Synchronous extraction and instrumental analysis method for tracer organic compounds in sewage in water environment

Abstract

The invention discloses a synchronous extraction and instrumental analysis method for sewage tracer organic compounds in a water environment, which is used for detecting the sewage tracer organic compounds in the water environment under different environment matrixes including surface water, sewage treatment plant inlet water, sewage treatment plant outlet water, dewatered sludge and sediments. The sewage tracing organic compound comprises an artificial sweetener, a contrast agent and caffeine; the method comprises the following steps: preparing a target compound, a standard substance, a deuterated internal standard substance, a reagent, an experimental material and instrument equipment for synchronous extraction and instrumental analysis; preparing and storing a standard sample; sewage samples are collected, the sewage samples comprise water samples and solid samples, the water samples comprise surface water, sewage treatment plant inlet water and sewage treatment plant outlet water, and the solid samples comprise sediments and dewatered sludge; the method comprises the following steps: pre-treating a sewage sample so as to synchronously extract a tracer organic compound; and performing instrumental analysis on the tracer organic compound. The invention further discloses a corresponding system, electronic equipment and a computer readable storage medium.

Description

Technical Field

[0001] The invention relates to the technical field of sewage detection, and in particular to a method for synchronous extraction and instrumental analysis of sewage tracer organic compounds in a water environment. Background Art

[0002] In recent years, artificial sweeteners, contrast agents and caffeine have been detected in large quantities in the environment, and these substances are all artificially synthesized and have no natural sources. Therefore, many studies have shown that these substances are ideal sewage indicators. However, these three types of compounds are highly water-soluble, making extraction and analysis difficult.

[0003] Artificial sweeteners are a type of non-caloric sugar. As a substitute for sucrose, they are widely used in food and beverages. Therefore, there have been a large number of reports on the detection methods of artificial sweeteners in food and beverages, including high performance liquid chromatography (HPLC), gas chromatography (GC), ion chromatography (IC), thin layer chromatography (TLC), capillary electrophoresis (CEP), spectrum, etc. (Zygler et al., 2009) 2830. Although there are many studies on the detection methods of artificial sweeteners in environmental samples, there is still no standard method for detecting them in environmental samples domestically and internationally. Due to the high sensitivity and selectivity of tandem mass spectrometry, and the fact that artificial sweeteners are weakly acidic and exist in the form of ions in natural water environments, most of the methods for detecting trace levels of artificial sweeteners are now combined with other technologies and tandem mass spectrometry, including LC-MS / MS, LC-HRMS and IC-MS / MS.

[0004] Contrast agents are a type of diagnostic drug that can be used for medical imaging of soft tissues in the body, such as blood vessels and internal organs. So far, a variety of methods for detecting contrast agents in the environment have been established. LC-MS / MS is the most commonly used method for detecting contrast agents in the environment. Sacher et al. established a method for directly injecting IC-MS / MS to detect contrast agents in water samples. The detection limit of this method is less than 0.2 μg / L -1 .

[0005] As a stimulant, caffeine is mostly found in tea, coffee, functional drinks, food and medicine. These products have high quality requirements in international trade. At present, a large number of detection methods for caffeine in various matrices have been reported, including HPLC, GC-MS and LC-MS / MS. Due to its high sensitivity and good selectivity, LC-MS / MS is currently the most commonly used instrument for detecting caffeine.

[0006] At present, the extraction and enrichment of artificial sweeteners, contrast agents and caffeine in water samples mostly adopt the solid phase extraction (SPE) method. Since these three types of compounds are highly hydrophilic, the adsorption of these substances in solid samples such as sediments and sludge is very small, so there are relatively few studies on the extraction of these compounds in solid environmental samples. In short, due to the large differences in the scope of use and physical and chemical properties of these three types of compounds, there are few reports on the simultaneous detection of these three types of compounds in environmental media. However, when screening sewage indicators, it is necessary to conduct a comprehensive investigation of the distribution of these three types of substances in the environment. If these three types of substances are detected separately, the operation is repeated, the analysis time is long, and the cost is high. Therefore, it is very necessary to develop a detection method that can simultaneously detect artificial sweeteners, contrast agents and caffeine in different environmental matrices. Summary of the invention

[0007] The purpose of the present invention is to address the problems existing in the prior art and propose a method and system for simultaneous extraction and instrumental analysis of sewage tracer organic compounds in a water environment, wherein water samples are pretreated by SPE, solid samples are pretreated by ultrasonic extraction and solid phase extraction purification methods, and extracted samples are detected by ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS / MS), and a method for simultaneously detecting artificial sweeteners, contrast agents and caffeine in different environmental matrices (surface water, sewage treatment plant influent, sewage treatment plant effluent, dehydrated sludge and sediment) is established, thereby providing an accurate and efficient detection means for the screening of sewage indicators.

