Method for detecting intermediate product methanol in preparation of low-methanol-grade glutaraldehyde from acetylene and application thereof

Abstract

The invention provides a method for detecting an intermediate product methanol of acetylene-to-low methanol-grade glutaraldehyde and application thereof, and the method comprises the following steps: detecting a to-be-detected sample solution and a standard solution by using a quartz glass capillary chromatographic column of which the inner wall is coated with an OV-1701 stationary liquid and a gas chromatograph provided with a hydrogen flame ion test detector, a to-be-detected sample is directly injected and vaporized after being injected, flows through the chromatographic column, is detected by the detector, and is quantified by adopting an area normalization method after the peak area of each component is measured. The methanol detection method provided by the invention can detect low-content methanol in a sample, and is high in sensitivity, good in accuracy and good in stability; the low-methanol-grade glutaraldehyde product can be delivered after being confirmed to be qualified through inspection and an inspection report is issued, so that the delivery qualification rate is ensured.

Description

Technical Field

[0001] The invention belongs to the field of analysis and detection, and particularly relates to a method for detecting methanol, an intermediate product of preparing low-methanol-grade glutaraldehyde from acetylene, and application thereof. Background Art

[0002] Glutaraldehyde is an organic compound with the chemical formula C5H8O2. It is a colorless or light yellow transparent liquid that is soluble in water and easily soluble in organic solvents such as ethanol and ether. Glutaraldehyde is an important chemical product that is widely used in medical and industrial production.

[0003] Glutaraldehyde is a broad-spectrum, fast-acting chemical fungicide with a strong killing effect against bacteria, viruses, mycobacteria, molds, and bacterial spores. It is also used in cosmetic preservation and has good compatibility with surfactants, but is incompatible with proteins. It is also a permitted food preservative, used to preserve fruits and vegetables. The two aldehyde groups of glutaraldehyde are excellent protein crosslinkers and are also widely used in leather making and photographic reagents. In the textile and papermaking industries, it can be used as a crosslinker and curing agent. Glutaraldehyde is commonly used as a fungicide, food processing aid, disinfectant, tanning agent, wood preservative, pharmaceutical, and raw material for polymer synthesis. Glutaraldehyde is irritating to the skin and mucous membranes of humans and animals.

[0004] CN107903157A discloses a method for preparing glutaraldehyde, which uses acetylene, methanol, and acrolein as raw materials to produce 2-methoxy-3,4-dihydropyran, and then hydrolyzes 2-methoxy-3,4-dihydropyran under negative pressure to prepare glutaraldehyde. When acetylene is used to prepare the middle of glutaraldehyde, an intermediate low methanol (low methanol refers to low-content methanol) will be produced. Whether glutaraldehyde is qualified after leaving the factory is crucial to the detection and analysis of low methanol content. However, there is currently no detection method specifically for methanol in low methanol-grade glutaraldehyde. Therefore, developing a method for analyzing the intermediate product methanol of glutaraldehyde prepared from acetylene has important application value. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for detecting methanol, an intermediate product of acetylene-based low-methanol-grade glutaraldehyde, and its application. The present invention adjusts various instruments under certain conditions, waits for the baseline to stabilize, quickly injects the sample with a micro-injector, and directly injects the sample into the vaporized state. The sample flows through the aged chromatographic column, thereby separating the components in the sample. The separated components are then detected by a gas chromatograph. After the gas chromatograph detects the components, a chromatographic data processor or a chromatographic workstation calculates the content of each component using an area normalization method. The detection method provided by the present invention can detect low levels of methanol in the sample with high sensitivity, good accuracy, and good stability. The low-methanol-grade glutaraldehyde product can only be shipped after being tested and confirmed to be qualified and a test report is issued, thereby ensuring the qualified rate of the product.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for detecting methanol, an intermediate product of the production of low-methanol-grade glutaraldehyde from acetylene. The method comprises: using a quartz glass capillary chromatographic column with an inner wall coated with OV-1701 stationary liquid and a gas chromatograph equipped with a hydrogen flame ionization detector to detect a sample solution and a standard solution. After the sample is injected, it is directly vaporized and flows through the chromatographic column, and then detected by a detector. After the peak area of ​​each component is measured, the peak area is quantified using an area normalization method.

[0008] In the present invention, a quartz glass capillary chromatographic column coated with OV-1701 stationary liquid is used to detect methanol, an intermediate product in the production of low-methanol-grade glutaraldehyde from acetylene. The chromatographic column is a medium-polarity column with good separation effect for methanol and glutaraldehyde and is resistant to acid corrosion.

[0009] Preferably, the capillary chromatographic column is made of elastic quartz capillary; the column specifications are (28-30)m×(0.3-0.32)mm×(0.45-0.50)μm.

