should be stored refrigerated at below 4 °C for testing.

[0012] The above technical solution utilizes the high adsorption capacity of Fe3O4@SiO2-C18 magnetic particles and the rapid separation characteristics of a 0.8 T neodymium iron boron magnet to achieve high-selectivity enrichment and rapid purification of hexabromocyclododecane in the complex matrix of petrochemical wastewater. It has the advantages of large enrichment capacity, strong anti-fouling ability, short separation time, and less solvent consumption, providing high-purity samples for subsequent high-sensitivity LC-MS / MS detection. It is the preferred pretreatment technology for detecting hexabromocyclododecane in petrochemical wastewater.

[0013] In the above technical solution, the elution-elution system is a n-hexane-ethyl acetate mixed solution-ethyl acetate-acetone mixed solution system. This system can selectively purify and remove lipid interference, prevent the premature elution of HBCD, efficiently elute and improve the recovery rate, has stronger anti-interference ability, reduces the toxicity of the mixed solvent system, reduces the solvent consumption, and achieves the effect of cost-efficiency optimization.

[0014] Preferably, the internal standard working solution in step S2 is an isotope internal standard of hexabromocyclododecane with a concentration of 100 ng / mL 13 C-HBCD. This isotope-labeled substance is used as a recovery rate indicator for hexabromocyclododecane. While being fully miscible with the sample, it is also stable enough not to chemically react with the compounds in the sample. It can correct for the losses during sample pretreatment, increase the accuracy and precision of the results, and achieve accurate quantification of the concentration of hexabromocyclododecane in the sample.

[0015] Preferably, the magnetic particles have a particle size of 50 μm and a specific surface area of 800 m² / g.

[0016] Preferably, the standard curve data in step S3 is shown in Table 1; Table 1: Standard curve data table 。

[0017] Preferably, the elution program for gradient elution by liquid chromatography in step S3 is shown in Table 2; Table 2: Liquid chromatography gradient elution program table 。

[0018] The beneficial effects of the present invention: The present invention uses magnetic solid phase extraction-high performance liquid chromatography-electrospray-tandem triple quadrupole mass spectrometer to perform trace detection of hexabromocyclododecane in petrochemical wastewater, provides a more complete and comprehensive LC-MS / MS detection method for hexabromocyclododecane in petrochemical wastewater, and on the premise of ensuring the recovery rate, accuracy, and precision of the detection results, optimizes and adjusts the sample pretreatment method and detection conditions, strengthens the purification ability for problems such as high turbidity, high oil content, and high salinity in petrochemical wastewater, makes the experimental process more convenient and fast, saves time and effort, reduces experimental errors, can meet the trace detection of hexabromocyclododecane in petrochemical wastewater, and provides data support for quality supervision and risk warning in petrochemical wastewater. Description of the Drawings

[0019] Figure 1 It is the chromatogram of hexabromocyclododecane for the detection result of Example 1. Detailed Embodiments

[0020] The present invention will be further described below in conjunction with embodiments and accompanying drawings, but the present invention is not limited in any way. Any transformation or replacement based on the teachings of the present invention falls within the protection scope of the present invention.

