Method for detecting content of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate

Abstract

The invention relates to the technical field of chemical detection, in particular to a method for detecting the content of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate, which comprises the following steps: (1) respectively dissolving a standard substance and a sample to be detected by using acetonitrile to obtain a standard sample and a sample; (2) respectively detecting the standard sample and the sample by adopting a liquid chromatograph, and calculating the average peak area value of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate in a measured chromatogram by taking an acetonitrile / water / acid mixed system as a mobile phase; and (3) calculating the mass fraction X1 of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate in the sample. According to the detection method provided by the invention, the detected chromatographic peak shape is good, the integral calculation result is accurate, the repeatability is good, the obtained result is high in credibility, more accurate and timely, the specificity is strong, and the precision is good.

Description

Technical Field

[0001] The invention relates to the technical field of chemical detection, and in particular to a method for detecting the content of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate. Background Art

[0002] Trifloxystrobin is a synthetic analogue of the natural antibiotic strobilurin A with bactericidal activity. It belongs to the methoxyacrylate fungicide class and has good activity against imperfect fungi, basidiomycetes and oomycetes. (E)-Methyl 2-(methoxyimino)-2-(o-tolyl)acetate is an intermediate product in the synthesis of trifloxystrobin. Its English name is (E)-Methyl 2-(methoxyimino)-2-(o-tolyl)acetate, and its molecular formula is C 11 H 13 NO3, molecular weight is 207.22, (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester is an off-white powder, melting point is 66-68°C, and is easily soluble in organic solvents such as acetonitrile and methanol.

[0003] The quality of (E)2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester will affect the quality of trifloxystrobin, so its quality problem is also taken seriously. Chinese invention patent application CN 110845358 A provides a preparation method of (E)2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester, which can realize the conversion of (Z)2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester to obtain E-configuration product. In order to verify the effect of this technology, the mother liquor containing (E / Z)2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester mixture and the product after saponification of the mother liquor were tested by high-performance liquid chromatography using Shimadzu high-performance liquid chromatograph LC-20A. The chromatographic column was C18 (5μm, 4.6×150mm), the mobile phase was methanol / water = 40 / 60, the flow rate was 1.0mL / min, and the wavelength was 210nm. Under this condition, the elution times of the two isomers were 7.713 min and 24.988 min, respectively, and the elution times were longer.

[0004] In the process of preparing trifloxystrobin, Chinese invention patent application CN 117820163 A detected the content of the intermediate product by liquid chromatography, but did not describe the liquid chromatography conditions. In the prior art, the elution time of the (E)-isomer is about 5.5 min, and the elution time of the (Z)-isomer is about 7 min, and there is still room for improvement in the detection efficiency. Summary of the invention

[0005] Aiming at the technical problem that the existing method for detecting (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate has a slow peak output, the present invention provides a method for detecting the content of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate.

[0006] The technical solution of the present invention is as follows: A method for detecting the content of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate comprises the following steps: (1) Using acetonitrile to dissolve the standard substance and the sample to be tested respectively to obtain the standard sample and the test sample; (2) The standard sample and the sample were detected by liquid chromatography, with a mixed system of acetonitrile / water / acid as the mobile phase, and the volume ratio of acetonitrile, water, and acid being 40-60:60-40:0.05-0.1. The average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the measured chromatogram was calculated; (3) Calculate the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample according to the following formula: X 1: , In the formula, A 1 is the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetate in the standard sample, A 2 is the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample, m 1 is the mass of the standard substance, m 2 is the mass of the sample to be tested, P 1 is the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the standard substance.

[0007] Further, the detection wavelength of the liquid chromatograph is set to 230~260nm. At this wavelength, the ultraviolet absorption of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate is appropriate and stable, the linear range of the sample is wider, the peak area is appropriate, and the absorption is stable, which is conducive to improving the detection accuracy and stability; preferably, the detection wavelength of the liquid chromatograph is set to 254nm.

[0008] Furthermore, the liquid chromatograph adopts a C8 reverse phase chromatographic column; preferably, the C8 reverse phase chromatographic column has a column length of 100 mm, a column inner diameter of 3 to 4.6 mm, and a particle size of 1.9 to 2.7 μm. Compared with conventional 4 μm and 5 μm particle size chromatographic columns, the chromatographic column has a higher theoretical plate number and better separation, and the chromatographic peak shape obtained by using this chromatographic column is more symmetrical.

[0009] Furthermore, the temperature of the chromatographic column is 30-40°C, which is easy to control and can ensure the stability of the retention time, which is beneficial to improving the reproducibility of sample detection; preferably, the temperature of the chromatographic column is 30°C.

