A method for detecting related substances in acetaldehyde

Abstract

The present invention relates to the technical field of analytical chemistry, and specifically discloses a method for detecting related substances in acetaldehyde, comprising the following steps: preparing a test solution; taking the test solution and detecting the test solution by gas chromatography, wherein the chromatographic conditions include: the stationary phase of the chromatographic column is polyethylene glycol or nitroterephthalic acid-modified polyethylene glycol, the detector is a hydrogen flame ionization detector, and the detector temperature is 200-300° C.; 35-50° C. is maintained for 5-15 min, and then the temperature is increased to 210-230° C. at a rate of 5-15° C. / min, and maintained for 5-15 min; the injection port temperature is 140-180° C. The detection method provided by the present invention can simultaneously detect propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in acetaldehyde, realize the effective separation and quantitative detection of propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid, and the detection method is convenient, efficient and accurate.

Description

Technical Field

[0001] The invention relates to the technical field of analytical chemistry, and in particular to a method for detecting related substances in acetaldehyde. Background Art

[0002] Acetaldehyde, also known as acetic aldehyde, has a chemical formula of CH3CHO. It is the basic raw material for synthetic drugs, pesticides, spices and other fine organic chemical products and has important industrial application value.

[0003] In the synthesis process of acetaldehyde, process impurities such as propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid inevitably appear, which directly affects the application of acetaldehyde. In particular, the pharmaceutical industry has higher requirements for drug purity. Therefore, the content of these components needs to be strictly controlled.

[0004] Currently, there is no report on the method for simultaneously detecting propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in acetaldehyde in the prior art, and the separate detection of each substance is bound to increase the complexity of the detection work, resulting in a waste of detection resources and reduced work efficiency. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for detecting related substances in acetaldehyde, which can effectively separate and quantitatively detect propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in acetaldehyde at the same time. The detection method is convenient, efficient and accurate.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution provided by the present invention is:

[0007] A method for detecting related substances in acetaldehyde, wherein the related substances include propionaldehyde, formaldehyde, ethanol, paraldehyde and acetic acid, and the detection method comprises the following steps:

[0008] (1) Prepare the test solution: Take an acetaldehyde sample and prepare a test solution with a solvent;

[0009] (2) Take the test solution and test it according to the following gas chromatography conditions:

[0010] Chromatographic column: capillary column with polyethylene glycol or nitroterephthalic acid-modified polyethylene glycol as the stationary phase;

[0011] Detector: Hydrogen flame ionization detector;

[0012] Detector temperature: 200-300℃;

[0013] Column temperature: 35-50℃ for 5-15min, then increase the temperature to 210℃-230℃ at a rate of 5-15℃ / min, and maintain for 5-15min;

[0014] Inlet temperature: 140-180℃.

[0015] Compared with the prior art, the detection method of related substances in acetaldehyde provided by the present invention adopts gas chromatography, and cooperates with gas chromatography conditions such as specific program temperature rising mode, specific detector temperature, injection port temperature, etc., to effectively separate and quantitatively detect propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in acetaldehyde. And the methodological verification shows that the detection method of related substances in acetaldehyde provided by the present invention has good specificity, accuracy, sensitivity, repeatability, stability, durability, and is easy to operate, providing a reliable reference basis for the detection of propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in acetaldehyde, and has high practical value.

[0016] Further optionally, the detector temperature is 250°C and the injection port temperature is 150°C.

[0017] Further optionally, the column temperature is: maintained at 40°C for 10 minutes, then raised to 220°C at a rate of 10°C per minute, and maintained for 10 minutes. Optionally, the carrier gas is nitrogen, the column flow rate is 2.5-3.5 mL / min, and the split ratio is 5:1-20:1.

[0018] Optionally, the carrier gas is nitrogen, the column flow rate is 2.5-3.5 mL / min, and the split ratio is 5:1-20:1.

[0019] Further optionally, the column flow rate is 3 mL / min and the split ratio is 10:1.

[0020] Optionally, the chromatographic column has a column length of 15-60 mL, an inner diameter of 0.25-0.53 mm, and a stationary phase coating liquid film thickness of 0.1-1.0 μm.

