Method for detecting diethyl aminoethyl hexanoate in diethyl aminoethyl hexanoate ethephon soluble concentrate

Abstract

The invention belongs to the field of detection of diethyl aminoethyl hexanoate, and particularly relates to a method for detecting diethyl aminoethyl hexanoate in a diethyl aminoethyl hexanoate-ethephon soluble concentrate. The method comprises the following steps: adding an alkaline reagent into a diethyl aminoethyl hexanoate-ethephon soluble solution, and mixing to prepare a solution to be detected, the pH value of the solution to be detected being 6-8; and measuring the content of diethyl aminoethyl hexanoate in the solution to be measured by using a gas chromatographic method. According to the method, an alkaline reagent is added into a diethyl aminoethyl hexanoate ethephon soluble solution to prepare a to-be-detected solution with the pH value of 6-8, and after testing on a machine, the relative difference value between the retention time of a diethyl aminoethyl hexanoate chromatographic peak and the retention time of a diethyl aminoethyl hexanoate chromatographic peak in a standard sample solution can be kept within 1.5%; and the method has the characteristics of good peak shape and good detection result repeatability, so that accurate qualitative and quantitative determination of the diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate-ethephon soluble concentrate is realized.

Description

Technical Field

[0001] The present invention belongs to the field of detection of diethyl aminoethyl hexanoate, and particularly relates to a method for detecting diethyl aminoethyl hexanoate in a diethyl aminoethyl hexanoate·ethephon soluble concentrate. Background Art

[0002] Diethyl aminoethyl hexanoate (abbreviated as DA-6), chemical name: 2-(diethylamino)ethyl hexanoate, is a high-energy plant growth regulator with broad-spectrum and breakthrough effects discovered by American scientists in the 1990s. Its molecular formula is:

[0003] As a plant growth regulator of the growth promoter type, diethyl aminoethyl hexanoate has the functions of improving the activities of plant peroxidase and nitrate reductase, increasing the content of chlorophyll, accelerating the photosynthetic rate, promoting the division and elongation of plant cells, promoting the development of roots, and regulating the balance of nutrients in the body. The technical material of diethyl aminoethyl hexanoate is a colorless to light yellow oily liquid, poorly soluble in water, and easily soluble in organic solvents such as ethanol, acetone, and chloroform.

[0004] Ethephon (abbreviated as ETH), chemical name: 2-chloroethylphosphonic acid, molecular formula:

[0005] Ethephon is a high-quality and efficient plant growth regulator, which has effects such as promoting fruit ripening, stimulating bleeding, and regulating the sex transformation of some plants, and has a wide range of applications in production practice. The technical material of ethephon is a white to light brown crystalline solid, with a melting point of 70°C to 72°C, a boiling point of about 333.4°C, and a density of 1.568 g / cm 3 . Ethephon is soluble in ethanol, methanol, isopropanol, acetone, ethyl acetate and other polar organic solvents, slightly soluble in non-polar organic solvents such as benzene and toluene, and insoluble in kerosene and diesel. The aqueous solution of ethephon is stable at pH < 3.5, and ethylene is released by hydrolysis as the pH increases. Ethephon is sensitive to ultraviolet light and is stable below 75°C.

[0006] The diethyl aminoethyl hexanoate·ethephon soluble concentrate is prepared by compounding the two technical materials of diethyl aminoethyl hexanoate and ethephon into a soluble concentrate (SL concentrate) form. It combines the characteristics of the two plant growth regulators of diethyl aminoethyl hexanoate and ethephon, and has good dilutability and stability after dilution, and is easy to spray and be absorbed by crops. Therefore, it is an efficient agricultural production assistant. The accurate qualitative and quantitative analysis of the active ingredients in agricultural production assistants is one of the important auxiliary means to ensure the production and processing quality and guarantee the safety and effectiveness of the use of assistants.