[0010] Furthermore, the acid in the mobile phase is selected from one of glacial acetic acid, formic acid, phosphoric acid and trifluoroacetic acid.

[0011] Furthermore, the flow rate of the mobile phase is 0.8~1.2mL / min. If the flow rate is <0.8mL / min, the analysis time will increase, and the chromatographic peak will be tailed, resulting in peak broadening and poor symmetry. If the flow rate is >1.2mL / min, although it will not have a significant impact on the separation and the analysis time will be reduced, it will cause the chromatograph system pressure to be too high. If it runs for a long time, the pressure will be too high, which will cause great damage to the instrument. Preferably, the flow rate of the mobile phase is 1.0mL / min.

[0012] Furthermore, the injection volume of each liquid chromatograph is 3 μL.

[0013] The beneficial effects of the present invention are: The method for detecting the content of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester provided by the present invention has good chromatographic peak shape, accurate integral calculation results, good repeatability, high credibility and more accurate and timely results, strong specificity and good precision, and is particularly suitable for quality control of intermediate products, plays an important role and practical significance in ensuring the quality of final products, and provides strong data support for the production of trifloxystrobin.

[0014] By adjusting the mobile phase system and the ratio range, the retention time of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate is within the range of 1.5-3 minutes, and the peak time of the Z isomer is within the range of 2.5-4 minutes, thereby ensuring the rapid detection of the standard sample and the sample and ensuring the separation degree from the solvent and the impurities. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is the chromatogram of the standard sample obtained in Example 1.

[0017] Figure 2 This is the sample chromatogram obtained in Example 1.

[0018] Figure 3 This is the linear regression curve obtained in Experimental Example 2. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] Except as otherwise mentioned, the liquid chromatograph in the specific embodiment of the present invention is an Agilent ultra-high performance liquid chromatograph, using a G7112B infusion pump and a DAD detector. Example 1 The pilot test yielded 60 kg of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate, which was used as a sample to be tested and purity was tested using a liquid chromatograph. The specific steps were as follows: (1) Preparation of standard samples and test samples Accurately weigh 0.0513 g of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate methyl ester standard substance, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain a standard sample for use; Accurately weigh 0.0508 g of the sample to be tested, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it by ultrasonic oscillation, cool it to room temperature, and dilute it to the scale with acetonitrile to obtain the sample for use; (2) Ultra-high performance liquid chromatography detection A C8 reverse phase column was used with a length of 100 mm, an inner diameter of 3 mm, a particle size of 2.7 μm, a column temperature of 40°C, a mixed system of acetonitrile / water / phosphoric acid in a volume ratio of 40:60:0.05 as the mobile phase, a flow rate of 1.0 mL / min, a detection wavelength of 254 nm, and an injection volume of 3 μL. After the machine self-check is turned on and the baseline of the instrument is stable under the specified operating conditions, several needles of standard sample are injected continuously and the relative response value of each needle is calculated. When the relative response value change between two adjacent needles is less than 1.5%, the standard sample, sample, sample, and standard sample are injected in sequence. The chromatograms of the standard sample and sample are as follows: Figure 1 and 2 As shown, Figure 1 , Figure 2 The 2.4 min is (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester, and the 3.5 min is the Z isomer. Figure 1 , Figure 2 The average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester is shown in Table 1.

[0021] Table 1 Chromatographic test data of standard sample and sample in Example 1

[0022] (3) Calculation The mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample was calculated according to the following formula (1): X 1: (1) In the formula, A 1 is the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetate in the standard sample, A 2 is the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample, m 1 is the mass of the standard substance, m 2 is the mass of the sample to be tested, P 1 is the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the standard substance; After calculation, the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample to be tested is X 1=97.7%.

[0023] Example 2 The pilot test yielded 57 kg of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate, which was used as a sample to be tested and purity was tested using a liquid chromatograph. The specific steps were as follows: (1) Preparation of standard samples and test samples Accurately weigh 0.0534 g of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate methyl ester standard substance, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain a standard sample for use; Accurately weigh 0.0539 g of the sample to be tested, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it by ultrasonic oscillation, cool it to room temperature, and dilute it to the scale with acetonitrile to obtain the sample for use; (2) Ultra-high performance liquid chromatography detection A C8 reverse phase column was used with a length of 100 mm, an inner diameter of 4.6 mm, a particle size of 2.7 μm, a column temperature of 30 °C, a mixed system of acetonitrile / water / phosphoric acid with a volume ratio of 60:40:0.1 as the mobile phase, a flow rate of 1.0 mL / min, a detection wavelength of 254 nm, and an injection volume of 3 μL. After the machine self-check is turned on and passed, under the specified operating conditions, after the instrument baseline is stable, several needles of standard sample are continuously injected, and the relative response value of each needle is calculated. After the relative response value change between two adjacent needles is less than 1.5%, the standard sample, sample, sample, and standard sample are injected in sequence to obtain the chromatograms of the standard sample and sample. The retention time of the (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester peak is 2.0 min, and the retention time of the Z isomer is 3.2 min. The average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the chromatogram is calculated, and the obtained data are shown in Table 2.