[0021] Further optionally, the model of the chromatographic column is HP-FFAP.

[0022] Optionally, the injection volume is 1 μL.

[0023] By limiting the column flow rate, split ratio and injection volume, the separation degree of propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid can be further improved.

[0024] Optionally, the concentration of the test solution is 90-110 mg / mL.

[0025] By limiting the concentration of the test solution, the peak shapes of propionaldehyde, formaldehyde, ethanol, paraldehyde and acetic acid are better, the column efficiency is higher, and the integration is more accurate, which is beneficial to the effective separation of propionaldehyde, formaldehyde, ethanol, paraldehyde and acetic acid in the test sample, and more accurate calculation of the contents of propionaldehyde, formaldehyde, ethanol, paraldehyde and acetic acid.

[0026] Optionally, the solvent is dimethyl sulfoxide.

[0027] Dimethyl sulfoxide is used as a solvent, which can extract propionaldehyde, formaldehyde, ethanol, paraldehyde and acetic acid from acetaldehyde, and has substantially no interference with gas chromatography detection, thereby ensuring that the gas chromatography detection result provided by the present invention is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The gas chromatogram of the blank solution provided in Example 1 of the present invention;

[0029] Figure 2 A gas chromatogram of the mixed solution provided in Example 1 of the present invention;

[0030] Figure 3 This is a gas chromatogram of the test solution provided in Example 5 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Example 1

[0033] Exclusive inspection

[0034] (1) Prepare blank solution and spiked sample solution:

[0035] The blank solution was dimethyl sulfoxide solvent.

[0036] Take appropriate amounts of propionaldehyde reference substance, formaldehyde standard solution, ethanol reference substance, paraldehyde reference substance, acetic acid reference substance and acetaldehyde sample, accurately weigh them, dissolve them in dimethyl sulfoxide and prepare a mixed solution containing 100 μg of propionaldehyde, 100 μg of formaldehyde, 500 μg of ethanol, 10000 μg of paraldehyde, 500 μg of acetic acid and 20 μg of acetaldehyde per 1 mL.

[0037] (2) The blank solution and the mixed solution are tested by gas chromatography, and the gas chromatography conditions are:

[0038] The model of the chromatographic column is HP-FFAP (30m×0.053mm×1m), the detector is a hydrogen flame ionization detector, the detector temperature is 250°C, and the carrier gas is nitrogen; the column flow rate is 3mL / min; the split ratio is 10:1; the injection volume is 1μL; the starting temperature is 40°C, maintained for 10 minutes, and then increased to 220°C at a rate of 10°C per minute and maintained for 10 minutes; the injection port temperature is 150°C.

[0039] The chromatogram results recorded are as follows Figure 1 , 2 As shown, Figure 1 is the chromatogram of the blank solution. Figure 2 It is the chromatogram of the mixed solution, wherein the detection results of the mixed solution are shown in Table 1.

[0040] Table 1 Specificity test results

[0041] Specificity comparison Retention time Peak area Separation Theoretical plates Acetaldehyde 3.258 47717 -- 24044 Propionaldehyde 4.107 93736 8.492 20118 formaldehyde 6.348 9737 13.990 15411 Ethanol 7.636 507836 5.793 16157 Paraldehyde 14.424 8647341 35.155 156453 Acetic acid 22.608 279520 65.896 778118 Dimethyl sulfoxide 24.278 - 5.659 39656

[0042] The test results show that the blank solvent does not interfere with the detection of acetaldehyde, propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid, the chromatographic peak separation of each substance is good, there is no interference between the substances, and the specificity requirements are met. The detection method of related substances in acetaldehyde provided by the present invention has good specificity.

