Quantitative detection method for mixture of bis (2-ethoxyl) disulfide and mercaptoethanol
By using a polysiloxane column containing phenyl functional groups in gas chromatography and optimizing chromatographic conditions, the problem of detection accuracy of bis(2-hydroxyethyl) disulfide and mercaptoethanol mixtures was solved, and rapid and accurate quantitative analysis was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG SUNION ADVANCED NOVEL TECHNOLOGIES CO LTD
- Filing Date
- 2026-03-12
- Publication Date
- 2026-05-05
AI Technical Summary
Existing technologies are insufficient for the accurate detection of a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol in gas chromatography, due to issues such as adsorption, tailing, and poor separation, leading to inaccurate quantitative analysis.
A polysiloxane column containing phenyl functional groups was used, and gas chromatography conditions such as temperature control and temperature ramping were optimized. A flame ionization detector was used to control the split ratio and carrier gas flow rate to ensure good separation and detection of the two components.
It enables rapid and accurate quantification of bis(2-hydroxyethyl) disulfide and mercaptoethanol, with high detection accuracy, good reproducibility, and good chromatographic peak resolution, meeting the requirements for product quality testing.
Smart Images
Figure CN121978249A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of analytical detection, and more particularly to a quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol. Background Technology
[0002] Bis(2-hydroxyethyl) disulfide is a polar small molecule containing two hydroxyl groups (-OH) and one disulfide bond (-SS-). Due to the strong polarity and active hydrogen at both ends of its molecule, it readily adsorbs in gas chromatography. Mercaptoethanol also contains active hydroxyl and sulfur groups. Therefore, for the two-component detection of bis(2-hydroxyethyl) disulfide and mercaptoethanol on ordinary nonpolar or weakly polar columns (such as 100% polydimethylsiloxane), bis(2-hydroxyethyl) disulfide and mercaptoethanol interact with the silanol groups on the stationary phase or column wall, resulting in severe peak tailing, extremely poor symmetry, and difficulty in accurate integration. This leads to extremely high column selectivity, making it difficult to choose a suitable column.
[0003] Secondly, mercaptoethanol has a relatively low boiling point of approximately 157 °C, while bis(2-hydroxyethyl) disulfide has a higher boiling point of approximately 282 °C. The significant difference in boiling points between the two, coupled with the fact that mercaptoethanol (HS-CH2CH2OH) contains reactive thiol groups (-SH) and hydroxyl groups (-OH), makes it prone to oxidation, decomposition, or adsorption / reaction with metal injection ports and the inner wall of the chromatographic column at high temperatures, leading to inaccurate quantitative analysis. Therefore, achieving both the separation of low-boiling-point substances (such as solvents) and the sensitivity of high-boiling-point substances (such as avoiding target analyte diffusion and adsorption) on the chromatographic column requires extremely high-precision gas chromatography conditions, necessitating further research to overcome this detection challenge. Summary of the Invention
[0004] This invention provides a quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol. This method is suitable for the detection of both large and trace amounts. The detection precision, linearity, and recovery rate all meet the requirements. Furthermore, the method is fast, accurate, sensitive, reproducible, and has good chromatographic peak resolution. It can achieve rapid and accurate quantification of the two components, bis(2-hydroxyethyl) disulfide and mercaptoethanol, thereby achieving the purpose of product quality testing.
[0005] To address the aforementioned technical problems, the present invention aims to provide a method for the quantitative detection of a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol, characterized by comprising the following steps: (1) Prepare standard solutions of bis(2-hydroxyethyl) disulfide and mercaptoethanol of different concentrations respectively; (2) The standard solution and the test sample are quantitatively measured by gas chromatography equipment. A standard curve is plotted based on the test results of the standard solution. The test sample is quantitatively analyzed by combining the standard curve and the chromatogram of the standard solution. In step (2), the chromatographic conditions are as follows: the column packing material is phenyl or cyanopropylphenyl-substituted dimethyl polysiloxane, the film thickness is 0.3-0.4 μm, the column temperature is 70-90 ℃, the detector is a flame ionization detector, the detector temperature is 280-320 ℃, the split ratio is (40-50):1, the initial temperature of the temperature program is 70-90 ℃, held for 1-3 min, then increased to 250-270 ℃ at 8-12 ℃ / min, and held for 3-8 min.
