A method for the determination of halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry
The solid-phase extraction-liquid chromatography-tandem mass spectrometry method has solved the problem of detecting halogenated benzamide disinfection byproducts in drinking water, achieving trace detection with high sensitivity and low detection limit, and providing a theoretical basis for health risk assessment.
Patent Information
- Application Number
- CN202310991711.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-08
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2043-08-08
AI Technical Summary
Existing technologies are insufficient for the rapid and accurate identification of halogenated benzamide disinfection byproducts in drinking water, and are subject to significant matrix interference, high detection limits, and inability to effectively assess health risks.
A solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method was adopted to enrich halogenated benzamides through solid-phase extraction and combine it with multiple reaction monitoring (MRM) to reduce matrix interference and achieve efficient detection of trace halogenated benzamides.
It achieves high sensitivity and low detection limit under complex matrix conditions, enabling the detection of halogenated benzamides in drinking water at the ng/L level, providing a basis for health risk assessment.
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Figure CN117110458B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of detection of micro-pollutants in drinking water, and in particular relates to a method for detecting halogenated benzamides by solid phase extraction-liquid chromatography-tandem mass spectrometry. Background Technology
[0002] Drinking water safety is fundamental to human survival and life. Currently, the main challenges to drinking water safety are pathogen control and contamination by high-risk chemical substances. Disinfection effectively controls waterborne diseases. my country's "Standards for Drinking Water Quality" (GB 5749-2022) stipulates that the total chlorine concentration in tap water leaving the treatment plant should be within the range of 0.5–3 mg / L. However, the chlorine disinfection process can react with organic matter in the source water to form disinfection byproducts (DBPs), which are among the major pollutants threatening drinking water safety. Among these, halogenated amide disinfection byproducts exhibit high toxicity due to their strong nucleophilic substitution reactivity. Halogenated benzonitrile compounds in drinking water can hydrolyze to form halogenated benzoamides, and natural organic matter rich in aromatic compounds during disinfection has the potential to generate various halogenated benzoamides. Therefore, it is urgent to determine the environmental concentration of novel disinfection byproducts such as halogenated benzoamides in drinking water to gain a deeper understanding of their potential environmental and health risks.
[0003] Halogenated benzamide disinfection byproducts in drinking water are present in low concentrations and have complex matrices. In order to quickly and accurately identify potential halogenated benzamide disinfection byproducts in drinking water, it is urgent to develop an analytical method with high sensitivity and low detection limit to provide a theoretical basis for assessing health risks. Summary of the Invention
[0004] The purpose of this invention is to solve the technical challenges of low concentrations and significant matrix interference of halogenated benzamide disinfection byproducts in drinking water, and to provide a method for the detection of halogenated benzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry. This method combines high sensitivity and low detection limit, and features simple pretreatment and high recovery rates, enabling efficient detection of trace amounts of halogenated benzamide disinfection byproducts under complex matrix conditions.
[0005] The specific technical solution adopted in this invention is as follows:
[0006] This invention provides a method for detecting halogenated benzamides using solid-phase extraction-liquid chromatography-tandem mass spectrometry, the specific steps of which are as follows:
[0007] S1: After removing residual chlorine from the sample to be tested, filter it to obtain the filtered sample.
[0008] S2: The filtered sample is passed through an activated solid-phase extraction (SPE) column to enrich the target substance on the packing material. After desalting and cleaning the SPE column with ultrapure water, the liquid in the SPE column is dried under vacuum. The SPE column is a polystyrene-divinylbenzene column.
[0009] S3: The target substance enriched on the solid-phase extraction column is eluted with methanol under normal pressure to obtain the first test solution dissolved in methanol.
[0010] S4: After reducing the volume of the first test solution obtained in step S3 by nitrogen blowing, add ultrapure water and mix thoroughly to obtain the second test solution. The ratio of ultrapure water to the first test solution in the second test solution is 1:(1 / 9 to 4).
[0011] S5: Gradient elution was performed using aqueous formic acid and methanolic formic acid as the mobile phases for liquid chromatography-tandem mass spectrometry.
[0012] The mass spectrometry conditions were as follows: ion source temperature range of 300–550℃. Multiple reaction monitoring (MRM) was employed to detect specific precursor ions. The selected specific precursor ions were subjected to collision-induced degradation, and interference from other daughter ions was removed. Mass spectrometry signals were acquired only for the selected specific daughter ions. The concentrations of 2-chlorobenzamide, 2,4-dichlorobenzamide, 2,6-dichlorobenzamide, 2-bromobenzamide, 2-iodobenzamide, 3,5-dibromobenzamide, 2-chloro-4-hydroxybenzamide, and 5-bromo-2-hydroxybenzamide in the second analyte were determined.
