Method for full-automatic on-line rapid detection of perfluorinated compounds in water

Abstract

The invention relates to the technical field of perfluorinated compound detection, and discloses a method for full-automatic on-line rapid detection of perfluorinated compounds in water, which comprises the following steps: pretreating a water sample to obtain a sample to be detected, and placing the sample to be detected in a sample introduction disc of an on-line solid-phase extraction device; full-automatic online solid-phase extraction (Online SPE) enrichment and purification: automatically enriching and purifying the to-be-detected liquid in the step 1 by utilizing the Online SPE through an online solid-phase extraction small column, realizing alternate sample injection of double columns through valve switching, washing the other column during sample loading of one column, eluting a target object, and performing UPLC-MS / MS analysis. On the basis of a full-automatic on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry technology, the method for full-automatic on-line rapid detection of the perfluorinated compounds in the water is successfully established in combination with an iRefx rapid screening intelligent working process, and the perfluorinated compounds in the water can be rapidly detected in a full-automatic on-line mode through the Online SPE and the iRefx rapid screening intelligent working process. Automatic sample injection, online enrichment and purification, intelligent judgment of sample concentration, overlimit sample redetection and accurate quantitative analysis are realized, and the detection efficiency is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of perfluorinated compound detection, and in particular to a method for fully automatic online rapid detection of perfluorinated compounds in water. Background Art

[0002] In recent years, online solid phase extraction technology (Online SPE) has gradually emerged. The detection methods of perfluorinated compounds in water reported at home and abroad mainly rely on the extraction and purification of solid phase extraction (SPE), and use liquid chromatography tandem mass spectrometry for analysis and detection. However, there are many shortcomings in the whole process, such as the need for a large sample volume, long time consumption, complex operation process, and consumption of a large amount of organic solvents and SPE columns; at the same time, after the sample is tested, manual calculations are required to identify over-limit samples, and manual second batch analysis is required. For this reason, we propose a method for fully automatic online rapid detection of perfluorinated compounds in water. Summary of the invention

[0003] The main purpose of the present invention is to provide a method for fully automatic online rapid detection of perfluorinated compounds in water, which can effectively solve the problems of requiring a large sample amount, taking a long time, having a complicated operation process, and consuming a large amount of organic solvents and SPE columns; at the same time, after the sample detection is completed, manual calculation is required to identify the over-limit samples, and a manual second batch analysis is required.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for fully automatic online rapid detection of perfluorinated compounds in water, comprising:

[0006] Step 1: pre-treat the water sample to obtain the sample to be tested, and place it in the sample injection tray of the online solid phase extraction device;

[0007] Step 2: Fully automatic online solid phase (Online SPE) enrichment and purification: Use Online SPE to automatically enrich and purify the test solution in step 1 through an online solid phase extraction column. By switching the valve, double columns are alternately injected. When one column is loaded, the other column is cleaned. After the target is eluted, it enters UPLC-MS / MS analysis;

[0008] Step 3: High performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS / MS) determination: The test solution in step 2 enters UPLC-MS / MS for detection, and the qualitative analysis is based on the retention time and characteristic ion abundance ratio, and the quantitative analysis is based on the internal standard method;

[0009] Step 4: Use Intelligent Reflex (iReflex) to quickly screen the intelligent workflow, automatically identify samples that exceed the limit, and re-sample and analyze in a small volume.

[0010] Furthermore, the water sample pretreatment method in step 1 specifically includes the following steps:

[0011] Mix the water sample, let it stand, and return it to room temperature; if the pH of the water sample is <6 or pH>8, adjust the pH to 6-8 with formic acid or ammonia water;

[0012] Use a polypropylene syringe to take an appropriate amount of supernatant and filter it through a 0.2 μm regenerated cellulose (RC) filter membrane;

[0013] Accurately transfer 5.0 ml of the filtrate to a 15 ml polypropylene centrifuge tube, add 100 μl of the internal standard working solution (20 μg / L) and 5 ml of methanol, and mix well;

[0014] If turbidity occurs, centrifuge at 4000 rpm for 10 min; take about 1.5 ml to 2 ml of polypropylene injection vial as the sample to be tested.