[0007] At present, there are two industry implementation standards for the detection method of diethyl aminoethyl hexanoate, namely NY / T 4115-2022 Diethyl aminoethyl hexanoate (diethyl aminoethyl hexanoate citrate) soluble concentrate, and NY / T 4116-2022 Diethyl aminoethyl hexanoate (diethyl aminoethyl hexanoate citrate) technical material. When applying these two standards to qualitatively and quantitatively detect diethyl aminoethyl hexanoate in 30% diethyl aminoethyl hexanoate·ethephon SL, problems such as a large deviation in the retention time of the diethyl aminoethyl hexanoate chromatographic peak, a poor peak shape, and poor reproducibility of the detection results all occur in practice, making it difficult to accurately qualitatively and quantitatively analyze diethyl aminoethyl hexanoate in 30% diethyl aminoethyl hexanoate·ethephon soluble concentrate. Summary of the Invention

[0008] The purpose of the present invention is to provide a detection method for diethyl aminoethyl hexanoate in diethyl aminoethyl hexanoate·ethephon soluble concentrate to solve the problems of a large deviation in the retention time of the diethyl aminoethyl hexanoate chromatographic peak, a poor peak shape, and poor reproducibility of the detection results when the existing method is used to detect diethyl aminoethyl hexanoate in diethyl aminoethyl hexanoate·ethephon soluble concentrate.

[0009] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0010] A detection method for diethyl aminoethyl hexanoate in diethyl aminoethyl hexanoate·ethephon soluble concentrate, comprising the following steps: adding a basic reagent to the diethyl aminoethyl hexanoate·ethephon soluble concentrate and mixing to obtain a test solution, wherein the pH of the test solution is 6-8; using gas chromatography to determine the content of diethyl aminoethyl hexanoate in the test solution.

[0011] The present invention belongs to a pioneering invention. By adding a basic reagent to the diethyl aminoethyl hexanoate·ethephon soluble concentrate to obtain a test solution with a pH of 6-8, after being tested on the machine, it can keep the relative difference between the retention time of the diethyl aminoethyl hexanoate chromatographic peak and the retention time of the diethyl aminoethyl hexanoate chromatographic peak in the standard sample solution within 1.5%, greatly reducing the deviation of the chromatographic peak retention time and having the characteristics of a good peak shape and good repeatability of the detection results, thereby realizing the accurate qualitative and quantitative determination of diethyl aminoethyl hexanoate in diethyl aminoethyl hexanoate·ethephon soluble concentrate.

[0012] Preferably, the basic reagent is selected from one of monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, and aqueous calcium hydroxide solution.

[0013] Further preferably, for the diethyl aminoethyl hexanoate·ethephon soluble concentrate containing 0.05 g of diethyl aminoethyl hexanoate, the dosage of the basic reagent is 1-4 mL, wherein the mass fraction of the aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, and aqueous calcium hydroxide solution is 0.5-2%.

[0014] Preferably, when preparing the test solution, the diethyl aminoethyl hexanoate·ethephon soluble concentrate, the basic reagent, and the internal standard solution are mixed, fixed volume with acetone and then allowed to stand, and the test solution is obtained after standing.

[0015] Further preferably, the standing time is at least 1 h.

[0016] Preferably, the DA-6 · ethephon soluble concentrate is a 10-30% DA-6 · ethephon soluble concentrate, wherein the mass content of DA-6 is 1-8%, the mass content of ethephon is 9-27%, and pH < 3.0.