[0008] The first aspect of the present invention provides a method for simultaneous extraction and instrumental analysis of wastewater tracer organic compounds in a water environment, which is used for detecting wastewater tracer organic compounds in a water environment under different environmental matrices including surface water, wastewater treatment plant influent, wastewater treatment plant effluent, dewatered sludge and sediment, wherein the wastewater tracer organic compounds include artificial sweeteners, contrast agents and caffeine; the method comprises:

[0009] S1, prepare target compounds, standards, deuterated internal standards, reagents, experimental materials and instruments for simultaneous extraction and instrumental analysis;

[0010] S2, prepare and store standard samples;

[0011] S3, collecting sewage samples, wherein the sewage samples include water samples and solid samples, the water samples include surface water, sewage treatment plant inlet water and sewage treatment plant effluent, and the solid samples include sediment and dehydrated sludge; after the water samples are collected, the pH value is adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms and stored in a refrigerated state for pretreatment; after the solid samples are collected, an appropriate amount of sodium azide is added to inhibit the growth of microorganisms; after freeze-drying in a refrigerated state, the samples are sieved with a 60-mesh sieve and stored in a 4°C cold storage for later use;

[0012] S4, pre-treating the sewage sample to simultaneously extract sewage tracer organic compounds in the water environment;

[0013] S5, performing instrumental analysis on the extracted tracer organic compound.

[0014] Preferably, the target compounds include: 5 artificial sweeteners, 6 contrast agents and caffeine; the standard substances include: acesulfame potassium (ACE), cyclamate (CYC), aspartame (ASP), sucralose (SUC), diatrizoate (DTZ), iopamidol (IOD), iopromide (IOP), iomeprol (IOM), iohexol (IOX), caffeine (CAF), saccharin sodium (SAC) and iothalamic acid (ITA); the deuterated internal standards include: acesulfame potassium-d4 (ACE-d4), aspartame-d5 (ASP-d5), saccharin-d5 (SAC-d5), cyclamate-d11 (CYC-d11), sucralose-d6 (SUC-d 6), diatrizoate-d6 (DTZ-d6), iopamidol-d8 (IOD-d8), iopromide-d3 (IOP-d3), iomeprol-d3 (IOM-d3), iohexol-d5 (IOX-d5) and caffeine-d3; the chemical reagents include: chromatographically pure reagents of methanol and acetonitrile, chromatographically pure formic acid and ammonium acetate, chromatographically pure ion pair reagents of Tris and sulfuric acid; the experimental materials include: HR-X solid phase extraction column, HLB solid phase extraction column, glass fiber filter membrane, nylon filter and ultrapure water; the instruments and equipment include: 16-well solid phase extraction device, nitrogen blowdown instrument, desktop centrifuge, vortex mixer and ultra high performance liquid chromatography tandem G6460A triple quadrupole mass spectrometer.

[0015] Preferably, S2 includes:

[0016] The standard and deuterated internal standard are dissolved in methanol to prepare single standard stock solutions, wherein the single standard stock solution concentration of each standard is 100 mg / L, and the single standard stock solution concentration of each deuterated internal standard is 10 mg / L;

[0017] The single standard stock solutions of the standard substances and the single standard stock solutions of the deuterated internal standard are respectively prepared with methanol to prepare mixed standard stock solutions with a concentration of 10 mg / L and mixed deuterated internal standard stock solutions with a concentration of 1 mg / L;

[0018] The working solution is prepared by diluting the mixed standard stock solution and the mixed deuterated internal standard stock solution and mixing them for use;

[0019] The mixed standard sample stock solution dilution and the mixed deuterated internal standard stock solution were stored in a -20°C freezer for later use.

[0020] Preferably, S4 includes:

[0021] S41, performing solid phase extraction on the water sample to extract sewage tracer organic compounds;

[0022] S42, performing solid phase extraction on the solid sample to extract and purify wastewater tracer organic compounds.

[0023] Preferably, the S41 includes:

[0024] (1) Before the solid phase extraction, all the collected water samples are filtered through a filter membrane to remove particulate matter and suspended matter in the water samples;

[0025] (2) Accurately measure a certain volume of water sample for solid phase extraction experiment; optimize the solid phase extraction conditions using ultrapure water as the matrix, use HR-X column for solid phase extraction, and select pH 3.0 for the water sample;

[0026] (3) The optimized solid phase extraction method for water samples is:

[0027] Add the mixed internal standards to the filtered water sample so that the concentration of each internal standard in the water sample is 100 μg / L, and shake well;

[0028] The HR-X column was activated with 10 mL of methanol and 10 mL of ultrapure water in sequence, and the pH was adjusted to 3.0 with 4 M sulfuric acid;

[0029] Pass the water sample through the solid phase extraction column at a flow rate of 5-10 mL / min;

[0030] After the water sample is loaded, the column is drained under vacuum for 2-3 h;

[0031] Elute the column with 4 × 4 mL of methanol, blow the eluted liquid nitrogen to near dryness, then dilute to 1 mL with methanol, filter through a 0.22 μm organic phase nylon filter, and store at -18 °C;

[0032] Before instrument analysis, take out 100 μL of sample, blow dry it, and then re-adjust the volume with the corresponding mode buffer for testing.