[0015] Furthermore, the fully automatic online solid phase extraction (Online SPE) conditions in step 2 are:

[0016] Online solid phase extraction column: WAX (NP3, 4x 10mm)

[0017] Sample pump mobile phase: mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.4% ammonia-methanol / acetonitrile (1+1) solution;

[0018] Injection volume: 900 μl for large volume injection and 20 μl for small volume injection.

[0019] Furthermore, the HPLC conditions in step 3 are:

[0020] Chromatographic column: HPH-C18, 3.0x 100mm, 2.7μm

[0021] Column temperature: 40°C; flow rate: 0.4 mL / min

[0022] Analytical pump mobile phase: mobile phase A is 5mmol / L ammonium fluoride solution, mobile phase B is 0.4% ammonia-methanol solution;

[0023] Gradient elution: 0-5.0 min, 90% mobile phase A, 10% mobile phase B; 5.0-7.0 min, mobile phase B increased linearly from 10% to 55%; 7.0-16.0 min, mobile phase B increased linearly from 55% to 98%; 16.0-18.0 min, 98% mobile phase B.

[0024] Furthermore, the mass spectrometry conditions in step 3 are:

[0025] Electrospray ionization source: negative ion mode

[0026] Mass spectrometry scanning mode: multiple reaction monitoring DMRM mode

[0027] Atomizer pressure: 20psi

[0028] Drying gas temperature: 230℃, Drying gas flow rate: 6L / min

[0029] Sheath gas temperature: 375°C, sheath gas flow rate: 12L / min

[0030] Capillary voltage: 2500V.

[0031] Furthermore, in step 4, the intelligent workflow is quickly screened:

[0032] First, the original method is used to test the sample. For example, if a compound in a sample exceeds the limit, taking sample SD as an example, the limit is exceeded after the first injection, triggering the iReflex function, automatically adding a blank sample and re-analyzing using the second method.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The invention adopts a fully automatic online solid phase extraction system (Online SPE), an ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS / MS), and an Intelligent Reflex (iReflex) rapid screening intelligent workflow; utilizes Online SPE for automatic sampling, and after enrichment, purification, and elution through an online solid phase extraction column, enters UPLC-MS / MS to realize the detection of perfluorinated compounds in water quality; utilizes Intelligent Reflex (iReflex) for rapid screening intelligent workflow to automatically determine over-limit samples, and initiates a small volume sampling scheme in real time to re-analyze the samples, and automatically completes the analysis of conventional samples and over-limit samples in one batch; significantly improves the efficiency of detection, and reduces the manpower, time, and solvent costs required for detection; uses Intelligent Reflex (iReflex) for rapid screening intelligent workflow to automatically determine over-limit samples, and initiates a small volume sampling scheme in real time to re-analyze the samples, and automatically completes the analysis of conventional samples and over-limit samples in one batch; significantly improves the efficiency of detection, and reduces the manpower, time, and solvent costs required for detection; Reflex (iReflex) rapid screening intelligent workflow expands the linear range to 500,000 times, automatically determines out-of-limit samples and re-analyzes them in real time; eliminates the process of manual judgment and sorting of out-of-limit samples; shortens the sample re-analysis cycle; avoids the impact of manual re-analysis of out-of-limit samples on sample stability and timeliness, and provides more accurate test results that can meet the needs of large-scale simultaneous determination of various types of water quality samples.

[0035] The present invention is based on the fully automatic online solid phase extraction-high performance liquid chromatography-tandem mass spectrometry technology, combined with the iReflex rapid screening intelligent workflow, and successfully established a fully automatic online rapid detection method for perfluorinated compounds in water. Through Online SPE and iReflex rapid screening intelligent workflow, automatic injection, online enrichment and purification, intelligent judgment of sample concentration, retesting of over-limit samples and accurate quantitative analysis, the detection efficiency is significantly improved. The method is easy to operate, has excellent repeatability, high sensitivity, and a wide detection range. It can meet the synchronous analysis of different types of water quality samples and meet the needs of large-scale sample detection. It has broad application prospects and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is one of the system valve positions and pipeline switching diagrams of a method for fully automatic online rapid detection of perfluorinated compounds in water according to the present invention.

