Application of thiosalicylic acid in the detection of 3-chloro-1,2-propanediol

Abstract

The present application embodiment proposes the use of thiosalicylic acid in detecting 3-chloro-1,2-propylene glycol. The present application embodiment uses thiosalicylic acid as a derivatization reagent, and 3-chloro-1,2-propylene glycol and thiosalicylic acid undergo a nucleophilic substitution reaction to generate 3-(2-carboxymethylphenylthio)-1,2-propylene glycol. Among them, the 3-(2-carboxymethylphenylthio)-1,2-propylene glycol generated by derivatization is very easy to separate in high performance liquid chromatography, and the purpose of separation and detection can be achieved through high performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve detection accuracy; Therefore, the detection method of the present application embodiment is not only easy to operate, but also can effectively improve separation effect, detection accuracy and precision.

Description

Technical Field

[0001] The present application relates to the technical field of analytical chemistry, and in particular to the use of thiosalicylic acid in detecting 3-chloro-1,2-propanediol. Background Art

[0002] 3-Chloro-1,2-propanediol is also called chloroglycerol, abbreviated as 3-MCPD. 3-MCPD is widely used as a solvent for cellulose acetate, etc. It is also used as a plasticizer, cationic surfactant (such as oleamidopropyl PG-dimethylammonium chloride), and a synthetic raw material for dyes.

[0003] Current toxicity studies have shown that 3-MCPD is highly harmful to human health. Among them, oleamidopropyl PG-dimethyl ammonium chloride acts directly on the human body when used as a cleaning agent. Therefore, when oleamidopropyl PG-dimethyl ammonium chloride is produced using 3-chloro-1,2-propanediol as a raw material, the residual amount in the product should be limited.

[0004] At present, the detection method of residual 3-chloro-1,2-propanediol is commonly used in the detection of soy sauce and other food flavorings. The detection method is mainly gas chromatography and gas chromatography-mass spectrometry. Gas chromatography and gas chromatography-mass spectrometry mainly use heptafluorobutyrylimidazole and phenylboronic acid as derivatization reagents to react with the hydroxyl group in 3-chloro-1,2-propanediol to generate heptafluorobutyryl chloropropane ester for detection. The operation process is relatively complicated. However, since the ultraviolet absorption wavelength of 3-chloro-1,2-propanediol is short, at about 210nm; at this wavelength, almost all substances respond, and direct liquid chromatography ultraviolet detection has serious interference. In addition, 3-chloro-1,2-propanediol is a highly water-soluble substance, which is difficult to purify in pretreatment, and has a very short retention time in the liquid chromatography column, and cannot be effectively separated from impurities, thus affecting the detection results.

[0005] In view of this, how to achieve rapid and accurate detection of the content of 3-chloro-1,2-propanediol in oleamidopropyl PG-dimethylammonium chloride is a technical problem that urgently needs to be solved. Summary of the invention

[0006] The purpose of the embodiments of the present application is to provide the use of thiosalicylic acid in detecting 3-chloro-1,2-propanediol.

[0007] To achieve the above objectives, the present application proposes the following technical solutions:

[0008] The embodiments of the present application provide the use of thiosalicylic acid in detecting 3-chloro-1,2-propanediol, wherein the thiosalicylic acid is used as a derivatization reagent.

[0009] As an embodiment, the detection method of 3-chloro-1,2-propanediol comprises:

[0010] Prepare 3-chloro-1,2-propylene glycol standard solutions of different concentrations; react the 3-chloro-1,2-propylene glycol standard solutions of different concentrations with thiosalicylic acid in a water bath under alkaline conditions to obtain standard samples of different concentrations;

[0011] Performing high performance liquid chromatography ultraviolet detection on standard samples of different concentrations to obtain the peak areas of 3-chloro-1,2-propanediol in the standard samples of different concentrations; obtaining a linear equation of the corresponding relationship between concentration x and peak area y based on the peak areas corresponding to the standard samples of different concentrations;

[0012] Prepare an oleamidopropyl PG-dimethylammonium chloride solution, and react the oleamidopropyl PG-dimethylammonium chloride solution with thiosalicylic acid in a water bath under alkaline conditions to obtain a sample to be tested;

[0013] The sample to be tested is subjected to high performance liquid chromatography ultraviolet detection to obtain the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested; the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested is substituted into a linear equation to obtain the concentration of 3-chloro-1,2-propanediol in the sample to be tested.

[0014] As an embodiment, under alkaline conditions, 3-chloro-1,2-propylene glycol standard solutions of different concentrations are reacted with thiosalicylic acid in a water bath to obtain standard samples of different concentrations, including:

[0015] Alkaline reagent and thiosalicylic acid were added to standard solutions of 3-chloro-1,2-propanediol of different concentrations, respectively, and the solutions were placed in a 70°C water bath for reaction to obtain standard samples of different concentrations.