[0043] Example 2

[0044] Limit of detection and limit of quantification

[0045] Take an appropriate amount of propionaldehyde reference substance, accurately weigh it, dissolve it in dimethyl sulfoxide and quantitatively dilute it to prepare reference substance solutions of different concentrations. Use the same method to prepare reference substance solutions of formaldehyde standard solution, ethanol reference substance, triacetaldehyde reference substance, and acetic acid reference substance respectively. Detect according to the chromatographic conditions in Example 1, and the quantitative limit is when the peak height is 10 times the baseline noise; the detection limit is when the peak height is 3 times the baseline noise. The specific test results are shown in Table 2. And according to the quantitative limit concentration, prepare 6 reference substance solutions containing propionaldehyde reference substance, formaldehyde standard solution, ethanol reference substance, triacetaldehyde reference substance, and acetic acid reference substance, respectively, and detect according to the gas chromatography conditions in Example 1. The results are shown in Table 3.

[0046] Table 2 Results of limit of quantitation and limit of detection tests

[0047]

[0048] Note: Equivalent to sample % refers to the proportion of each substance in the acetaldehyde sample in the mixed solution.

[0049] Table 3 Results of repeatability test of limit of quantitation

[0050] Element 1 2 3 4 5 6 RSD% Propionaldehyde 2145 2275 2345 2414 2394 2124 5.46 formaldehyde 2473 2423 2312 2475 2294 2307 3.61 Ethanol 4898 5023 4495 4786 4821 5181 4.78 Paraldehyde 3002 3086 3079 3073 3055 3064 0.99 Acetic acid 2363 2376 2383 2422 2394 2391 0.84

[0051] It can be seen from the data in Tables 2 and 3 that the quantitative limit solution was repeatedly injected 6 times, and the maximum RSD of the peak area of ​​each substance was 5.46%, and the quantitative limit and detection limit of propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid were all in the microgram level, indicating that the detection method provided by the present invention has high sensitivity and good repeatability of quantitative limit, and can accurately and quantitatively detect propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in the test solution.

[0052] Example 3

[0053] Linear inspection

[0054] Take an appropriate amount of propionaldehyde reference substance, accurately weigh it, dissolve it in dimethyl sulfoxide and quantitatively dilute it to prepare a series of concentration reference substance solutions. Use the same method to prepare reference substance solutions of formaldehyde standard solution, ethanol reference substance, triacetaldehyde reference substance, and acetic acid reference substance respectively. Detect according to the chromatographic conditions in Example 1, record the chromatogram, measure the peak area, and make a linear regression curve with concentration (μg / mL) as the horizontal coordinate and peak area as the vertical coordinate. The test results are shown in Tables 4-8.

[0055] Table 4 Propionaldehyde linear test results

[0056]

[0057] Table 5 Formaldehyde linear test results

[0058]

[0059] Table 6 Ethanol linearity test results

[0060]

[0061] Table 7 Results of linear test of triacetaldehyde

[0062]

[0063] Table 8 Benzene acetate linear test results

[0064]

[0065] From the data in Tables 4-8, it can be seen that propionaldehyde has good linearity in the range of 2.79-225.04 μg / mL, formaldehyde has good linearity in the range of 19.38-193.8 μg / mL, ethanol has good linearity in the range of 5.50-1007.00 μg / mL, triacetaldehyde has good linearity in the range of 4.03-19869.73 μg / mL, and phenyl acetate has good linearity in the range of 5.14-991.30 μg / mL.

