Phenolic compound detection method

Abstract

The invention relates to the technical field of environmental analytical chemistry, and discloses a phenolic compound detection method. The phenolic compound detection method comprises the following steps that a to-be-detected sample and a solid-phase extraction column are prepared, and the to-be-detected sample contains a target compound; the solid-phase extraction column is subjected to activating treatment, and methanol and acidic water are adopted for activating treatment. The sample to be detected flows through the solid-phase extraction column for extraction, so that the target compound is adsorbed on the solid-phase extraction column. The target compound adsorbed by the solid-phase extraction column is subjected to desorption treatment, desorption liquid is obtained, and methanol is adopted for desorption treatment. And carrying out quantitative analysis on the desorption liquid to obtain the content of the target compound. The efficiency of measuring the content of the phenolic compound is improved.

Description

Technical Field

[0001] This application belongs to the technical field of environmental analytical chemistry, and particularly relates to a detection method for phenolic compounds. Background Art

[0002] Currently, when determining the contents of bisphenol A and alkylphenol compounds in surface water, the method of solid phase extraction - high performance liquid chromatography - fluorescence detector is generally adopted. This method includes the following steps: membrane filtration, solid phase extraction, nitrogen blowing concentration, volume fixation and standard addition, and machine detection. Specifically, the sample is first filtered through a quartz membrane with a pore size of 0.45 μm. The filtered sample is completely transferred to a graduated cylinder and the volume is accurately recorded. In the solid phase extraction stage, a solid phase extraction column is activated successively with n - hexane, dichloromethane, methanol and ultrapure water; when the sample passes through the solid phase extraction column at a stable flow rate, the target compounds are adsorbed on the stationary phase of the solid phase extraction column; after draining the residual water sample in the solid phase extraction column, the solid phase extraction column is rinsed with methanol; finally, the target compounds are eluted with dichloromethane, and the eluate is collected into a concentration bottle. The eluate is concentrated by a nitrogen blowing instrument. After concentration, acetonitrile is added for further concentration. After the solvent is completely replaced with acetonitrile, it is fixed with acetonitrile, filtered through a membrane and then to be measured. Then, the contents of bisphenol A and alkylphenol compounds in surface water are measured by high performance liquid chromatography and a fluorescence detector. Among them, the chromatographic conditions are that acetonitrile and ultrapure water are used as the mobile phase, the excitation wavelength of the fluorescence detector is 227 nm, and the emission wavelength is 315 nm. Bisphenol A and alkylphenol compounds have fluorescence characteristics at specific excitation wavelength (227 nm) and emission wavelength (315 nm). The fluorescence detector can detect the fluorescence signals of these compounds, thus realizing qualitative and quantitative analysis.

[0003] In the related technology, the method for determining the contents of bisphenol A and alkylphenol compounds in surface water activates the solid phase extraction column successively with n - hexane, dichloromethane, methanol and ultrapure water, with cumbersome steps and complex operations, resulting in low measurement efficiency. Rinsing the solid phase extraction column with methanol will cause loss of target compounds. Eluting the target compounds with dichloromethane requires solvent replacement, which prolongs the pretreatment time, increases the workload and reduces the measurement efficiency. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the related technology.

[0005] Therefore, the present application provides a method for detecting phenolic compounds, comprising the following steps: preparing a sample to be tested and a solid-phase extraction column, wherein the sample to be tested contains a target compound; activating the solid-phase extraction column, wherein the activation treatment uses methanol and acidic water; allowing the sample to be tested to flow through the solid-phase extraction column for extraction, so that the target compound is adsorbed on the solid-phase extraction column; performing a desorption treatment on the target compound adsorbed on the solid-phase extraction column to obtain a desorbed solution, wherein the desorption treatment uses methanol; and performing quantitative analysis on the desorbed solution to obtain the content of the target compound.

[0006] Optionally, before the step of performing a desorption treatment on the target compound adsorbed on the solid-phase extraction column, the detection method further comprises: performing a rinsing treatment on the solid-phase extraction column, wherein the rinsing treatment uses acidic water; and performing a drying treatment on the solid-phase extraction column after the rinsing treatment.

[0007] Optionally, the pH value of the acidic water is 2 ± 0.1.

[0008] Optionally, the step of performing quantitative analysis on the desorbed solution to obtain the content of the target compound comprises: concentrating the desorbed solution to obtain a concentrated solution; redissolving the concentrated solution with methanol water to obtain a redissolved solution; mixing the redissolved solution with an internal standard to obtain a mixed solution; performing high performance liquid chromatography-tandem mass spectrometry detection on the mixed solution to obtain the peak area of the target compound and the peak area of the internal standard; and obtaining the concentration of the target compound according to the peak area of the target compound, the peak area of the internal standard, and a preset standard curve.

[0009] Optionally, the high performance liquid chromatography-tandem mass spectrometry detection comprises high performance liquid chromatography detection and mass spectrometry detection; the conditions for the high performance liquid chromatography detection include: mobile phase: phase A is an aqueous solution of ammonium fluoride, and phase B is methanol; chromatographic column: C18 column; liquid phase parameters: column temperature is 30°C to 40°C, flow rate is 0.1 mL / min to 0.6 mL / min, injection volume is 20 μL; elution program: from 0 min to 1 min, the volume percentage of phase B is 20%; from 1 min to 3 min, the volume percentage of phase B increases to 70%; from 3 min to 9 min, the volume percentage of phase B increases to 100%; from 9 min to 11 min, the volume percentage of phase B remains at 100%; from 11 min to 11.1 min, the volume percentage of phase B drops to 20%; from 11.1 min to 15 min, the volume percentage of phase B remains at 20%; the conditions for the mass spectrometry detection include: ion source is an electrospray ionization source, ion mode is a negative ion mode, the pressure of the curtain gas is 35 psi, the voltage of the ion source is -4500 V, the pressure of the nebulizing gas is 55 psi, the pressure of the auxiliary gas is 55 psi, and the temperature of the auxiliary gas is 550°C.

[0010] Optionally, the preset standard curve is a linear relationship equation between the ratio of the peak area of the target compound to the peak area of the internal standard and the ratio of the concentration of the target compound to the concentration of the internal standard.

[0011] Optionally, the internal standard is bisphenol A-D4.

[0012] Optionally, in the step of flowing the sample to be tested through the solid-phase extraction column for extraction, the flow rate of the sample to be tested is 4 mL / min to 6 mL / min.

[0013] Optionally, after the steps of preparing the sample to be tested and the solid-phase extraction column, the detection method further includes: filtering the sample to be tested; acidifying the filtered sample to be tested.

[0014] Optionally, the target compound includes one or more of bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol.

[0015] A detection method for phenolic compounds provided by the present application can at least achieve the following technical effects:

[0016] In the detection method for phenolic compounds of the present application, the solid-phase extraction column is activated. Among them, the activation treatment uses methanol and acidic water. That is to say, the solid-phase extraction column is activated by methanol and acidic water, which simplifies the activation treatment steps and improves the measurement efficiency. The target compound adsorbed on the solid-phase extraction column is desorbed to obtain a desorbed solution. Among them, the desorption treatment uses methanol. That is to say, the target compound adsorbed on the solid-phase extraction column is eluted by methanol, and solvent replacement is not required, saving the time of desorption treatment and improving the efficiency. The detection method for phenolic compounds of the present application improves the efficiency of determining the content of phenolic compounds.

[0017] The above general description and the following description are only exemplary and explanatory and are not used to limit the present application. Description of the Drawings

[0018] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation, and among them:

[0019] Figure 1 is a flowchart of a detection method for phenolic compounds provided by an embodiment of the present disclosure;

[0020] Figure 2 Flow chart of a method for detecting phenolic compounds provided by another embodiment of the present disclosure;

[0021] Figure 3 Schematic diagram of an elution program provided by an embodiment of the present disclosure. Detailed implementation manners

[0022] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration purposes only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0023] Unless otherwise specified, the term "plurality" means two or more.

[0024] In the embodiments of the present disclosure, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0025] The term "and / or" is a description of the association relationship of an object, indicating that three relationships may exist. For example, A and / or B means: A or B, or, A and B these three relationships.

[0026] It should be noted that, without conflict, the embodiments in the embodiments of the present disclosure and the features in the embodiments may be combined with each other.

