Method for rapidly determining haloacetic acid and oxyhalide

Abstract

The invention discloses a method for rapidly determining haloacetic acid and oxyhalide, and belongs to the technical field of water quality analysis and detection. The method for rapidly determining haloacetic acid and oxyhalide comprises the following steps: S1, detecting a water sample to be detected by adopting liquid chromatography-mass spectrometry; wherein acetonitrile is added into the water sample to be detected, and the volume fraction of the acetonitrile is 15-50%; the chromatographic column is an AG18 chromatographic column; the phase A of the mobile phase is an ammonia water solution with the concentration of 0.3-3 mol / L; the phase B of the mobile phase is acetonitrile or methanol; the volume fraction of the phase A in the mobile phase is 5-50%; and S2, substituting the detected peak area of the substance into the standard working curve to calculate the concentration of the target substance.

Description

Technical Field

[0001] The present invention belongs to the technical field of water quality analysis and detection, and more specifically, relates to a method for rapidly determining haloacetic acids and halogen oxides. Background Art

[0002] Haloacetic acids are one of the most common disinfection by-products in drinking water, with concentrations in drinking water reaching dozens to hundreds of μg / L, and they are the carbon-containing disinfection by-products second only to trihalomethanes in content. However, haloacetic acids are more toxic than trihalomethanes and are difficult to volatilize, posing a greater threat to drinking water safety and human health. Halogen oxides are an important class of inorganic DBPs, mainly including BrO3 - , ClO3 - and ClO4 - . For example, bromate (BrO3 - ) is the most important disinfection by-product during the ozonation of water bodies containing a relatively high concentration of Br−. In addition, bromate (BrO3 - ) is a Group 2B carcinogen. The "Hygienic Standard for Drinking Water" (GB / T 5749-2006) in China has limited the concentrations of dichloroacetic acid, trichloroacetic acid, and bromate, and their maximum limits are 50 μg / L, 100 μg / L, and 10 μg / L, respectively. Establishing a sensitive, simple, and rapid analytical method for haloacetic acids and halogen oxides is the basis for understanding the pollution status of these substances in drinking water and their potential health risks.

[0003] Currently, there are many methods for determining haloacetic acids. The most mainstream methods are the standard method provided by the US Environmental Protection Agency (USEPA, 552.3) and the standard test method "Standard Test Methods for Drinking Water - Part 10: Disinfection By-Product Indicators" (GB / T 5750-2023) supporting the "Hygienic Standard for Drinking Water" in China. Both of these detection methods require derivatization of water samples and then gas chromatography detection. These methods have problems such as complex operation processes, low enrichment multiples, and high detection limits, and thus need to be further improved.

[0004] At present, many researchers at home and abroad have improved the standard methods. The patent document (Patent No.: 201810740490.7) "A Gas Chromatography Method for Determining Nine Trace Haloacetic Acids in Barreled Drinking Water" enriches haloacetic acids by means of dispersive solid-phase extraction and finally uses gas chromatography for detection. The extraction materials for this method are difficult to obtain and have a high price. It involves multiple extractions and elutions, and the process is cumbersome. The patent document (Patent No.: 201610060522.X) "A Method for Simultaneously Determining the Contents of Trihalomethanes and Haloacetic Acids in Drinking Water" requires acidifying the water sample to be measured, enhancing the polarity of the water sample to be measured and then performing extraction and derivatization. Bromate has high toxicity, and the limit value specified for it in the drinking water hygiene standard is low. It often needs to be enriched to remove the interference of other substances. For example, the patent document (Patent No.: 202111558375.6) "A Method for Determining Bromate in Drinking Water Using an Ion Chromatography On-line Matrix Elimination System" requires a more sensitive test technology to achieve its accurate quantification.

[0005] In addition, since haloacetic acids are a type of disinfection by-products in drinking water and have potential health risks. During the drinking water treatment and monitoring process, quickly and accurately determining the content of haloacetic acids can promptly detect whether the haloacetic acids in the water quality exceed the standard. Once an abnormality is found, measures can be taken quickly. Rapid analysis of haloacetic acids can more efficiently evaluate the pollution status of water bodies and the sewage treatment effect. Shortening the analysis time means that more samples can be processed within the same time, improving the laboratory work efficiency. This can not only save labor costs but also reduce the occupation time of instrument equipment and improve the equipment utilization rate. For example, for some large-scale water quality monitoring projects, if the analysis speed is slow, more manpower and time may be required to complete the task, while improving the analysis speed can reduce these costs. Or, in the event of a sudden water pollution incident, such as accidental pollution of the water source, etc., quickly analyzing the content of pollutants such as haloacetic acids is crucial for formulating emergency treatment plans. Being able to accurately determine the content of haloacetic acids within a short time helps relevant departments quickly understand the pollution degree and take targeted countermeasures to reduce the losses and impacts caused by the pollution. In addition, in the related research of haloacetic acids, such as studying its formation mechanism, degradation law, etc., a rapid and accurate analysis method can enable researchers to conduct more groups of experiments in a shorter time, thereby more deeply understanding the formation law of haloacetic acids.