[0016] As an embodiment, the preparation of the oleamidopropyl PG-dimethylammonium chloride solution, reacting the oleamidopropyl PG-dimethylammonium chloride solution with thiosalicylic acid in a water bath under alkaline conditions to obtain a sample to be tested, comprises:

[0017] Prepare an oleamidopropyl PG-dimethylammonium chloride solution, add an alkali reagent and thiosalicylic acid to the oleamidopropyl PG-dimethylammonium chloride solution respectively, place the solution in a 70° C. water bath for reaction, and obtain a sample to be tested.

[0018] As an embodiment, the alkaline agent is sodium carbonate.

[0019] As an implementation method, the linear equation is:

[0020] y=59.0228x+5.4471, correlation coefficient R 2 =0.99959.

[0021] As an embodiment, the chromatographic column used in the high performance liquid chromatography ultraviolet detection is Agilent SB-C8.

[0022] As an embodiment, the column temperature of the chromatographic column is 30°C.

[0023] As an embodiment, the chromatographic conditions of the high performance liquid chromatography ultraviolet detection include:

[0024] The detection wavelength was 250-260 nm, and the injection volume was 20 μL;

[0025] Mobile phase A was acetonitrile;

[0026] The mobile phase B was a mixed solution of acetonitrile, water and phosphoric acid in a volume ratio of 100:898:2.

[0027] As an embodiment, the gradient elution program of mobile phase A and mobile phase B is:

[0028] Elution was performed with mobile phase A and mobile phase B in a volume ratio of 10:90 for 10 min;

[0029] Elution was performed with mobile phase A and mobile phase B in a volume ratio of 80:20 for 5 min;

[0030] Elution was performed with mobile phase A and mobile phase B in a volume ratio of 20:80 for 5 min;

[0031] Among them, the flow rate is 1.0mL / min.

[0032] The embodiments of the present application have at least the following beneficial effects:

[0033] In the embodiment of the present application, thiosalicylic acid is used as a derivatization reagent, and 3-chloro-1,2-propylene glycol undergoes a nucleophilic substitution reaction with thiosalicylic acid to generate 3-(2-carboxymethylphenylthio)-1,2-propylene glycol. Among them, the 3-(2-carboxymethylphenylthio)-1,2-propylene glycol generated by derivatization is very easy to separate in high-performance liquid chromatography, and can achieve the purpose of separation and detection through high-performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve the detection accuracy; therefore, the detection method of the embodiment of the present application is not only easy to operate, but also can effectively improve the separation effect, detection accuracy and precision.

[0034] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram showing the effect of the derivatization reaction temperature on the peak area of ​​3-chloro-1,2-propanediol;

[0036] Figure 2 is a liquid chromatogram of 3-chloro-1,2-propanediol;

[0037] Figure 3 Schematic diagram of the linear equation between 3-chloro-1,2-propanediol concentration and peak area. DETAILED DESCRIPTION

[0038] The technical scheme in the embodiments will be clearly and completely described below in combination with the embodiments of the present application and the accompanying drawings. Obviously, the embodiments described below are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0040] It should also be understood that the terms used in this specification of the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present application. As used in the specification of the embodiments of the present application and the appended claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms.

[0041] The use of thiosalicylic acid in the detection of 3-chloro-1,2-propanediol in the examples of the present application will be described in detail below.

[0042] It can be understood that the thiosalicylic acid in this embodiment is used as a derivatization agent. That is, this embodiment provides the use of thiosalicylic acid as a derivatization agent in the detection of 3-chloro-1,2-propanediol in the high performance liquid chromatography ultraviolet detection method.

[0043] Those skilled in the art know that 3-chloro-1,2-propylene glycol (3-MCPD) is highly harmful to human health. Therefore, when oleamidopropyl PG-dimethylammonium chloride is produced using 3-chloro-1,2-propylene glycol as a raw material, the residual amount in the product should be limited.

[0044] The existing detection method is mainly gas chromatography-mass spectrometry detection. Since 3-chloro-1,2-propanediol has strong polarity, high boiling point, and severe tailing in the gas chromatography column, it is not suitable for direct sampling for detection. Therefore, the sample needs to be extracted through a solid phase column first, 3-chloro-1,2-propanediol is purified and extracted, the solvent is evaporated, and then heptafluorobutyrylamide is used to react to generate 3-chloro-propylene glycol diheptafluorobutyryl ester, and then detection is performed. This method is complicated to operate, time-consuming, and has high requirements for detection personnel.

[0045] In view of this, this embodiment provides the use of thiosalicylic acid as a derivatization reagent in the detection of 3-chloro-1,2-propanediol in a high performance liquid chromatography ultraviolet detection method.