[0037] Figure 2 This is the second diagram of the system valve position and pipeline switching of the method for fully automatic online rapid detection of perfluorinated compounds in water according to the present invention.

[0038] Figure 3 This is a total ion chromatogram of target compounds in a method for fully automatic online rapid detection of perfluorinated compounds in water according to the present invention.

[0039] Figure 4 This is an example diagram of the iReflex workflow for intelligently judging over-limit samples in a method for fully automatic online rapid detection of perfluorinated compounds in water according to the present invention. DETAILED DESCRIPTION

[0040] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0041] like Figure 1-4 As shown, a method for fully automatic online rapid detection of perfluorinated compounds in water comprises:

[0042] Step 1: pre-treat the water sample to obtain the sample to be tested, and place it in the sample injection tray of the online solid phase extraction device;

[0043] Step 2: Fully automatic online solid phase (Online SPE) enrichment and purification: Use Online SPE to automatically enrich and purify the test solution in step 1 through an online solid phase extraction column. By switching the valve, double columns are alternately injected. When one column is loaded, the other column is cleaned. After the target is eluted, it enters UPLC-MS / MS analysis;

[0044] Step 3: High performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS / MS) determination: The test solution in step 2 enters UPLC-MS / MS for detection, and the qualitative analysis is based on the retention time and characteristic ion abundance ratio, and the quantitative analysis is based on the internal standard method;

[0045] Step 4: Use Intelligent Reflex (iReflex) to quickly screen the intelligent workflow, automatically identify samples that exceed the limit, and re-sample and analyze in a small volume.

[0046] Furthermore, the water sample pretreatment method in step 1 specifically includes the following steps:

[0047] Mix the water sample, let it stand, and return it to room temperature; if the pH of the water sample is <6 or pH>8, adjust the pH to 6-8 with formic acid or ammonia water;

[0048] Use a polypropylene syringe to take an appropriate amount of supernatant and filter it through a 0.2 μm regenerated cellulose (RC) filter membrane;

[0049] Accurately transfer 5.0 ml of the filtrate to a 15 ml polypropylene centrifuge tube, add 100 μl of the internal standard working solution (20 μg / L) and 5 ml of methanol, and mix well;

[0050] If turbidity occurs, centrifuge at 4000 rpm for 10 min; take about 1.5 ml to 2 ml of polypropylene injection vial as the sample to be tested.

[0051] The liquid chromatography conditions and mass spectrometry conditions were:

[0052] (1) Fully automatic online solid phase extraction (Online SPE) conditions:

[0053] Online solid phase extraction column: WAX (NP3, 4x 10mm)

[0054] Sample pump mobile phase: mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.4% ammonia-methanol / acetonitrile (1+1) solution;

[0055] Injection volume: 900 μl for large volume injection and 20 μl for small volume injection.

[0056] The gradient program is as follows: see Table 1.

[0057] System valve position and pipeline switching see Figure 1 and Figure 2 .

[0058] Table 1 Conditions of fully automatic online solid phase extraction system

[0059]

[0060] (2) HPLC conditions:

[0061] Chromatographic column: HPH-C18, 3.0x 100mm, 2.7μm

[0062] Column temperature: 40°C; flow rate: 0.4 mL / min

[0063] Analytical pump mobile phase: mobile phase A is 5mmol / L ammonium fluoride solution, mobile phase B is 0.4% ammonia-methanol solution;

[0064] Gradient elution: 0-5.0 min, 90% mobile phase A, 10% mobile phase B; 5.0-7.0 min, mobile phase B increased linearly from 10% to 55%; 7.0-16.0 min, mobile phase B increased linearly from 55% to 98%; 16.0-18.0 min, 98% mobile phase B.

[0065] The gradient program is as follows: see Table 2.