[0006] As a preferred option, in the chromatographic conditions of step (2), the temperature of the vaporization chamber is 200-280 °C.
[0007] As a preferred embodiment, in the chromatographic conditions of step (2), the carrier gas is nitrogen and the carrier gas flow rate is 0.5-2 mL / min.
[0008] As a preferred option, in the chromatographic conditions of step (2), the injection volume is 0.3-1.5 μL.
[0009] As a preferred embodiment, in step (1), the concentrations of the bis(2-hydroxyethyl) disulfide standard solution and the mercaptoethanol standard solution are each independent and range from 0 to 10,000 mg / kg.
[0010] As a preferred embodiment, the gas chromatograph is an Agilent gas chromatograph 7820A, Agilent gas chromatograph 7890A, Agilent 8860, Shimadzu 2030, Shimadzu 2010, Shimadzu GC-2010Plus, or Shimadzu GC-2014C.
[0011] As a preferred option, the sample to be tested is pre-treated to remove moisture using at least one of 3A molecular sieve, 4A molecular sieve, anhydrous sodium sulfate, anhydrous magnesium sulfate, and phosphorus pentoxide.
[0012] As a preferred embodiment, the standard solution includes an organic solvent, which is at least one selected from acetonitrile, methanol, isopropanol, ethanol, acetone, N,N-dimethylformamide, and dimethyl sulfoxide.
[0013] As a preferred embodiment, the chromatographic column is an SPB-1701 capillary column or an Rxi-17 capillary column.
[0014] As a preferred embodiment, the chromatographic column has a length of 40-60 mm and an inner diameter of 0.3-0.4 mm.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This application relates to a gas chromatography quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol. By optimizing the gas chromatography conditions and selecting polysiloxane containing phenyl functional groups as the packing material for the chromatographic column, the detection accuracy of the two components of bis(2-hydroxyethyl) disulfide and mercaptoethanol can be improved. At the same time, controlling the detection temperature and temperature program can improve the separation of low-boiling-point substances and solvents to avoid interference, while avoiding the diffusion and adsorption of high-boiling-point target substances, so as to ensure separation and detector sensitivity. Controlling the split ratio avoids nonlinear response and peak overlap, resulting in good chromatographic peak separation. The detection error of the two components of bis(2-hydroxyethyl) disulfide and mercaptoethanol is small, and the analysis is fast, accurate, sensitive, and reproducible, which can meet the product quality testing requirements.
[0016] 2. The chromatographic column packing material selected in this application is a polysiloxane containing phenyl functional groups. This is because both bis(2-hydroxyethyl) disulfide and mercaptoethanol contain hydroxyl groups and are polar compounds. Since the disulfide molecule of bis(2-hydroxyethyl) disulfide is relatively large and its polarity is weak, a phenyl-containing polysiloxane is used. While it possesses some polarity, it is less polar than the strongly polar polyethylene glycol column, allowing for better interaction with the polarity of bis(2-hydroxyethyl) disulfide and mercaptoethanol, thus achieving better solubility and optimized peak shape. Secondly, the phenyl functional group provides interaction forces and high selectivity, effectively widening the retention time difference between bis(2-hydroxyethyl) disulfide and mercaptoethanol, ensuring baseline separation. This is because the disulfide, due to its large molecular weight and high boiling point, exhibits stronger retention on the phenyl column, resulting in more thorough separation from mercaptoethanol. Attached Figure Description
[0017] Figure 1 This is a standard curve of the chromatographic peak area and different concentrations of bis(2-hydroxyethyl) disulfide standard solutions in Example 1 of the present invention; Figure 2 This is a standard curve of different concentrations of mercaptoethanol standard solutions and chromatographic peak areas in Example 1 of the present invention; Figure 3 This is the chromatogram of sample A to be tested in Example 1 of the present invention. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0020] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0021] As used in this article: In these embodiments, unless otherwise specified, the portions and percentages are all by weight.
[0022] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).
[0023] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0024] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available, and the same raw materials were used in parallel experiments.
[0025] Sample A was selected as the test sample, consisting of 65 mg / Kg of bis(2-hydroxyethyl) disulfide, 35 mg / Kg of mercaptoethanol, and the remainder acetonitrile; Sample B was selected as the test sample, consisting of 100 mg / Kg of bis(2-hydroxyethyl) disulfide and the remainder acetonitrile.