[0027] In the related art, solid-phase extraction is a sample pretreatment technique used to extract and enrich target compounds from complex sample matrices. For example, alkylphenolic compounds are separated from samples through a solid-phase extraction column (SPE) with a stationary phase.

[0028] In the related art, there are limitations in the use of fluorescence detection methods. First, the selectivity is limited. Non-specific responses and background interference may cause cross-interference and background noise, affecting the accuracy of the detection results. Second, the sensitivity is restricted by various factors, including differences in fluorescence quantum yields and quenching effects caused by environmental factors, which may reduce the detection sensitivity. Finally, the quantitative range is relatively narrow. The linear range of the fluorescence detector is limited, resulting in that target compounds at high and low concentrations may not be accurately measured within the same linear range.

[0029] As Figure 1 shown, an embodiment of the present disclosure provides a method for detecting phenolic compounds. The method for detecting phenolic compounds includes the following steps:

[0030] S101. Prepare a sample to be tested and a solid-phase extraction column, where the sample to be tested contains a target compound.

[0031] In this embodiment, a sample to be tested and a solid-phase extraction column are prepared to prepare for determining the content of the target compound in the sample to be tested. The sample to be tested contains a target compound, that is, the sample to be tested contains the target compound.

[0032] Exemplarily, the sample to be tested is surface water, and the target compounds are bisphenol A and 9 alkylphenol compounds (pollutants) in the surface water.

[0033] In some embodiments, the target compound includes one or more of bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol.

[0034] In this embodiment, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol are all alkylphenol compounds. The detection method of this embodiment can be used to determine the content of one or more of bisphenol A and the above alkylphenol compounds. For example, the detection method of this embodiment can simultaneously determine the content of bisphenol A and the above alkylphenol compounds in surface water.

[0035] Optionally, the solid-phase extraction column includes a stationary phase, and the stationary phase is used to adsorb the target compound in the sample to be tested. Specifically, the stationary phase can be formed by setting a packing material in the solid-phase extraction column. It should be noted that the specific type of the packing material is not limited. For example, the packing material is made of hydrophilic N-vinylpyrrolidone and lipophilic divinylbenzene in a preset ratio and is used to adsorb bisphenol A and the above alkylphenol compounds in surface water.

[0036] S102. Activate the solid-phase extraction column, where the activation treatment uses methanol and acidic water.

[0037] In this embodiment, the solid-phase extraction column is activated by methanol and acidic water, which simplifies the activation treatment steps and improves the measurement efficiency.

[0038] It should be noted that during the activation treatment, the stationary phase (packing material) in the solid-phase extraction column does not expose above the liquid level to improve the activation effect.

[0039] Optionally, the solid-phase extraction column is activated successively with methanol and acidic water to improve the adsorption performance of the stationary phase and thus improve the accuracy of the detection results.

[0040] S103. Let the sample to be tested flow through a solid-phase extraction column for extraction so that the target compound is adsorbed on the solid-phase extraction column.

[0041] In this embodiment, letting the sample to be tested flow through the solid-phase extraction column to achieve extraction. During the process of the sample to be tested flowing through the solid-phase extraction column, the stationary phase of the solid-phase extraction column can adsorb the target compound.

[0042] S104. Perform desorption treatment on the target compound adsorbed on the solid-phase extraction column to obtain a desorption solution, wherein methanol is used for the desorption treatment.

[0043] In this embodiment, the target compound adsorbed by the stationary phase is eluted by methanol, and there is no need to perform solvent replacement, which saves the time of desorption treatment and improves the efficiency.

[0044] It can be understood that during the process of performing desorption treatment on the target compound adsorbed on the solid-phase extraction column, it is necessary to collect the desorption solution to prepare for subsequent steps.

[0045] S105. Perform quantitative analysis on the desorption solution to obtain the content of the target compound.

[0046] In this embodiment, by performing quantitative analysis on the desorption solution, the content of the target compound is obtained, and the content of phenolic compounds is measured. For example, by performing quantitative analysis on the desorption solution, the contents of bisphenol A and the above 9 alkylphenol compounds in surface water are measured.

[0047] The detection method in this embodiment improves the efficiency of measuring the content of phenolic compounds and the accuracy of detection results.

[0048] In some embodiments, before the step of performing desorption treatment on the target compound adsorbed on the solid-phase extraction column, the detection method further includes: performing a rinsing treatment on the solid-phase extraction column, and acidic water is used for the rinsing treatment. Perform a drying treatment on the solid-phase extraction column after the rinsing treatment.

[0049] In this embodiment, the solid-phase extraction column is rinsed with acidic water to remove interfering substances such as salts remaining in the solid-phase extraction column, and the acidic water can prevent or reduce the loss of the target compound during the rinsing treatment, improving the accuracy of the detection results.

[0050] In this embodiment, performing a drying treatment on the solid-phase extraction column after the rinsing treatment can fully remove the residual moisture in the solid-phase extraction column, improving the accuracy of the detection results.

[0051] It should be noted that the equipment for performing the drying treatment on the solid-phase extraction column is not limited. For example, a vacuum pump can be used. The duration of the drying treatment is not limited and can be set according to needs.

[0052] In some embodiments, the pH value of the acidic water is 2 ± 0.1.

[0053] Specifically, when activating the solid-phase extraction column and rinsing the solid-phase extraction column, the pH value of the acidic water used is 2±0.1. The acidic water with a pH value of 2±0.1 can activate the solid-phase extraction column during the activation process, remove interfering substances such as salts retained in the solid-phase extraction column during the rinsing process, and also prevent or reduce the loss of target compounds during the rinsing process, thereby improving the accuracy of the detection results.

[0054] In some embodiments, the steps of quantitatively analyzing the eluent to obtain the content of the target compound include: concentrating the eluent to obtain a concentrated solution. Redissolving the concentrated solution with methanol-water to obtain a redissolved solution. Mixing the redissolved solution with an internal standard to obtain a mixed solution. Performing high-performance liquid chromatography-tandem mass spectrometry detection on the mixed solution to obtain the peak area of the target compound and the peak area of the internal standard. Calculating the concentration of the target compound based on the peak area of the target compound, the peak area of the internal standard, and a preset standard curve.

[0055] In this embodiment, concentrating the eluent to obtain a concentrated solution reduces the solution volume and prepares for subsequent preparation of the redissolved solution and the mixed solution. In practical applications, the eluent can be concentrated to a nearly dry state. For example, concentrating 6 mL of the eluent to obtain a concentrated solution of 200 μL to 1 mL.

[0056] It should be noted that the equipment for concentrating the eluent is not limited. For example, a nitrogen evaporator or a vacuum centrifugal concentrator.

[0057] In this embodiment, redissolving the concentrated solution with methanol-water to obtain a redissolved solution means dissolving the concentrated solution in methanol-water so that the concentrated target compound is dissolved in methanol-water, improving the stability during high-performance liquid chromatography-tandem mass spectrometry detection, and thus improving the accuracy of the detection results.

[0058] In this embodiment, mixing the redissolved solution with an internal standard to obtain a mixed solution can improve the quantitative accuracy and stability during high-performance liquid chromatography-tandem mass spectrometry detection. The internal standard can be a known-concentration compound with properties similar to those of the target compound but without interfering with the detection of the target compound. In practical applications, the system error can be corrected by the ratio of the peak area of the internal standard to the peak area of the target compound, improving the accuracy of quantitative analysis. By using the internal standard method for quantification, errors can be reduced, and the accuracy and stability of the detection results can be improved while increasing the detection efficiency.

[0059] In this embodiment, the mixed solution is detected by high performance liquid chromatography tandem mass spectrometry to obtain the peak area of the target compound, providing data for obtaining the concentration of the target compound. According to the peak area of the target compound, the peak area of the internal standard, and the preset standard curve, the concentration of the target compound is obtained, realizing the determination of the content of phenolic compounds and improving the detection efficiency and the accuracy of the detection results at the same time.

[0060] Optionally, the volume of the concentrated solution is 200 μL to 1 mL.

[0061] Optionally, in the methanol water, the volume ratio of methanol to water is 1:1.