[0017] Preferably, the gas chromatography uses a capillary column filled with methyl polysiloxane containing 5% phenyl and a flame ionization detector; the initial column temperature is 160 °C, maintained for 2 min, then heated at a rate of 30 °C / min to 280 °C and maintained for 5 min. Description of the Drawings

[0018] Figure 1 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 1 of the present invention;

[0019] Figure 2 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 2 of the present invention;

[0020] Figure 3 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 3 of the present invention;

[0021] Figure 4 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 4 of the present invention;

[0022] Figure 5 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 5 of the present invention;

[0023] Figure 6 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 6 of the present invention;

[0024] Figure 7 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 7 of the present invention;

[0025] Figure 8 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 8 of the present invention;

[0026] Figure 9 From top to bottom are the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 in Example 9 of the present invention;

[0027] Figure 10 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Comparative Example 1;

[0028] Figure 11 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Comparative Example 2;

[0029] Figure 12 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Comparative Example 3;

[0030] Figure 13 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Example 10;

[0031] Figure 14 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Example 11;

[0032] Figure 15 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Comparative Example 4;

[0033] Figure 16 From top to bottom are the chromatograms of standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in Comparative Example 5. Detailed implementation mode

[0034] DA-6·ethephon SL is an important type of agricultural adjuvant. Among them, 30% DA-6·ethephon SL is a compound preparation with an ethephon content of 27% and a DA-6 content of 3%. In practice, when using two industry implementation standards, NY / T 4115-2022 DA-6 (DA-6 citrate) soluble concentrate and NY / T 4116-2022 DA-6 (DA-6 citrate) technical to detect DA-6 in the soluble concentrate, problems such as a large deviation in the retention time of the DA-6 chromatographic peak, a poor peak shape, and poor reproducibility of the detection results occur, making it difficult to accurately qualitatively and quantitatively analyze DA-6 in 30% DA-6·ethephon soluble concentrate.

[0035] In the present invention, an alkaline reagent is added to the DA-6·ethephon soluble concentrate and mixed to obtain a test solution with a pH of 6-8, and then the DA-6 content is detected by means of gas chromatography analysis. After being tested on the machine, the effects of stable retention time of the DA-6 chromatographic peak, good peak shape, and good repeatability of the detection results are achieved, realizing the accurate qualitative and quantitative analysis of DA-6 in 30% DA-6·ethephon soluble concentrate (pH < 3.0 system).

[0036] The detection method of diethyl aminoethyl hexanoate in the soluble solution of diethyl aminoethyl hexanoate and ethephon of the present invention can be summarized as follows:

[0037] (1) Reagents and reference samples: acetone, N, N-dimethylformamide, diethyl phthalate (internal standard), basic reagents (monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, 0.5% sodium hydroxide aqueous solution, 1% potassium hydroxide aqueous solution, 2% calcium hydroxide aqueous solution), diethyl aminoethyl hexanoate reference sample (known mass fraction of diethyl aminoethyl hexanoate ≥ 98.0%)

[0038] (2) Preparation of internal standard solution: Weigh 2.5 g of diethyl phthalate and place it in a 500 mL volumetric flask. Add acetone to dilute to the scale, shake well, and store sealed.

[0039] (3) Determination steps:

[0040] Preparation of reference sample solution: Weigh a reference sample containing about 0.05 g of diethyl aminoethyl hexanoate (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of internal standard solution with a pipette, and make up the volume to the scale with acetone, then shake well.

[0041] Preparation of test sample solution: Weigh a 30% soluble solution sample of diethyl aminoethyl hexanoate and ethephon containing about 0.05 g of diethyl aminoethyl hexanoate (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of internal standard solution and 1 mL - 4 mL of basic reagent with a pipette respectively, make up the volume to the scale with acetone, and shake well. Let it stand for 1 h, and adjust the pH of the test sample solution to 6 - 8.

[0042] (4) Instruments: Gas chromatograph: equipped with a hydrogen flame ionization detector; Chromatographic column: 30 m × 0.32 mm (inner diameter) × 0.25 μm capillary column, filled with a methyl polysiloxane packing containing 5% phenyl.

[0043] (5) Gas chromatographic operating conditions: Column temperature, initial column temperature 160 °C, hold for 2 min, increase the temperature to 280 °C at a rate of 30 °C / min, and hold for 5 min. Vaporization chamber temperature 285 °C, detector temperature 300 °C. Gas flow rate (mL / min): carrier gas (N2) 2.0, hydrogen 40, air 400, tail gas 25. Split ratio 20:1. Injection volume 1.0 μL. Retention time: diethyl aminoethyl hexanoate is about 2.82 min, internal standard is about 3.68 min.