[0026] Example 1 A method for the quantitative detection of a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol, comprising the following steps: (1) Prepare standard solutions of bis(2-hydroxyethyl) disulfide by dissolving bis(2-hydroxyethyl) disulfide in acetonitrile organic solvent to prepare standard solutions with concentrations of 0 mg / kg, 25 mg / kg, 50 mg / kg, 75 mg / kg, 100 mg / kg, 125 mg / kg, 150 mg / kg, 175 mg / kg and 200 mg / kg. Simultaneously, standard solutions of mercaptoethanol were prepared by dissolving mercaptoethanol in acetonitrile organic solvent to prepare standard solutions with concentrations of 0 mg / kg, 10 mg / kg, 20 mg / kg, 30 mg / kg, 40 mg / kg, 50 mg / kg, 60 mg / kg, 70 mg / kg, 80 mg / kg, 90 mg / kg, and 100 mg / kg. (2) The samples A, B and the standard were all analyzed by a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions were as follows: the column was a Supelco SPB-1701 capillary column, the column packing was cyanopropylphenyl-substituted dimethyl polysiloxane, the column length was 50 mm, the column inner diameter was 0.32 mm, the film thickness was 0.32 μm, the column temperature was 80 ℃, the detector was a flame ionization detector, the detector temperature was 300 ℃, the vaporization chamber temperature was 260 ℃, the carrier gas was nitrogen, the carrier gas flow rate was 1.0 mL / min, the injection volume was 0.8 μL, and the split ratio was 50:1; the temperature program started at 80 ℃, held for 2 min, increased to 260 ℃ at 10 ℃ / min, held for 5 min, and ended at 30 min. (3) Plot the standard curve with concentration as the x-axis and corresponding peak area as the y-axis. Prepare the standard curves for bis(2-hydroxyethyl) disulfide and mercaptoethanol standards as follows: Figure 1-2 As shown in Table 1, within the detection concentration range of bis(2-hydroxyethyl) disulfide and mercaptoethanol, their concentrations and peak areas exhibit a good linear relationship. (4) Based on the standard curve, qualitative and quantitative analyses were performed on the test samples. The analysis results are shown in Table 2 below. Figure 3 As shown.
[0027] Table 1 - Linear regression equations for standard solutions and the limits of detection, limits of quantitation, and linear range of the method. Example 2 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is a Shimadzu Rxi-17 capillary column; the column packing material is phenyl-substituted dimethyl polysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is a flame ionization detector with a detector temperature of 300 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen with a flow rate of 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0028] Example 3 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the samples A and B and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an SPB-1701 capillary column; the column packing material is cyanopropylphenyl-substituted dimethyl polysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is a flame ionization detector; the detector temperature is 280 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, then increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0029] Example 4 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an SPB-1701 capillary column; the column packing material is cyanopropylphenyl-substituted dimethylpolysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is a flame ionization detector; the detector temperature is 320 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0030] Example 5 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an SPB-1701 capillary column; the column packing material is cyanopropylphenyl-substituted dimethyl polysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is a flame ionization detector; the detector temperature is 300 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 40:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0031] Comparative Example 1 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an SPB-1701 capillary column; the column packing material is cyanopropylphenyl-substituted dimethyl polysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is an electron capture detector; the detector temperature is 300 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0032] Comparative Example 2 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference is that in step (2), the test samples A and B and the standard are all detected and analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the chromatographic column is an SPB-1701 capillary column, the column packing is cyanopropylphenyl-substituted dimethyl polysiloxane, the column length is 50 mm, the column inner diameter is 0.32 mm, the film thickness is 0.32 μm, the column temperature is 200 ℃, the detector is a flame ionization detector, the detector temperature is 300 ℃, the vaporization chamber temperature is 260 ℃, the carrier gas is nitrogen, the carrier gas flow rate is 1.0 mL / min, the injection volume is 0.8 μL, and the split ratio is 50:1. Isothermal separation is used, and the end time is 30 min.