[0062] In some embodiments, the high performance liquid chromatography tandem mass spectrometry detection includes high performance liquid chromatography detection and mass spectrometry detection. The conditions for the high performance liquid chromatography detection include: mobile phase: phase A is an aqueous ammonium fluoride solution, and phase B is methanol. Chromatographic column: C18 column. Liquid phase parameters: the column temperature is 30 °C to 40 °C, the flow rate is 0.1 mL / min to 0.6 mL / min, and the injection volume is 20 μL. Elution program: from 0 min to 1 min, the volume percentage of phase B is 20%. From 1 min to 3 min, the volume percentage of phase B increases to 70%. From 3 min to 9 min, the volume percentage of phase B increases to 100%. From 9 min to 11 min, the volume percentage of phase B remains at 100%. From 11 min to 11.1 min, the volume percentage of phase B drops to 20%. From 11.1 min to 15 min, the volume percentage of phase B remains at 20%. The conditions for the mass spectrometry detection include: the ion source is an electrospray (ESI) ionization source, the ion mode is the negative ion mode, the pressure of the curtain gas is 35 psi, the voltage of the ion source is -4500 V, the pressure of the nebulizing gas is 55 psi, the pressure of the auxiliary gas is 55 psi, and the temperature of the auxiliary gas is 550 °C.

[0063] In this embodiment, the high performance liquid chromatography tandem mass spectrometry detection includes high performance liquid chromatography detection and mass spectrometry detection, which can improve the detection sensitivity and the accuracy of the detection results.

[0064] Optionally, the high performance liquid chromatography detection uses a high performance liquid chromatograph (HPLC), and the mass spectrometry detection uses a triple quadrupole mass spectrometer. Compared with the fluorescence detection method in the related technology, this embodiment improves the detection sensitivity and the accuracy of the detection results through the high performance liquid chromatography tandem mass spectrometry detection.

[0065] In this embodiment, phase A is an aqueous ammonium fluoride solution. Specifically, phase A is 0.2 mM ammonium fluoride (NH 4F) Aqueous solution. The chromatographic column used is a C18 column. Specifically, a 2.7-micron particle size (2.7-Micron) C18 chromatographic column with dimensions of 2.1×100 mm can be used. The column temperature is from 30°C to 40°C. Specifically, the column temperature can be 30°C, 35°C, 40°C, or other values between 30°C and 40°C. The flow rate is from 0.1 mL / min to 0.6 mL / min. Specifically, the flow rate can be 0.1 mL / min, 0.4 mL / min, 0.6 mL / min, or other values between 0.1 mL / min and 0.6 mL / min. The injection volume is 20 μL, which can improve the sensitivity of the instrument.

[0066] In this embodiment, gradient elution is used for elution. Specifically, as Figure 3 shown, from 0 min to 1 min, the volume percentage of phase B is 20%. From 1 min to 3 min, the volume percentage of phase B increases to 70%. From 3 min to 9 min, the volume percentage of phase B increases to 100%. From 9 min to 11 min, the volume percentage of phase B remains at 100%. From 11 min to 11.1 min, the volume percentage of phase B drops to 20%.

[0067] In this embodiment, by setting the above-mentioned mass spectrometry detection conditions, the detection sensitivity and the reliability of the detection results can be improved.

[0068] In some embodiments, the preset standard curve is: the linear relationship equation of the ratio of the peak area of the target compound to the peak area of the internal standard, and the ratio of the concentration of the target compound to the concentration of the internal standard.

[0069] Specifically, for each target compound, the preset standard curve is: the linear relationship equation of the ratio of the peak area of this target compound to the peak area of the internal standard, and the ratio of the concentration of this target compound to the concentration of the internal standard. That is to say, each target compound corresponds to a preset standard curve. In actual application, the concentration of the internal standard is known. Substituting the peak area of the target compound and the peak area of the internal standard into the corresponding preset standard curve equation, the concentration of the target compound can be obtained, realizing the determination of the content of the target compound.

[0070] In some embodiments, the internal standard is bisphenol A-D4.

[0071] In this embodiment, during high performance liquid chromatography-tandem mass spectrometry detection, the system error can be corrected by the ratio of the peak area of bisphenol A-D4 to the peak area of the target compound, improving the accuracy of quantitative analysis.

[0072] In actual application, the complex solution can be mixed with 10 μL of an internal standard of bisphenol A-D4 with a concentration of 1 ppm to obtain a mixed solution.

[0073] Exemplarily, the internal standard is bisphenol A-D4, and the target compounds include one or more of bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol.

[0074] In some embodiments, in the step of flowing the sample to be tested through a solid-phase extraction column for extraction, the flow rate of the sample to be tested is 4 mL / min to 6 mL / min.

[0075] Specifically, the flow rate of the sample to be tested is 4 mL / min, 5 mL / min, 6 mL / min, or other values between 4 mL / min and 6 mL / min, so that the target compounds are effectively adsorbed on the solid-phase extraction column. For example, the sample to be tested can flow through the solid-phase extraction column at a rate of 12 drops every 5 seconds.

[0076] In some embodiments, after the step of preparing the sample to be tested and the solid-phase extraction column, the detection method further includes: filtering the sample to be tested. Acidifying the filtered sample to be tested.

[0077] In this embodiment, the sample to be tested is filtered to remove insoluble impurities in the sample to be tested. For example, when the sample to be tested is surface water, the sample to be tested can be filtered through a quartz filter membrane with a pore size of 0.45 μm.

[0078] In this embodiment, the filtered sample to be tested is acidified so that the pH value of the sample to be tested ranges from 1 to 2 to improve the detection accuracy and efficiency. Specifically, hydrochloric acid can be added to the sample to be tested to acidify the filtered sample to be tested and adjust the pH value of the sample to be tested to range from 1 to 2.

[0079] In practical applications, after acidifying the filtered sample to be tested, 4-nonylphenol-D4 can be added to the acidified sample to be tested as a recovery standard for calibrating 4-linear nonylphenol. Specifically, 10 μL of 4-nonylphenol-D4 with a concentration of 1 ppm can be added to the acidified sample to be tested, and the system error can be calibrated by the ratio of the peak area of 4-nonylphenol-D4 to the peak area of 4-linear nonylphenol, improving the accuracy of the detection result of 4-linear nonylphenol.

[0080] As Figure 2 shown, another embodiment of the present disclosure provides a method for detecting phenolic compounds. The method for detecting phenolic compounds includes the following steps:

[0081] S201. Prepare a sample to be tested and a solid-phase extraction column, and the sample to be tested contains target compounds.

[0082] S202. Filter the sample to be tested.

[0083] S203. Acidify the filtered sample to be measured.

[0084] S204. Activate the solid-phase extraction column, where the activation treatment uses methanol and acidic water.

[0085] S205. The sample to be measured flows through the solid-phase extraction column for extraction, so that the target compound is adsorbed on the solid-phase extraction column.

[0086] S206. Wash the solid-phase extraction column, and the washing treatment uses acidic water.

[0087] S207. Dry the solid-phase extraction column after the washing treatment.

[0088] S208. Desorb the target compound adsorbed on the solid-phase extraction column to obtain a desorbed solution, where the desorption treatment uses methanol.

[0089] S209. Concentrate the desorbed solution to obtain a concentrated solution.

[0090] S210. Re-dissolve the concentrated solution with methanol water to obtain a re-dissolved solution.

[0091] S211. Mix the re-dissolved solution with an internal standard to obtain a mixed solution.

[0092] S212. Perform high performance liquid chromatography-tandem mass spectrometry detection on the mixed solution to obtain the peak area of the target compound and the peak area of the internal standard.

[0093] S213. Obtain the concentration of the target compound according to the peak area of the target compound, the peak area of the internal standard, and the preset standard curve.

[0094] A specific example:

[0095] The mixed solution contains a target compound, a recovery standard, and an internal standard. Among them, the target compounds include bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol. The internal standard is bisphenol A-D4. The recovery standard is 4-nonylphenol-D4. As shown in Table 1, set the ion pair information of the target compound, the recovery standard, and the internal standard. The ion pair information includes the mass-to-charge ratio (Q1) of the parent ion and the mass-to-charge ratio (Q3) of the daughter ion obtained after the parent ion collides. Among them, Q3 can have multiple, and different values of Q3 can be different, so as to identify the target compound, the recovery standard, and the internal standard during high performance liquid chromatography-tandem mass spectrometry detection.

[0096] As shown in Table 1, for 4-butylphenol, Q1 is set to 149 and Q3 is set to 106. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 149 and Q3 is 106, it is determined that the compound is 4-butylphenol.

[0097] As shown in Table 1, for 4-heptylphenol, Q1 is set to 191.1 and Q3 is set to 106. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 191.1 and Q3 is 106, it is determined that the compound is 4-heptylphenol.