[0010] Preferably, the capillary chromatographic column further includes an aging step of the chromatographic column before use, the aging step comprising: connecting the chromatographic inlet end to the vaporization chamber, temporarily not connecting the outlet end to the detector, introducing carrier gas at a flow rate of 18-20 mL / min (for example, 18 mL / min, 19 mL / min or 20 mL / min, etc.), and aging at a temperature of 220-230° C. for at least 24 hours, and connecting the column outlet end to the detector after aging.

[0011] Preferably, the vaporization temperature of the gas chromatograph is 130-140°C, for example, it can be 130°C, 132°C, 134°C, 135°C, 136°C, 138°C or 140°C.

[0012] Preferably, the detection temperature of the gas chromatograph is 220-230°C, for example, it can be 220°C, 222°C, 224°C, 225°C, 226°C, 228°C or 230°C.

[0013] Preferably, the column box temperature of the gas chromatograph is 230-250°C, for example, it can be 230°C, 235°C, 240°C, 245°C or 250°C.

[0014] Preferably, the carrier gas N2 flow rate during gas chromatograph detection is 25-30 mL / min, for example, it can be 25 mL / min, 26 mL / min, 27 mL / min, 28 mL / min, 29 mL / min or 30 mL / min, the hydrogen flow rate is 20-22 mL / min, for example, it can be 20 mL / min, 21 mL / min or 22 mL / min, and the supporting gas flow rate is 290-300 mL / min, for example, it can be 290 mL / min, 292 mL / min, 294 mL / min, 295 mL / min, 296 mL / min, 298 mL / min or 300 mL / min, etc.

[0015] Preferably, the injection volume of the gas chromatograph is 0.1-0.2 μL, for example, 0.1 μL, 0.15 μL or 0.2 μL.

[0016] In the present invention, the purity of the carrier gas N2 is not less than 99.99%; the purity of the hydrogen is not less than 99.99%; and the combustion-supporting gas is purified air.

[0017] In the present invention, the standard solution is methanol, and the purity is not less than 99.99%.

[0018] Preferably, the gas chromatograph is also calibrated before detection, and the calibration step includes: adjusting various instruments under the condition of an injection volume of 0.1-0.2 μL, and after the baseline is stable, injecting 0.1-0.2 μL again, performing gas chromatography detection, and using a chromatography data processor or a chromatography workstation to calculate the content of each component using the area normalization method; repeating the above steps to perform a second experiment, and the difference between the two experimental results should be less than or equal to 0.5%, indicating that the calibration is completed.

[0019] In the present invention, various instruments are adjusted under the condition that the injection volume during calibration is 0.1-0.2 μL. After the baseline is stabilized, 0.1-0.2 μL of sample is quickly injected using a microinjector. After the sample is directly injected and vaporized, the sample flows through an aged chromatographic column, thereby separating the components in the sample. The separated components are then detected by a gas chromatograph. After the gas chromatograph detects the components, a chromatographic data processor or a chromatographic workstation calculates the content of each component using an area normalization method. The above steps are repeated to perform a second experiment. The difference between the two experimental results should be less than or equal to 0.1%, indicating that the calibration is complete. If the difference between the two experimental results is greater than 0.1%, the chromatographic column is re-aged and a second parallel experiment is performed for detection.

[0020] In a second aspect, the present invention provides application of the method for detecting methanol, an intermediate product of acetylene-based low-methanol-grade glutaraldehyde, described in the first aspect, in the production and detection analysis of glutaraldehyde.

[0021] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention provides a method for detecting methanol, an intermediate product of acetylene-based low-methanol-grade glutaraldehyde. The method comprises adjusting various instruments according to the following conditions: a vaporization temperature of 130-140° C., a detection temperature of 220-230° C., a column box temperature of 230-250° C., a carrier gas N2 flow rate of 25-30 mL / min, a hydrogen flow rate of 20-22 mL / min, an oxidant gas flow rate of 290-300 mL / min, and an injection volume of 0.1-0.2 μL. After a baseline is stabilized, 0.2 μL of the sample is rapidly injected using a microinjector. After the sample is directly injected and vaporized, the sample flows through an aged chromatographic column, thereby separating various components in the sample. The separated components are then detected by a gas chromatograph. After the gas chromatograph detects the various components, a chromatographic data processor or a chromatographic workstation calculates the content of the various components by using an area normalization method. The products are shipped only after being tested and confirmed as qualified according to a test method specified in this standard and a test report is issued, thereby ensuring a qualified rate before shipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The graph and analysis results of Example 1 are shown in FIG.

[0025] Figure 2 The graph and analysis results of Example 2 are shown. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0027] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0028] The quartz glass capillary chromatographic column with the inner wall coated with OV-1701 stationary liquid was purchased from Agilent Technologies (China) Co., Ltd.