[0006] Considering that in actual production, haloacetic acids and halogen oxides often need to be analyzed simultaneously. If they can be analyzed simultaneously, it can greatly shorten the detection time required. In addition, it is of great practical significance to improve the speed and / or accuracy of the test results. Summary of the Invention

[0007] 1. Problems to be Solved

[0008] In view of the problems of complex pretreatment and long time consumption for the analysis of haloacetic acids in the prior art, the present invention provides a method for rapidly determining haloacetic acids and halooxides, which can simultaneously analyze haloacetic acids and halooxides.

[0009] 2. Technical solution

[0010] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0011] The first aspect of the present invention provides a method for rapidly determining haloacetic acids and halooxides, comprising:

[0012] S1. Detecting the water sample to be tested by liquid chromatography-mass spectrometry;

[0013] Among them,

[0014] The chromatographic column is an AG18 chromatographic column;

[0015] The A phase of the mobile phase is an ammonia water solution with a concentration of 0.3 - 3 mol / L;

[0016] The B phase of the mobile phase is acetonitrile or methanol;

[0017] The volume fraction of the A phase in the mobile phase is 5 - 50%;

[0018] S2. Substituting the peak area of the detected substance into the standard working curve to calculate the concentration of the target substance.

[0019] As mentioned herein, the "concentration of the ammonia water solution in the A phase of the mobile phase" will affect the retention time and response intensity of the analyte on the chromatographic column. If the concentration is too high, the chromatographic peaks of the analyte cannot be separated; if the concentration is too low, the chromatographic peaks of the analyte will be too low or no chromatographic peaks will appear. Based on this, according to any embodiment of the first aspect of the object of the present invention, the A phase of the mobile phase is preferably an ammonia water solution with a concentration of 0.4 - 2.5 mol / L; further preferably, the A phase of the mobile phase is an ammonia water solution with a concentration of 0.5 - 2.0 mol / L.

[0020] In addition, the "volume fraction of the A phase in the mobile phase" will also affect the peak shape and retention time of the analyte chromatographic peak. If the volume is too large, the retention time will be too short; if the volume is too low, the analyte chromatographic peak will be very wide and the retention time will be too long. Based on this, according to any embodiment of the first aspect of the object of the present invention, the volume fraction of the A phase in the mobile phase is preferably 10 - 45%.

[0021] Further preferably, the volume fraction of the A phase in the mobile phase is 15 - 40%.

[0022] The "acetonitrile added to the water sample to be tested" as described herein can reduce the interference of dissolved organic matter and chloride ions in water, and part of the dissolved organic matter in the water sample is absorbed into the acetonitrile; further, if the "volume fraction of acetonitrile added to the water sample to be tested" is too high, the interference of inorganic ions will increase, and if the concentration is too low, the interference cannot be eliminated. Based on this, according to any embodiment of the first aspect of the object of the present invention, acetonitrile is added to the water sample to be tested, and the volume fraction of the acetonitrile is 15-50%;

[0023] Preferably, in the water sample to be tested, the volume fraction of acetonitrile is 18-47%.

[0024] More preferably, in the water sample to be tested, the volume fraction of acetonitrile is 20-45%.

[0025] According to any embodiment of the first aspect of the object of the present invention, it further includes the steps of performing solid impurity removal and residual chlorine removal treatment on the water sample to be tested.

[0026] According to any embodiment of the first aspect of the object of the present invention, it further includes the steps of filtering and residual chlorine removal treatment on the water sample to be tested.

[0027] According to any embodiment of the first aspect of the object of the present invention, the pore size of the filter membrane used for filtration is 0.22-0.45 μm.

[0028] According to any embodiment of the first aspect of the object of the present invention, it further includes the step of drawing a standard working curve.

[0029] According to any embodiment of the first aspect of the object of the present invention, the drawing of the standard working curve includes:

[0030] 1) Preparation of standard solutions: Prepare a series of standard solutions with known concentrations and concentration gradients containing haloacetic acids and halogen oxides, and control the concentration of each disinfection by-product to be measured in the same standard solution to be the same;

[0031] 2) Detection of standard solutions: Use liquid chromatography-mass spectrometry to detect the prepared standard solutions;

[0032] 3) Data analysis: Taking the concentration of each disinfection by-product as the abscissa and the peak area as the ordinate, draw the standard working curves of haloacetic acids and halogen oxides respectively.

[0033] According to any embodiment of the first aspect of the object of the present invention, the mass concentrations of the standard solutions may be, for example: 0.5 μg / L, 1 μg / L, 5 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, and 100 μg / L respectively; or they may also be 1 μg / L, 5 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, 100 μg / L, and 200 μg / L respectively.