[0098] As shown in Table 1, for 4-hexylphenol, Q1 is set to 177.1 and Q3 is set to 106. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 177.1 and Q3 is 106, it is determined that the compound is 4-hexylphenol.

[0099] Table 1 Ion pair information

[0100]

[0101] As shown in Table 1, for 4-nonylphenol-D4, Q1 is set to 223.1 and Q3 is set to 110. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 223.1 and Q3 is 110, it is determined that the compound is 4-nonylphenol-D4.

[0102] As shown in Table 1, for 4-linear nonylphenol, Q1 is set to 219.1 and Q3 is set to 106. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 219.1 and Q3 is 106, it is determined that the compound is 4-linear nonylphenol.

[0103] As shown in Table 1, for 4-octylphenol, Q1 is set to 205.1 and Q3 is set to 106. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 205.1 and Q3 is 106, it is determined that the compound is 4-octylphenol.

[0104] As shown in Table 1, for branched nonylphenol, Q1 is set to 219.1. Among multiple Q3 values, some Q3 values are 133 and some Q3 values are 147. That is to say, during the detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 219.1 and Q3 is 133, and also satisfies that Q1 is 219.1 and Q3 is 147, it is determined that the compound is branched nonylphenol.

[0105] As shown in Table 1, for 4-pentylphenol, Q1 is set to 163.1 and Q3 is set to 106. That is to say, during detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 163.1 and Q3 is 106, it is determined that the compound is 4-pentylphenol.

[0106] As shown in Table 1, for 4-tert-butylphenol, Q1 is set to 149 and Q3 is set to 133. That is to say, during detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 149 and Q3 is 133, it is determined that the compound is 4-tert-butylphenol.

[0107] As shown in Table 1, for 4-tert-octylphenol, Q1 is set to 205.1. Among multiple Q3 values, some Q3 values are 133 and some Q3 values are 134. That is to say, during detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 205.1 and Q3 is 133, and also satisfies that Q1 is 205.1 and Q3 is 134, it is determined that the compound is 4-tert-octylphenol.

[0108] As shown in Table 1, for bisphenol A-D4, Q1 is set to 231.1. Among multiple Q3 values, some Q3 values are 135 and some Q3 values are 216.1. That is to say, during detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 231.1 and Q3 is 135, and also satisfies that Q1 is 231.1 and Q3 is 216.1, it is determined that the compound is bisphenol A-D4.

[0109] As shown in Table 1, for bisphenol A, Q1 is set to 227.1. Among multiple Q3 values, some Q3 values are 133.1 and some Q3 values are 211.1. That is to say, during detection, when the ion pair information of the compound recognized by the mass spectrometer satisfies that Q1 is 227.1 and Q3 is 133.1, and also satisfies that Q1 is 227.1 and Q3 is 211.1, it is determined that the compound is bisphenol A.

[0110] In practical applications, the dwell time (DWELL), declustering potential (DP), and collision energy (CE) of ions in the mass spectrometer can also be set according to different compounds, which helps to identify the types of compounds.

[0111] Another specific example:

[0112] The target compounds of the sample to be tested include bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol. The internal standard is bisphenol A-D4. When the concentration range of each target compound is 0.01 ppb to 500 ppb, the preset standard curves of each target compound are shown in Table 2.

[0113] In Table 2, the preset standard curve equation of bisphenol A is y1 = 0.52608x1. Where x1 represents the ratio of the concentration of bisphenol A to the concentration of bisphenol A-D4, and y1 represents the ratio of the peak area of bisphenol A to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.999, and 0.999 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the samples to be tested with the concentration range of bisphenol A from 0.01 ppb to 500 ppb.

[0114] In Table 2, the preset standard curve equation of 4-tert-butylphenol is y2 = 0.35855x2. Where x2 represents the ratio of the concentration of 4-tert-butylphenol to the concentration of bisphenol A-D4, and y2 represents the ratio of the peak area of 4-tert-butylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.999, and 0.999 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the samples to be tested with the concentration range of 4-tert-butylphenol from 0.01 ppb to 500 ppb.

[0115] Table 2 Preset Standard Curves

[0116] Compound Preset standard curve Fitting coefficient r2 Concentration range Bisphenol A y1 = 0.52608x1 0.999 0.01 - 500 ppb 4-tert-Butylphenol y2 = 0.35855x2 0.999 0.01 - 500 ppb 4-Butylphenol y3 = 1.00007x3 0.998 0.01 - 500 ppb 4-Pentylphenol y4 = 1.22763x4 0.998 0.01 - 500 ppb 4-Hexylphenol y5 = 1.34907x5 0.997 0.01 - 500 ppb 4-tert-Octylphenol y6 = 0.82438x6 0.997 0.01 - 500 ppb 4-Octylphenol y7 = 1.35481x7 0.996 0.01 - 500 ppb 4-Heptylphenol y8 = 1.38561x8 0.996 0.01 - 500 ppb Branched nonylphenol y9 = 1.58700x9 0.997 0.01 - 500 ppb 4-Linear nonylphenol Y10 = 1.19345x10 0.997 0.01 - 500 ppb

[0117] In Table 2, the preset standard curve equation of 4-butylphenol is y3 = 1.00007x3. Where x3 represents the ratio of the concentration of 4-butylphenol to the concentration of bisphenol A-D4, and y3 represents the ratio of the peak area of 4-butylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.998, and 0.998 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the samples to be tested with the concentration range of 4-butylphenol from 0.01 ppb to 500 ppb.

[0118] In Table 2, the preset standard curve equation for 4-pentylphenol is y4 = 1.22763x4. Here, x4 represents the ratio of the concentration of 4-pentylphenol to the concentration of bisphenol A-D4, and y4 represents the ratio of the peak area of 4-pentylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.998, and 0.998 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of 4-pentylphenol from 0.01 ppb to 500 ppb.

[0119] In Table 2, the preset standard curve equation for 4-hexylphenol is y5 = 1.34907x5. Here, x5 represents the ratio of the concentration of 4-hexylphenol to the concentration of bisphenol A-D4, and y5 represents the ratio of the peak area of 4-hexylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.997, and 0.997 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of 4-hexylphenol from 0.01 ppb to 500 ppb.

[0120] In Table 2, the preset standard curve equation for 4-tert-octylphenol is y6 = 0.82438x6. Here, x6 represents the ratio of the concentration of 4-tert-octylphenol to the concentration of bisphenol A-D4, and y6 represents the ratio of the peak area of 4-tert-octylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.997, and 0.997 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of 4-tert-octylphenol from 0.01 ppb to 500 ppb.

[0121] In Table 2, the preset standard curve equation for 4-octylphenol is y7 = 1.35481x7. Here, x7 represents the ratio of the concentration of 4-octylphenol to the concentration of bisphenol A-D4, and y7 represents the ratio of the peak area of 4-octylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.996, and 0.996 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of 4-octylphenol from 0.01 ppb to 500 ppb.

[0122] In Table 2, the preset standard curve equation for 4-heptylphenol is y8 = 1.38561x8. Among them, x8 represents the ratio of the concentration of 4-heptylphenol to the concentration of bisphenol A-D4, and y8 represents the ratio of the peak area of 4-heptylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.996, and 0.996 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of 4-heptylphenol from 0.01 ppb to 500 ppb.

[0123] In Table 2, the preset standard curve equation for branched nonylphenol is y9 = 1.58700x9. Among them, x9 represents the ratio of the concentration of branched nonylphenol to the concentration of bisphenol A-D4, and y9 represents the ratio of the peak area of branched nonylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.997, and 0.997 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of branched nonylphenol from 0.01 ppb to 500 ppb.

[0124] In Table 2, the preset standard curve equation for 4-linear nonylphenol is y10 = 1.19345x10. Among them, x10 represents the ratio of the concentration of 4-linear nonylphenol to the concentration of bisphenol A-D4, and y10 represents the ratio of the peak area of 4-linear nonylphenol to the peak area of bisphenol A-D4. The fitting coefficient r of this preset standard curve 2 is 0.997, and 0.997 is greater than 0.995 (reference standard), indicating that the reliability of this preset standard curve is relatively high. This preset standard curve equation is applicable to the test samples with the concentration range of 4-linear nonylphenol from 0.01 ppb to 500 ppb.