[0024] Table 2 Chromatographic test data of standard sample and sample of Example 2

[0025] (3) Calculation According to formula (1), the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample to be tested is calculated: X 1=98.4%.

[0026] Example 3 (1) Preparation of standard samples and test samples Accurately weigh 0.0521 g of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate methyl ester standard substance, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain a standard sample for use; Accurately weigh 0.0515 g of the sample to be tested from the same batch as in Example 2, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute it to the scale with acetonitrile to obtain a sample for use; (2) Ultra-high performance liquid chromatography detection A C8 reverse phase column was used with a length of 100 mm, an inner diameter of 3.0 mm, a particle size of 1.9 μm, a column temperature of 30 °C, a mixed system of acetonitrile / water / formic acid with a volume ratio of 40:60:0.1 as the mobile phase, a flow rate of 0.8 mL / min, a detection wavelength of 230 nm, and an injection volume of 3 μL. After the machine self-check is turned on and passed, under the specified operating conditions, after the instrument baseline is stable, several needles of standard sample are injected continuously, and the relative response value of each needle is calculated. After the relative response value change between two adjacent needles is less than 1.5%, the standard sample, sample, sample, and standard sample are injected in sequence to obtain the chromatograms of the standard sample and sample. The retention time of the (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester peak is 2.2 min, and the retention time of the Z isomer is 3.4 min. At the same time, the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the chromatogram is calculated. The obtained data are shown in Table 3.

[0027] Table 3 Chromatographic test data of standard sample and sample of Example 3

[0028] (3) Calculation According to formula (1), the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample to be tested is calculated: X 1=98.2%.

[0029] Example 4 The samples of Example 2 were used for verification, and the method steps and results are as follows: (1) Preparation of standard samples and test samples Accurately weigh 0.0542 g of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate methyl ester standard substance, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain a standard sample for use; Accurately weigh 0.0526 g of the sample to be tested, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool it to room temperature, and dilute it to the scale with acetonitrile to obtain the sample for use; (2) Ultra-high performance liquid chromatography detection A C8 reverse phase column was used with a length of 100 mm, an inner diameter of 4.6 mm, a particle size of 2.7 μm, a column temperature of 40 °C, a mixed system of acetonitrile / water / glacial acetic acid with a volume ratio of 60:40:0.1 as the mobile phase, a flow rate of 1.2 mL / min, a detection wavelength of 260 nm, and an injection volume of 3 μL. After the machine self-check is turned on and passed, under the specified operating conditions, after the instrument baseline is stable, several needles of standard sample are injected continuously, and the relative response value of each needle is calculated. After the relative response value change between two adjacent needles is less than 1.5%, the standard sample, sample, sample, and standard sample are injected in sequence to obtain the chromatograms of the standard sample and sample. The retention time of the (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester peak is 1.6 min, and the retention time of the Z isomer is 2.7 min. At the same time, the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the chromatogram is calculated. The obtained data are shown in Table 4.

[0030] Table 4 Chromatographic test data of standard sample and sample of Example 4

[0031] (3) Calculation According to formula (1), the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample to be tested is calculated: X 1=98.3%.

[0032] In order to verify the repeatability, linearity, intermediate precision, time stability and accuracy of the detection method of the content of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate of the present invention, the following verification test was carried out: Test Example 1 (1) Preparation of standard samples and test samples Accurately weigh 0.0521 g of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate methyl ester standard substance, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain a standard sample for use; Accurately weigh 6 samples to be tested from the same batch as in Example 2, place the 6 samples in 100 mL volumetric flasks, add 50 mL of acetonitrile, dissolve under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain samples for use; (2) Ultra-high performance liquid chromatography detection A C8 reverse phase column was used with a length of 100 mm, an inner diameter of 3.0 mm, a particle size of 2.7 μm, a column temperature of 30 °C, a mixed system of acetonitrile / water / phosphoric acid with a volume ratio of 50:50:0.05 as the mobile phase, a flow rate of 1.0 mL / min, a detection wavelength of 254 nm, and an injection volume of 3 μL. After the machine self-check is turned on and the baseline of the instrument is stable under the specified operating conditions, several needles of standard sample are continuously injected, and the relative response value of each needle is calculated. When the relative response value change between two adjacent needles is less than 1.5%, the standard sample, sample, sample, and standard sample are injected in sequence. The six samples are tested separately to obtain the chromatograms of the standard sample and the sample. The average peak area of ​​(E)2-methoxyimino-[(2-o-methylphenyl)]acetate in the chromatogram is calculated. The mass fraction of (E)2-methoxyimino-[(2-o-methylphenyl)]acetate in the sample to be tested is calculated according to formula (1). X 1, and the obtained data are shown in Table 5.