[0033] Preferably, the S42 includes:

[0034] (1) Weigh a certain amount of freeze-dried solid sample into a 30 mL glass centrifuge tube, then add 100 μL of a mixed standard sample stock solution diluted with a concentration of 1 mg / L and a mixed deuterated internal standard stock solution to the sample, and shake the glass centrifuge tube thoroughly to make the solution formed by the mixed standard sample stock solution diluted with the mixed deuterated internal standard stock solution evenly dispersed in the sample;

[0035] (2) Place the glass centrifuge tube in a fume hood, wait for the mixed standard stock solution to be diluted and the internal standard solvent in the mixed deuterated internal standard stock solution to evaporate, then place the glass centrifuge tube in a 4°C cold storage in the dark overnight, and perform extraction the next day;

[0036] (3) Spiked recovery experiments were conducted on dewatered sludge and Liuxi River reservoir sediments with spike concentrations of 50 ng / L, 100 ng / L, and 200 ng / L;

[0037] (4) The solid phase extraction conditions were optimized, and the pH of the extraction solvent was selected to be 3.0;

[0038] (5) The optimized extraction and purification method of solid samples is:

[0039] Add 5 mL of 0.2 M citric acid buffer to the glass centrifuge tube containing the sample to make the pH value of the extraction solvent 3, vortex for 30 seconds, and ultrasonicate for 15 minutes; centrifuge at 3500 r / min for 10 minutes, and then draw the supernatant into a 50 mL beaker with a glass pipette;

[0040] Repeat the above steps twice;

[0041] Pre-treating the HR-X column according to the solid phase extraction method of the water sample, and then adding the combined supernatant to the HR-X column for enrichment and purification;

[0042] Wash the beaker twice with 10 mL of Milli-Q water, and add the washed Milli-Q water to the HR-X column;

[0043] Elution and volume adjustment were performed according to the solid phase extraction method for water samples.

[0044] Preferably, S5 includes: the tracer organic compound is measured by the ultra-high performance liquid chromatography-tandem G6460A triple quadrupole mass spectrometer, and the ion source is an electrospray ion source; wherein the artificial sweetener is analyzed in ESI(-) mode, the contrast agent and caffeine are analyzed in ESI(+) mode, and the scanning mode is multiple reaction monitoring (MRM) mode; the single standard and internal standard of each target compound are scanned, and the two groups of parent ion / daughter ion pairs with the highest abundance are selected as quantitative and qualitative ions, respectively, and their corresponding fragmentation voltages and collision energies are recorded.

[0045] The second aspect of the present invention is to provide a wastewater tracer organic compound synchronous extraction and instrumental analysis system in a water environment, which is used for detecting wastewater tracer organic compounds in a water environment under different environmental matrices including surface water, wastewater treatment plant influent, wastewater treatment plant effluent, dewatered sludge and sediment, wherein the wastewater tracer organic compounds include artificial sweeteners, contrast agents and caffeine; the system comprises:

[0046] A test preparation module (101) is used to prepare target compounds, standards, deuterated internal standards, reagents, experimental materials and instruments for simultaneous extraction and instrumental analysis;

[0047] A preparation and preservation module (102), used for preparing and preserving standard samples;

[0048] The sample collection module (103) is used to collect sewage samples, wherein the sewage samples include water samples and solid samples, the water samples include surface water, sewage treatment plant influent and sewage treatment plant effluent, and the solid samples include sediment and dehydrated sludge; after the water samples are collected, the pH value is adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms and stored in a refrigerated state for pre-treatment; after the solid samples are collected, an appropriate amount of sodium azide is added to inhibit the growth of microorganisms; after freeze-drying in a refrigerated state, the samples are sieved with a 60-mesh screen and stored in a 4°C cold storage for future use;

[0049] A synchronous extraction module (104) is used to pre-treat the sewage sample so as to synchronously extract sewage tracer organic compounds in the water environment;

[0050] The analysis module (105) is used to perform instrumental analysis on the extracted tracer organic compound.

[0051] A third aspect of the present invention provides an electronic device, comprising a processor and a memory, wherein the memory stores a plurality of instructions, and the processor is configured to read the instructions and execute the method described in the first aspect.

[0052] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a plurality of instructions, and the plurality of instructions can be read by a processor and execute the method described in the first aspect.

[0053] Beneficial effects of the method and system of the present invention:

[0054] (1) A UHPLC-MS / MS analytical test method that can be applied to different environmental matrices (surface water, sewage treatment plant influent, sewage treatment plant effluent, dewatered sludge and sediment) to simultaneously detect 5 artificial sweeteners, 6 contrast agents and caffeine. Water samples were mainly extracted and purified using the SPE method. Solid samples were first extracted using ultrasonic solvent extraction and then enriched and purified using solid phase extraction. For the extraction method of water samples, we optimized the type of solid phase extraction cartridge and the pH of the sample, while for the extraction of solid samples, we mainly optimized the pH value of the extract. All extracted samples were analyzed using UHPLC-MS / MS in MRM mode, contrast agents and caffeine were analyzed under ESI+ mode conditions, and artificial sweeteners were analyzed under ESI- mode conditions.