[0066] Example 4

[0067] Recovery rate investigation

[0068] Take appropriate amount of propionaldehyde reference substance, ethanol reference substance and triacetaldehyde reference substance, accurately weigh them, dissolve them with dimethyl sulfoxide and quantitatively dilute them to prepare a mixed solution containing approximately 1000 μg of propionaldehyde, 4500 μg of ethanol and 88000 μg of triacetaldehyde reference substance per 1 mL as the stock solution; take 1.0 g of acetaldehyde sample, accurately weigh it, put it in a 10 mL volumetric flask, prepare 9 portions in parallel, then add appropriate amount of stock solution to make the concentration of each component at three levels of low, medium and high, prepare 3 portions in parallel for each concentration, then make up to the scale with dimethyl sulfoxide, shake well, and use it as the spiked sample test solution for recovery detection; take appropriate amount of formaldehyde standard solution, quantitatively dilute it with dimethyl sulfoxide to prepare a solution containing approximately 1000 μg per 1 mL as the formaldehyde stock solution ; Take 1.0g of acetaldehyde sample, accurately weigh, place in 10mL volumetric flask, prepare 6 parts in parallel, then add 1ml of formaldehyde stock solution respectively, then dilute to scale with dimethyl sulfoxide, shake well, as the spiked sample test solution for formaldehyde recovery detection; Take an appropriate amount of acetic acid reference substance, accurately weigh, dissolve with dimethyl sulfoxide and quantitatively dilute to make a solution containing about 5000μg reference substance per 1mL, as acetic acid stock solution; Take 1.0g of acetaldehyde sample, accurately weigh, place in 10mL volumetric flask, prepare 9 parts in parallel, then add 0.5mL, 1.0mL, 1.5mL of acetic acid stock solution respectively, prepare 3 parts in parallel for each concentration, then dilute to scale with dimethyl sulfoxide, shake well, as the spiked sample test solution for acetic acid recovery detection. Detect according to the chromatographic conditions in Example 1, and the test results are shown in Tables 9-13.

[0069] Table 9 Propionaldehyde recovery test results

[0070]

[0071] Table 10 Formaldehyde recovery test results

[0072]

[0073]

[0074] Table 11 Ethanol recovery test results

[0075]

[0076] Table 12 Triacetaldehyde recovery test results 50 / 100 / 150

[0077]

[0078] Table 13 Acetic acid recovery test results

[0079]

[0080] From the data in Tables 9-13, it can be seen that the average recovery rate of propionaldehyde is 96.80%, and the RSD is 3.70%; the average recovery rate of formaldehyde is 111.02%, and the RSD is 4.22%; the average recovery rate of ethanol is 104.38%, and the RSD is 2.01%; the average recovery rate of triacetaldehyde is 101.92%, and the RSD is 0.85%; the average recovery rate of acetic acid is 105.98%, and the RSD is 7.07%, indicating that the detection method provided by the present invention has a good recovery rate.

[0081] Example 5

[0082] Repeatability test

[0083] Take an appropriate amount of acetaldehyde sample, accurately weigh it, and prepare 6 portions of 100 mg / mL test solution with dimethyl sulfoxide solvent. Detect it according to the chromatographic conditions in Example 1, and record the chromatographic column. The results are as follows: Figure 3 The test data are shown in Table 14.

[0084] Table 14 Repeatability results

[0085] Element 1 2 3 4 5 6 average value RSD% Propionaldehyde Not detected Not detected Not detected Not detected Not detected Not detected Not detected - formaldehyde Not detected Not detected Not detected Not detected Not detected Not detected Not detected - Ethanol Not detected Not detected Not detected Not detected Not detected Not detected Not detected - Paraldehyde 0.200 0.202 0.198 0.195 0.191 0.193 0.196 2.06 Acetic acid 0.286 0.299 0.302 0.299 0.299 0.323 0.301 3.92 purity% 99.39 99.373 99.364 99.350 99.334 99.350 99.360 0.020

[0086] It can be seen from the data in Table 14 that the detection method provided by the present invention has good repeatability.

[0087] Example 6

[0088] Stability test

[0089] The stability was investigated according to the solution preparation method and chromatographic conditions in Example 1. Samples were injected and tested at 0 h, 2 h, and 4 h, the chromatograms were recorded, and the RSD was calculated by the peak area. The test results are shown in Table 15.

[0090] Table 15 Solution stability results

[0091]

[0092]

[0093] It can be seen from the data in Table 15 that the peak areas of propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid in the test solution are stable within 4 hours, indicating that the detection method provided by the present invention has good stability.

[0094] Example 7

[0095] Durability test

[0096] Take appropriate amounts of propionaldehyde reference substance, formaldehyde standard solution, ethanol reference substance, triacetaldehyde reference substance and acetic acid reference substance, accurately weigh them, and quantitatively dilute them with dimethyl sulfoxide to make a mixed solution containing 1000μg propionaldehyde, 1000μg formaldehyde, 5000μg ethanol, 100000μg triacetaldehyde and 5000μg acetic acid per 1mL as the stock solution. Take 1.0g of acetaldehyde sample, accurately weigh it, place it in a 10mL volumetric flask, add 1mL of the stock solution respectively, and then dilute to the mark with dimethyl sulfoxide and shake well. Prepare 4 copies in parallel as the mixed solution for durability inspection.