[0125] Example 1

[0126] Prepare the test sample A. The target compounds in the test sample A include bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol, and 4-linear nonylphenol. As shown in Table 3, prepare 200 mL of the test sample A, and the spiked concentrations of each target compound in the test sample A are as follows: the spiked concentration of 4-butylphenol is 8.46 ng / L, the spiked concentration of 4-heptylphenol is 8.00 ng / L, the spiked concentration of 4-hexylphenol is 8.28 ng / L, the spiked concentration of 4-linear nonylphenol is 8.60 ng / L, the spiked concentration of 4-octylphenol is 8.09 ng / L, the spiked concentration of branched nonylphenol is 8.02 ng / L, the spiked concentration of 4-pentylphenol is 8.39 ng / L, the spiked concentration of 4-tert-butylphenol is 8.51 ng / L, the spiked concentration of 4-tert-octylphenol is 8.44 ng / L, and the spiked concentration of bisphenol A is 9.16 ng / L. It can be understood that the spiked concentration of each target compound in the test sample A is between 0.01 ng / L and 30 ng / L, which is a low concentration.

[0127] In this example, 9 groups of the test sample A are prepared for 9 parallel detections. The detections are carried out over 3 days, with 3 detections per day. The specific detection process is as follows:

[0128] Filter the test sample using a quartz filter membrane with a pore size of 0.45 μm. Add hydrochloric acid to the test sample to adjust the pH value of the test sample to between 1 and 2.

[0129] Add 10 μL of 4-nonylphenol-D4 with a concentration of 1 ppm to the test sample as a recovery standard.

[0130] Activate the solid-phase extraction column with 5 mL of methanol and 5 mL of acidic water with a pH value of 2 ± 0.1.

[0131] Flow the test sample through the solid-phase extraction column at a flow rate of 4 mL / min to 6 mL / min for extraction, so that the target compounds are adsorbed on the solid-phase extraction column.

[0132] Wash the solid-phase extraction column with 5 mL of acidic water with a pH value of 2 ± 0.1.

[0133] Dry the washed solid-phase extraction column using a vacuum pump for 90 minutes.

[0134] Elute the target compounds adsorbed on the solid-phase extraction column with 6 mL of methanol to obtain a desorption solution.

[0135] Concentrate the desorption solution using a nitrogen evaporator to obtain 1 mL of concentrated solution.

[0136] Add 200 μL of methanol-water to the concentrated solution to obtain a reconstituted solution. Among them, in the methanol-water, the volume ratio of methanol to water is 1:1.

[0137] Add 10 μL of bisphenol A-D4 with a concentration of 50 ng / L as an internal standard to the reconstituted solution to obtain a mixture.

[0138] Use a high performance liquid chromatograph (HPLC) and a triple quadrupole mass spectrometer to perform high performance liquid chromatography tandem mass spectrometry detection on the mixture. The specific detection conditions are as follows.

[0139] The conditions for high performance liquid chromatography detection include:

[0140] Mobile phase: Phase A is an aqueous solution of 0.2 mM ammonium fluoride (NH 4 F), and phase B is methanol.

[0141] Chromatographic column: Use a 2.1×100 mm C18 chromatographic column with a particle size of 2.7 microns (2.7-Micron).

[0142] Liquid phase parameters: The column temperature is maintained at 40 °C, the flow rate is 0.4 mL / min, and the injection volume is 20 μL.

[0143] As Figure 3 shown, the elution program:

[0144] From 0 min to 1 min, the volume percentage of phase B is 20%.

[0145] From 1 min to 3 min, the volume percentage of phase B increases to 70%.

[0146] From 3 min to 9 min, the volume percentage of phase B increases to 100%.

[0147] From 9 min to 11 min, the volume percentage of phase B remains at 100%.

[0148] From 11 min to 11.1 min, the volume percentage of phase B drops to 20%.

[0149] From 11.1 min to 15 min, the volume percentage of phase B remains at 20%.

[0150] The conditions for mass spectrometry detection include: The ion source is an electrospray (ESI) ionization source, the ion mode is the negative ion mode, the pressure of the curtain gas is 35 psi, the voltage of the ion source is -4500 V, the pressure of the nebulizing gas is 55 psi, the pressure of the auxiliary gas is 55 psi, and the temperature of the auxiliary gas is 550 °C.

[0151] On the first day, three tests are conducted. Among them, for the first test, the detected concentration of the target compound is recorded as A1. For the second test, the detected concentration of the target compound is recorded as A2. For the third test, the detected concentration of the target compound is recorded as A3. Similarly, on the second day, three tests are conducted, and the detected concentrations of the target compound in the three tests are respectively recorded as A4, A5, and A6. On the third day, three tests are conducted, and the detected concentrations of the target compound in the three tests are respectively recorded as A7, A8, and A9.

[0152] Table 3 Sample A to be measured

[0153]

[0154] As shown in Table 3, among A1 to A9: the detected concentrations of 4-butylphenol are 7.41 ng / L, 8.34 ng / L, 7.72 ng / L, 8.16 ng / L, 8.71 ng / L, 10.10 ng / L, 8.67 ng / L, 8.31 ng / L, and 8.75 ng / L respectively. The detected concentrations of 4-heptylphenol are 6.24 ng / L, 7.11 ng / L, 6.81 ng / L, 6.31 ng / L, 6.72 ng / L, 8.39 ng / L, 7.97 ng / L, 7.66 ng / L, and 8.02 ng / L respectively. The detected concentrations of 4-hexylphenol are 7.23 ng / L, 8.38 ng / L, 7.32 ng / L, 7.44 ng / L, 7.73 ng / L, 9.34 ng / L, 8.52 ng / L, 8.13 ng / L, and 8.87 ng / L respectively. The detected concentrations of 4-linear nonylphenol are 3.72 ng / L, 6.16 ng / L, 5.95 ng / L, 6.55 ng / L, 5.59 ng / L, 6.56 ng / L, 7.15 ng / L, 4.57 ng / L, and 5.66 ng / L respectively. The detected concentrations of 4-octylphenol are 5.39 ng / L, 4.36 ng / L, 5.34 ng / L, 4.38 ng / L, 4.26 ng / L, 6.57 ng / L, 6.73 ng / L, 5.75 ng / L, and 6.41 ng / L respectively. The detected concentrations of branched nonylphenol are 6.79 ng / L, 7.61 ng / L, 8.56 ng / L, 5.99 ng / L, 6.49 ng / L, 8.41 ng / L, 6.18 ng / L, 5.93 ng / L, and 7.31 ng / L respectively. The detected concentrations of 4-pentylphenol are 7.67 ng / L, 8.52 ng / L, 7.77 ng / L, 7.91 ng / L, 8.24 ng / L, 9.12 ng / L, 8.57 ng / L, 8.24 ng / L, and 8.44 ng / L respectively. The detected concentrations of 4-tert-butylphenol are 7.39 ng / L, 8.22 ng / L, 7.91 ng / L, 6.96 ng / L, 8.36 ng / L, 9.30 ng / L, 7.50 ng / L, 7.64 ng / L, and 7.89 ng / L respectively. The detected concentrations of 4-tert-octylphenol are 8.57 ng / L, 9.21 ng / L, 8.89 ng / L, 7.87 ng / L, 8.79 ng / L, 10.47 ng / L, 8.58 ng / L, 9.42 ng / L, and 9.53 ng / L respectively. The detected concentrations of bisphenol A are 7.29 ng / L, 6.89 ng / L, 6.37 ng / L, 8.50 ng / L, 7.66 ng / L, 9.52 ng / L, 6.66 ng / L, 6.84 ng / L, and 7.59 ng / L respectively.

[0155] In this embodiment, according to the spiked concentration of the target compound and each detection concentration among A1 to A9, the recovery rate of the target compound is calculated according to the following formula.

[0156]

[0157] Taking 4-butylphenol as an example, the calculation process of the recovery rate is as follows: The average value of each (9) detection concentration of 4-butylphenol = (7.41 + 8.34 + 7.72 + 8.16 + 8.71 + 10.10 + 8.67 + 8.31 + 8.75) / 9 = 8.46 ng / L. The spiked concentration of 4-butylphenol is 8.46 ng / L. The recovery rate of 4-butylphenol = (8.46 / 8.46)×100% = 100%. Similarly, the recovery rates of each target compound are shown in Table 6. Specifically, the recovery rate of 4-heptylphenol is 90.6%, the recovery rate of 4-hexylphenol is 97.9%, the recovery rate of 4-linear nonylphenol is 67.0%, the recovery rate of 4-octylphenol is 67.5%, the recovery rate of branched nonylphenol is 87.7%, the recovery rate of 4-pentylphenol is 98.6%, the recovery rate of 4-tert-butylphenol is 92.9%, the recovery rate of 4-tert-octylphenol is 107.1%, and the recovery rate of bisphenol A is 81.6%. It can be seen that the recovery rate of each target compound is greater than 65%, that is, the method of this embodiment has good accuracy when detecting low-concentration samples to be measured.