[0021] Example 1 The detection method of hexabromocyclododecane in petrochemical wastewater in this example includes the following steps: S1. Sample collection and preservation: Collect water body water samples and seal them in 1L hard narrow-mouth brown glass bottles (with PTFE-coated pistons). After collection, they should be transported back to the laboratory as soon as possible, refrigerated at a temperature below 4°C, protected from light, and sealed. The preservation time should not exceed 7 days; when collecting water body water samples, fill the sampling bottle completely without leaving air bubbles; add 1 mL of 10% ascorbic acid solution, and add 80 mg of sodium thiosulfate to remove chlorine per liter of water. Collect blank control samples simultaneously during on-site sampling; the samples need to be analyzed within 40 days; S2. Sample pretreatment: Filter the water samples using a three-stage series filtration system (5μm stainless steel screen → 1.0μm glass fiber → 0.22μm lipophilic PTFE membrane, flow rate 12 mL / min); add internal standard working solution, specifically add 50 μL of 100 ng / mL internal standard working solution to 1L of water sample. The internal standard working solution is the isotope internal standard of hexabromocyclododecane with a concentration of 100 ng / mL 13 C-HBCD; add 40 mL of n-hexane containing 0.1% formic acid, and vortex extract for 7 min at 1800 rpm; add 80 mg Magnetic particles for adsorption for 20 min, The magnetic particles have a particle size of 50μm and a specific surface area of 800 m² / g; quickly separate with a 0.8T neodymium iron boron magnet for 2 min; use 8 mL of n-hexane-ethyl acetate mixed solution, with the volume ratio of n-hexane to ethyl acetate being 95:5, and elute non-polar interfering substances at a flow rate of 3.0 mL / min; use 6 mL of ethyl acetate-acetone mixed solution, with the volume ratio of ethyl acetate to acetone being 8:2, and elute HBCD (hexabromocyclododecane) at a flow rate of 1.25 mL / min; after the eluate is purified by a 0.22μm PTFE syringe filter; slowly blow to near dry with a nitrogen blower at 45°C; make up the volume to 1.0 mL with a formic acid-methanol mixed solution, with the volume ratio of formic acid to methanol being 0.1:99.9, and ultrasonically mix for 30 s. The samples are stored refrigerated at a temperature below 4°C for testing; S3. LC-MS / MS detection: Use ultra-high performance liquid chromatography-tandem mass spectrometry to determine hexabromocyclododecane in petrochemical wastewater, and obtain the concentration of hexabromocyclododecane in the sample according to the standard curve; The standard curve data is shown in Table 1; Table 1: Standard curve data table ; Liquid chromatography conditions: Chromatographic column: Shim-pack GIST C18-AQ, specification 2.1 mm × 100 mm, 3 μm; Mobile phase: Phase A: 0.1% formic acid + 5 mM ammonium acetate aqueous solution, Phase B: Acetonitrile and methanol mixed in a volume ratio of 1:1; Flow rate: 0.3 mL / min; Column temperature: 45 °C; Injection volume: 10 μL; Elution method: Gradient elution; The elution program for gradient elution in liquid chromatography is shown in Table 2; Table 2: Liquid chromatography gradient elution program table ; Triple quadrupole mass spectrometer mass conditions: Ion source scan mode: Electrospray negative ion mode; Monitoring mode: MRM; Nitrogen as carrier gas; Dry gas temperature: 300 °C; Dry gas flow rate: 10.0 L / min; Sheath gas temperature: 350 °C; Sheath gas flow rate: 12 L / min; Capillary voltage: -3200 V; The multiple reaction ion detection parameters for hexabromocyclododecane mass spectrometry are shown in Table 3; Table 3: Multiple reaction ion detection parameters for hexabromocyclododecane mass spectrometry

[0022] The experimental results are shown in Table 4, Appendix Figure 1 ; Table 4: Detection results of hexabromocyclododecane

[0023] Note: Low concentration (10 μg / L), medium concentration (40 μg / L), high concentration (400 μg / L).

[0024] Example 2 The detection method of hexabromocyclododecane in petrochemical wastewater in this example is based on Example 1. The differences from Example 1 are as follows: In step S2, 30 mL of n-hexane containing 0.1% formic acid is added, and vortex extraction is carried out at 1600 rpm for 6 min; 70 mg Magnetic particles are added for adsorption for 15 min; 6 mL of n-hexane-ethyl acetate mixed solution is used to wash away non-polar interfering substances at a flow rate of 2.0 mL / min; 4 mL of ethyl acetate-acetone mixed solution is used to elute HBCD at a flow rate of 1.0 mL / min.

[0025] Example 3 The detection method of hexabromocyclododecane in petrochemical wastewater in this example is based on Example 1. The differences from Example 1 are as follows: In step S2, 50 mL of n-hexane containing 0.1% formic acid is added, and vortex extraction is carried out at 2000 rpm for 8 min; 90 mg The magnetic particles were adsorbed for 25 min; 10 mL of a mixed solution of n-hexane and ethyl acetate was used to elute and remove non-polar interfering substances at a flow rate of 4.0 mL / min; 8 mL of a mixed solution of ethyl acetate and acetone was used to elute HBCD at a flow rate of 1.5 mL / min.