[0013] Preferably, the above-mentioned residual chlorine removal process uses formic acid with a volume fraction of 2.5% to quench the residual chlorine in the sample to be tested.
[0014] Preferably, the above filtration process is carried out using a filter membrane with a pore size of 0.45 μm.
[0015] Preferably, in step S2 above, the activation process involves washing away organic matter with 6–18 mL of methanol and washing away inorganic ions with 6–18 mL of ultrapure water.
[0016] Preferably, the filtered sample passes through the activated solid-phase extraction column at a rate of 5–6 mL / min.
[0017] Preferably, the ratio of ultrapure water to the first test solution in the second test solution is 1:1.
[0018] Preferably, in step S5 above, the volume fraction of the formic acid aqueous solution is 0.1%, and the volume fraction of the formic acid methanol solution is 0.1%.
[0019] Preferably, the gradient elution process in step S5 is performed for 15 minutes, specifically set as follows: From 0 to 5 minutes, the volume ratio of formic acid aqueous solution to formic acid methanol solution decreases from 90:10 to 40:60. From 5 to 12 minutes, the volume ratio increases from 40:60 to 80:20. From 12 to 13 minutes, the volume ratio increases from 80:20 to 90:10. From 13 to 15 minutes, the volume ratio remains at 90:10. The chromatographic column is a BEH C18 column with a particle size of 1.7 μm.
[0020] Preferably, the ion source temperature for the mass spectrometry conditions in step S5 above is 550°C.
[0021] Preferably, the declustering voltage in the above-mentioned mass spectrometry multiple reaction monitoring methods is 40V;
[0022] When the target substance is 2-chlorobenzamide, the specific precursor ion has a mass-to-charge ratio of 156, and the collision voltages are 17V and 20V when the corresponding daughter ion mass-to-charge ratios are 75 and 111, respectively. When the target substance is 2,4-dichlorobenzamide or 2,6-dichlorobenzamide, the specific precursor ion has a mass-to-charge ratio of 190, and the collision voltages are 32V and 26V when the corresponding daughter ion mass-to-charge ratios are 109 and 145, respectively. When the target substance is 2-bromobenzamide, the specific precursor ion has a mass-to-charge ratio of 200, and the collision voltages are 32V and 13V when the corresponding daughter ion mass-to-charge ratios are 76 and 155, respectively. When the target substance is 2-iodobenzamide, the specific precursor ion has a mass-to-charge ratio of 248, and the corresponding daughter ion mass-to-charge ratios are 17V and 20V, respectively. When the mass-to-charge ratios were 76, 121, and 203, the collision voltages were 35V, 16V, and 27V, respectively. When the target substance was 3,5-dibromobenzamide, the specific precursor ion had a mass-to-charge ratio of 278, and the corresponding daughter ion mass-to-charge ratios were 154 and 233, respectively, with collision voltages of 44V and 31V, respectively. When the target substance was 2-chloro-4-hydroxybenzamide, the specific precursor ion had a mass-to-charge ratio of 172, and the corresponding daughter ion mass-to-charge ratios were 127 and 155, respectively, with collision voltages of 22V and 15V, respectively. When the target substance was 5-bromo-2-hydroxybenzamide, the specific precursor ion had a mass-to-charge ratio of 216, and the corresponding daughter ion mass-to-charge ratios were 171 and 199, respectively, with collision voltages of 24V and 16V, respectively.
[0023] Compared with the prior art, the present invention has the following advantages:
[0024] This invention enriches halogenated benzamides through solid-phase extraction, reduces matrix interference, and uses a multiple reaction monitoring (MRM) method for targeted qualitative and quantitative analysis of halogenated benzamides in drinking water. The analytical method in this invention enables the enrichment and concentration of halogenated benzamides through solid-phase extraction under complex matrix conditions. The use of methanol as the eluent improves elution efficiency and significantly reduces the method detection limit and matrix interference. An MRM method for quantitative analysis of halogenated benzamides was developed using characteristic fragment ions, establishing a method for detecting trace amounts of halogenated benzamides in drinking water. This enables the detection of halogenated benzamides in drinking water at levels as low as ng / L, providing a theoretical basis for assessing health risks.