[0044] (6) Determination: Under the above operating conditions, after the instrument is stable, inject several needles of reference sample solution continuously until the relative change in the peak area of diethyl aminoethyl hexanoate between adjacent two needles is less than 1.2%, and then carry out the determination in the order of reference sample solution, test sample solution, test sample solution, reference sample solution.

[0045] (7) Calculation: The peak areas of the two injections of the sample solution and the standard sample solutions of the sample solution before and after the injection are averaged respectively. The mass fraction of DA-6 in the sample is calculated according to the following formula.

[0046]

[0047] Where: ω1 - mass fraction of DA-6, %; γ2 - average value of the peak area ratio of DA-6 to the internal standard in the sample solution; m1 - mass of the standard sample, g; ω b1 - mass fraction of DA-6 in the standard sample, %; γ1 - average value of the peak area ratio of DA-6 to the internal standard in the standard sample solution; m2 - mass of the sample, g.

[0048] The implementation process of the present invention will be described in detail below in conjunction with specific embodiments.

[0049] I. Detection example of 30% DA-6·ethephon (3% + 27%) soluble concentrate

[0050] Example 1

[0051] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of this example includes the following steps:

[0052] (1) Preparation of the standard sample solution: Weigh a standard sample containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution with a pipette, and make up to the mark with acetone, then shake well.

[0053] Preparation of the sample solution: Weigh a 30% DA-6·ethephon soluble concentrate sample containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 4 mL of monoethylamine respectively with a pipette, make up to the mark with acetone, and shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 6.6.

[0054] (2) Test the sample solution by gas chromatography.

[0055] Gas chromatography operating conditions:

[0056] Instrument: Gas chromatograph: with a hydrogen flame ionization detector; Chromatographic column: 30 m × 0.32 mm (inner diameter) × 0.25 μm capillary column, filled with a methyl polysiloxane filler containing 5% phenyl. Column temperature: Initial column temperature 160 °C, hold for 2 min, increase the temperature to 280 °C at a rate of 30 °C / min, and hold for 5 min. Vaporization chamber temperature 285 °C, detection chamber temperature 300 °C. Gas flow rate (mL / min): Carrier gas (N2) 2.0, hydrogen 40, air 400, make-up gas 25. Split ratio 20:1. Injection volume 1.0 μL.

[0057] Under the above operating conditions, after the instrument is stabilized, inject several needles of the standard solution continuously until the relative change in the peak area of DA-6 between two adjacent needles is less than 1.2%, and then conduct the determination in the order of standard solution, sample solution, sample solution, and standard solution.

[0058] In this example, the chromatograms of standard solution 1, sample solution 1, sample solution 2, and standard solution 2 are as Figure 1 shown. The retention times of different injection solutions are shown in Table 1.

[0059] Table 1 Retention times of DA-6 and internal standard

[0060] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 2.983 2.983 2.983 Retention time of internal standard, min 3.832 3.832 3.832 3.832

[0061] It can be seen from Table 1 that when the alkaline reagent added in the determination step is monoethylamine, under the same chromatographic operating conditions, the relative difference between the retention time of the DA-6 chromatographic peak in the sample solution and the retention time of the DA-6 chromatographic peak in the standard solution should be within 1.5%. The calculation formula for the relative difference A is as follows:

[0062]

[0063] In the above formula, T1 is the absolute value of the difference between the retention time of the DA-6 chromatographic peak in the sample solution and the retention time of the DA-6 chromatographic peak in the standard solution; T2 is the average value of the retention time of the DA-6 chromatographic peak in the sample solution and the retention time of the DA-6 chromatographic peak in the standard solution.