[0097] The injection port temperature, initial temperature, heating rate and detector temperature were changed respectively, and other conditions were tested according to the chromatographic conditions of Example 1. The test results are shown in Tables 16-19.

[0098] Table 16 Separation of different injection port temperatures

[0099] Element Inlet 150℃ Inlet 145℃ Inlet 155℃ Propionaldehyde N / A N / A N / A formaldehyde 12.978 13.796 13.104 Ethanol 5.423 5.696 5.491 Paraldehyde 34.677 34.86 34.929 Acetic acid 65.527 64.789 66.012 Dimethyl sulfoxide 5.222 6.209 5.896

[0100] Table 17 Separation degree at different initial temperatures

[0101] Element Initial temperature 40℃ Initial temperature 38℃ Initial temperature 42℃ Propionaldehyde N / A N / A N / A formaldehyde 12.978 14.471 12.49 Ethanol 5.423 5.688 5.185 Paraldehyde 34.677 31.724 35.892 Acetic acid 65.527 66.287 65.695 Dimethyl sulfoxide 5.222 5.989 5.758

[0102] Table 18 Separation degree at different heating rates

[0103] Element Heating rate 10℃ / min Heating rate 9℃ / min Heating rate: 11℃ / min Propionaldehyde N / A N / A N / A formaldehyde 12.978 13.358 13.536 Ethanol 5.423 5.602 5.616 Paraldehyde 34.677 35.545 34.846 Acetic acid 65.527 67.185 64.855 Dimethyl sulfoxide 5.222 6.001. 5.784

[0104] Table 19 Separation of different detector temperatures

[0105] Element Detector 250℃ Detector 245℃ Detector 255℃ Propionaldehyde N / A N / A N / A formaldehyde 12.978 12.948 12.948 Ethanol 5.423 5.319 5.355 Paraldehyde 34.677 34.3 34.56 Acetic acid 65.527 66.75 66.475 Dimethyl sulfoxide 5.222 5.984 5.953

[0106] It can be seen from the data in Tables 16-19 that by changing the conditions such as the injection port temperature, initial temperature, heating rate and detector temperature, the separation degrees of propionaldehyde, formaldehyde, ethanol, triacetaldehyde and acetic acid all meet the requirements, indicating that the detection method provided by the present invention has good durability.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting related substances in acetaldehyde, characterized in that: The related substances include propionaldehyde, formaldehyde, ethanol, paraldehyde and acetic acid, and the detection method includes the following steps: (1) Prepare the test solution: Take an acetaldehyde sample and prepare a test solution with dimethyl sulfoxide; (2) Take the test solution and test it according to the following gas chromatography conditions: Chromatographic column: HP-FFAP; Detector: Hydrogen flame ionization detector; Detector temperature: 200-300℃; Column temperature: 40°C for 10 min, then raised to 220°C at a rate of 10°C / min and maintained for 10 min; Inlet temperature: 140-180℃.

2. The method for detecting related substances in acetaldehyde according to claim 1, characterized in that: The detector temperature was 250 °C and the injection port temperature was 150 °C.

3. The method for detecting related substances in acetaldehyde according to claim 1, characterized in that: The carrier gas was nitrogen, the column flow rate was 2.5-3.5 mL / min, and the split ratio was 5:1-20:

1.

4. The method for detecting related substances in acetaldehyde according to claim 3, characterized in that: The column flow rate was 3 mL / min and the split ratio was 10:

1.

5. The method for detecting related substances in acetaldehyde according to claim 1, characterized in that: The injection volume was 1 μL.

6. The method for detecting related substances in acetaldehyde according to claim 1, characterized in that: The concentration of the test solution is 90-110 mg / mL.

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