[0034] According to any embodiment of the first aspect of the object of the present invention, the haloacetic acids include but are not limited to trichloroacetic acid (TCAA), dichloroacetic acid (DCAA);

[0035] The halooxides include but are not limited to bromate (BrO3 - )

[0036] According to any embodiment of the first aspect of the object of the present invention, when detecting by liquid chromatography - mass spectrometry, the elution order of haloacetic acids and halooxides is in sequence: trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), bromate (BrO3 - )

[0037] According to any embodiment of the first aspect of the object of the present invention, the A - phase and B - phase of the mobile phase are mixed and run according to a volume - ratio gradient.

[0038] According to any embodiment of the first aspect of the object of the present invention, within the initial 1.2 minutes (0 - 1.2 minutes), the gradient starts from 5% by volume of the A - phase;

[0039] Then, within the next 0.1 minute, it increases to 25 - 30% by volume of the A - phase and maintains this ratio for 2 - 3 minutes;

[0040] After that, the volume fraction of the A - phase decreases to 5% within 0.1 minute, and before the next sample injection, the system is equilibrated for 1 minute.

[0041] According to any embodiment of the first aspect of the object of the present invention, within the initial 1.2 minutes (0 - 1.2 minutes), the gradient starts from 5% by volume of the A - phase;

[0042] Then, within the next 0.1 minute, it increases to 25% by volume of the A - phase and maintains this ratio for 2 minutes;

[0043] After that, the volume fraction of the A - phase decreases to 5% within 0.1 minute, and before the next sample injection, the system is equilibrated for 1 minute.

[0044] According to any embodiment of the first aspect of the object of the present invention, the liquid chromatography conditions are as follows:

[0045] Flow rate: 0.15 - 0.35 mL / min;

[0046] Injection volume: 5 - 15 μL;

[0047] Column temperature: 30 °C.

[0048] According to any embodiment of the first aspect of the object of the present invention, the mass spectrometry uses triple quadrupole mass spectrometry and an electrospray ion source, and the ion source parameters are:

[0049] Curtain gas is 28 - 32 L / min;

[0050] Collision gas is medium speed, and the temperature is 420 - 480 °C;

[0051] Ion source gas 1 is 36 - 45 L / min;

[0052] Ion source gas 2 is 36 - 45 L / min.

[0053] According to any embodiment of the first aspect of the object of the present invention, the mass spectrometry uses triple quadrupole mass spectrometry and an electrospray ion source, and the ion source parameters are:

[0054] Curtain gas is 30 L / min;

[0055] Collision gas is medium speed, and the temperature is 450 °C;

[0056] Ion source gas 1 is 40 L / min;

[0057] Ion source gas 2 is 40 L / min.

[0058] According to any embodiment of the first aspect of the object of the present invention, the liquid chromatography conditions are that the parameters of the multiple reaction monitoring mode are:

[0059] Declustering potential (DP): -80 - -20 V;

[0060] Entrance potential (EP): -18 - -5 V;

[0061] Collision energy (CE): -40 - -8 eV;

[0062] And collision cell exit potential (CXP): -16 - -5 V;

[0063] Dwell time: 50 - 150 ms.

[0064] Advantageous effects

[0065] Compared with the prior art, the advantageous effects of the present invention are:

[0066] (1) The method for rapid determination of haloacetic acids and halooxides provided by the present invention uses an AG18 chromatographic column as the analytical column, which can greatly shorten the analysis time and measure a larger number of samples within a certain period of time.

[0067] Meanwhile, compared with the liquid chromatography-mass spectrometry method using a reversed-phase chromatographic column or a hydrophilic chromatographic column for separation, the method for rapid determination of haloacetic acids and halooxides provided by the present invention has the advantages of low detection limit and strong anti-interference ability, and has strong anti-interference ability against common anions such as sulfate ions.

[0068] (2) The method for rapid determination of haloacetic acids and halooxides provided by the present invention uses an AG18 chromatographic column as the analytical column. On this basis, the alkaline eluent (phase A) in its mobile phase can be replaced with an ammonia water solution, and the ammonia water solution is used for elution. Compared with methylamine, sodium hydroxide, potassium hydroxide, etc., the ammonia water solution has weak alkaline corrosiveness and can be used on the widely popular liquid chromatography-mass spectrometry system without additional ion suppression system.

[0069] (3) The method for rapid determination of haloacetic acids and halooxides provided by the present invention has a simple pretreatment step for the water sample to be measured. By adding acetonitrile and supplemented with operations such as filtration, it can meet the injection requirements and the accuracy of the detection results of liquid chromatography-mass spectrometry; compared with the treatment of the water sample to be measured in the existing gas chromatography or gas chromatography-mass spectrometry detection method for haloacetic acids (HAAs), the water sample to be measured in the method of the present invention can be directly injected after simple membrane filtration, without cumbersome sample pretreatment steps such as liquid-liquid extraction and derivatization, saving time and effort.