[0046] In the embodiment of the present application, thiosalicylic acid is used as a derivatization reagent, and 3-chloro-1,2-propylene glycol undergoes a nucleophilic substitution reaction with thiosalicylic acid to generate 3-(2-carboxymethylphenylthio)-1,2-propylene glycol. Among them, the 3-(2-carboxymethylphenylthio)-1,2-propylene glycol generated by derivatization is very easy to separate in high-performance liquid chromatography, and can achieve the purpose of separation and detection through high-performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve the detection accuracy; therefore, the detection method of the embodiment of the present application is not only easy to operate, but also can effectively improve the separation effect, detection accuracy and precision.

[0047] Next, the detection method of 3-chloro-1,2-propanediol in this embodiment will be described in detail.

[0048] Specifically, the detection method of 3-chloro-1,2-propanediol includes:

[0049] (1) preparing 3-chloro-1,2-propylene glycol standard solutions of different concentrations; reacting the 3-chloro-1,2-propylene glycol standard solutions of different concentrations with thiosalicylic acid in a water bath under alkaline conditions to obtain standard samples of different concentrations;

[0050] (2) performing high performance liquid chromatography ultraviolet detection on standard samples of different concentrations to obtain the peak areas of 3-chloro-1,2-propanediol in the standard samples of different concentrations; based on the peak areas corresponding to the standard samples of different concentrations, obtaining a linear equation for the corresponding relationship between concentration x and peak area y;

[0051] (3) preparing an oleamidopropyl PG-dimethylammonium chloride solution, and reacting the oleamidopropyl PG-dimethylammonium chloride solution with thiosalicylic acid in a water bath under alkaline conditions to obtain a sample to be tested;

[0052] (4) Performing high performance liquid chromatography ultraviolet detection on the sample to be tested to obtain the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested; substituting the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested into a linear equation to obtain the concentration of 3-chloro-1,2-propanediol in the sample to be tested.

[0053] It can be understood that the thiosalicylic acid used in this embodiment is 2-mercaptobenzoic acid, and the thiosalicylic acid in this embodiment is added in the form of a thiosalicylic acid solution; wherein, in the nucleophilic substitution reaction, the greater the alkalinity and the larger the atomic diameter, the stronger the nucleophilicity. However, the reaction conditions of strong nucleophilic substances such as alkyl sodium, alkyl potassium, Grignard reagent, sodium amide, alkyl potassium alcohol, etc. are relatively harsh: anhydrous conditions and air isolation are required, and there are certain requirements for the solvent type, and there are many side reactions. Such substances are not suitable for derivatization detection. Derivatization reagents suitable for derivatization detection have low solvent requirements and can be carried out in aqueous solvents. The reaction is complete and there are no side reactions. The radius of the nitrogen atom is smaller than that of the sulfur atom, and the nucleophilic substitution ability of thiol compounds is greater than that of amino compounds. The alkylation reaction of primary amines with halogenated alkanes can generate secondary amines, tertiary amines and quaternary ammoniums, and the alkylation reaction of secondary amines with halogenated alkanes can generate tertiary amines and quaternary ammoniums, so primary amines and secondary amine compounds are not suitable for halogenated alkanes. Derivatization detection.

[0054] In particular, when using a UV detector for detection, derivatization should introduce a group with strong UV absorption, such as a compound containing a phenyl group, and the derivatization reagent should be soluble in methanol or acetonitrile.

[0055] In this embodiment, thiosalicylic acid is used as a derivatization reagent, and 3-chloro-1,2-propanediol undergoes a nucleophilic substitution reaction with thiosalicylic acid to generate 3-(2-carboxymethylphenylthio)-1,2-propanediol. Among them, the 3-(2-carboxymethylphenylthio)-1,2-propanediol generated by derivatization is very easy to separate in high-performance liquid chromatography, and can achieve the purpose of separation and detection through high-performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve the detection accuracy.

[0056] Specifically, in this embodiment, standard samples of different concentrations are obtained by deriving the 3-chloro-1,2-propylene glycol standard solution, and a linear equation (correction model) of the corresponding relationship between concentration x and peak area y is obtained based on the peak areas corresponding to the standard samples of different concentrations; based on the linear equation (correction model), the content (concentration) of 3-chloro-1,2-propylene glycol in oleamidopropyl PG-dimethylammonium chloride can be quickly obtained according to the peak area of ​​the sample to be tested.

[0057] Next, the relevant steps of the above detection method will be further explained.

[0058] In step (1), different concentrations of 3-chloro-1,2-propylene glycol standard solutions are prepared, which can be:

[0059] Weigh 0.2044 g of 3-chloro-1,2-propanediol standard into a 100 mL volumetric flask and dilute to the mark with distilled water. The concentration is 2044 mg / L. Transfer 10 mL to another 100 mL volumetric flask and dilute to the mark with distilled water as a stock solution (204.4 mg / L).