[0033] Comparative Example 3 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the samples A and B and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an SPB-1701 capillary column; the column packing material is cyanopropylphenyl-substituted dimethylpolysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is a flame ionization detector; the detector temperature is 300 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 80:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0034] Comparative Example 4 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an SPB-1701 capillary column; the column packing material is cyanopropylphenyl-substituted dimethylpolysiloxane; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 1.0 μm; the column temperature is 80 ℃; the detector is a flame ionization detector; the detector temperature is 300 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0035] Comparative Example 5 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 1. The difference lies in step (2), where the samples A and B and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: the column is an Agilent DB-FFAP capillary column; the column packing material is nitro-terephthalic acid modified polyethylene glycol; the column length is 50 mm; the column inner diameter is 0.32 mm; the film thickness is 0.32 μm; the column temperature is 80 ℃; the detector is a flame ionization detector; the detector temperature is 300 ℃; the vaporization chamber temperature is 260 ℃; the carrier gas is nitrogen; the carrier gas flow rate is 1.0 mL / min; the injection volume is 0.8 μL; and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, and holds for 5 min. min, end time is 30 min.
[0036] Comparative Example 6 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 2. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: an Rxi-17 capillary column is used, the column packing material is phenyl-substituted polysiloxane, the column length is 50 mm, the inner diameter is 0.32 mm, the film thickness is 0.32 μm, the column temperature is 80 ℃, the detector is a flame ionization detector, the detector temperature is 300 ℃, the vaporization chamber temperature is 260 ℃, the carrier gas is nitrogen, the carrier gas flow rate is 1.0 mL / min, the injection volume is 0.8 μL, and the split ratio is 60:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, holds for 5 min, and ends at 30 ℃. min.
[0037] Comparative Example 7 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment, and process parameters used in each step are the same as in Example 2. The difference lies in step (2), where the test samples A and B, and the standard are all analyzed using a Shimadzu GC-2014C gas chromatograph. The chromatographic conditions are as follows: an Rxi-17 capillary column is used, the column packing material is phenyl-substituted polysiloxane, the column length is 50 mm, the column inner diameter is 0.32 mm, the film thickness is 0.32 μm, the column temperature is 80 ℃, the detector is a flame ionization detector, the detector temperature is 250 ℃, the vaporization chamber temperature is 260 ℃, the carrier gas is nitrogen, the carrier gas flow rate is 1.0 mL / min, the injection volume is 0.8 μL, and the split ratio is 50:1. The temperature program starts at 80 ℃, holds for 2 min, increases to 260 ℃ at 10 ℃ / min, holds for 5 min, and ends at 30 ℃. min.
[0038] Comparative Example 8 A quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol is provided. The steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (2), the chromatographic column is a Thermo Fisher TG-1 column and the chromatographic column packing is polysiloxane.
[0039] Table 2 - Results of testing samples using the methods described in the embodiments and comparative examples of this application. like Figure 3 As shown in Table 1, in Examples 1-5 of this application, when gas chromatography was used to quantitatively analyze sample A containing bis(2-hydroxyethyl) disulfide and mercaptoethanol, the chromatographic conditions were optimized to achieve high accuracy, small error, and good peak separation, thus enabling rapid and accurate quantification of the two components, bis(2-hydroxyethyl) disulfide and mercaptoethanol.
[0040] In Example 1 of this application, the gas chromatography uses a flame ionization detector. In contrast to Example 1, the gas chromatography in Comparative Example 1 uses an electron capture detector. Since the electron capture detector has a significant response to compounds of elements with strong electronegativity, it does not have a significant response or selectivity when detecting bis(2-hydroxyethyl) disulfide and mercaptoethanol compounds, resulting in the inability to accurately test the content.
[0041] In Example 1 of this application, the gas chromatography uses a programmed temperature ramp method to control the temperature of the chromatographic column, while Comparative Example 2 uses an isothermal separation method. Due to the large difference in boiling points and polarities between the two target compounds in this application, there is no single temperature point that can simultaneously satisfy the optimal chromatographic retention behavior of both. The programmed temperature ramp provides personalized separation conditions for each compound by dynamically adjusting the temperature, thereby better widening the gap in retention times between bis(2-hydroxyethyl) disulfide and mercaptoethanol, and ensuring baseline separation.