[0070] (4) The method for rapid determination of haloacetic acids and halooxides provided by the present invention uses a liquid chromatography-mass spectrometry instrument, the mobile phase uses ammonia water and acetonitrile, the mass spectrometry selects the negative ion mode, and the analytical column uses AG18. Compared with the existing ion chromatography method for bromate, the method of the present invention has the advantages of low detection limit and strong anti-interference ability. Description of the Drawings

[0071] Figure 1 It is the chromatogram of dichloroacetic acid, trichloroacetic acid and bromate during separation by the AG18 chromatographic column in Example 1. Detailed Embodiments

[0072] The present disclosure can be more easily understood by referring to the following description in conjunction with the drawings and examples, all of which form a part of the present disclosure. It should be understood that the present disclosure is not limited to the specific products, methods, conditions or parameters described and / or illustrated herein. Further, the terms used herein are for the purpose of describing specific embodiments by way of example only and are not intended to be limiting unless otherwise specified.

[0073] It should also be understood that, for clarity, certain features of the present disclosure may be described herein in the context of separate embodiments, but may also be provided in combination with each other in a single embodiment. That is, unless clearly incompatible or specifically excluded, each individual embodiment is considered combinable with any other embodiment, and such combination is considered to represent another distinct embodiment. Conversely, for the sake of brevity, the various features of the present disclosure described in the context of a single embodiment may also be provided separately or in any sub-combination. Finally, although a particular embodiment may be described as part of a series of steps or part of a more general structure, each step or sub-structure itself may also be considered an independent embodiment.

[0074] Unless otherwise stated, it should be understood that each individual element in a list and each combination of the individual elements in that list will be construed as a different embodiment. For example, a list of embodiments represented as "A, B, or C" should be construed as including the embodiments "A", "B", "C", "A or B", "A or C", "B or C", or "A, B, or C".

[0075] In the present disclosure, the singular forms of the articles "a", "an", and "the" also include the corresponding plural referents, and a reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Thus, for example, a reference to "a substance" is a reference to at least one of such substance and its equivalents.

[0076] When items are described by use of the conjunctive term "…… and / or ……" etc., the description should be understood to include any one of the associated listed items and all combinations of one or more of them.

[0077] Generally, the use of the term "about" indicates an approximation that may vary depending on the desired properties obtained from the disclosed subject matter and will be interpreted in a context-dependent manner based on function. Thus, one of ordinary skill in the art will be able to interpret a certain degree of variance on a case-by-case basis. In some cases, the number of significant digits used in expressing a particular value may be a representative technique for determining the variance allowed by the term "about". In other cases, a gradient within a series of values may be used to determine the range of variance allowed by the term "about". Further, all ranges in the present disclosure are inclusive and combinable, and a reference to a value stated in a range includes each value within that range.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs; the terms used herein and / or include any and all combinations of one or more of the associated listed items.

[0079] In the analysis method of the present invention, an AB SCIEX QTRAP 5500 mass spectrometer is used for mass spectrometry, the ion source is an electrospray ionization source (ESI), and the triple quadrupole mass spectrometry adopts a flow injection injection mode to inject a single standard sample, that is, two haloacetic acids including dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) and BrO3 - , determine the mass-to-charge ratios (m / z) of the parent ions and daughter ions of each target compound, and then optimize the declustering potential (DP), focusing potential (FP), entrance potential (EP), collision energy (CE) and collision cell exit potential (CXP) of the negative ion multiple reaction monitoring mode (MRM). The optimized multiple reaction monitoring mode parameters for each target compound are shown in Table 1. Each analyte uses two ion channels.

[0080] Table 1 Multiple reaction monitoring mode parameters for dichloroacetic acid, trichloroacetic acid and BrO3 -

[0081]

[0082]

[0083] The present invention will be further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. The essential features and remarkable effects of the present invention can be reflected from the following embodiments. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, they do not limit the present invention. Those skilled in the art make some non-essential improvements and adjustments based on the content of the present invention, which all belong to the protection scope of the present invention.

[0084] Example 1

[0085] Standard curve and quantification limit

[0086] 1) Preparation of standard solution: Mix known concentrations of dichloroacetic acid, trichloroacetic acid and BrO3 - to prepare a mixed standard solution with the same concentration of each single disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and acetonitrile (80:20, v / v) to prepare standard working solutions with mass concentrations of 0.5, 1, 5, 10, 20, 50 and 100 μg / L;

[0087] ​2) The separation column used is an AG 18 anion analytical column (2×50 mm) from Thermo Fisher Scientific, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A is 0.7 mol / L ammonia aqueous solution, and mobile phase B is acetonitrile. The liquid phase uses gradient elution mode as shown in Table 2;

[0088] Table 2 Liquid Phase Gradient Elution Program Table

[0089]

[0090] 3) The mass spectrometer used is a QTRAP 5500 mass spectrometer from AB SCIEX. The ion source is an electrospray ionization source (ESI). The triple quadrupole mass spectrometer injects a single standard sample using the flow injection injection mode, namely two haloacetic acids including dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) and BrO3 - . The mass spectrometer uses the multiple reaction monitoring mode. The ion source parameters are: curtain gas is 30 L / min, collision gas is medium speed, temperature is 450 °C, ion source gas 1 is 40 L / min, and ion source gas 2 is 40 L / min;