[0055] (2) The instrumental method has high selectivity, sensitivity and resolution for each target compound, as well as low method detection limit and quantification limit. Most target compounds have satisfactory recovery rates (70-120%) in different environmental matrices. The established extraction and instrumental analysis methods for 5 artificial sweeteners, 6 contrast agents and caffeine can be used to detect the above target compounds in a variety of environmental matrices, providing a reliable basic data analysis method for a comprehensive survey of the content levels and distribution characteristics of artificial sweeteners, contrast agents and caffeine in a variety of environmental matrices. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 A flow chart of a method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to an embodiment of the present invention;

[0058] Figure 2 A schematic diagram of the architecture of a system for simultaneous extraction and instrumental analysis of tracer organic compounds in wastewater in a water environment according to an embodiment of the present invention;

[0059] Figure 3 A structural diagram of an electronic device provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0062] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] Embodiment 1

[0064] like Figure 1 As shown, this embodiment provides a method for simultaneous extraction and instrumental analysis of sewage tracer organic compounds in a water environment, which is used for detecting sewage tracer organic compounds in a water environment under different environmental matrices including surface water, sewage treatment plant influent, sewage treatment plant effluent, dewatered sludge and sediment, wherein the sewage tracer organic compounds include artificial sweeteners, contrast agents and caffeine; the method comprises:

[0065] S1, prepare target compounds, standards, deuterated internal standards, reagents, experimental materials and instruments for simultaneous extraction and instrumental analysis;

[0066] In this embodiment:

[0067] Target compounds: including 5 artificial sweeteners, 6 contrast agents and caffeine;

[0068] Standard products: acesulfame potassium (ACE), cyclamate (CYC), aspartame (ASP), sucralose (SUC), diatrizoate (DTZ), iopamidol (IOD), iopromide (IOP), iomeprol (IOM), iohexol (IOX), caffeine (CAF), etc. were purchased from Dr. Ehrenstorfer, Germany; saccharin sodium (SAC) was purchased from SUPELCO, USA; iodalamic acid (ITA) was purchased from the United States Pharmacopeia (USP);

[0069] Deuterated internal standards: acesulfame-d4 (ACE-d4), aspartame-d5 (ASP-d5), saccharin-d5 (SAC-d5), cyclamate-d11 (CYC-d11), sucralose-d6 (SUC-d6), diatrizoate-d6 (DTZ-d6), iopamidol-d8 (IOD-d8), iopromide-d3 (IOP-d3), iomeprol-d3 (IOM-d3), and iohexol-d5 (IOX-d5) were all purchased from Toronto Research Chemicals, Canada, and caffeine-d3 (CAF-d3) was purchased from o2si, USA.

[0070] Chemical reagents: Chromatographically pure reagents (methanol, acetonitrile) were purchased from Merck, Germany; chromatographically pure formic acid and ammonium acetate were purchased from CNW, Germany; chromatographically pure ion pair reagent Tris was purchased from Sigma-Aldrich, USA; sulfuric acid was a domestic analytically pure solvent.

[0071] Experimental materials: HR-X solid phase extraction column (500 mg, 6 mL) was purchased from Chromabond; HLB solid phase extraction column (500 mg, 6 mL) was purchased from Waters, USA; glass fiber filter membrane (GF / F, pore size 70 mm) was purchased from Whatman, UK; nylon filter (13 mm×0.22 μm) was purchased from Shanghai Anpu Company; ultrapure water used in the experiment was from Milli-Q ultrapure water device (Millipore, USA).

[0072] Instruments and equipment: 16-well solid phase extraction device was purchased from Alltech, USA; MTN-2800D nitrogen blowdown apparatus was purchased from Tianjin Aotesense Instrument Co., Ltd.; L550 desktop centrifuge was purchased from Changsha Xiangyi Centrifuge Instrument Co., Ltd.; XW-80A vortex mixer was purchased from Shanghai Jingke Instrument Factory; 1200 series ultra-high performance liquid chromatography tandem G6460A triple quadrupole mass spectrometer (UHPLC-MS / MS) was purchased from Agilent, USA.

[0073] S2, prepare and store standard samples, including:

[0074] The standard and deuterated internal standard are dissolved in methanol to prepare single standard stock solutions, wherein the single standard stock solution concentration of each standard is 100 mg / L, and the single standard stock solution concentration of each deuterated internal standard is 10 mg / L;

[0075] The single standard stock solutions of the standard substances and the single standard stock solutions of the deuterated internal standard are respectively prepared with methanol to prepare mixed standard stock solutions with a concentration of 10 mg / L and mixed deuterated internal standard stock solutions with a concentration of 1 mg / L;

[0076] The working solution is prepared by diluting the mixed standard stock solution and the mixed deuterated internal standard stock solution and mixing them for use;

[0077] The mixed standard sample stock solution dilution and the mixed deuterated internal standard stock solution were stored in a -20°C freezer for later use.

[0078] S3, collecting sewage samples, wherein the sewage samples include water samples and solid samples, the water samples include surface water, sewage treatment plant inlet water and sewage treatment plant effluent, and the solid samples include sediment and dehydrated sludge; after the water samples are collected, the pH value is adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms and stored in a refrigerated state for pretreatment; after the solid samples are collected, an appropriate amount of sodium azide is added to inhibit the growth of microorganisms; after freeze-drying in a refrigerated state, the samples are sieved through a 60-mesh sieve and stored in a 4°C cold storage for later use.