[0033] Table 5 Calculation results of test example 1

[0034] It can be seen from the data in Table 5 that the experimental results of the detection method of the present invention have good repeatability.

[0035] Test Example 2 (1) Sample preparation Accurately weigh the (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester standard substance, add acetonitrile to dissolve into a group of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester samples with concentrations of 204 μg / mL, 312 μg / mL, 405 μg / mL, 511 μg / mL, 602 μg / mL, 658 μg / mL, and 708 μg / mL, respectively, for later use; (2) Ultra-high performance liquid chromatography detection The above samples of different concentrations were detected using a liquid chromatograph, and the chromatographic conditions were as follows: C8 reverse phase chromatographic column, column length 100 mm, column inner diameter 3.0 mm, particle size 2.7 μm, column temperature 30 ° C, acetonitrile / water / phosphoric acid mixed system with a volume ratio of 50:50:0.05 as the mobile phase, flow rate 1.0 mL / min, detection wavelength set to 254 nm, injection volume 3 μL; A linear regression was performed using the peak area (A) on the y-axis against the sample concentration (μg / mL) on the x-axis. The resulting linear regression curve is shown in Figure 2. Figure 3 As shown, the linear regression equation is as follows: y=8.1963x+11.276, R 2 =0.9998; It can be seen that (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester has a good linear relationship in the range of 200~700μg / mL.

[0036] Test Example 3 In Example 2, the pilot product of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate was used as the sample to be tested. Six personnel accurately weighed the standard substance and the sample to be tested in different laboratories and performed the detection operation. The chromatographic conditions were the same as those in Example 1, and the chromatograms of the standard sample and the sample were obtained. The average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate in the chromatogram was calculated, and the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)] methyl acetate in the sample to be tested was calculated according to formula (1): X 1, the obtained data are shown in Table 6.

[0037] Table 6 Calculation results of test example 3

[0038] It can be seen from the data in Table 6 that the intermediate precision of the experimental results of the detection method of the present invention is good.

[0039] Test Example 4 (1) Sample preparation Accurately weigh 0.0521 g of the sample to be tested from the same batch as in Example 2, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute it to the scale with acetonitrile to obtain a sample for use; (2) Ultra-high performance liquid chromatography detection The samples were tested at different times (0, 1, 2, 4, 8, and 24 hours) using a liquid chromatograph. The chromatographic conditions were as follows: a C8 reverse phase column with a length of 100 mm, an inner diameter of 3.0 mm, a particle size of 2.7 μm, a column temperature of 30°C, a mobile phase consisting of a mixture of acetonitrile / water / phosphoric acid in a volume ratio of 50:50:0.05, a flow rate of 1.0 mL / min, a detection wavelength of 254 nm, and an injection volume of 3 μL.

[0040] The obtained chromatogram has good peak shape, and the peak area results are shown in Table 7.

[0041] Table 7 Peak areas corresponding to the samples in Experimental Example 4

[0042] It can be seen from the data in Table 7 that the experimental results of the detection method of the present invention have good time stability.