[0025] This method has the advantages of small sample volume requirement, low detection limit and high sensitivity for drinking water, and is suitable for the detection of trace halogenated benzamides under complex aquatic environment conditions. Attached Figure Description
[0026] Figure 1 The flowchart of the method for detecting halogenated benzamides by solid phase extraction-liquid chromatography-tandem mass spectrometry provided by the present invention is shown below.
[0027] Figure 2 This is a graph showing the effect of different ion source temperatures on the detection signal intensity of eight halobenzamides in Example 1.
[0028] Figure 3 This is a graph showing the effect of different ratios of ultrapure water and methanol in the test solution on the detection signal intensity of eight halogenated benzamides in Example 2.
[0029] Figure 4 Chromatograms comparing 2-chlorobenzamide in raw water and disinfected drinking water: Figure 4 (a) shows the chromatogram of the raw water. Figure 4 (b) shows the chromatogram in drinking water. Figure 4 (c) is the chromatogram of 2-chlorobenzamide standard;
[0030] Figure 5 Chromatograms comparing 2,4-dichlorobenzamide and 2,6-dichlorobenzamide in raw water and disinfected drinking water: Figure 5 (a) shows the chromatogram of the raw water. Figure 5 (b) shows the chromatogram of the disinfected drinking water. Figure 5 (c) is a chromatogram of 2,4-dichlorobenzamide and 2,6-dichlorobenzamide standards;
[0031] Figure 6 Chromatograms comparing 2-bromobenzamide in raw water and disinfected drinking water: Figure 6 (a) shows the chromatogram of the raw water. Figure 6 (b) shows the chromatogram of the disinfected drinking water. Figure 6 (c) shows the chromatogram of 2-bromobenzamide standard;
[0032] Figure 7 Chromatograms comparing 2-iodobenzamide in raw water and disinfected drinking water: Figure 7 (a) shows the chromatogram of the raw water. Figure 7 (b) shows the chromatogram of the disinfected drinking water. Figure 7 (c) shows the chromatogram of 2-iodobenzamide standard;
[0033] Figure 8 Chromatograms comparing 3,5-dibromobenzamide in raw water and disinfected drinking water: Figure 8 (a) shows the chromatogram of the raw water. Figure 8 (b) shows the chromatogram of the disinfected drinking water. Figure 8 (c) shows the chromatogram of 3,5-dibromobenzamide standard;
[0034] Figure 9 Chromatograms comparing 2-chloro-4-hydroxybenzamide in raw water and disinfected drinking water: Figure 9 (a) shows the chromatogram of the raw water. Figure 9 (b) shows the chromatogram of the disinfected drinking water. Figure 9 (c) shows the chromatogram of 2-chloro-4-hydroxybenzamide standard;
[0035] Figure 10 Chromatograms comparing 5-bromo-2-hydroxybenzamide in raw water and disinfected drinking water: Figure 10 (a) shows the chromatogram of the raw water. Figure 10 (b) shows the chromatogram of the disinfected drinking water. Figure 10 (c) shows the chromatogram of 5-bromo-2-hydroxybenzamide standard; Detailed Implementation
[0036] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.
[0037] Example 1
[0038] A method for detecting eight halogenated benzamides using solid-phase extraction-liquid chromatography-tandem mass spectrometry at different ion source temperatures is described below. Figure 1 As shown, the specific steps include:
[0039] (1) Collect disinfected drinking water, add 2.5% formic acid (by volume) to quench the residual chlorine in the water, and store it at 4°C for later use. Prepare solutions containing eight different halogenated benzamides at the same concentration as standards for later use.
[0040] (2) The sample in step (1) after removing residual chlorine is filtered through a filter membrane with a pore size of 0.45 μm to obtain a filtered sample.
[0041] (3) The polystyrene-divinylbenzene column (HLB) required for solid-phase extraction was activated using 12 mL of methanol and 6–18 mL of ultrapure water.
[0042] (4) Pass the filtered sample from step (2) slowly through the activated solid-phase extraction column at a rate of 5-6 mL / min to enrich the target substance to be detected, namely halogenated benzamide, on the packing material; then use 12-30 mL of ultrapure water to desalinate and clean the solid-phase extraction column enriched with the target substance, and then dry the solid-phase extraction column under vacuum for 15 min until the bottom of the column turns white and the liquid is dried.