[0079] In this embodiment, five typical environmental matrices were selected for the recovery test. The water samples were: (1) surface water, collected from Liuxi River Reservoir; (2) sewage treatment plant inlet water, collected from Xintang Sewage Treatment Plant; (3) sewage treatment plant effluent, collected from Xintang Sewage Treatment Plant; after all water samples were collected, the pH value was adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms; the water samples were brought back to the laboratory as soon as possible for pretreatment under refrigeration. The solid samples were: (1) sediment, surface sediments of Liuxi River Reservoir were collected using a grab sampler; (2) dehydrated sludge, collected from Xintang Sewage Treatment Plant. After the solid samples were collected, an appropriate amount of sodium azide was added to inhibit the growth of microorganisms; they were brought back to the laboratory under refrigeration, freeze-dried, sieved through a 60-mesh sieve, and stored in a 4°C cold storage for later use.

[0080] S4, pre-treating the sewage sample to simultaneously extract sewage tracer organic compounds in the water environment;

[0081] As a preferred implementation, S4 includes:

[0082] S41, performing solid phase extraction on the water sample to extract wastewater tracer organic compounds, comprising:

[0083] (1) Before the solid phase extraction, all the collected water samples were filtered through a 70 mm GF / F filter membrane to remove particulate matter and suspended matter in the water samples;

[0084] (2) Accurately measure a certain volume of water sample (in this example: 500 mL of sewage treatment plant influent; 500 mL of sewage treatment plant effluent; 1 L of surface water) to conduct a solid phase extraction experiment; the solid phase extraction conditions are optimized using ultrapure water as the matrix. The specific optimized conditions are as follows:

[0085] (A) Different solid phase extraction columns (HLB column and HR-X column);

[0086] The spike recovery experiment was carried out with ultrapure water as the matrix to investigate the extraction efficiency of HLB and HR-X solid phase extraction columns. The fillers in both HLB and HR-X solid phase extraction columns are reverse phase fillers with hydrophilic-lipophilic balance, but the surface area and particle size of the two fillers are different. The surface area and particle size of the HLB column filler are 801m2 / g and 87A°, while the surface area and particle size of HR-X column packing are 1061m 2 / g and 57A°. Since the present invention uses an isotope internal standard to calibrate the recovery rate, both columns have good relative recovery rates (82%-125%) for each target compound. Since the surface area of ​​the HR-X filler is larger than that of the HLB filler, the extraction efficiency of the two columns is compared by absolute recovery rate. The results show that, except for ASP and SUC, the absolute recovery rates of the HR-X column for the other 10 compounds are higher than those of the HLB column. Therefore, the HR-X column is used for solid phase extraction in this embodiment.

[0087] (B) Different pH conditions (3.0, 5.0, and 7.0);

[0088] The pH value can affect the form of the target compound in water, so the pH value has a greater impact on the extraction efficiency. Therefore, the present invention compares the extraction efficiency of each target compound under different pH values ​​(3.0, 5.0 and 7.0). Due to the correction of the internal standard, the relative recovery rate of each target compound under the three pH conditions is basically between 70% and 120%, but by comparing the absolute recovery rates of each target compound under the three pH conditions, it is found that when pH = 7.0, the absolute recovery rate of each target compound is relatively low. When pH = 3.0, the sweeteners ACE, SAC, CYC, ASP and the ionic contrast agents ITA and DTZ have a higher absolute recovery rate, especially ASP, which has a significantly improved absolute recovery rate under the condition of pH = 3.0. Therefore, in this embodiment, the pH of the water sample is selected to be 3.0.

[0089] (3) The optimized solid phase extraction method for water samples is:

[0090] Add the mixed internal standards to the filtered water sample (so that the concentration of each internal standard in the water sample is 100 μg / L) and shake well;

[0091] An HR-X column was activated with 10 mL of methanol and 10 mL of ultrapure water (4 M sulfuric acid adjusted to pH 3.0) in sequence;

[0092] Pass the water sample through the solid phase extraction column at a flow rate of 5-10 mL / min;

[0093] After the water sample is loaded, the column is drained under vacuum for 2-3 h;

[0094] Elute the column with 4 × 4 mL of methanol, blow the eluted liquid nitrogen to near dryness, then dilute to 1 mL with methanol, filter through a 0.22 μm organic phase nylon filter, and store at -18 °C;

[0095] Before instrument analysis, take out 100 μL of sample, blow dry it, and then re-adjust the volume with the corresponding mode buffer for testing.

[0096] S42, performing solid phase extraction on the solid sample to extract and purify wastewater tracer organic compounds, comprising:

[0097] (1) Weigh a certain amount of freeze-dried solid sample (0.5 g of dehydrated sludge and 1.0 g of sediment in this example) into a 30 mL glass centrifuge tube, then add 100 μL of a mixed standard sample dilution solution and a mixed deuterated internal standard solution with a concentration of 1 mg / L to the sample, and shake the glass centrifuge tube thoroughly to ensure that the solution formed by the mixed standard sample dilution solution and the mixed deuterated internal standard solution is evenly dispersed in the sample;

[0098] (2) Place the glass centrifuge tube in a fume hood, wait for the mixed standard stock solution to be diluted and the internal standard solvent in the mixed deuterated internal standard stock solution to evaporate, then place the glass centrifuge tube in a 4°C cold storage in the dark overnight, and perform extraction the next day;

[0099] (3) Spiked recovery experiments were conducted on dewatered sludge and Liuxi River reservoir sediments with spiked concentrations of 50 ng / L, 100 ng / L and 200 ng / L.