[0064] The retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the average value of the retention time of DA-6 in the standard solution is 2.983 min. The relative differences are 0% and 0% respectively; both are less than 1.5%. This shows that the retention time shift of DA-6 in the sample solution is extremely small and meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 2 below.

[0065] Table 2 Peak areas of DA-6 and internal standard

[0066] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1180.21 1203.56 1197.55 1182.51 Peak area of internal standard 1135.69 1158.16 1153.60 1140.43 Ratio of peak area of DA-6 to peak area of internal standard 1.0392 1.0392 1.0381 1.0369

[0067] It can be seen from Table 2 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0068] The detection result of the mass fraction of DA-6 in 30% DA-6·ethephon soluble concentrate is 3.01%, which meets the requirement of the mass fraction of DA-6 (3.0 ± 0.3)%, and the detection result is qualified.

[0069] Example 2

[0070] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of this example includes the following steps:

[0071] (1) Preparation of the sample solution: Weigh about 0.05 g of the 30% DA-6·ethephon soluble concentrate sample containing DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 2 mL of diethylamine respectively with a pipette, make up the volume to the mark with acetone, and shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 6.9. The preparation of the standard sample solution is the same as that in Example 1.

[0072] (2) Conduct gas chromatography testing according to the method in Example 1.

[0073] The chromatograms of the first standard sample solution, the first sample solution, the second sample solution, and the second standard sample solution in this example are as Figure 2 shown. The retention times of different injection solutions are shown in Table 3.

[0074] Table 3 Retention times of DA-6 and the internal standard

[0075] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.982 2.983 2.983 2.982 Retention time of internal standard, min 3.832 3.832 3.832 3.832

[0076] It can be seen from Table 3 that when the alkaline reagent added in the determination step is diethylamine, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the average value of the retention time of DA-6 in the standard sample solution is 2.982 min. The relative differences are 0.03% and 0.03% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 4 below.

[0077] Table 4 Peak areas of DA-6 and the internal standard

[0078] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1184.71 1203.79 1202.38 1184.89 Peak area of internal standard 1139.91 1160.28 1159.37 1141.62 Ratio of peak area of DA-6 to peak area of internal standard 1.0393 1.0375 1.0371 1.0379

[0079] It can be seen from Table 4 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0080] The detection result of the mass fraction of DA-6 in the 30% DA-6·ethephon soluble concentrate is 2.99%, and the detection result is qualified.

[0081] Example 3

[0082] The detection method of DA-6 in the DA-6·ethephon soluble concentrate in this example includes the following steps:

[0083] (1) Preparation of sample solution: Weigh a 30% DA-6 · ethephon soluble concentrate sample containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of internal standard solution and 1 mL of triethylamine respectively with a pipette, make up the volume to the mark with acetone, and shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 7.1. The preparation of the standard sample solution is the same as that in Example 1.

[0084] (2) Perform gas chromatography testing according to the method in Example 1.

[0085] The chromatograms of the standard sample solution 1, sample solution 1, sample solution 2, and standard sample solution 2 in this example are as Figure 3 shown. The retention times of different injection solutions are shown in Table 5.

[0086] Table 5 Retention times of DA-6 and internal standard

[0087] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 2.986 2.986 2.983 Retention time of internal standard, min 3.832 3.833 3.833 3.832

[0088] It can be seen from Table 5 that when the alkaline reagent added in the determination step is triethylamine, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.986 min and 2.986 min respectively; the average value of the retention time of DA-6 in the standard sample solution is 2.983 min. The relative differences are 0.10% and 0.10% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 6 below.

[0089] Table 6 Peak areas of DA-6 and internal standard

[0090] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1181.27 1199.46 1202.94 1182.81 Peak area of internal standard 1133.66 1160.36 1158.34 1138.63 Ratio of peak area of DA-6 to peak area of internal standard 1.0420 1.0337 1.0385 1.0388

[0091] It can be seen from Table 6 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0092] The detection result of the mass fraction of DA-6 in the 30% DA-6 · ethephon soluble concentrate is 2.98%, and the detection result is qualified.