Claims

1. A detection method for hexabromocyclododecane in petrochemical wastewater, characterized in that It includes the following steps: S1. Sample collection and preservation: Collect the petrochemical wastewater sample, seal it to avoid light, preserve it refrigerated, and the preservation time shall not exceed 7 days; the extracted sample shall be sealed to avoid light and preserved refrigerated, and the preservation time shall not exceed 40 days; S2. Sample pretreatment: Filter the water sample using a three-stage series filtration system, add the internal standard working solution and n-hexane containing formic acid, after vortex extraction, add magnetic particles, separate with a magnet, wash with a mixed solution of n-hexane - ethyl acetate, elute with a mixed solution of ethyl acetate - acetone, filter, and then slowly blow to nearly dry with a nitrogen blower, volume-fix with a mixed solution of formic acid - methanol, ultrasonically mix evenly and wait for on-machine detection; S3. LC-MS / MS detection: Use ultra-high performance liquid chromatography - tandem mass spectrometry to determine hexabromocyclododecane in petrochemical wastewater, and obtain the concentration of hexabromocyclododecane in the sample according to the standard curve; Liquid chromatography conditions: Chromatographic column: Shim-pack GIST C18-AQ, specification 2.1mm×100mm, 3μm; Mobile phase: Phase A: 0.1% formic acid + 5mM ammonium acetate aqueous solution, Phase B: Acetonitrile and methanol mixed in a volume ratio of 1:1; Flow rate: 0.3mL / min; Column temperature: 45°C; Injection volume: 10μL; Elution mode: Gradient elution; Triple quadrupole mass spectrometer mass conditions: Ion source scan mode: Electrospray negative ion mode; Monitoring mode: MRM; Nitrogen is used as the carrier gas; Dry gas temperature: 300°C; Dry gas flow rate: 10.0L / min; Sheath gas temperature: 350°C; Sheath gas flow rate: 12L / min; Capillary voltage: -3200V.

2. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 1, wherein When collecting the petrochemical wastewater in step S1, completely fill the sampling container without leaving air bubbles, add 1mL of 10% ascorbic acid solution to the water sample, add 80mg of sodium thiosulfate per liter of water to remove chlorine, and collect a blank control sample during on-site sampling.

3. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 1, wherein In step S2, the three-stage series filtration system sequentially passes through a 5μm stainless steel sieve, a 1.0μm glass fiber, and a 0.22μm lipophilic PTFE membrane at a flow rate of 12mL / min.

4. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 1, wherein In step S2, the internal standard working solution is added to 1 L of water sample in the following way: 50 μL of 100 ng / mL internal standard working solution is added; 30 mL to 50 mL of n-hexane containing 0.1% formic acid is added, and vortex extraction is carried out at 1600 rpm to 2000 rpm for 6 min to 8 min; 70 mg to 90 mg of magnetic particles are added for adsorption for 15 min to 25 min; rapid separation is carried out with a 0.8 T neodymium iron boron magnet for 2 min; 6 mL to 10 mL of a n-hexane-ethyl acetate mixed solution with a volume ratio of n-hexane to ethyl acetate of 95:5 is used to wash away non-polar interfering substances at a flow rate of 2.0 mL / min to 4.0 mL / min; 4 mL to 8 mL of an ethyl acetate-acetone mixed solution with a volume ratio of ethyl acetate to acetone of 8:2 is used to elute HBCD at a flow rate of 1.0 mL / min to 1.5 mL / min; after the eluate is purified by a 0.22 μm PTFE syringe filter; it is slowly blown to nearly dry at 45 °C with a nitrogen blower; it is made up to 1.0 mL with a formic acid-methanol mixed solution with a volume ratio of formic acid to methanol of 0.1:99.9, and ultrasonic mixing treatment is carried out for 30 s.

5. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 1, characterized in that In step S2, the internal standard use solution is an isotopic internal standard of hexabromocyclododecane with a concentration of 100 ng / mL 13 C-HBCD.

6. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 4, characterized in that The magnetic particles have a particle size of 50 μm and a specific surface area of 800 m² / g.

7. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 1, characterized in that The standard curve data for step S3 is shown in Table 1; Table 1: Standard curve data table 。 8. The detection method of hexabromocyclododecane in petrochemical wastewater according to claim 1, wherein The elution program for the liquid chromatography gradient elution in step S3 is shown in Table 2; Table 2: Liquid chromatography gradient elution program table 。

Images