[0043] (5) Elute the target substance retained on the solid-phase extraction column with 5-10 mL of methanol under normal atmospheric pressure to obtain the first test solution dissolved in methanol.
[0044] (6) Reduce the volume of the first test solution obtained in step (5) to 0.2 mL by nitrogen blowing, add 0.2 mL of ultrapure water, and mix thoroughly by vortexing to obtain the second test solution. This makes the ratio of ultrapure water to the first test solution in the second test solution 1:1.
[0045] (7) A 0.1% (v / v) aqueous formic acid solution and a 0.1% (v / v) methanolic formic acid solution were used as the mobile phases for liquid chromatography-tandem mass spectrometry, with gradient elution for 15 minutes. The specific gradient elution conditions are as follows:
[0046] Within 0–5 min, the volume ratio of formic acid aqueous solution to formic acid methanol solution decreased from 90:10 to 40:60; within 5–12 min, the volume ratio increased from 40:60 to 80:20; within 12–13 min, the volume ratio increased from 80:20 to 90:10; and within 13–15 min, the volume ratio remained at 90:10.
[0047] A BEH C18 liquid chromatography column (2.1 × 100 mm id, 1.7 μm) was used. Multiple reaction monitoring (MRM) was employed to detect specific precursor ions. The selected specific precursor ions were subjected to collision-induced degradation, and interference from other daughter ions was removed. Mass spectrometry signals were acquired only for the selected specific daughter ions. The concentrations of 2-chlorobenzamide, 2,4-dichlorobenzamide, 2,6-dichlorobenzamide, 2-bromobenzamide, 2-iodobenzamide, 3,5-dibromobenzamide, 2-chloro-4-hydroxybenzamide, and 5-bromo-2-hydroxybenzamide in the second analyte were separated and quantified. The specific conditions for MRM are shown in Table 1. The ion source temperatures were set to 300℃, 350℃, 400℃, 450℃, 500℃, and 550℃.
[0048] Table 1. Setup conditions for multiple reaction monitoring methods
[0049]
[0050]
[0051] The results are as follows Figure 2 As shown, the horizontal axis represents the ion source temperature, and the vertical axis represents the ratio of the detection signal intensity of halobenzamide to the highest signal intensity at different ion source temperatures. Experimental results show that as the ion source temperature continuously increases from 300 to 550℃, the detection signal intensity of halobenzamide also continuously increases. The increase in temperature enhances the ionization degree of the substance; therefore, the preferred ionization temperature setting is 550℃.
[0052] Example 2
[0053] Considering the differences in ionization efficiency of halogenated benzamides in different solvents, this embodiment investigates the effect of different ratios of ultrapure water and methanol in the test solution solvent on the mass spectrometry response signal intensity of eight halogenated benzamides. The specific steps include the following:
[0054] (1) Collect disinfected drinking water, add 2.5% formic acid (by volume) to quench the residual chlorine in the water, and store it at 4°C for later use. Prepare solutions containing eight different halogenated benzamides at the same concentration as standards for later use.
[0055] (2) The sample in step (1) after removing residual chlorine is filtered through a filter membrane with a pore size of 0.45 μm to obtain a filtered sample.
[0056] (3) The polystyrene-divinylbenzene column (HLB) required for solid-phase extraction was activated using 12 mL of methanol and 6–18 mL of ultrapure water.
[0057] (4) Pass the filtered sample from step (2) slowly through the activated solid-phase extraction column at a rate of 5-6 mL / min to enrich the target substance to be detected, namely halogenated benzamide, on the packing material; then use 12-30 mL of ultrapure water to desalinate and clean the solid-phase extraction column enriched with the target substance, and then dry the solid-phase extraction column under vacuum for 15 min until the bottom of the column turns white and the liquid is dried.
[0058] (5) Elute the target substance retained on the solid-phase extraction column with 5-10 mL of methanol under normal atmospheric pressure to obtain the first test solution dissolved in methanol.
[0059] (6) The volume of the first test solution obtained in step (5) is reduced by nitrogen blowing, and different volumes of ultrapure water are added. After vortex mixing, the second test solution is obtained. The ratio of ultrapure water to methanol in the second test solution is 90:10, 80:20, 60:40, 50:50, 20:80, and 0:100, respectively.