[0066] Table 2 Liquid chromatography mobile phase gradient elution program

[0067]

[0068] (3) Mass spectrometry conditions:

[0069] Electrospray ionization source: negative ion mode

[0070] Mass spectrometry scanning mode: multiple reaction monitoring DMRM mode

[0071] Atomizer pressure: 20psi

[0072] Drying gas temperature: 230℃, Drying gas flow rate: 6L / min

[0073] Sheath gas temperature: 375°C, sheath gas flow rate: 12L / min, capillary voltage: 2500V.

[0074] The mass spectrometry analysis parameters of the target compounds and internal standards are shown in Table 3.

[0075] Table 3 Mass spectrometry parameters of target compounds and internal standards

[0076]

[0077]

[0078]

[0079]

[0080] The total ion chromatogram of the target compound is shown in Figure 3 .

[0081] Rapid screening smart workflow:

[0082] First, use the original method to test the sample. For example, if a compound in a sample exceeds the limit, take sample SD as an example. After the first injection, the limit exceeds the limit and triggers the iReflex function, which automatically adds a blank sample and re-analyzes it using the second method. Figure 4 .

[0083] Draw a working curve:

[0084] Different volumes of standard working solution were respectively drawn into a group of 15 ml polypropylene centrifuge tubes, diluted to 10 ml with 50% methanol aqueous solution, shaken, and two working curves with different concentration ranges were prepared, wherein the mass concentrations of perfluorinated compounds in the high concentration curve were 0.10, 0.25, 0.50, 1.00, 2.50, 5.00, 10.0, 25.0 μg / L, respectively, and the mass concentrations of perfluorinated compounds in the low concentration curve were 0.50, 1.00, 2.5, 5.00, 10.0, 25.0, 50.0, 100 ng / L, respectively. 100 μl of internal standard solution was added to the standard series solutions respectively, and the analysis was performed according to the above working conditions. The high and low concentration working curves were drawn with the response value ratio of the target compound to the internal standard as the ordinate and the corresponding mass concentration ratio of the target compound to the internal standard as the abscissa. The working curve preparation is shown in Table 4.

[0085] Table 4 Working curve preparation

[0086]

[0087]

[0088] The invention adopts a fully automatic online solid phase extraction system (Online SPE), an ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS / MS), and an Intelligent Reflex (iReflex) rapid screening intelligent workflow; utilizes Online SPE for automatic sampling, and after enrichment, purification, and elution through an online solid phase extraction column, enters UPLC-MS / MS to realize the detection of perfluorinated compounds in water quality; utilizes Intelligent Reflex (iReflex) for rapid screening intelligent workflow to automatically determine over-limit samples, and initiates a small volume sampling scheme in real time to re-analyze the samples, and automatically completes the analysis of conventional samples and over-limit samples in one batch; significantly improves the efficiency of detection, and reduces the manpower, time, and solvent costs required for detection; uses Intelligent Reflex (iReflex) for rapid screening intelligent workflow to automatically determine over-limit samples, and initiates a small volume sampling scheme in real time to re-analyze the samples, and automatically completes the analysis of conventional samples and over-limit samples in one batch; significantly improves the efficiency of detection, and reduces the manpower, time, and solvent costs required for detection; Reflex (iReflex) rapid screening intelligent workflow expands the linear range to 500,000 times, automatically determines out-of-limit samples and re-analyzes them in real time; eliminates the process of manual judgment and sorting of out-of-limit samples; shortens the sample re-analysis cycle; avoids the impact of manual re-analysis of out-of-limit samples on sample stability and timeliness, and provides more accurate test results that can meet the needs of large-scale simultaneous determination of various types of water quality samples.

[0089] The present invention is based on the fully automatic online solid phase extraction-high performance liquid chromatography-tandem mass spectrometry technology, combined with the iReflex rapid screening intelligent workflow, and successfully established a fully automatic online rapid detection method for perfluorinated compounds in water. Through Online SPE and iReflex rapid screening intelligent workflow, automatic injection, online enrichment and purification, intelligent judgment of sample concentration, retesting of over-limit samples and accurate quantitative analysis, the detection efficiency is significantly improved. The method is easy to operate, has excellent repeatability, high sensitivity, and a wide detection range. It can meet the synchronous analysis of different types of water quality samples and meet the needs of large-scale sample detection. It has broad application prospects and promotion value.