[0158] In this embodiment, according to the spiked concentration of the target compound and the detection concentrations for 3 days (i.e., each detection concentration among A1 to A9), the within-day precision of the target compound is calculated according to the following steps.

[0159] The three detection concentration values of a certain target compound detected on the nth day are Sn1, Sn2, and Sn3 respectively, where n is 1, 2, 3,....

[0160] Calculate the average value Sn0 of Sn1, Sn2, and Sn3.

[0161] Calculate the standard deviation Xn1 of Sn1, Sn2, and Sn3.

[0162]

[0163] Calculate the within-day precision Pn of this target compound on the nth day = Xn1 / Sn0.

[0164] Among them, the minimum value of the within-day precision of this target compound for n days is the within-day precision of this target compound.

[0165] Next, taking 4-butylphenol as an example, with 3 detections per day for 3 days, the calculation process of the within-day precision of 4-butylphenol is as follows:

[0166] On the first day, the three detected concentration values of 4-butylphenol were S11 = 7.41 ng / L, S12 = 8.34 ng / L, and S13 = 7.72 ng / L respectively. On the second day, the three detected concentration values of 4-butylphenol were S21 = 8.16 ng / L, S22 = 8.71 ng / L, and S23 = 10.10 ng / L respectively. On the third day, the three detected concentration values of 4-butylphenol were S31 = 8.67 ng / L, S32 = 8.31 ng / L, and S33 = 8.75 ng / L respectively.

[0167] Calculate the average value S10 of the three detected concentrations on the first day: S10 = (7.41 + 8.34 + 7.72) / 3 = 7.82 ng / L. Calculate the average value S20 of the three detected concentrations on the second day: S20 = (8.16 + 8.71 + 10.1) / 3 = 8.99 ng / L. Calculate the average value S30 of the three detected concentrations on the third day: S30 = (8.67 + 8.31 + 8.75) / 3 = 8.58 ng / L.

[0168] Calculate the standard deviation of the three detected concentrations on the first day:

[0169]

[0170] Calculate the standard deviation of the three detected concentrations on the second day:

[0171]

[0172] Calculate the standard deviation of the three detected concentrations on the third day:

[0173]

[0174] Calculate the within-day precision P1 of 4-butylphenol on the first day: P1 = (X11 / S10)×100% = (0.39 / 7.82)×100% = 4.9%.

[0175] Calculate the within-day precision P2 of 4-butylphenol on the second day: P2 = (X21 / S20)×100% = (X21 / 8.99)×100% = 9.1%.

[0176] Calculate the within-day precision P3 of 4-butylphenol on the third day: P3 = (X31 / S30)×100% = (X31 / 8.58)×100% = 2.2%.

[0177] Among them, the minimum value of the within-day precision of 4-butylphenol in three days is 2.2%, that is, the within-day precision of 4-butylphenol is 2.2%.

[0178] Similarly, the within-day precision of each target compound was calculated as shown in Table 6. Specifically, the within-day precision of 4-heptylphenol was 2.0%, that of 4-hexylphenol was 3.5%, that of 4-linear nonylphenol was 7.3%, that of 4-octylphenol was 6.5%, that of branched nonylphenol was 9.3%, that of 4-pentylphenol was 1.6%, that of 4-tert-butylphenol was 2.1%, that of 4-tert-octylphenol was 2.9%, and that of bisphenol A was 5.5%. It can be seen that the within-day precision of each target compound is less than 15%, that is, when the method of this example is used to detect low-concentration samples to be tested, the consistency is good, stable and reliable.

[0179] In this example, based on the calculation of the within-day precision of the target compound, the within-day precision of the target compound was calculated as follows.

[0180] According to the average value Sn0 of the three detection concentrations of a certain target compound detected on the nth day, calculate the average value T of the detection concentrations of this target compound detected in n days.

[0181] Calculate the between-day standard deviation of this target compound:

[0182]

[0183] Calculate the between-day precision of this target compound = (Y1 / T) × 100%.

[0184] Next, taking 4-butylphenol as an example, with 3 detections per day for 3 days, the calculation process of the between-day precision of 4-butylphenol is as follows:

[0185] The three detection concentration values of 4-butylphenol detected on the first day were S11 = 7.41 ng / L, S12 = 8.34 ng / L, and S13 = 7.72 ng / L. The three detection concentration values of 4-butylphenol detected on the second day were S21 = 8.16 ng / L, S22 = 8.71 ng / L, and S23 = 10.10 ng / L. The three detection concentration values of 4-butylphenol detected on the third day were S31 = 8.67 ng / L, S32 = 8.31 ng / L, and S33 = 8.75 ng / L.

[0186] Calculate the average value S10 of the three detected concentrations on the 1st day: S10 = (7.41 + 8.34 + 7.72) / 3 = 7.82 ng / L. Calculate the average value S20 of the three detected concentrations on the 2nd day: S20 = (8.16 + 8.71 + 10.1) / 3 = 8.99 ng / L. Calculate the average value S30 of the three detected concentrations on the 3rd day: S30 = (8.67 + 8.31 + 8.75) / 3 = 8.58 ng / L.

[0187] According to S10, S20 and S30, calculate the average value T of the detected concentrations of 4-butylphenol detected in 3 days: T = (S10 + S20 + S30) / 3 = (7.82 + 8.99 + 8.58) / 3 = 8.46 ng / L.

[0188] Calculate the inter-day standard deviation of 4-butylphenol:

[0189]

[0190] Calculate the inter-day precision of 4-butylphenol = (Y1 / 8.46)×100% = 5.7%.

[0191] Similarly, the inter-day precision of each target compound is calculated as shown in Table 6. Specifically, the inter-day precision of 4-heptylphenol is 6.6%, the inter-day precision of 4-hexylphenol is 4.4%, the inter-day precision of 4-linear nonylphenol is 6.8%, the inter-day precision of 4-octylphenol is 10.7%, the inter-day precision of branched nonylphenol is 6.9%, the inter-day precision of 4-pentylphenol is 2.5%, the inter-day precision of 4-tert-butylphenol is 2.8%, the inter-day precision of 4-tert-octylphenol is 1.3%, and the inter-day precision of bisphenol A is 10.3%. It can be seen that the inter-day precision of each target compound is less than 15%, that is, when the method of this example is used to detect low-concentration samples to be detected, the consistency is good, stable and reliable.

[0192] Example 2

[0193] The detection process of this example is the same as that of Example 1, except that the spiked concentration of each target compound in the sample to be detected is different, as follows.

[0194] Prepare the sample B to be tested. As shown in Table 4, prepare 200 mL of the sample B to be tested. The spiked concentrations of each target compound in the sample B to be tested are as follows: the spiked concentration of 4-butylphenol is 47.81 ng / L, the spiked concentration of 4-heptylphenol is 44.54 ng / L, the spiked concentration of 4-hexylphenol is 45.44 ng / L, the spiked concentration of 4-linear nonylphenol is 41.79 ng / L, the spiked concentration of 4-octylphenol is 42.74 ng / L, the spiked concentration of branched nonylphenol is 43.45 ng / L, the spiked concentration of 4-pentylphenol is 47.58 ng / L, the spiked concentration of 4-tert-butylphenol is 47.44 ng / L, the spiked concentration of 4-tert-octylphenol is 46.48 ng / L, and the spiked concentration of bisphenol A is 48.03 ng / L. It can be understood that the spiked concentration of each target compound in the sample B to be tested is between 30 ng / L and 80 ng / L, which is a medium concentration.

[0195] In this example, 9 groups of the sample B to be tested are prepared for 9 parallel detections. The detections are carried out in 3 days, with 3 detections per day. The specific detection process is as follows:

[0196] On the first day, 3 detections are carried out. During the 3 detections, the detected concentrations of the target compounds are recorded as B1, B2, and B3 respectively. On the second day, 3 detections are carried out. During the 3 detections, the detected concentrations of the target compounds are recorded as B4, B5, and B6 respectively. On the third day, 3 detections are carried out. During the 3 detections, the detected concentrations of the target compounds are recorded as B7, B8, and B9 respectively.