[0060] Based on the above-mentioned stock solution concentration, different volumes of the stock solution can be measured to obtain 3-chloro-1,2-propanediol standard solutions of different concentrations.

[0061] In step (1), under alkaline conditions, different concentrations of 3-chloro-1,2-propylene glycol standard solutions are reacted with thiosalicylic acid in a water bath to obtain standard samples of different concentrations, specifically comprising:

[0062] Alkaline reagent and thiosalicylic acid were added to standard solutions of 3-chloro-1,2-propanediol of different concentrations, respectively, and the solutions were placed in a 70°C water bath for reaction to obtain standard samples of different concentrations.

[0063] For example, based on a stock solution with a concentration of 204.4 mg / L, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL and 5.00 mL of the stock solution were respectively measured into 6 50 mL volumetric flasks, filled up to 20 mL with distilled water, 1 mL of 10% mass concentration sodium carbonate was added, 0.5 mL of 1% mass concentration thiosalicylic acid was added, and the mixture was placed in a water bath at 70°C for 1 hour; after the reaction was completed, the volumetric flask was taken out, 0.5 mL of 10% mass concentration phosphoric acid was added to terminate the reaction, 10 mL of acetonitrile was added, the mixture was filled up to the scale with distilled water, ultrasonicated for 5-10 minutes to remove bubbles, and filtered with a syringe filter to obtain standard samples of different concentrations.

[0064] It can be understood that the alkaline conditions described in this embodiment are pH values ​​greater than 7, and in this implementation, an alkaline environment is created by adding an alkaline reagent, sodium carbonate.

[0065] Among them, this embodiment found through relevant experiments that the peak area of ​​3-chloro-1,2-propanediol increases with the increase of temperature, and after reaching the peak value, it decreases with the increase of temperature. When the temperature is 70°C, the peak area is the largest, and this temperature has a good derivatization effect.

[0066] In this embodiment, the preparation method of the thiosalicylic acid solution is as follows: weigh 0.5 g of thiosalicylic acid, add 49.5 g of acetonitrile, and dissolve by ultrasonication to obtain a thiosalicylic acid solution with a mass concentration of 1%.

[0067] In step (1), thiosalicylic acid is used as a derivatization reagent, and under alkaline conditions, 3-chloro-1,2-propanediol and thiosalicylic acid undergo a nucleophilic substitution reaction to generate 3-(2-carboxymethylphenylthio)-1,2-propanediol. The 3-(2-carboxymethylphenylthio)-1,2-propanediol generated by derivatization is very easy to separate in the subsequent high-performance liquid chromatography, and the purpose of separation and detection can be achieved through high-performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve the detection accuracy and precision.

[0068] In step (2), high performance liquid chromatography ultraviolet detection is performed on standard samples of different concentrations to obtain the peak area of ​​3-chloro-1,2-propanediol in the standard samples of different concentrations, specifically comprising:

[0069] Standard samples of different concentrations were injected into a high performance liquid chromatograph for high performance liquid ultraviolet detection to obtain the corresponding peak area of ​​3-chloro-1,2-propanediol.

[0070] Among them, based on the peak areas corresponding to the standard samples with different concentrations, a linear equation for the corresponding relationship between the concentration x and the peak area y is obtained, specifically including:

[0071] With 3-chloro-1,2-propanediol concentration as the horizontal coordinate x and peak area as the vertical coordinate y, linear regression was performed and the linear equation was obtained as follows: y=59.0228x+5.4471, and the correlation coefficient R 2 =0.99959.

[0072] In step (2), the standard sample after the above derivatization reaction is separated and detected by high performance liquid chromatography ultraviolet; wherein the 3-(2-carboxymethylphenylthio)-1,2-propanediol generated by derivatization is very easy to separate in high performance liquid chromatography, and the purpose of separation and detection can be achieved through high performance liquid chromatography, so it is easy to eliminate the interference of matrix effect and improve the detection accuracy.

[0073] At the same time, in step (2), based on the above test results (peak area of ​​3-chloro-1,2-propylene glycol), a linear equation (calibration model) for the corresponding relationship between concentration x and peak area y is obtained; based on the linear equation (calibration model), when the content of the sample to be tested is tested, the content (concentration) of 3-chloro-1,2-propylene glycol in the cationic surfactant can be quickly obtained according to the peak area of ​​the sample to be tested.

[0074] In step (3), a cationic surfactant is prepared, and under alkaline conditions, the cationic surfactant is reacted with thiosalicylic acid in a water bath to obtain a sample to be tested, comprising:

[0075] A cationic surfactant was prepared, and an alkali reagent and thiosalicylic acid were respectively added to the cationic surfactant, and the mixture was placed in a 70° C. water bath for reaction to obtain a sample to be tested.

[0076] The oleamidopropyl PG-dimethylammonium chloride solution can be prepared by dissolving oleamidopropyl PG-dimethylammonium chloride in water.