[0042] In Examples 1 and 5 of this application, the split ratio of gas chromatography is (40-50):1, while in Comparative Example 3, the split ratio of gas chromatography is 80:1. Due to the excessively large split ratio, nonlinear response and peak overlap occur, resulting in inaccurate final test concentrations of bis(2-hydroxyethyl) disulfide and mercaptoethanol with large errors.
[0043] In Example 1 of this application, the gas chromatograph has a membrane thickness of 0.32 μm. Compared with Example 1, the gas chromatograph of Comparative Example 4 has a membrane thickness of 1 μm. The excessive membrane thickness leads to slower mass transfer and lower capacity in the separation system, which affects the detection accuracy of the target analyte.
[0044] In Example 1 of this application, the gas chromatograph column packing material is cyanopropylphenyl-substituted dimethyl polysiloxane. In contrast, in Comparative Example 5, the gas chromatograph column packing material is cross-linked polyethylene glycol. This column packing material is a linear, homogeneous, and strongly polar polymer. Bis(2-hydroxyethyl) disulfide and mercaptoethanol molecules will undergo very strong, irreversible, or partially reversible hydrogen bond adsorption with polar sites on the stationary phase. The molecules desorb slowly on the stationary phase, resulting in severe peak tailing. Furthermore, some molecules are permanently adsorbed at the column head or inside the column and cannot reach the detector, leading to a decrease in sensitivity.
[0045] In Examples 1 and 3-4 of this application, the detector temperature of the gas chromatograph is 280-320 ℃, while the detector temperature of the gas chromatograph in Comparative Example 7 is 250 ℃. The detector temperature of Comparative Example 7 is too low, and the sensitivity of the detector is not optimal, which indirectly leads to poorer precision of the sample results, slightly lower systematic response values, resulting in the loss of some samples and lower results.
[0046] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.
Claims
1. A method for the quantitative detection of a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol, characterized in that, Includes the following steps: (1) Prepare standard solutions of bis(2-hydroxyethyl) disulfide and mercaptoethanol of different concentrations respectively; (2) The standard solution and the test sample are quantitatively measured by gas chromatography equipment. A standard curve is plotted based on the test results of the standard solution. The test sample is quantitatively analyzed by combining the standard curve and the chromatogram of the standard solution. In step (2), the chromatographic conditions are as follows: the column packing material is phenyl or cyanopropylphenyl-substituted dimethyl polysiloxane, the film thickness is 0.3-0.4 μm, the column temperature is 70-90 ℃, the detector is a flame ionization detector, the detector temperature is 280-320 ℃, the split ratio is (40-50):1, the initial temperature of the temperature program is 70-90 ℃, held for 1-3 min, then increased to 250-270 ℃ at 8-12 ℃ / min, and held for 3-8 min.
2. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, In the chromatographic conditions of step (2), the temperature of the vaporization chamber is 200-280 °C.
3. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, In the chromatographic conditions of step (2), the carrier gas is nitrogen and the carrier gas flow rate is 0.5-2 mL / min.
4. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, In the chromatographic conditions of step (2), the injection volume is 0.3-1.5 μL.
5. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, In step (1), the concentrations of the bis(2-hydroxyethyl) disulfide standard solution and the mercaptoethanol standard solution are independent and range from 0 to 10,000 mg / kg.
6. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, The gas chromatograph equipment is an Agilent gas chromatograph 7820A, Agilent gas chromatograph 7890A, Agilent 8860, Shimadzu 2030, Shimadzu 2010, Shimadzu GC-2010Plus or Shimadzu GC-2014C.
7. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, The sample to be tested is pre-treated to remove moisture using at least one of 3A molecular sieve, 4A molecular sieve, anhydrous sodium sulfate, anhydrous magnesium sulfate, and phosphorus pentoxide.
8. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, The standard solution includes an organic solvent, which is at least one selected from acetonitrile, methanol, isopropanol, ethanol, acetone, N,N-dimethylformamide, and dimethyl sulfoxide.
9. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, The chromatographic column is an SPB-1701 capillary column or an Rxi-17 capillary column.
10. The quantitative detection method for a mixture of bis(2-hydroxyethyl) disulfide and mercaptoethanol as described in claim 1, characterized in that, The chromatographic column has a length of 40-60 mm and an inner diameter of 0.3-0.4 mm.