[0197] As shown in Table 4, among B1 to B9, the detected concentrations of 4-butylphenol are 41.71 ng / L, 42.09 ng / L, 38.24 ng / L, 38.44 ng / L, 40.04 ng / L, 40.54 ng / L, 40.29 ng / L, 42.92 ng / L, and 42.17 ng / L respectively. The detected concentrations of 4-heptylphenol are 38.25 ng / L, 37.87 ng / L, 34.54 ng / L, 33.34 ng / L, 34.55 ng / L, 36.83 ng / L, 38.67 ng / L, 41.65 ng / L, and 39.94 ng / L respectively. The detected concentrations of 4-hexylphenol are 42.66 ng / L, 43.47 ng / L, 39.35 ng / L, 38.24 ng / L, 38.44 ng / L, 39.89 ng / L, 43.12 ng / L, 44.35 ng / L, and 44.76 ng / L respectively. The detected concentrations of 4-linear nonylphenol are 37.52 ng / L, 26.68 ng / L, 26.81 ng / L, 25.45 ng / L, 24.05 ng / L, 33.47 ng / L, 33.98 ng / L, 34.73 ng / L, and 29.90 ng / L respectively. The detected concentrations of 4-octylphenol are 29.28 ng / L, 29.35 ng / L, 23.62 ng / L, 23.64 ng / L, 25.02 ng / L, 25.78 ng / L, 32.78 ng / L, 33.14 ng / L, and 29.93 ng / L respectively. The detected concentrations of branched nonylphenol are 37.95 ng / L, 38.80 ng / L, 34.54 ng / L, 30.86 ng / L, 34.36 ng / L, 34.67 ng / L, 37.58 ng / L, 37.11 ng / L, and 36.38 ng / L respectively. The detected concentrations of 4-pentylphenol are 42.49 ng / L, 43.51 ng / L, 39.30 ng / L, 38.60 ng / L, 38.57 ng / L, 41.44 ng / L, 40.57 ng / L, 42.33 ng / L, and 42.33 ng / L respectively. The detected concentrations of 4-tert-butylphenol are 44.95 ng / L, 43.12 ng / L, 42.07 ng / L, 43.58 ng / L, 46.81 ng / L, 44.11 ng / L, 46.59 ng / L, 47.17 ng / L, and 46.50 ng / L respectively. The detected concentrations of 4-tert-octylphenol are 45.08 ng / L, 45.90 ng / L, 41.13 ng / L, 39.65 ng / L, 39.82 ng / L, 41.85 ng / L, 46.03 ng / L, 46.46 ng / L, and 46.85 ng / L respectively.The detected concentrations of bisphenol A were 38.87 ng / L, 39.51 ng / L, 37.59 ng / L, 43.54 ng / L, 40.59 ng / L, 39.10 ng / L, 38.00 ng / L, 39.10 ng / L, and 38.49 ng / L, respectively.

[0198] Table 4 Test sample B

[0199]

[0200] In this embodiment, the recoveries, within-day precisions, and between-day precisions of the target compounds are shown in Table 6, as follows.

[0201] As can be seen from Table 6, the recovery of 4-butylphenol was 85.2%, the recovery of 4-heptylphenol was 83.7%, the recovery of 4-hexylphenol was 91.5%, the recovery of 4-linear nonylphenol was 72.5%, the recovery of 4-octylphenol was 65.6%, the recovery of branched nonylphenol was 82.4%, the recovery of 4-pentylphenol was 86.2%, the recovery of 4-tert-butylphenol was 94.8%, the recovery of 4-tert-octylphenol was 93.9%, and the recovery of bisphenol A was 82.1%. The recovery of each target compound was greater than 65%. It can be seen that the method of this embodiment has good accuracy when detecting test samples with medium concentrations.

[0202] As can be seen from Table 6, the within-day precision of 4-butylphenol was 2.3%, the within-day precision of 4-heptylphenol was 3.0%, the within-day precision of 4-hexylphenol was 1.6%, the within-day precision of 4-linear nonylphenol was 6.5%, the within-day precision of 4-octylphenol was 3.6%, the within-day precision of branched nonylphenol was 1.3%, the within-day precision of 4-pentylphenol was 2.0%, the within-day precision of 4-tert-butylphenol was 0.6%, the within-day precision of 4-tert-octylphenol was 0.7%, and the within-day precision of bisphenol A was 1.2%. It can be seen that the within-day precision of each target compound was less than 15%. That is, the method of this embodiment has good consistency, stability, and reliability when detecting test samples with medium concentrations.

[0203] As can be seen from Table 6, the inter-day precision of 4-butylphenol is 2.1%, that of 4-heptylphenol is 5.7%, that of 4-hexylphenol is 5.1%, that of 4-linear nonylphenol is 7.0%, that of 4-octylphenol is 10.5%, that of branched nonylphenol is 5.0%, that of 4-pentylphenol is 2.5%, that of 4-tert-butylphenol is 3.1%, that of 4-tert-octylphenol is 5.7%, and that of bisphenol A is 3.0%. It can be seen that the inter-day precision of each target compound is less than 15%. That is, when the method of this example is used to detect the samples to be tested with medium concentration, the consistency is good, stable and reliable.

[0204] Example 3

[0205] The detection process of this example is the same as that of Example 1, except that the spiked concentrations of each target compound in the samples to be tested are different, as follows.

[0206] Prepare the sample to be tested C. As shown in Table 5, prepare 200 mL of the sample to be tested C, and the spiked concentrations of each target compound in the sample to be tested C are as follows: the spiked concentration of 4-butylphenol is 84.30 ng / L, the spiked concentration of 4-heptylphenol is 79.13 ng / L, the spiked concentration of 4-hexylphenol is 81.39 ng / L, the spiked concentration of 4-linear nonylphenol is 79.80 ng / L, the spiked concentration of 4-octylphenol is 80.92 ng / L, the spiked concentration of branched nonylphenol is 77.83 ng / L, the spiked concentration of 4-pentylphenol is 81.74 ng / L, the spiked concentration of 4-tert-butylphenol is 85.00 ng / L, the spiked concentration of 4-tert-octylphenol is 78.80 ng / L, and the spiked concentration of bisphenol A is 81.97 ng / L. It can be understood that the spiked concentration of each target compound in the sample to be tested C is between 70 ng / L and 100 ng / L, which is a high concentration.

[0207] In this example, 9 groups of the sample to be tested C are prepared for 9 parallel detections. The detections are carried out for 3 days, and 3 detections are carried out every day. The specific detection process is as follows:

[0208] Three detections are carried out on the first day. During the three detections, the detected concentrations of the target compounds are recorded as C1, C2, and C3 respectively. Three detections are carried out on the second day. During the three detections, the detected concentrations of the target compounds are recorded as C4, C5, and C6 respectively. Three detections are carried out on the third day. During the three detections, the detected concentrations of the target compounds are recorded as C7, C8, and C9 respectively.