[0077] Specifically, the above steps can be: weigh 5g (accurate to 1mg) of oleamidopropyl PG-dimethylammonium chloride, put it into a 50mL volumetric flask, and fill it up to 20mL with distilled water; add 0.5mL of 5% mass concentration sodium carbonate, add 0.5mL of thiosalicylic acid dropwise, and place it in a water bath at 70°C for 1-3 hours to carry out a derivatization reaction.

[0078] Usually, after the reaction is completed, 0.5 mL of 10% phosphoric acid solution is added to terminate the reaction, 10 mL of acetonitrile is added, and the volume is made up to 50 mL with distilled water. The bubbles are removed by ultrasonication for 5-10 minutes, and the sample to be tested is filtered with a syringe filter.

[0079] It can be understood that in step (3), thiosalicylic acid is used as a derivatization reagent, and under alkaline conditions, 3-chloro-1,2-propanediol in oleamidopropyl PG-dimethylammonium chloride is subjected to a nucleophilic substitution reaction with thiosalicylic acid to generate 3-(2-carboxymethylphenylthio)-1,2-propanediol. The 3-(2-carboxymethylphenylthio)-1,2-propanediol generated by derivatization is very easy to separate in the subsequent high performance liquid chromatography, which can eliminate the interference of matrix effect and improve the accuracy of the detection result.

[0080] In step (4), the sample to be tested is subjected to high performance liquid chromatography ultraviolet detection to obtain the peak area of ​​3-chloro-1,2-propylene glycol in the sample to be tested; the peak area of ​​3-chloro-1,2-propylene glycol in the sample to be tested is substituted into a linear equation to obtain the concentration of 3-chloro-1,2-propylene glycol in the sample to be tested, specifically comprising:

[0081] The sample to be tested obtained in step (3) is injected into a high performance liquid chromatograph for high performance liquid ultraviolet detection to obtain the peak area of ​​3-chloro-1,2-propanediol; the peak area of ​​3-chloro-1,2-propanediol obtained is substituted into the linear equation described in step (2) to calculate the concentration of 3-chloro-1,2-propanediol.

[0082] Therefore, in this embodiment, the sample to be tested after the above derivatization reaction is separated and detected by high performance liquid chromatography ultraviolet; the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested is obtained. At the same time, based on the linear equation (calibration model) obtained in step (2), the content of 3-chloro-1,2-propanediol in oleamidopropyl PG-dimethylammonium chloride can be quickly obtained according to the peak area of ​​the sample to be tested.

[0083] Therefore, the testing scheme of this embodiment has better detection accuracy, and the testing process is more convenient and faster.

[0084] It is understandable that in the test processes in steps (2) and (4), the sample (standard sample or sample to be tested) is injected into a high performance liquid chromatograph for high performance liquid ultraviolet detection.

[0085] As an implementation mode, the chromatographic column used in the above-mentioned high performance liquid chromatography ultraviolet detection is Agilent SB-C8, and the column temperature of the chromatographic column is 30°C.

[0086] As an embodiment, the chromatographic conditions of the above-mentioned high performance liquid chromatography ultraviolet detection include:

[0087] The detection wavelength is 250-260 nm (e.g., 256 nm), and the injection volume is 20 μL;

[0088] Mobile phase A was acetonitrile;

[0089] The mobile phase B is a mixed solution of acetonitrile, water and phosphoric acid (such as phosphoric acid with a mass concentration of 85%) in a volume ratio of 100:898:2.

[0090] In this embodiment, the gradient elution program of mobile phase A and mobile phase B is:

[0091] Elution was performed with mobile phase A and mobile phase B in a volume ratio of 10:90 for 10 min;

[0092] Elution was performed with mobile phase A and mobile phase B in a volume ratio of 80:20 for 5 min;

[0093] Elution was performed with mobile phase A and mobile phase B in a volume ratio of 20:80 for 5 min;

[0094] Among them, the flow rate is 1.0mL / min.

[0095] Therefore, in this embodiment, thiosalicylic acid is used as a derivatization reagent, and 3-chloro-1,2-propylene glycol and thiosalicylic acid undergo a nucleophilic substitution reaction to generate 3-(2-carboxymethylphenylthio)-1,2-propylene glycol. Among them, the 3-(2-carboxymethylphenylthio)-1,2-propylene glycol generated by derivatization is very easy to separate in high performance liquid chromatography, and can achieve the purpose of separation and detection through high performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve the detection accuracy; at the same time, there is no need for extraction and purification before or after derivatization, the operation steps are few, and it is convenient and fast.

[0096] In summary, the detection method of this embodiment is not only easy to operate, but also can effectively improve the separation effect, detection accuracy and precision.

[0097] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate / explain the present application and are not used to limit the scope of the present application.

[0098] In the following examples, the materials, reagents and instruments used can be purchased from commercial sources unless otherwise specified.