[0043] Test Example 5 (1) Preparation of standard samples and test samples Accurately weigh (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate methyl ester standard substance, place it in a 100 mL volumetric flask, add 50 mL of acetonitrile, dissolve it under ultrasonic vibration, cool to room temperature, and dilute to the scale with acetonitrile to obtain a standard sample with a concentration of 9.759 mg / mL for use; Accurately weigh three portions of 0.02g, 0.03g and 0.04g of the sample to be tested (the same batch as in Example 2), place 9 portions of the sample to be tested in 100mL volumetric flasks, add 50mL of acetonitrile, dissolve by ultrasonic oscillation, cool to room temperature, and dilute to the scale with acetonitrile to obtain 9 samples for use, and divide the 9 samples into 3 groups according to the mass of the dissolved sample to be tested, respectively named as 0.02 sample, 0.03 sample and 0.04 sample; (2) Ultra-high performance liquid chromatography detection A C8 reverse phase column was used with a length of 100 mm, an inner diameter of 3.0 mm, a particle size of 2.7 μm, a column temperature of 30 °C, a mixed system of acetonitrile / water / phosphoric acid with a volume ratio of 50:50:0.05 as the mobile phase, a flow rate of 1.0 mL / min, a detection wavelength of 254 nm, and an injection volume of 3 μL. After the machine self-check is turned on and the baseline of the instrument is stable under the specified operating conditions, several needles of standard sample are continuously injected, and the relative response value of each needle is calculated. After the relative response value change between two adjacent needles is less than 1.5%, the standard sample, sample, sample, and standard sample are injected in sequence. The 9 samples are tested separately to obtain the chromatograms of the standard sample and the sample. The average peak area of ​​(E)2-methoxyimino-[(2-o-methylphenyl)]acetate in the chromatogram is calculated. The mass fraction of (E)2-methoxyimino-[(2-o-methylphenyl)]acetate in the sample to be tested is calculated according to formula (1). X 1. Then calculate the content of active ingredients in each sample; 3.0 mL of the standard sample was added to the 0.02 sample, 2.0 mL of the standard sample was added to the 0.03 sample, and 1.0 mL of the standard sample was added to the 0.04 sample to obtain 9 mixed samples. The above method was repeated to determine the content of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in each mixed sample, and the content of the active ingredient in each mixed sample was calculated. The specific results are shown in Table 8. m 2 represents the weight of the sample to be tested. M 1 indicates the content of active ingredients in the sample, M 2 indicates the content of active ingredients in the standard sample, M 3 indicates the content of active ingredients in the mixed sample.

[0044] Table 8 Results and recovery rates of active ingredient content in mixed samples of Experimental Example 5

[0045] It can be seen from the data in Table 8 that the detection method provided by the present invention has high accuracy and good operability, and can be widely used in the analysis and detection of the content of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester.

[0046] Comparative Example 1 The standard sample and the sample prepared in step (1) of Example 1 were used for ultra-high performance liquid chromatography detection, with a mixed system of methanol / water / phosphoric acid in a volume ratio of 40:60:0.05 as the mobile phase, and the remaining operating steps and chromatographic conditions were the same as those in Example 1.

[0047] Under the chromatographic conditions, the retention time of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester is about 3.8 min, and the retention time of the Z isomer is 6.2 min. Compared with the conditions selected in the present invention, the detection time is about 50% longer.

[0048] Comparative Example 2 The standard sample and the sample prepared in step (1) of Example 1 were used for ultra-high performance liquid chromatography detection, using a C18 reverse phase chromatography column with a column length of 100 mm, a column inner diameter of 3 mm, and a particle size of 2.7 μm. The remaining operating steps and chromatographic conditions were the same as those in Example 1.

[0049] Under the chromatographic conditions, the retention time of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester is about 4.6 min, and the retention time of the Z isomer is 9.2 min. Compared with the conditions selected in the present invention, the detection time is longer.

[0050] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A method for detecting the content of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetate, characterized in that: The steps include: (1) Using acetonitrile to dissolve the standard substance and the sample to be tested respectively to obtain the standard sample and the test sample; (2) The standard sample and the sample were detected by liquid chromatography, with a mixed system of acetonitrile / water / acid as the mobile phase, and the volume ratio of acetonitrile, water, and acid being 40-60:60-40:0.05-0.

1. The average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the measured chromatogram was calculated; (3) Calculate the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample according to the following formula: X 1: ， In the formula, A 1 is the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetate in the standard sample, A 2 is the average peak area of ​​(E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the sample, m 1 is the mass of the standard substance, m 2 is the mass of the sample to be tested, P 1 is the mass fraction of (E) 2-methoxyimino-[(2-o-methylphenyl)]acetic acid methyl ester in the standard substance.

2. The detection method according to claim 1, characterized in that The detection wavelength of the liquid chromatograph was set to 230-260 nm.

3. The detection method according to claim 1, characterized in that The liquid chromatograph used a C8 reverse phase column.

4. The detection method according to claim 3, characterized in that The column length of the C8 reverse phase chromatography column is 100 mm, the inner diameter of the column is 3~4.6 mm, and the particle size is 1.9~2.7 μm.

5. The detection method according to claim 1, characterized in that The column temperature is 30~40℃.

6. The detection method according to claim 1, characterized in that The acid in the mobile phase is selected from glacial acetic acid, formic acid, phosphoric acid, and trifluoroacetic acid.

7. The detection method according to claim 1, characterized in that The flow rate of the mobile phase is 0.8~1.2mL / min.

8. The detection method according to claim 1, characterized in that The injection volume of each liquid chromatograph was 3 μL.

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