[0209] As shown in Table 5, among C1 to C9: the detected concentrations of 4-butylphenol are 74.31 ng / L, 69.65 ng / L, 72.75 ng / L, 82.23 ng / L, 80.90 ng / L, 80.28 ng / L, 82.86 ng / L, 81.20 ng / L, and 76.78 ng / L respectively. The detected concentrations of 4-heptylphenol are 68.87 ng / L, 64.83 ng / L, 67.25 ng / L, 80.95 ng / L, 78.25 ng / L, 77.87 ng / L, 77.37 ng / L, 74.59 ng / L, and 72.37 ng / L respectively. The detected concentrations of 4-hexylphenol are 76.33 ng / L, 73.18 ng / L, 74.44 ng / L, 88.41 ng / L, 85.19 ng / L, 85.56 ng / L, 86.81 ng / L, 84.15 ng / L, and 79.85 ng / L respectively. The detected concentrations of 4-linear nonylphenol are 67.87 ng / L, 66.06 ng / L, 85.47 ng / L, 87.53 ng / L, 78.51 ng / L, 90.63 ng / L, 77.85 ng / L, 77.37 ng / L, and 79.75 ng / L respectively. The detected concentrations of 4-octylphenol are 52.65 ng / L, 50.20 ng / L, 56.61 ng / L, 68.06 ng / L, 60.92 ng / L, 61.25 ng / L, 57.43 ng / L, 53.85 ng / L, and 51.45 ng / L respectively. The detected concentrations of branched nonylphenol are 59.20 ng / L, 59.71 ng / L, 64.78 ng / L, 77.67 ng / L, 74.13 ng / L, 75.14 ng / L, 76.05 ng / L, 75.32 ng / L, and 73.24 ng / L respectively. The detected concentrations of 4-pentylphenol are 76.17 ng / L, 71.39 ng / L, 73.88 ng / L, 86.54 ng / L, 82.08 ng / L, 80.78 ng / L, 85.98 ng / L, 84.00 ng / L, and 79.82 ng / L respectively. The detected concentrations of 4-tert-butylphenol are 73.80 ng / L, 69.73 ng / L, 71.86 ng / L, 85.77 ng / L, 86.32 ng / L, 79.48 ng / L, 87.53 ng / L, 86.80 ng / L, and 79.99 ng / L respectively. The detected concentrations of 4-tert-octylphenol are 75.58 ng / L, 71.04 ng / L, 76.21 ng / L, 88.31 ng / L, 83.72 ng / L, 84.36 ng / L, 92.53 ng / L, 85.33 ng / L, and 81.69 ng / L respectively.The detected concentrations of bisphenol A were 68.91 ng / L, 64.15 ng / L, 69.89 ng / L, 81.65 ng / L, 79.20 ng / L, 80.38 ng / L, 77.07 ng / L, 74.58 ng / L, and 73.03 ng / L, respectively.

[0210] Table 5 Test sample C

[0211]

[0212] In this embodiment, the recoveries, intra-day precisions, and inter-day precisions of the target compounds are shown in Table 6 as follows.

[0213] As can be seen from Table 6, the recovery of 4-butylphenol was 92.4%, the recovery of 4-heptylphenol was 93.0%, the recovery of 4-hexylphenol was 100.2%, the recovery of 4-linear nonylphenol was 99.0%, the recovery of 4-octylphenol was 70.4%, the recovery of branched nonylphenol was 90.7%, the recovery of 4-pentylphenol was 99.0%, the recovery of 4-tert-butylphenol was 94.3%, the recovery of 4-tert-octylphenol was 104.2%, and the recovery of bisphenol A was 90.7%. It can be seen that the recovery of each target compound is greater than 65%. That is, when the method of this embodiment is used to detect high-concentration test samples, the accuracy is good.

[0214] As can be seen from Table 6, the intra-day precision of 4-butylphenol was 1.0%, the intra-day precision of 4-heptylphenol was 1.7%, the intra-day precision of 4-hexylphenol was 1.7%, the intra-day precision of 4-linear nonylphenol was 1.3%, the intra-day precision of 4-octylphenol was 4.5%, the intra-day precision of branched nonylphenol was 1.6%, the intra-day precision of 4-pentylphenol was 2.6%, the intra-day precision of 4-tert-butylphenol was 2.3%, the intra-day precision of 4-tert-octylphenol was 2.4%, and the intra-day precision of bisphenol A was 1.2%. It can be seen that the intra-day precision of each target compound is less than 15%. That is, when the method of this embodiment is used to detect medium-concentration test samples, the consistency is good, stable and reliable.

[0215] Table 6 Recoveries and precisions

[0216]

[0217] As can be seen from Table 6, the inter-day precision of 4-butylphenol is 5.1%, that of 4-heptylphenol is 6.8%, that of 4-hexylphenol is 6.1%, that of 4-linear nonylphenol is 6.4%, that of 4-octylphenol is 8.1%, that of branched nonylphenol is 9.4%, that of 4-pentylphenol is 5.5%, that of 4-tert-butylphenol is 7.4%, that of 4-tert-octylphenol is 6.7%, and that of bisphenol A is 7.0%. It can be seen that the inter-day precision of each target compound is less than 15%. That is, when the method of this embodiment is used to detect the samples to be tested with medium concentration, the consistency is good, stable and reliable.

[0218] In summary, the detection method of this embodiment is applicable to the detection of the contents of target compounds with low, medium and high concentrations. Moreover, the target compounds with low, medium and high concentrations can be accurately and efficiently determined within the same linear range (concentration range: 0.01 - 500 ppb). The detection method of this embodiment improves the detection efficiency while improving the accuracy of the detection results, and is stable and reliable.

[0219] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present application, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A method for detecting phenolic compounds, characterized in that: The steps include: Preparing a sample to be tested and a solid phase extraction column, wherein the sample to be tested contains a target compound; The solid phase extraction column is subjected to activation treatment, wherein the activation treatment uses methanol and acidic water; Allowing the sample to be tested to flow through the solid phase extraction column for extraction, so that the target compound is adsorbed on the solid phase extraction column; Desorbing the target compound adsorbed by the solid phase extraction column to obtain a desorbed liquid, wherein the desorption process uses methanol; The desorption liquid is quantitatively analyzed to obtain the content of the target compound.

2. The detection method according to claim 1, characterized in that: Before the step of desorbing the target compound adsorbed by the solid phase extraction column, the detection method further comprises: The solid phase extraction column is subjected to elution treatment, wherein the elution treatment adopts acidic water; The solid phase extraction column after elution treatment is drained.

3. The detection method according to claim 2, characterized in that: The pH value of the acidic water is 2±0.

1.

4. The detection method according to any one of claims 1 to 3, characterized in that: The step of quantitatively analyzing the desorption liquid to obtain the content of the target compound comprises: Concentrating the desorption liquid to obtain a concentrated liquid; re-dissolving the concentrated solution with methanol water to obtain a re-solution; Mixing the complex solution with an internal standard to obtain a mixed solution; The mixed solution is subjected to high performance liquid chromatography tandem mass spectrometry detection to obtain the peak area of ​​the target compound and the peak area of ​​the internal standard; The concentration of the target compound is obtained according to the peak area of ​​the target compound, the peak area of ​​the internal standard and a preset standard curve.

5. The detection method according to claim 4, characterized in that: The high performance liquid chromatography tandem mass spectrometry detection includes high performance liquid chromatography detection and mass spectrometry detection; The conditions for the high performance liquid chromatography detection include: Mobile phase: Phase A is ammonium fluoride aqueous solution, Phase B is methanol; Chromatographic column: C18 column; Liquid phase parameters: column temperature is 30°C to 40°C, flow rate is 0.1mL / min to 0.6mL / min, injection volume is 20μL; Elution program: 0min to 1min, the volume percentage of the B phase is 20%; 1min to 3min, the volume percentage of the B phase increases to 70%; 3min to 9min, the volume percentage of the B phase increases to 100%; 9min to 11min, the volume percentage of the B phase is maintained at 100%; 11min to 11.1min, the volume percentage of the B phase decreases to 20%; 11.1min to 15min, the volume percentage of the B phase is maintained at 20%; The conditions for mass spectrometry detection include: The ion source is an electrospray ionization source, the ion mode is a negative ion mode, the pressure of the curtain gas is 35 psi, the voltage of the ion source is -4500 V, the pressure of the nebulizer gas is 55 psi, the pressure of the auxiliary gas is 55 psi, and the temperature of the auxiliary gas is 550°C.

6. The detection method according to claim 4, characterized in that: The preset standard curve is: a linear relationship equation of the ratio of the peak area of ​​the target compound to the peak area of ​​the internal standard, and the ratio of the concentration of the target compound to the concentration of the internal standard.

7. The detection method according to claim 4, characterized in that: The internal standard is bisphenol A-D4.

8. The detection method according to any one of claims 1 to 3, characterized in that: In the step of allowing the sample to be tested to flow through the solid phase extraction column for extraction, the flow rate of the sample to be tested is 4 mL / min to 6 mL / min.

9. The detection method according to any one of claims 1 to 3, characterized in that: After the steps of preparing the sample to be tested and the solid phase extraction column, the detection method further comprises: filtering the sample to be tested; The filtered sample to be tested is acidified.

10. The detection method according to any one of claims 1 to 3, characterized in that: The target compound includes one or more of bisphenol A, 4-tert-butylphenol, 4-butylphenol, 4-pentylphenol, 4-hexylphenol, 4-tert-octylphenol, 4-octylphenol, 4-heptylphenol, branched nonylphenol and 4-straight nonylphenol.

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