[0091] 4) In the mixed standard solution, calibration curves are constructed for each analyte in the concentration range of 0.5 μg / L to 100 μg / L. By performing eight repeated measurements on the mixed standard containing DCAA, TCAA, and BrO3 - , the detection limit and quantification limit of the newly established gradient elution, non-suppressed IC-ESI-MS / MS method based on the AG18 column are determined. The concentrations of DCAA, TCAA, and BrO3 - in the mixed standard are 1.0 μg / L, 1.0 μg / L, and 0.5 μg / L respectively;

[0092] 5) Using the concentration of each disinfection by-product in the standard solution as the abscissa and the peak area as the ordinate, standard working curves are plotted respectively. The results are shown in Table 3. All target analytes achieved satisfactory linearity, and the determination coefficient (R 2 ) is higher than 0.995.

[0093] Table 3 Standard Curves and Correlation Coefficient R of Three Disinfection By-Products 2

[0094] Equation <![CDATA[Linear coefficient (R 2 )]]> DCAA y = 1438.42x + 756.62 0.9956 TCAA y = 464.74x + 392.48 0.9978 <![CDATA[BrO3 - > y = 816.63x + 589.25 0.9990

[0095] 6) The limit of detection (LOD) was calculated as the standard deviation (SD) × Student's t-value. The measurements were taken 8 times with a degree of freedom of n - 1 = 7. At a 99% confidence level, t was 3, so LOD = 3 × SD. The limit of quantification (LOQ) was calculated as 3 × LOD. The calculation results are shown in Table 4. All three analytes exhibited relatively low limits of quantification: 1.13 μg / L for DCAA, 0.92 μg / L for TCAA, and - 0.48 μg / L for BrO3

[0096] Table 4 Sensitivity of three disinfection by-products in this method

[0097]

[0098] Example 2

[0099] Multiple measurements of a water sample, within-day deviation and between-day deviation

[0100] 1) Preparation of standard solution: Mix dichloroacetic acid, trichloroacetic acid, and BrO3 - with known concentrations to prepare a mixed standard solution with the same concentration of each disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and acetonitrile (75:25, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L;

[0101] 2) The separation column used was an AG 18 anion analytical column (2 × 50 mm) from ThermoFlsherScientitific, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A was 1.0 mol / L ammonia aqueous solution, and mobile phase B was acetonitrile. The liquid phase used gradient elution, as shown in Table 2 in Example 1;

[0102] 3) The mass spectrometry conditions were the same as in Example 1;

[0103] 4) Analysis steps: Measure 3 standard working solutions of 5 μg / L at 9 am on the first day, 3 standard working solutions of 5 μg / L at 1 pm, and 3 standard working solutions of 5 μg / L at 5 pm; measure 3 standard working solutions of 5 μg / L at 9 am on the second day; measure 3 standard working solutions of 5 μg / L at 9 am on the third day;

[0104] 5) The test results are shown in Table 5. It can be seen from the table that the within-day and between-day deviations are both less than 10%, and the method has good stability.

[0105] Table 5 Stability of Three Kinds of Disinfection By-products in This Method

[0106]

[0107] Example 3

[0108] Recovery Rate Test in Tap Water

[0109] 1) Preparation of Tap Water and Standard Solution: After quenching the residual chlorine with 100 mg / L ammonium chloride, the water sample was filtered through a 0.45-μm filter membrane. 0.25 mL of acetonitrile was added to 1 mL of tap water to make the ratio of water to acetonitrile (80:20, v / v). The known concentrations of dichloroacetic acid, trichloroacetic acid, and BrO3 - were mixed to prepare a mixed standard solution with the same concentration of each single disinfection by-product, placed in a brown injection vial, and then the prepared solution was diluted with tap water and acetonitrile (80:20, v / v) to prepare standard working solutions with mass concentrations of 5 μg / L, 20 μg / L, and 40 μg / L;

[0110] 2) The separation column used was an AG 18 anion analytical column (2 × 50 mm) from ThermoFlsherScientitific, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A was 1.5 mol / L ammonia aqueous solution, and mobile phase B was acetonitrile. The liquid phase used gradient elution mode as shown in Table 2 in Example 1;

[0111] 3) The mass spectrometry conditions were the same as those in Example 1;

[0112] 4) Analysis procedure: After measuring the concentration of disinfection by-products in tap water, the concentration of the spiked sample was measured, and the recovery rate was calculated;

[0113] 5) The test results are shown in Table 6 below. The low, medium, and high concentration spike recoveries of the three disinfection by-products in tap water were good, all between 75 - 110%, and the deviation between multiple measurements was small, between 2.4 - 4.9%.