[0100] (4) The solid phase extraction conditions were optimized. The specific optimized conditions are as follows:

[0101] different extraction solvent pH conditions (3.0, 5.0, and 7.0);

[0102] Ultrasonic solvent extraction can be used to extract artificial sweeteners, contrast agents and caffeine from solid samples. The present invention uses ultrasonic solvent extraction to simultaneously extract artificial sweeteners, contrast agents and caffeine from solid samples. Since each target compound is a substance with high polarity, no organic solvent is used in the extraction solution, and only water extraction is used. The form of each target compound in water has a great influence on the extraction efficiency. Therefore, the present invention uses the sediment of Liuxi River Reservoir as the matrix, and compares the recovery rates of the extraction solutions used at different pH values ​​(3.0, 5.0 and 7.0). It is found that the relative recovery rates of the target compounds in the sediments are all between 70% and 120% when the extraction solutions with different pH values ​​are used to extract the target compounds. By comparing the absolute recovery rates, it is found that the effect of pH on the extraction of each target compound in the solid sample is similar to its effect on the extraction of each target compound in the water sample. When the pH of the extraction solvent is 7.0, the recovery rates of each target compound are relatively low. When the pH of the extraction solvent is 3.0, the absolute recovery rates of five artificial sweeteners, ionic contrast agents (ITA and DTZ) and caffeine are the best. Therefore, the pH of the extraction solvent is selected to be 3.0.

[0103] (5) The optimized extraction and purification method of solid samples is:

[0104] Add 5 mL of 0.2 M citric acid buffer (pH 3) to the glass centrifuge tube containing the sample, vortex for 30 seconds, and sonicate for 15 minutes; centrifuge at 3500 r / min for 10 minutes, and then draw the supernatant into a 50 mL beaker with a glass pipette;

[0105] Repeat the above steps twice;

[0106] Pre-treating the HR-X column according to the solid phase extraction method of the water sample, and then adding the combined supernatant to the HR-X column for enrichment and purification;

[0107] Wash the beaker twice with 10 mL of Milli-Q water, and add the washed Milli-Q water to the HR-X column;

[0108] Elution and volume adjustment were performed according to the solid phase extraction method for water samples.

[0109] S5, performing instrumental analysis on the extracted tracer organic compound.

[0110] In this embodiment, the target compounds were all determined by UHPLC-MS / MS (1200 series, 6460A triple quadrupole tandem mass spectrometer), and the ion source was an electrospray ionization (ESI) source.

[0111] Among them, artificial sweeteners were analyzed in ESI(-) mode, contrast agents and caffeine were analyzed in ESI(+) mode, and the scanning mode was multiple reaction monitoring (MRM) mode.

[0112] The chromatographic column was ZorbaxSB-C18 (100 mm × 3 mm, 1.8 μm), and its front section was connected to an online filter (2.1 mm, 0.2 μm) to remove fine particles in the mobile phase and sample. Column temperature: 40°C, flow rate: 0.3 mL / min, injection volume: 20 μL.

[0113] In ESI(+) mode

[0114] The mobile phases were: A: water (10 mM ammonium acetate, 0.01% formic acid), B: acetonitrile.

[0115] Gradient elution program: 0-6 min, 2% B; 6-8 min, 2%-60% B; 8-13 min, 60% B; 13-18 min, 60%-2% B.

[0116] Drying gas temperature: 350°C; Drying gas flow rate: 10.0 mL / min; Nebulizer pressure: 206.9 KPa; Electrospray voltage: 200 V.

[0117] ESI(-) mode

[0118] The mobile phases were: A: water (5 mM ammonium acetate, 1 mM Tris), B: acetonitrile.

[0119] Gradient elution program: 0-3 min, 5% B; 3-5 min, 5%-90% B; 5-16 min, 90%-5% B.

[0120] Drying gas temperature: 350°C; drying gas flow rate: 6.0 mL / min; nebulizer pressure: 344.8 KPa; electrospray voltage: 200 V.

[0121] Using Opitimizer software (Agilent, USA), the single standard and internal standard of each target compound were scanned, and the two most abundant parent ion / daughter ion pairs were selected as quantitative and qualitative ions, and their corresponding fragmentor voltages and collision energies were recorded. The mass spectrometry acquisition parameters of each target compound and internal standard are shown in Table 1.