[0093] Example 4

[0094] The detection method of DA-6 in the DA-6 · ethephon soluble concentrate in this example includes the following steps:

[0095] (1) Preparation of sample solution: Weigh a 30% DA-6 · ethephon soluble concentrate sample containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of internal standard solution and 3 mL of monoethanolamine respectively with a pipette, make up the volume to the mark with acetone, and shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 7.5. The preparation of the standard sample solution is the same as that in Example 1.

[0096] (2) Conduct gas chromatography testing according to the method of Example 1.

[0097] The chromatograms of Standard Sample Solution 1, Sample Solution 1, Sample Solution 2, and Standard Sample Solution 2 in this example are as Figure 4 shown. The retention times of different injection solutions are shown in Table 7.

[0098] Table 7 Retention Times of DA-6 and Internal Standard

[0099] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 2.989 2.986 2.982 Retention time of internal standard, min 3.832 3.835 3.833 3.832

[0100] It can be obtained from Table 7 that when the alkaline reagent added in the determination step is monoethanolamine, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solutions are 2.989 min and 2.986 min respectively; the average retention time of DA-6 in the standard sample solution is 2.983 min. The relative differences are 0.20% and 0.10% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 8 below.

[0101] Table 8 Peak Areas of DA-6 and Internal Standard

[0102] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1172.04 1192.10 1198.09 1175.91 Peak area of internal standard 1131.66 1160.32 1158.64 1136.63 Ratio of peak area of DA-6 to peak area of internal standard 1.0357 1.0274 1.0340 1.0346

[0103] It can be obtained from Table 8 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0104] The mass fraction detection result of DA-6 in the 30% DA-6·ethephon soluble concentrate is 2.99%, and the detection result is qualified.

[0105] Example 5

[0106] The detection method of DA-6 in the DA-6·ethephon soluble concentrate in this example includes the following steps:

[0107] (1) Preparation of sample solution: Weigh a sample of 30% DA-6·ethephon soluble concentrate containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of internal standard solution and 2 mL of diethanolamine respectively with a pipette, and make up the volume to the mark with acetone, then shake well. Let it stand for 1 h and adjust the pH of the sample solution to 6.7. The preparation of the standard sample solution is the same as that in Example 1.

[0108] (2) Conduct gas chromatography testing according to the method of Example 1.

[0109] The chromatograms of Standard Sample Solution 1, Sample Solution 1, Sample Solution 2, and Standard Sample Solution 2 in this example are as Figure 5 shown. The retention times of different injection solutions are shown in Table 9.

[0110] Table 9 Retention Times of DA-6 and Internal Standard

[0111] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 2.983 2.983 2.983 Retention time of internal standard, min 3.833 3.832 3.832 3.832

[0112] It can be seen from Table 9 that when the alkaline reagent added in the determination step is diethanolamine, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the average value of the retention time of DA-6 in the standard sample solution is 2.983 min. The relative differences are 0% and 0% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 10 below.

[0113] Table 10 Peak Areas of DA-6 and Internal Standard

[0114] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1176.04 1200.10 1197.09 1173.91 Peak area of internal standard 1135.66 1161.12 1163.65 1140.63 Ratio of peak area of DA-6 to peak area of internal standard 1.0356 1.0336 1.0287 1.0292

[0115] It can be seen from Table 10 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0116] The mass fraction of DA-6 detected in the 30% DA-6·ethephon soluble concentrate is 3.00%, and the test result is qualified.

[0117] Example 6

[0118] The method for detecting DA-6 in the DA-6·ethephon soluble concentrate of this example includes the following steps:

[0119] (1) Preparation of sample solution: Weigh a sample of 30% DA-6·ethephon soluble concentrate containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of internal standard solution and 1 mL of triethanolamine respectively with a pipette, dilute to the mark with acetone, and shake well. Let it stand for 1 h and adjust the pH of the sample solution to 7.0. The preparation of the standard sample solution is the same as that in Example 1.