[0099] It should be noted that, in the following examples, unless otherwise specified, the method and conditions for analysis (separation and detection) using a high performance liquid chromatograph are as follows:

[0100] The preparation method of the thiosalicylic acid solution is as follows: weigh 0.5 g of thiosalicylic acid, add 49.5 g of acetonitrile, and dissolve by ultrasonication to obtain a thiosalicylic acid solution with a mass concentration of 1%.

[0101] Agilent 1260 liquid chromatograph was used for high performance liquid chromatography, and the concentration of phosphoric acid solution in mobile phase B was 85%.

[0102] Mobile phase A was acetonitrile; mobile phase B was acetonitrile: water: phosphoric acid = 100: 898: 2 (volume ratio).

[0103] The gradient elution program is shown in Table 1 below:

[0104] Table 1:

[0105] Time (min) Mobile phase A(%) Mobile phase B(%) Flow rate (mL / min) 0.00 10 90 1 10.00 10 90 1 11.00 80 20 1 16.00 80 20 1 17.00 20 80 1 22.00 20 80 1

[0106] Among them, the chromatographic column selected is Agilent ZORBAX SB-C8, the chromatographic column length is 250mm, the chromatographic column inner diameter is 4.6mm, and the chromatographic column filler particle diameter is 5μm; the detection wavelength is set to 256nm, the column temperature of the chromatographic column is 30℃, and the injection volume is 20μL.

[0107] Embodiment 1-10:

[0108] The present application found that the derivatization temperature of 3-chloro-1,2-propylene glycol affects its peak area. Therefore, by setting a gradient water bath temperature, the peak area of ​​3-chloro-1,2-propylene glycol is detected, specifically:

[0109] Weigh 0.2037g of 3-chloro-1,2-propylene glycol standard, dissolve in distilled water, dilute to 100mL, shake well; use a pipette to transfer 10mL to another 100mL volumetric flask, dilute to volume, mix well, and obtain a stock solution with a concentration of 203.7mg / L. Take 10 50mL volumetric flasks, transfer 2mL of 3-chloro-1,2-propylene glycol solution with a concentration of 203.7mg / L to each volumetric flask, and fill to 20mL with distilled water;

[0110] Add 1 mL of 5% sodium carbonate and 0.5 mL of 1% thiosalicylic acid, mix well, and place in a water bath at 40, 45, 50, 55, 60, 65, 70, 75, 80, 85°C for 1 hour respectively;

[0111] After the reaction, the volumetric flask was taken out, 1 mL of 10% phosphoric acid and 10 mL of acetonitrile were added, and distilled water was added to the scale line. The bubbles were removed by ultrasonication for 5 minutes. The solution was filtered into a sample bottle with a syringe filter and injected into a high performance liquid chromatograph for separation and detection. The test results are shown in Table 2.

[0112] The water bath temperature is the horizontal axis and the peak area is the vertical axis. The test results are as follows: Figure 1 shown.

[0113] Table 2: Water bath temperature and resolution

[0114] Example Water bath temperature (℃) Peak area Example 1 40 80.4 Example 2 45 143.3 Example 3 50 211.7 Example 4 55 306.1 Example 5 60 436.5 Example 6 65 482.3 Example 7 70 490.6 Example 8 75 488.2 Example 9 80 477.8 Example 10 85 453.4

[0115] Combined with Table 2 and Figure 1 The peak area of ​​3-chloro-1,2-propanediol increases with the increase of temperature. After reaching the peak value, it decreases with the increase of temperature. When the temperature is 70℃, the peak area is the largest, and the derivatization effect is good at this temperature. Therefore, the derivatization temperature is determined to be 70℃.

[0116] Among them, the liquid chromatogram after separation is as follows Figure 2 As shown. Combined Figure 2 It can be seen from the liquid chromatogram that no interference peak appears in the liquid chromatogram; that is, in this embodiment, thiosalicylic acid is used as a derivatization reagent to eliminate the interference of matrix effects and improve the accuracy of the detection results.

[0117] Accuracy experiment

[0118] Embodiment 11-16:

[0119] Weigh 0.2044 g of 3-chloro-1,2-propanediol standard into a 100 mL volumetric flask, dilute to the mark with distilled water, the concentration is 2044 mg / L; transfer 10 mL to another 100 mL volumetric flask, dilute to the mark with distilled water, as a stock solution (204.4 mg / L) for later use; measure 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL and 5.00 mL of the stock solution into 6 50 mL volumetric flasks, fill to 20 mL with distilled water, add 1 mL of 10% sodium carbonate was added, and 0.5 mL of 1% thiosalicylic acid was added, and the mixture was placed in a water bath at 70°C for 1 hour. After the reaction was completed, the volumetric flask was taken out, and 0.5 mL of 10% phosphoric acid was added to terminate the reaction. 10 mL of acetonitrile was added, and the mixture was filled to the mark with distilled water. Ultrasonic treatment was performed for 5 minutes to remove bubbles. The mixture was filtered into a sample bottle with a syringe filter, and the mixture was injected into a high performance liquid chromatograph for ultraviolet spectrum detection to obtain the peak area of ​​3-chloro-1,2-propanediol. The test results are shown in Table 3:

[0120] Table 3: Peak area for detection of 3-chloro-1,2-propanediol

[0121] Example 3-Chloro-1,2-propanediol(mg / L) Peak area Embodiment 11 2.044 124.98 Example 12 4.088 245.59 Example 13 8.176 489.55 Embodiment 14 12.264 740.12 Embodiment 15 16.352 981.15 Example 16 20.440 1196.66

[0122] Among them, the concentration of 3-chloro-1,2-propanediol is used as the horizontal coordinate and the peak area is used as the vertical coordinate. Linear regression is performed and the linear equation is: y=59.0228x+5.4471, and the correlation coefficient R 2 =0.99959, the linear equation is Figure 3 As shown; combined with Table 3 and Figure 3 The test results show that 3-chloro-1,2-propanediol has good linearity in the concentration range of 0-20 mg / L.

[0123] Embodiment 17-19:

[0124] Accurately weigh 3 parts of oleamidopropyl PG-dimethylammonium chloride, the weight is shown in Table 4 (accurate to 1 mg), and are placed in 50 mL volumetric flasks, 15 mL of distilled water, 0.5 mL of 5% sodium carbonate by mass, 0.5 mL of 1% thiosalicylic acid by mass are added dropwise, and the mixture is placed in a water bath at 70 ° C for 1 hour; after the reaction is completed, the volumetric flask is taken out, 0.5 mL of 10% phosphoric acid by mass is added to terminate the reaction, 10 mL of acetonitrile is added, and distilled water is filled to the scale line, and the bubbles are removed by ultrasound for 5 minutes; filter into a sample bottle with a syringe filter, and inject the obtained sample into a high performance liquid chromatograph for ultraviolet spectrum detection to obtain the peak area of ​​3-chloro-1,2-propanediol, which is substituted into the linear equations obtained in the above Examples 11-16, respectively, and the content of 3-chloro-1,2-propanediol in each sample, that is, the content of the target substance contained in Examples 17-19, is calculated, and recorded as A value.

[0125] Embodiment 20-22:

[0126] Accurately weigh 3 parts of oleamidopropyl PG-dimethylammonium chloride, the weight is shown in Table 4 (accurate to 1 mg), and place them in 50 mL volumetric flasks respectively. Take the stock solution (204.4 mg / L) prepared in Examples 11-16 as the reference substance (known concentration), add 0.5 mL (parallel group 1), 1 mL (parallel group 2), and 2 mL (parallel group 3) respectively, add 15 mL of distilled water; add 0.5 mL of 5% mass concentration of sodium carbonate, add 0.5 mL of 1% mass concentration of thiosalicylic acid dropwise, place in a 70°C water bath for 1 hour, after the reaction is completed, take out the volumetric flask, add 0.5 mL of 10% mass concentration of phosphoric acid to terminate the reaction, add 10 mL of acetonitrile, fill to the mark with distilled water, and remove bubbles by ultrasound for 5 minutes. Filter into a sample bottle with a syringe filter.

[0127] The obtained sample was injected into a high performance liquid chromatograph for ultraviolet spectrum detection to obtain the peak area of ​​3-chloro-1,2-propanediol, which was substituted into the linear equation obtained in the above Examples 11-16 to calculate the content of 3-chloro-1,2-propanediol in the sample, which is the content of the target substance contained in Examples 20-22, recorded as C value.

[0128] The recovery rate was calculated based on the A value and the C value, where the recovery rate was calculated as follows:

[0129] .

[0130] In the above formula: A is the content of the target substance contained in Examples 17-19; B is the increase in sample concentration after adding the reference substance; C is the content of the target substance contained in Examples 20-22.

[0131] The calculation formula of B value is:

[0132] (Concentration of stock solution*volume of stock solution added) / weight of the corresponding test sample in Examples 20-22.

[0133] Three replicates were prepared for each concentration, and three sets of parallel experiments were performed. The recovery rates were determined according to the content determination items, and the test results are shown in Table 4 below; among them, the recovery rates in Table 4 were calculated by substituting the average value of the A values ​​(i.e., 40.68 mg / kg) into the above recovery rate calculation formula.

[0134] Table 4: Accuracy test results

[0135]

[0136] According to the test results in Table 4, the average recovery rate of the three parallel group experiments is greater than 97%, and the RSD is less than 3%, indicating that the loss of the analyte in the processing of the sample in this embodiment is extremely small, and the detection method has excellent accuracy and high precision.