[0090] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

[0091] The protection scope of the present invention is defined by the following claims and their equivalents.

Claims

1. A method for fully automatic online rapid detection of perfluorinated compounds in water, characterized in that: include: Step 1: pre-treat the water sample to obtain the sample to be tested, and place it in the sample injection tray of the online solid phase extraction device; Step 2: Fully automatic online solid phase (Online SPE) enrichment and purification: Use Online SPE to automatically enrich and purify the test solution in step 1 through an online solid phase extraction column. By switching the valve, double columns are alternately injected. When one column is loaded, the other column is cleaned. After the target is eluted, it enters UPLC-MS / MS analysis; Step 3: High performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS / MS) determination: The test solution in step 2 enters UPLC-MS / MS for detection, and the qualitative analysis is based on the retention time and characteristic ion abundance ratio, and the quantitative analysis is based on the internal standard method; Step 4: Use Intelligent Reflex (iReflex) to quickly screen the intelligent workflow, automatically identify samples that exceed the limit, and re-sample and analyze in a small volume.

2. The method for fully automatic online rapid detection of perfluorinated compounds in water according to claim 1, characterized in that: The water sample pretreatment method in step 1 specifically includes the following steps: Mix the water sample, let it stand, and return it to room temperature; if the pH of the water sample is <6 or pH>8, adjust the pH to 6~8 with formic acid or ammonia water; Use a polypropylene syringe to take an appropriate amount of supernatant and filter it through a 0.2µm regenerated cellulose (RC) filter membrane; Accurately transfer 5.0 ml of the filtrate to a 15 ml polypropylene centrifuge tube, add 100 µl of internal standard working solution (20 µg / L) and 5 ml of methanol, and mix well; If turbidity occurs, centrifuge at 4000 rpm for 10 min; take about 1.5 ml to 2 ml of the polypropylene injection vial as the sample to be tested.

3. The method for fully automatic online rapid detection of perfluorinated compounds in water according to claim 1, characterized in that: The conditions for fully automated online solid phase extraction (Online SPE) in step 2 are: Online SPE Column: WAX (NP3, 4 x 10 mm) Sample pump mobile phase: mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.4% ammonia-methanol / acetonitrile (1+1) solution; Injection volume: 900µl for large volume injection and 20µl for small volume injection.

4. The method for fully automatic online rapid detection of perfluorinated compounds in water according to claim 1, characterized in that: High performance liquid chromatography conditions in step 3: Column: HPH-C18, 3.0 x 100 mm, 2.7 µm Column temperature: 40°C; flow rate: 0.4 mL / min Analytical pump mobile phase: mobile phase A is 5mmol / L ammonium fluoride solution, mobile phase B is 0.4% ammonia-methanol solution; Gradient elution: 0-5.0 min, 90% mobile phase A, 10% mobile phase B; 5.0-7.0 min, mobile phase B increased linearly from 10% to 55%; From 7.0 to 16.0 min, mobile phase B increased linearly from 55% to 98%; 16.0~18.0min, 98% mobile phase B.

5. The method for fully automatic online rapid detection of perfluorinated compounds in water according to claim 1, characterized in that: Mass spectrometry conditions in step 3: Electrospray ionization source: negative ion mode Mass spectrometry scanning mode: multiple reaction monitoring DMRM mode Atomizer pressure: 20 psi Drying gas temperature: 230°C, Drying gas flow rate: 6 L / min Sheath gas temperature: 375°C, sheath gas flow rate: 12 L / min Capillary voltage: 2500V.

6. The method for fully automatic online rapid detection of perfluorinated compounds in water according to claim 1, characterized in that: In step 4, quickly screen the intelligent workflow: First, the original method is used to test the sample. If a compound in a sample exceeds the limit, taking sample SD as an example, the limit is exceeded after the first injection, triggering the iReflex function, automatically adding a blank sample and re-analyzing using the second method.

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