[0114] Table 6 Recovery Rates of Three Kinds of Disinfection By-products in Tap Water

[0115]

[0116]

[0117] Comparative Example 3-1

[0118] Comparative Test of Recovery Rate in Tap Water

[0119] This comparative example was basically the same as Example 3, with the only difference being:

[0120] In the "Step 1) Preparation of tap water and standard solution", the tap water used no longer undergoes the operation of "adding 0.25 mL of acetonitrile so that the ratio of water to acetonitrile is (80:20, v / v)", that is, the addition amount of acetonitrile is 0%;

[0121] The remaining steps 1) to 4) are the same as those in Example 3;

[0122] The test results are shown in Table 7 below. The recovery rates of the three disinfection by-products at low, medium, and high concentrations in tap water become worse, and some of the spiked recovery rates are lower than 60% and higher than 120%.

[0123] Table 7 Recovery rates of three disinfection by-products in tap water

[0124]

[0125] Comparative Example 3-2

[0126] Comparative test of recovery rate in tap water

[0127] This comparative example is basically the same as Example 3, with the only difference being:

[0128] When performing "Step 2) Liquid chromatography detection", mobile phase A is 0.4 mol / L ammonia aqueous solution;

[0129] The remaining steps 1) to 4) are the same as those in Example 3;

[0130] The test results are shown in Table 8 below. The recovery rates of the three disinfection by-products at low, medium, and high concentrations in tap water become worse, and some of the spiked recovery rates are lower than 60%.

[0131] Table 8 Recovery rates of three disinfection by-products in tap water

[0132]

[0133] Comparative Example 3-3

[0134] Comparative test of recovery rate in tap water

[0135] This comparative example is basically the same as Example 3, with the only difference being:

[0136] When performing "Step 2) Liquid chromatography detection", mobile phase A is 2.2 mol / L ammonia aqueous solution;

[0137] The remaining steps 1) to 4) are the same as those in Example 3;

[0138] The test results are shown in Table 9 below. The recovery rates of the three disinfection by-products at low, medium, and high concentrations in tap water become worse, and some of the spiked recovery rates are lower than 60% and higher than 110%.

[0139] Table 9 Recovery Rates of Three Kinds of Disinfection By-products in Tap Water

[0140]

[0141] Example 4

[0142] Interference of Inorganic Ion Chloride

[0143] 1) Preparation of standard solution: Mix dichloroacetic acid, trichloroacetic acid and BrO3 with known concentrations to prepare a mixed standard solution with the same concentration of each single disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and acetonitrile (70:30, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L; - 2) Add different volumes of chloride ion standard solution to the working solution to make the chloride ion concentrations 25 μg / L, 50 μg / L, 100 μg / L and 200 μg / L;

[0144] 3) Use a ThermoFlsherScientitific AG 18 anion analytical column (2×50 mm) for the separation column, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A is 2.0 mol / L ammonia water solution, and mobile phase B is acetonitrile. The liquid phase uses gradient elution mode as shown in Table 2 of Example 1;

[0145] 4) The mass spectrometry conditions are the same as those in Example 1;

[0146] 5) The test results are as shown in Table 10 below. The recovery rates of the three kinds of disinfection by-products are all between 70% and 100% under the influence of low, medium and high concentrations of chloride ions, and the anti-chloride ion interference is good.

[0147] Table 10 Recovery Rates of Three Kinds of Disinfection By-products under Different Chloride Ion Interferences

[0148] Table 10 Recovery Rates of Three Kinds of Disinfection By-products under Different Chloride Ion Interferences

[0149]

[0150] Comparative Example 4-1

[0151] Interference of Inorganic Ion Chloride

[0152] 1) Preparation of standard solution: Mix dichloroacetic acid, trichloroacetic acid and BrO3 with known concentrations to prepare a mixed standard solution with the same concentration of each single disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and acetonitrile (40:60, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L; - 2) Add different volumes of chloride ion standard solution to the working solution to make the chloride ion concentrations 25 μg / L, 50 μg / L, 100 μg / L and 200 μg / L;

[0153] 2) Add standard chloride solutions with different volumes to the working solution to make the chloride ion concentrations 25 μg / L, 50 μg / L, 100 μg / L, and 200 μg / L;

[0154] 3) Use an AG 18 anion analytical column (2 × 50 mm) from ThermoFlsherScientitific as the separation column, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; Mobile phase A is 2.0 mol / L ammonia aqueous solution, and mobile phase B is acetonitrile;

[0155] The liquid phase uses gradient elution as shown in Table 2 of Example 1;

[0156] 4) The mass spectrometry conditions are the same as those in Example 1;

[0157] 5) The test results are shown in Table 11 below. Compared with Example 4, the recovery rates of the three disinfection by-products in this comparative example generally decrease under the influence of low, medium, and high concentrations of chloride ions, and there are cases below 60%. This shows that the added volume fraction of acetonitrile in the water sample to be tested will affect the anti-chloride ion interference ability, and the excessive added volume fraction of acetonitrile in the water sample to be tested in this comparative example leads to poor anti-chloride ion interference.