[0122] Table 1

[0123]

[0124] * Quantitative ion, IS: internal standard Example 2

[0125] like Figure 2 As shown, this embodiment provides a system for simultaneous extraction and instrumental analysis of wastewater tracer organic compounds in a water environment, which is used for detecting wastewater tracer organic compounds in a water environment under different environmental matrices including surface water, wastewater treatment plant influent, wastewater treatment plant effluent, dewatered sludge and sediment, wherein the wastewater tracer organic compounds include artificial sweeteners, contrast agents and caffeine; the system comprises:

[0126] The test preparation module 101 is used to prepare target compounds, standards, deuterated internal standards, reagents, experimental materials and instruments for simultaneous extraction and instrumental analysis;

[0127] The preparation and preservation module 102 is used to prepare and preserve standard samples;

[0128] The sample collection module 103 is used to collect sewage samples, wherein the sewage samples include water samples and solid samples, the water samples include surface water, sewage treatment plant influent and sewage treatment plant effluent, and the solid samples include sediment and dehydrated sludge; after the water samples are collected, the pH value is adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms and stored in a refrigerated state for pre-treatment; after the solid samples are collected, an appropriate amount of sodium azide is added to inhibit the growth of microorganisms; after freeze-drying in a refrigerated state, the samples are sieved with a 60-mesh screen and stored in a 4°C cold storage for later use;

[0129] A synchronous extraction module 104, for pre-processing the sewage sample to synchronously extract sewage tracer organic compounds in the water environment;

[0130] The analysis module 105 is used to perform instrumental analysis on the extracted tracer organic compound.

[0131] The present invention also provides a memory storing a plurality of instructions, wherein the instructions are used to implement the method as in the first embodiment.

[0132] like Figure 3 As shown, the present invention also provides an electronic device, including a processor 301 and a memory 302 connected to the processor 301, the memory 302 stores a plurality of instructions, and the instructions can be loaded and executed by the processor so that the processor can execute the method as in the first embodiment.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment, characterized in that: Used for detecting sewage tracer organic compounds in water environments under different environmental matrices including surface water, sewage treatment plant influent, sewage treatment plant effluent, dewatered sludge and sediment, wherein the sewage tracer organic compounds include artificial sweeteners, contrast agents and caffeine; the method comprises: S1, prepare target compounds, standards, deuterated internal standards, reagents, experimental materials and instruments for simultaneous extraction and instrumental analysis; S2, prepare and store standard samples; S3, collecting sewage samples, wherein the sewage samples include water samples and solid samples, the water samples include surface water, sewage treatment plant inlet water and sewage treatment plant effluent, and the solid samples include sediment and dehydrated sludge; after the water samples are collected, the pH value is adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms and stored in a refrigerated state for pretreatment; after the solid samples are collected, an appropriate amount of sodium azide is added to inhibit the growth of microorganisms; after freeze-drying in a refrigerated state, the samples are sieved with a 60-mesh sieve and stored in a 4°C cold storage for later use; S4, pre-treating the sewage sample to simultaneously extract sewage tracer organic compounds in the water environment; S5, performing instrumental analysis on the extracted tracer organic compound.

2. The method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to claim 1, characterized in that: The target compounds include: 5 artificial sweeteners, 6 contrast agents and caffeine; the standard substances include: acesulfame potassium (ACE), cyclamate (CYC), aspartame (ASP), sucralose (SUC), diatrizoic acid (DTZ), iopamidol (IOD), iopromide (IOP), iomeprol (IOM), iohexol (IOX), caffeine (CAF), saccharin sodium (SAC) and iothalamic acid (ITA); the deuterated internal standards include: acesulfame potassium-d4 (ACE-d4), aspartame-d5 (ASP-d5), saccharin-d5 (SAC-d5), cyclamate-d11 (CYC-d11), sucralose-d6 (SUC-d6) , diatrizoate-d6 (DTZ-d6), iopamidol-d8 (IOD-d8), iopromide-d3 (IOP-d3), iomeprol-d3 (IOM-d3), iohexol-d5 (IOX-d5) and caffeine-d3; the chemical reagents include: chromatographically pure reagents of methanol and acetonitrile, chromatographically pure formic acid and ammonium acetate, chromatographically pure ion pair reagents of Tris and sulfuric acid; the experimental materials include: HR-X solid phase extraction column, HLB solid phase extraction column, glass fiber filter membrane, nylon filter and ultrapure water; the instruments and equipment include: 16-well solid phase extraction device, nitrogen blowdown instrument, desktop centrifuge, vortex mixer and ultra high performance liquid chromatography tandem G6460A triple quadrupole mass spectrometer.

3. The method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to claim 2, characterized in that: The S2 includes: The standard and deuterated internal standard are dissolved in methanol to prepare single standard stock solutions, wherein the single standard stock solution concentration of each standard is 100 mg / L, and the single standard stock solution concentration of each deuterated internal standard is 10 mg / L; The single standard stock solutions of the standard substances and the single standard stock solutions of the deuterated internal standard are respectively prepared with methanol to prepare mixed standard sample stock solutions with a concentration of 10 mg / L and mixed deuterated internal standard stock solutions with a concentration of 1 mg / L; The working solution is prepared by diluting the mixed standard stock solution and the mixed deuterated internal standard stock solution and mixing them for use; The mixed standard sample stock solution dilution and the mixed deuterated internal standard stock solution were stored in a -20°C freezer for later use.

4. The method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to claim 3, characterized in that: The S4 includes: S41, performing solid phase extraction on the water sample to extract sewage tracer organic compounds; S42, performing solid phase extraction on the solid sample to extract and purify wastewater tracer organic compounds.