[0060] (7) A 0.1% (v / v) aqueous formic acid solution and a 0.1% (v / v) methanolic formic acid solution were used as the mobile phases for liquid chromatography-tandem mass spectrometry, with gradient elution for 15 minutes. The specific gradient elution conditions are as follows:
[0061] Within 0–5 min, the volume ratio of formic acid aqueous solution to formic acid methanol solution decreased from 90:10 to 40:60; within 5–12 min, the volume ratio increased from 40:60 to 80:20; within 12–13 min, the volume ratio increased from 80:20 to 90:10; and within 13–15 min, the volume ratio remained at 90:10.
[0062] A BEH C18 liquid chromatography column (2.1 × 100 mm id, 1.7 μm) was used. Multiple reaction monitoring (MRM) was employed to detect specific precursor ions. The selected specific precursor ions were subjected to collision-induced degradation, and interference from other daughter ions was removed. Mass spectrometry signals were acquired only for the selected specific daughter ions. The concentrations of 2-chlorobenzamide, 2,4-dichlorobenzamide, 2,6-dichlorobenzamide, 2-bromobenzamide, 2-iodobenzamide, 3,5-dibromobenzamide, 2-chloro-4-hydroxybenzamide, and 5-bromo-2-hydroxybenzamide in the second analyte were separated and quantified. The specific conditions for the MRM are shown in Table 1. The ion source temperature was set to 550 °C.
[0063] The results are as follows Figure 3As shown, the horizontal axis represents the ratio of methanol to ultrapure water in the solution, and the vertical axis represents the ratio of the detection signal intensity of halogenated benzamides to the highest signal intensity under different ratios. Experimental results show that the detection signal intensity of the eight halogenated benzamides is higher when the ratio of ultrapure water to methanol is 60:40 and 50:50. Furthermore, when the ratio of ultrapure water to methanol is 50:50, the eight halogenated benzamides exhibit a more symmetrical peak shape. To obtain more symmetrical ion peaks, a 50:50 ratio of ultrapure water to methanol is preferred as the solvent ratio for the detection of the eight halogenated benzamides.
[0064] Figures 4 to 10 The images show the chromatographic tandem mass spectra of 2-chlorobenzamide, 2,4-dichlorobenzamide and 2,6-dichlorobenzamide, 2-bromobenzamide, 2-iodobenzamide, 3,5-dibromobenzamide, 2-chloro-4-hydroxybenzamide, and 5-bromo-2-hydroxybenzamide in raw water and disinfected drinking water, respectively, under the condition that the ion source temperature is set to 550°C in Example 1.
[0065] The results showed that the eight halogenated benzamides could only be detected in the disinfected drinking water but not in the raw water, indicating that all eight halogenated benzamides were disinfection byproducts.
[0066] To investigate the prevalence of halogenated benzamides in disinfected drinking water, this invention also collected 10 groups of drinking water samples from different water treatment plants. The detection method provided in Example 1 was used, and the ion source temperature was set to 550℃. The results are shown in Table 2; "not detected" indicates that the corresponding substance was not detected. The test results showed that 2,4-dichlorobenzamide, a disinfection byproduct, was not detected in the raw water of all ten groups of samples, but was detected in all of them in the drinking water, with a detection rate of 100%. 2-chlorobenzamide, 2-bromobenzamide, 3,5-dibromobenzamide, and 5-bromo-2-hydroxybenzamide, four disinfection byproducts, were not detected in the raw water of all ten groups of samples, but were detected in eight groups of drinking water, with a detection rate of 80%. 2-iodobenzamide, 2,6-dichlorobenzamide, and 2-chloro-4-hydroxybenzamide, three disinfection byproducts, were not detected in the raw water of all ten groups of samples, but were detected in seven groups of drinking water, with a detection rate of 70%. Therefore, novel but unregulated disinfection byproducts of halogenated benzamides deserve attention. The method provided in this invention combines solid-phase extraction pretreatment with liquid chromatography-tandem mass spectrometry (LC-MS / MS) for detection, enabling the detection of trace halogenated benzamides in the aquatic environment and providing a theoretical basis for assessing health risks.
[0067] Table 2. Detection data of eight halogenated benzamides in raw water and drinking water.
[0068]
[0069]
[0070]
[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.