[0158] Table 11 Recovery rates of three disinfection by-products under different chloride ion interferences

[0159]

[0160] Example 5

[0161] Inorganic ion sulfate interference

[0162] 1) Preparation of standard solution: Mix known concentrations of dichloroacetic acid, trichloroacetic acid, and BrO3 - to prepare a mixed standard solution with the same concentration of each single disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and methanol (65:35, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L;

[0163] 2) Add standard chloride solutions with different volumes to the working solution to make the sulfate ion concentrations 25 μg / L, 50 μg / L, 100 μg / L, and 200 μg / L;

[0164] 3) Use an AG 18 anion analytical column (2 × 50 mm) from ThermoFlsherScientitific as the separation column, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; Mobile phase A is 1.2 mol / L ammonia aqueous solution, and mobile phase B is acetonitrile. The liquid phase uses gradient elution as shown in Table 2 of Example 1;

[0165] 4) The mass spectrometry conditions were the same as those in Example 1;

[0166] 5) The test results are shown in Table 12 below. The recoveries of the three disinfection by-products were between 70% and 100% under the influence of low, medium, and high concentrations of sulfate ions, and the interference of sulfate ions was well resisted.

[0167] Table 12 Recoveries of Three Disinfection By-Products under Different Interferences of Sulfate Ions

[0168]

[0169]

[0170] Comparative Example 5-1

[0171] Interference of Inorganic Ion Sulfate

[0172] 1) Preparation of standard solution: Mix dichloroacetic acid, trichloroacetic acid, and BrO3 with known concentrations to prepare a mixed standard solution with the same concentration of each single disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and methanol (90:10, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L; - 2) Add different volumes of chloride ion standard solution to the working solution to make the sulfate ion concentrations 25 μg / L, 50 μg / L, 100 μg / L, and 200 μg / L;

[0173] 3) The separation column used was an AG 18 anion analytical column (2×50 mm) from ThermoFlsherScientitific, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A was 1.2 mol / L ammonia aqueous solution, and mobile phase B was acetonitrile. The liquid phase used gradient elution as shown in Table 2 in Example 1;

[0174] 3) The separation column used was an AG 18 anion analytical column (2×50 mm) from ThermoFlsherScientitific, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A was 1.2 mol / L ammonia aqueous solution, and mobile phase B was acetonitrile. The liquid phase used gradient elution as shown in Table 2 in Example 1;

[0175] 4) The mass spectrometry conditions were the same as those in Example 1;

[0176] 5) The test results are shown in Table 13 below. The recoveries of the three disinfection by-products decreased under the influence of low, medium, and high concentrations of sulfate ions, and the recovery was less than 50% under the interference of 200 μg / L sulfate ions.

[0177] Table 13 Recoveries of Three Disinfection By-Products under Different Interferences of Sulfate Ions

[0178]

[0179] Example 6

[0180] Interference of Inorganic Ion Carbonate

[0181] 1) Preparation of standard solution: Mix dichloroacetic acid, trichloroacetic acid and BrO3 with known concentrations to prepare a mixed standard solution with the same concentration of each disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and acetonitrile (55:45, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L; - 3) Add chloride ion standard solution with different volumes to the working solution to make the carbonate / bicarbonate ion concentration 1 mM, 2 mM, 4 mM and 6 mM;

[0182] 2) Add chloride ion standard solutions with different volumes to the working solution to make the carbonate / bicarbonate ion concentrations 1 mM, 2 mM, 4 mM and 6 mM;

[0183] 3) The separation column uses an AG 18 anion analytical column (2×50 mm) from ThermoFlsherScientitific, the flow rate is 0.3 mL / min, the injection volume is 10 μL, and the column temperature is 30 °C; mobile phase A is 1.2 mol / L ammonia water solution, and mobile phase B is acetonitrile. The liquid phase uses gradient elution mode as shown in Table 2 of Example 1;

[0184] 4) The mass spectrometry conditions are the same as those in Example 1;

[0185] 5) The test results are shown in Table 14 below. The recovery rates of the three disinfection by-products under the influence of low, medium and high concentrations of carbonate ions are all between 70% and 100%, and the interference of carbonate ions is well resisted.

[0186] Table 14 Recovery rates of three disinfection by-products under different carbonate interferences

[0187]

[0188] Comparative Example 6-1

[0189] Inorganic ion carbonate interference

[0190] 1) Preparation of standard solution: Mix dichloroacetic acid, trichloroacetic acid and BrO3 with known concentrations to prepare a mixed standard solution with the same concentration of each disinfection by-product, place it in a brown injection vial, and then dilute the prepared solution with ultrapure water and acetonitrile (95:5, v / v) to prepare a standard working solution with a mass concentration of 5 μg / L; - 2) Add chloride ion standard solutions with different volumes to the working solution to make the carbonate / bicarbonate ion concentrations 1 mM, 2 mM, 4 mM and 6 mM;

[0191] 3) Add chloride ion standard solution with different volumes to the working solution to make the carbonate / bicarbonate ion concentration 1 mM, 2 mM, 4 mM and 6 mM;