[0029] Example 1

[0030] This example provides a method for detecting methanol, an intermediate product in the production of low-methanol-grade glutaraldehyde from acetylene. The method utilizes a quartz glass capillary chromatographic column coated with OV-1701 stationary phase and a gas chromatograph equipped with a hydrogen flame ionization detector. The sample is directly injected, vaporized, and passed through the chromatographic column to separate its components. The sample is then detected by a detector, and the peak area of ​​each component is measured and quantified using area normalization. The method comprises the following steps:

[0031] (1) Preparation of reagents and materials

[0032] Fixative: OV-1701.

[0033] Carrier (N2): purity not less than 99.99%.

[0034] Fuel gas: hydrogen, with a purity of not less than 99.99%.

[0035] Combustion-supporting gas: air, purified.

[0036] (2) Preparation of instruments and equipment

[0037] Gas chromatograph: equipped with hydrogen flame ionization detector, the sensitivity and stability meet the requirements of GB / T9722.

[0038] Chromatography data processor or chromatography workstation.

[0039] Injection system: split flow injection device with quartz liner.

[0040] Chromatographic column:

[0041] a. Column material: elastic quartz capillary.

[0042] b. Column specifications: 30m×0.32mm×0.50μm.

[0043] c. Fixative: OV-1701.

[0044] Microinjector: 1 μL.

[0045] Aging of the chromatographic column: Connect the chromatographic inlet to the vaporization chamber, do not connect the outlet to the detector for the time being, introduce carrier gas (N2) at a flow rate of 20 mL / min, and age at this temperature for at least 24 hours. After aging, connect the column outlet to the detector.

[0046] (3) Detection method

[0047] Various instruments were adjusted according to the following conditions: vaporization temperature: 140°C, detection temperature: 230°C, column box temperature: 230°C, carrier gas (N2): 30 mL / min, hydrogen: 22 mL / min, air: 300 mL / min, injection volume: 0.1 μL.

[0048] After the baseline is stable, 0.2 μL of sample is quickly injected using a micro-injector. After the sample is directly injected and vaporized, the sample flows through the aged chromatographic column, thereby separating the components in the sample.

[0049] The separated components are then detected by a gas chromatograph. After the gas chromatograph detects the components, a chromatographic data processor or a chromatographic workstation calculates the content of the components using an area normalization method.

[0050] Repeat the above steps to conduct a second experiment. The difference between the two experimental results should not be greater than 0.1%.

[0051] Figure 1 The graph and analysis results of Example 1. As can be seen from the results, the peak time is stable, the peak separation effect is obvious, there is no tailing, the data authenticity is high, and the repeatability of multiple tests is good.

[0052] Example 2

[0053] This embodiment provides a method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde. The method is carried out with reference to Example 1, except that the chromatographic conditions are as follows:

[0054] Various instruments were adjusted according to the following conditions: vaporization temperature: 130°C, detection temperature: 220°C, column box temperature: 230°C, carrier gas (N2): 25 mL / min, hydrogen: 20 mL / min, air: 290 mL / min, injection volume: 0.2 μL.

[0055] Figure 2 The graph and analysis results of Example 2. As can be seen from the results, the peak time is stable, the peak separation effect is obvious, there is no tailing, the data authenticity is high, and the repeatability of multiple tests is good.

[0056] Example 3

[0057] This example examines the accuracy of the method for detecting methanol, an intermediate product of acetylene to low-methanol-grade glutaraldehyde.

[0058] The experimental steps include:

[0059] (1) Prepare three methanol standard solutions of different concentrations (low, medium, and high), and prepare three replicates of each concentration.

[0060] (2) Detection was performed according to the chromatographic conditions of Example 1, and the peak area of ​​methanol was recorded.

[0061] (3) The recovery rate was calculated based on the standard curve using the formula: Recovery rate (%) = measured concentration / theoretical concentration × 100%.

[0062] The results are shown in Table 1 below.

[0063] Table 1

[0064] Concentration level Average recovery rate (%) RSD (%) Low concentration 98.5 1.2 Medium concentration 99.8 0.8 High concentration 100.3 0.6

[0065] The results showed that the average recovery of the method was 98.5%-100.3%, RSD≤1.2%, which met the detection requirements and had good accuracy.

[0066] Example 4

[0067] This example investigates the durability of a method for detecting methanol, an intermediate product of acetylene-based production of low-methanol-grade glutaraldehyde.

[0068] The experimental steps include:

[0069] (1) Fine-tune the chromatographic conditions: column temperature ±5°C, carrier gas flow rate ±5 mL / min, injection volume ±0.05 μL. Except for the fine-tuned conditions, the remaining steps were carried out as in Example 1.

[0070] (2) The measurement was repeated three times under each condition, and the RSD of the methanol content was calculated.