Claims
1. A method for detecting halobenzamides using solid-phase extraction-liquid chromatography-tandem mass spectrometry, characterized in that, The specific steps are as follows: S1: After removing residual chlorine from the sample to be tested, filter it to obtain the filtered sample; S2: The filtered sample is passed through an activated solid-phase extraction column to enrich the target substance on the packing material; after desalting and cleaning the solid-phase extraction column enriched with ultrapure water, the liquid in the solid-phase extraction column is dried under vacuum; the solid-phase extraction column is a polystyrene-divinylbenzene column. S3: The target substance enriched on the solid-phase extraction column is eluted with methanol at normal pressure to obtain the first test solution dissolved in methanol. S4: After reducing the volume of the first test solution obtained in step S3 by nitrogen blowing, add ultrapure water and mix evenly to obtain the second test solution; the ratio of ultrapure water to the first test solution in the second test solution is 1:(1 / 9~4). S5: Formic acid aqueous solution and formic acid methanol solution are used as the mobile phase for liquid chromatography-tandem mass spectrometry for gradient elution; during the gradient elution process, a BEH C18 column with a particle size of 1.7 μm is used. The mass spectrometry conditions were as follows: the ion source temperature range was 300~550℃; multiple reaction monitoring (MRM) was used to detect specific precursor ions, and the selected specific precursor ions were subjected to collision-induced degradation. Finally, interference from other daughter ions was removed, and mass spectrometry signals were collected only for the selected specific daughter ions. The concentrations of 2-chlorobenzamide, 2,4-dichlorobenzamide, 2,6-dichlorobenzamide, 2-bromobenzamide, 2-iodobenzamide, 3,5-dibromobenzamide, 2-chloro-4-hydroxybenzamide, and 5-bromo-2-hydroxybenzamide in the second test solution were determined. The gradient elution process described in step S5 lasts for 15 minutes, with the following specific settings: From 0 to 5 minutes, the volume ratio of formic acid aqueous solution to formic acid methanol solution decreases from 90:10 to 40:60; from 5 to 12 minutes, the volume ratio increases from 40:60 to 80:20; from 12 to 13 minutes, the volume ratio increases from 80:20 to 90:10; and from 13 to 15 minutes, the volume ratio remains at 90:
10. In the described multiple reaction monitoring (MRM) mass spectrometry method, the declustering voltage is 40 V. When the target substance is 2-chlorobenzamide, the specific precursor ion has a mass-to-charge ratio (M / C ratio) of 156, and the corresponding daughter ion M / C ratios are 75 and 111, with collision voltages of 17 V and 20 V, respectively. When the target substance is 2,4-dichlorobenzamide or 2,6-dichlorobenzamide, the specific precursor ion has a M / C ratio of 190, and the corresponding daughter ion M / C ratios are 109 and 145, with collision voltages of 32 V and 26 V, respectively. When the target substance is 2-bromobenzamide, the specific precursor ion has a M / C ratio of 200, and the corresponding daughter ion M / C ratios are 76 and 155, with collision voltages of 32 V and 13 V, respectively. When the target substance is 2-iodobenzamide, the specific precursor ion has a M / C ratio of 248, and the corresponding daughter ion M / C ratios are 76, 121, and 203, with collision voltages of 35 V, 16 V, and 27 V, respectively. When the target substance is 3,5-dibromobenzamide, the mass-to-charge ratio of the specific precursor ion is 278, and the collision voltages are 44 V and 31 V when the corresponding daughter ion mass-to-charge ratios are 154 and 233, respectively. When the target substance is 2-chloro-4-hydroxybenzamide, the mass-to-charge ratio of the specific precursor ion is 172, and the collision voltages are 22 V and 15 V when the corresponding daughter ion mass-to-charge ratios are 127 and 155, respectively. When the target substance is 5-bromo-2-hydroxybenzamide, the mass-to-charge ratio of the specific precursor ion is 216, and the collision voltages are 24 V and 16 V when the corresponding daughter ion mass-to-charge ratios are 171 and 199, respectively.
2. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The process for removing residual chlorine involves quenching the sample with formic acid at a volume fraction of 2.5%.
3. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The filtration process is carried out using a filter membrane with a pore size of 0.45 µm.
4. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The activation process described in step S2 involves washing away organic matter with 6-18 mL of methanol and washing away inorganic ions with 6-18 mL of ultrapure water.
5. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The filtered sample passes through the activated solid-phase extraction column at a rate of 5-6 mL / min.
6. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The ratio of ultrapure water to the first test solution in the second test solution is 1:
1.
7. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The volume fraction of the formic acid aqueous solution in step S5 is 0.1%, and the volume fraction of the formic acid methanol solution is 0.1%.
8. The method for detecting halobenzamides by solid-phase extraction-liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, The ion source temperature for the mass spectrometry conditions described in step S5 is 550℃.