5. The method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to claim 4, characterized in that: The S41 includes: (1) Before the solid phase extraction, all the collected water samples are filtered through a filter membrane to remove particulate matter and suspended matter in the water samples; (2) Accurately measure a certain volume of water sample for solid phase extraction experiment; optimize the solid phase extraction conditions using ultrapure water as the matrix, use HR-X column for solid phase extraction, and select pH 3.0 for the water sample; (3) The optimized solid phase extraction method for water samples is: Add the mixed internal standards to the filtered water sample so that the concentration of each internal standard in the water sample is 100 μg / L, and shake well; The HR-X column was activated with 10 mL of methanol and 10 mL of ultrapure water in sequence, and the pH was adjusted to 3.0 with 4 M sulfuric acid; Pass the water sample through the solid phase extraction column at a flow rate of 5-10 mL / min; After the water sample is loaded, the column is drained under vacuum for 2-3 h; Elute the column with 4 × 4 mL of methanol, blow the eluted liquid nitrogen to near dryness, then dilute to 1 mL with methanol, filter through a 0.22 μm organic phase nylon filter, and store at -18 °C; Before instrument analysis, take out 100 μL of sample, blow dry it, and then re-adjust the volume with the corresponding mode buffer for testing.

6. The method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to claim 5, characterized in that: The S42 includes: (1) Weigh a certain amount of freeze-dried solid sample into a 30 mL glass centrifuge tube, then add 100 μL of a mixed standard sample stock solution diluted with a concentration of 1 mg / L and a mixed deuterated internal standard stock solution to the sample, and shake the glass centrifuge tube thoroughly to make the solution formed by the mixed standard sample stock solution diluted with the mixed deuterated internal standard stock solution evenly dispersed in the sample; (2) Place the glass centrifuge tube in a fume hood, wait for the mixed standard stock solution to be diluted and the internal standard solvent in the mixed deuterated internal standard stock solution to evaporate, then place the glass centrifuge tube in a 4°C cold storage in the dark overnight, and perform extraction the next day; (3) Spiked recovery experiments were conducted on dewatered sludge and Liuxi River reservoir sediments with spike concentrations of 50 ng / L, 100 ng / L, and 200 ng / L; (4) The solid phase extraction conditions were optimized, and the pH of the extraction solvent was selected to be 3.0; (5) The optimized extraction and purification method of solid samples is: Add 5 mL of 0.2 M citric acid buffer to the glass centrifuge tube containing the sample to make the pH value of the extraction solvent 3, vortex for 30 seconds, and ultrasonicate for 15 minutes; centrifuge at 3500 r / min for 10 minutes, and then draw the supernatant into a 50 mL beaker with a glass pipette; Repeat the above steps twice; Pre-treating the HR-X column according to the solid phase extraction method of the water sample, and then adding the combined supernatant to the HR-X column for enrichment and purification; Wash the beaker twice with 10 mL of Milli-Q water, and add the washed Milli-Q water to the HR-X column; Elution and volume adjustment were performed according to the solid phase extraction method for water samples.

7. The method for simultaneous extraction and instrumental analysis of tracer organic compounds in sewage in a water environment according to claim 6, characterized in that: The S5 includes: the tracer organic compound is measured by the ultra-high performance liquid chromatography-tandem G6460A triple quadrupole mass spectrometer, and the ion source is an electrospray ion source; wherein the artificial sweetener is analyzed in ESI(-) mode, the contrast agent and caffeine are analyzed in ESI(+) mode, and the scanning mode is multiple reaction monitoring (MRM) mode; the single standard and internal standard of each target compound are scanned, and the two groups of parent ion / daughter ion pairs with the highest abundance are selected as quantitative and qualitative ions, respectively, and their corresponding fragmentation voltages and collision energies are recorded.

8. A system for simultaneous extraction and instrumental analysis of wastewater tracer organic compounds in aquatic environments, characterized in that: Used to implement the method according to any one of claims 1 to 7, for detecting sewage tracer organic compounds in water environments under different environmental matrices including surface water, sewage treatment plant influent, sewage treatment plant effluent, dewatered sludge and sediment, wherein the sewage tracer organic compounds include artificial sweeteners, contrast agents and caffeine; the system comprises: A test preparation module (101) is used to prepare target compounds, standards, deuterated internal standards, reagents, experimental materials and instruments for simultaneous extraction and instrumental analysis; A preparation and preservation module (102), used for preparing and preserving standard samples; The sample collection module (103) is used to collect sewage samples, wherein the sewage samples include water samples and solid samples, the water samples include surface water, sewage treatment plant influent and sewage treatment plant effluent, and the solid samples include sediment and dehydrated sludge; after the water samples are collected, the pH value is adjusted to 3 with 4M sulfuric acid to inhibit the growth of microorganisms and stored in a refrigerated state for pre-treatment; after the solid samples are collected, an appropriate amount of sodium azide is added to inhibit the growth of microorganisms; after freeze-drying in a refrigerated state, the samples are sieved with a 60-mesh screen and stored in a 4°C cold storage for future use; A synchronous extraction module (104) is used to pre-treat the sewage sample so as to synchronously extract sewage tracer organic compounds in the water environment; The analysis module (105) is used to perform instrumental analysis on the extracted tracer organic compound.

9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores a plurality of instructions, and the processor is used to read the instructions and execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a plurality of instructions, and the plurality of instructions can be read by a processor to execute the method according to any one of claims 1 to 7.

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