[0120] (2) Perform gas chromatography testing according to the method in Example 1.

[0121] The chromatograms of the first standard sample solution, the first sample solution, the second sample solution, and the second standard sample solution of this example are as Figure 6 shown. The retention times of different injection solutions are shown in Table 11.

[0122] Table 11 Retention Times of DA-6 and Internal Standard

[0123] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 2.983 2.983 2.984 Retention time of internal standard, min 3.832 3.832 3.832 3.833

[0124] It can be seen from Table 11 that when the alkaline reagent added in the determination step is triethanolamine, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the average value of the retention time of DA-6 in the standard sample solution is 2.984 min. The relative differences are 0 and 0.03% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 12 below.

[0125] Table 12 Peak Areas of DA-6 and the Internal Standard

[0126] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1180.14 1205.03 1201.14 1182.36 Peak area of internal standard 1138.26 1158.98 1160.39 1141.25 Ratio of peak area of DA-6 to peak area of internal standard 1.0368 1.0397 1.0351 1.0360

[0127] It can be seen from Table 12 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0128] The detection result of the mass fraction of DA-6 in 30% DA-6·ethephon soluble concentrate is 3.00%, and the detection result is qualified.

[0129] Example 7

[0130] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of this example includes the following steps:

[0131] (1) Preparation of the sample solution: Weigh a sample of 30% DA-6·ethephon soluble concentrate containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 4 mL of 0.5% sodium hydroxide aqueous solution respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 6.8. The preparation of the standard sample solution is the same as that in Example 1.

[0132] (2) Perform gas chromatography testing according to the method in Example 1.

[0133] The chromatograms of the first standard sample solution, the first sample solution, the second sample solution, and the second standard sample solution of this example are as Figure 7 shown. The retention times of different injection solutions are shown in Table 13.

[0134] Table 13 Retention Times of DA-6 and the Internal Standard

[0135] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.984 2.983 2.983 2.984 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0136] It can be seen from Table 13 that when the alkaline reagent added in the determination step is 0.5% sodium hydroxide aqueous solution, under the same chromatographic operating conditions, the retention times of diethyl aminoethyl hexanoate in the sample solution are 2.983 min and 2.983 min respectively; the average retention time of diethyl aminoethyl hexanoate in the standard sample solution is 2.984 min. The relative differences are 0.03% and 0.03% respectively; both are less than 1.5%. The retention time deviation of diethyl aminoethyl hexanoate in the sample solution meets the qualified requirements. The peak areas of diethyl aminoethyl hexanoate and the internal standard are shown in Table 14.

[0137] Table 14 Peak Areas of Diethyl Aminoethyl Hexanoate and the Internal Standard

[0138] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1178.34 1189.03 1196.14 1175.15 Peak area of internal standard 1130.26 1155.36 1158.41 1131.78 Ratio of peak area of DA-6 to peak area of internal standard 1.0425 1.0291 1.0326 1.0383

[0139] It can be seen from Table 14 that the reproducibility of the peak area of diethyl aminoethyl hexanoate in the sample solution is good.

[0140] The detection result of the mass fraction of diethyl aminoethyl hexanoate in 30% diethyl aminoethyl hexanoate·ethephon soluble concentrate is 2.98%, and the detection result is qualified.

[0141] Example 8

[0142] The detection method of diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate·ethephon soluble concentrate of this example includes the following steps:

[0143] (1) Preparation of the sample solution: Weigh a sample of 30% diethyl aminoethyl hexanoate·ethephon soluble concentrate containing about 0.05 g of diethyl aminoethyl hexanoate (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 2 mL of 1% potassium hydroxide aqueous solution respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 6.9. The preparation of the standard sample solution is the same as that in Example 1.

[0144] (2) Perform gas chromatography testing according to the method in Example 1.