[0071] The results are shown in Table 2 below:

[0072] Table 2

[0073] Changing conditions RSD (%) Column temperature 235℃ (-5℃) 1.3 Column temperature 245℃ (+5℃) 1.5 Carrier gas flow rate 28mL / min 1.2 Injection volume 0.15 μL 1.0

[0074] The results show that the RSD is ≤1.5% when the parameters change slightly, and the method has good robustness.

[0075] Comparative Example 1

[0076] This comparative example investigates the detection effects of different chromatographic columns. The experimental steps include:

[0077] (1) Using the same sample, an OV-1701 column (the chromatographic column in Example 1) and a DB-5 column (specifications: 30 m×0.32 mm×0.25 μm) were used for detection. The remaining steps were carried out in accordance with Example 1.

[0078] (2) Compare the separation and peak shape of methanol.

[0079] The results are as follows: when the OV-1701 column is used for detection, the symmetry factor of the methanol peak is 0.98, and the separation degree is ≥1.5; when the DB-5 column is used for detection, the methanol peak is tailing (symmetry factor 1.3), and the separation degree from the impurities is ≤1.0; the above comparison results show that the chromatographic column selected by the present invention has a better separation effect.

[0080] Comparative Example 2

[0081] This comparative example investigates the effect of carrier gas flow rate on the detection effect. The experimental steps include:

[0082] (1) Set the carrier gas flow rate to 20 mL / min and measure the methanol content. The remaining steps are carried out as in Example 1. Compare the results with those at carrier gas flow rates of 25 mL / min and 30 mL / min.

[0083] The results are as follows: When the carrier gas flow rate was 25 mL / min and 30 mL / min, the methanol content was 15.2 ppm and 15.6 ppm, and the RSD was 0.7% and 1.1%; when the condition (1) was used for detection, the methanol content was 14.1 ppm, RSD = 2.5%, and the peak broadening was obvious.

[0084] The results showed that the unoptimized conditions (20 mL / min) led to an increase in the deviation of the test results, verifying the rationality of the parameters of the present invention.

[0085] In summary, the present invention provides a method for detecting methanol, an intermediate product of low-methanol-grade glutaraldehyde produced from acetylene, which solves the problem in the prior art of the lack of an analytical method for detecting low-methanol intermediate products of glutaraldehyde produced from acetylene. Products can only be shipped after being tested and confirmed as qualified according to the test method provided by the present invention and a test report is issued, thereby ensuring the qualified rate before shipment.

[0086] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for detecting methanol, an intermediate product of acetylene to low-methanol-grade glutaraldehyde, characterized in that: The method comprises: using a quartz glass capillary chromatographic column with an inner wall coated with OV-1701 stationary liquid and a gas chromatograph equipped with a hydrogen flame ionization detector to detect a sample solution and a standard solution; after the sample is injected, it is directly injected and vaporized, flows through the chromatographic column, and is then detected by a detector; after the peak area of ​​each component is measured, an area normalization method is used for quantification.

2. The method for detecting methanol, an intermediate product of acetylene to low-methanol-grade glutaraldehyde according to claim 1, is characterized in that: The capillary chromatographic column is made of elastic quartz capillary; the column specifications are (28-30)m×(0.3-0.32)mm×(0.45-0.50)μm.

3. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde according to claim 1 or 2, wherein: The capillary chromatographic column also includes an aging step before use. The aging step includes: connecting the chromatographic inlet end to the vaporization chamber, temporarily not connecting the outlet end to the detector, introducing carrier gas at a flow rate of 18-20 mL / min, and aging at a temperature of 220-230° C. for at least 24 hours. After aging, the column outlet end is connected to the detector.

4. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 3, characterized in that: The vaporization temperature of the gas chromatograph is 130-140°C.

5. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 4, characterized in that: The detection temperature of the gas chromatograph is 220-230°C.

6. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 5, characterized in that: The column box temperature of the gas chromatograph is 230-250°C.

7. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 6, characterized in that: The carrier gas N2 flow rate during the gas chromatograph detection is 25-30 mL / min, the hydrogen flow rate is 20-22 mL / min, and the oxidant gas flow rate is 290-300 mL / min.

8. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 7, characterized in that: The injection volume of the gas chromatograph is 0.1-0.2 μL.

9. The method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 8, characterized in that: Before detection, the gas chromatograph is also calibrated. The calibration steps include: adjusting various instruments under the condition of a sample volume of 0.1-0.2 μL, after the baseline is stable, injecting 0.1-0.2 μL again, performing gas chromatography detection, and using a chromatography data processor or a chromatography workstation to calculate the content of each component using the area normalization method; repeating the above steps to perform a second experiment. The difference between the two experimental results should be less than or equal to 0.1%, indicating that the calibration is complete.

10. Use of the method for detecting methanol, an intermediate product of acetylene-to-low-methanol-grade glutaraldehyde, according to any one of claims 1 to 9, in glutaraldehyde production and detection analysis.

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