[0192] 3) The separation column used is an AG 18 anion analytical column (2×50 mm) from Thermo Fisher Scientific, with a flow rate of 0.3 mL / min, an injection volume of 10 μL, and a column temperature of 30 °C; mobile phase A is 1.2 mol / L ammonia aqueous solution, and mobile phase B is acetonitrile. The liquid phase uses gradient elution as shown in Table 2 of Example 1;

[0193] 4) The mass spectrometry conditions are the same as those in Example 1;

[0194] 5) The test results are as shown in Table 15 below. The recoveries of the three disinfection by-products all decrease under the influence of carbonate ions at low, medium, and high concentrations. Especially at a carbonate ion concentration of 6 mM, the recoveries of all three analytes are lower than 60%, and the recovery of bromate is lower than 50%.

[0195] Table 15 Recoveries of three disinfection by-products under different carbonate interferences

[0196]

[0197] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for rapidly determining haloacetic acid and oxyhalide, characterized in that: Includes steps: S1. Use liquid chromatography-mass spectrometry to detect the water sample to be tested; in, Acetonitrile is added to the water sample to be tested, and the volume fraction of the acetonitrile is 15-50%; The chromatographic column is an AG18 chromatographic column; Phase A of the mobile phase is a 0.3-3 mol / L ammonia solution; Phase B of the mobile phase is acetonitrile or methanol; The volume fraction of phase A in the mobile phase is 5 to 50%; S2. Substitute the peak area of ​​the detected substance into the standard working curve to calculate the concentration of the target substance.

2. The method for rapidly determining haloacetic acid and oxyhalide according to claim 1, characterized in that: The volume fraction of phase A in the mobile phase is 10 to 45%; Alternatively, the volume fraction of phase A in the mobile phase is 15-40%.

3. The method for rapid determination of haloacetic acid and oxyhalide according to any one of claims 1 to 2, characterized in that: Phase A of the mobile phase is a 0.4-2.5 mol / L ammonia solution; Alternatively, the mobile phase A is a 0.5-2.0 mol / L ammonia aqueous solution.

4. The method for rapidly determining haloacetic acid and oxyhalide according to claim 3, characterized in that: In the water sample to be tested, the volume fraction of acetonitrile is 18-47%; Alternatively, in the water sample to be tested, the volume fraction of acetonitrile is 20-45%.

5. The method for rapid determination of haloacetic acid and oxyhalide according to any one of claims 1 to 2 and 4, characterized in that: The liquid chromatography uses the mobile phase for gradient elution; The mass spectrometer uses a negative ion multiple reaction monitoring mode to scan characteristic parent ions and daughter ions of the substance to be tested.

6. The method for rapidly determining haloacetic acid and oxyhalide according to any one of claim 5, characterized in that: The mobile phase A and B are mixed and run according to a volume ratio gradient; In 0–1.2 min, the gradient started from 5% volume fraction of phase A; Then, the volume fraction of phase A was increased to 25-30% in the next 0.1 min, and this ratio was maintained for 2-3 min; Afterwards, the volume fraction of phase A was reduced to 5% within 0.1 min, and the system was equilibrated for 1 min before the next sample injection.

7. The method for rapid determination of haloacetic acid and oxyhalide according to claim 6, characterized in that: The liquid chromatography conditions are: Flow rate: 0.15~0.35mL / min; Injection volume: 5-15 μL; Column temperature: 30℃.

8. The method for rapid determination of haloacetic acid and oxyhalide according to claim 5, characterized in that: The mass spectrometer uses a triple quadrupole mass spectrometer and an electrospray ion source, and the ion source parameters are: Curtain air is 28-32L / min; The collision gas is of medium speed and the temperature is 420-480°C; Ion source gas 1 is 36-45 L / min; The ion source gas 2 is 36-45 L / min.

9. The method for rapidly determining haloacetic acid and oxyhalide according to any one of claims 1 to 2, 4, 6 to 9, characterized in that: The mode parameters of the multiple reaction monitoring are: Declustering voltage: -80~-20V; Inlet voltage: -18~-5V; Collision energy: -40~-8eV; Collision chamber exit voltage: -16~-5V; Dwell time: 50~150ms.

10. The method for rapid determination of haloacetic acid and oxyhalide according to any one of claims 1 to 2, characterized in that: The method further comprises the step of drawing a standard working curve, wherein the drawing of the standard working curve comprises: 1) Preparation of standard solutions: Prepare a series of standard solutions containing haloacetic acid and oxyhalide with known concentrations and a concentration gradient, and control the concentration of each disinfection byproduct to be tested in the same standard solution to be the same; 2) Detection of standard solution: Detection is performed using a prepared standard solution coupled with liquid chromatography-mass spectrometry; 3) Data analysis: With the concentration of each disinfection by-product as the horizontal axis and the peak area as the vertical axis, the standard working curves of haloacetic acid and halogen oxide were drawn respectively.

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