[0137] Precision experiment

[0138] Embodiment 23-28:

[0139] The 3-chloro-1,2-propanediol solution of Example 14 was taken and injected 6 times continuously. The precision of the peak area of ​​the main component was recorded. The test results are shown in Table 5 below:

[0140] Table 5: Precision test results

[0141]

[0142] According to the test results in Table 5, it is shown that the detection method of this embodiment has excellent precision and repeatability.

[0143] Solution stability test

[0144] Examples 29-33:

[0145] The 3-chloro-1,2-propanediol solution of Example 14 was taken and sampled at room temperature for 4, 8, 12, 24 and 48 hours, and the peak area change of the main component was recorded. The test results are shown in Table 6 below:

[0146] Table 6: Solution stability test results

[0147]

[0148] According to the test results in Table 6, it is shown that the detection method of this embodiment has excellent stability of the derivatization solution within 48 hours at room temperature.

[0149] In summary, in this embodiment, thiosalicylic acid is used as a derivatization reagent, and 3-chloro-1,2-propylene glycol undergoes a nucleophilic substitution reaction with thiosalicylic acid to generate 3-(2-carboxymethylphenylthio)-1,2-propylene glycol. Among them, the 3-(2-carboxymethylphenylthio)-1,2-propylene glycol generated by derivatization is very easy to separate in high performance liquid chromatography, and can achieve the purpose of separation and detection through high performance liquid chromatography, so it is easy to eliminate the interference of matrix effects and improve the detection accuracy; therefore, the detection method provided in this embodiment is not only easy to operate, but also can effectively improve the separation effect, detection accuracy and precision.

[0150] The technical solutions provided in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present application. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present application. At the same time, for those skilled in the art, according to the embodiments of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present application.

Claims

1. The use of thiosalicylic acid in detecting 3-chloro-1,2-propanediol, characterized in that: The thiosalicylic acid is used as a derivatization agent; Wherein, the detection method of 3-chloro-1,2-propanediol comprises: Prepare 3-chloro-1,2-propylene glycol standard solutions of different concentrations; react the 3-chloro-1,2-propylene glycol standard solutions of different concentrations with thiosalicylic acid in a water bath under alkaline conditions to obtain standard samples of different concentrations; Performing high performance liquid chromatography ultraviolet detection on standard samples of different concentrations to obtain the peak areas of 3-chloro-1,2-propanediol in the standard samples of different concentrations; obtaining a linear equation of the corresponding relationship between concentration x and peak area y based on the peak areas corresponding to the standard samples of different concentrations; Prepare an oleamidopropyl PG-dimethylammonium chloride solution, and react the oleamidopropyl PG-dimethylammonium chloride solution with thiosalicylic acid in a water bath under alkaline conditions to obtain a sample to be tested; Performing high performance liquid chromatography ultraviolet detection on the sample to be tested to obtain the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested; substituting the peak area of ​​3-chloro-1,2-propanediol in the sample to be tested into a linear equation to obtain the concentration of 3-chloro-1,2-propanediol in the sample to be tested; Under alkaline conditions, 3-chloro-1,2-propylene glycol standard solutions of different concentrations are reacted with thiosalicylic acid in a water bath to obtain standard samples of different concentrations, including: Alkaline reagent and thiosalicylic acid were added to 3-chloro-1,2-propanediol standard solutions of different concentrations, and the solutions were placed in a 70°C water bath to react, thereby obtaining standard samples of different concentrations. The method comprises preparing an oleamidopropyl PG-dimethylammonium chloride solution, reacting the oleamidopropyl PG-dimethylammonium chloride solution with thiosalicylic acid in a water bath under alkaline conditions to obtain a sample to be tested, comprising: Prepare an oleamidopropyl PG-dimethylammonium chloride solution, add an alkali reagent and thiosalicylic acid to the oleamidopropyl PG-dimethylammonium chloride solution respectively, place the solution in a 70° C. water bath to react, and obtain a sample to be tested; Wherein, the chromatographic column used in the high performance liquid chromatography ultraviolet detection is Agilent SB-C8; The chromatographic conditions of the high performance liquid chromatography ultraviolet detection include: Mobile phase A was acetonitrile; Mobile phase B was a mixed solution of acetonitrile, water, and phosphoric acid in a volume ratio of 100:898:2; The gradient elution program of the mobile phase A and the mobile phase B is: 。 2. The use according to claim 1, characterized in that The alkaline agent is sodium carbonate.

3. The use according to claim 1, characterized in that The linear equation is: y=59.0228x+5.4471, correlation coefficient R 2 =0.99959.

4. The use according to claim 1, characterized in that The column temperature of the chromatographic column is 30°C.

5. The use according to claim 1, characterized in that: The detection wavelength of the high performance liquid chromatography ultraviolet detection is 250-260 nm, and the injection volume is 20 μL.

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