[0145] The chromatograms of the first standard sample solution, the first sample solution, the second sample solution, and the second standard sample solution of this example are as Figure 8 shown. The retention times of different injection solutions are shown in Table 15.

[0146] Table 15 Retention Times of Diethyl Aminoethyl Hexanoate and the Internal Standard

[0147] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.984 2.983 2.983 2.984 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0148] It can be seen from Table 15 that when the alkaline reagent added in the determination step is 1% potassium hydroxide aqueous solution, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the average retention time of DA-6 in the standard sample solution is 2.984 min. The relative differences are 0.03% and 0.03% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 16.

[0149] Table 16 Peak Areas of DA-6 and the Internal Standard

[0150] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1173.84 1194.25 1195.78 1174.65 Peak area of internal standard 1132.56 1165.01 1168.32 1137.34 Ratio of peak area of DA-6 to peak area of internal standard 1.0364 1.0251 1.0235 1.0328

[0151] It can be seen from Table 16 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0152] The detection result of the mass fraction of DA-6 in 30% DA-6·ethephon soluble concentrate is 2.97%, and the detection result is qualified.

[0153] Example 9

[0154] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of this example includes the following steps:

[0155] (1) Preparation of the sample solution: Weigh a sample of 30% DA-6·ethephon soluble concentrate containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 1 mL of 2% calcium hydroxide aqueous solution respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h, and adjust the pH of the sample solution to 7.6. The preparation of the standard sample solution is the same as that in Example 1.

[0156] (2) Perform gas chromatography testing according to the method in Example 1.

[0157] The chromatograms of the first standard sample solution, the first sample solution, the second sample solution, and the second standard sample solution of this example are as Figure 9 shown. The retention times of different injection solutions are shown in Table 17.

[0158] Table 17 Retention Times of DA-6 and the Internal Standard

[0159] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 2.983 2.983 2.983 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0160] It can be seen from Table 17 that when the alkaline reagent added in the determination step is 2% calcium hydroxide aqueous solution, under the same chromatographic operating conditions, the retention time of diethylaminoethyl in the sample solution is 2.983min and 2.983min respectively; the average retention time of diethylaminoethyl in the standard solution is 2.983min. The relative differences are 0% and 0% respectively; both are less than 1.5%. The retention time shift of diethylaminoethyl in the sample solution meets the qualified requirements. The peak areas of diethylaminoethyl and the internal standard are shown in Table 18.

[0161] Table 18 Peak areas of aminoethyl hexanoate and internal standard

[0162] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1182.12 1201.36 1205.29 1184.38 Peak area of internal standard 1142.25 1175.12 1170.39 1147.02 Ratio of peak area of DA-6 to peak area of internal standard 1.0349 1.0223 1.0298 1.0326

[0163] It can be seen from Table 18 that the peak area reproducibility of ampicillin in the sample solution is good.

[0164] The mass fraction of diethylaminoethyl hexanoate in 30% diethylaminoethyl hexanoate·ethephon solution was tested to be 2.98%, which was qualified.

[0165] Comparative Example 1: No alkaline reagent is added in the determination step

[0166] The detection method of diethylaminoethyl hexanoate in the diethylaminoethyl hexanoate-ethephon solution of the comparative example comprises the following steps:

[0167] (1) Preparation of sample solution: Weigh a 30% ammonium ethyl hexanoate-ethephon soluble solution sample containing about 0.05 g of ammonium ethyl hexanoate (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution with a pipette, dilute to the mark with acetone, shake well, and the pH value of the sample solution is 1.9. The preparation of the standard solution is the same as in Example 1.

[0168] (2) Perform gas chromatography test according to the method of Example 1.

[0169] The chromatograms of the standard solution 1, the sample solution 1, the sample solution 2, and the standard solution 2 of this comparative example are as follows: Figure 10 The retention times of different injection solutions are shown in Table 19.

[0170] Table 19 Retention time of diethylaminoethyl ester and internal standard

[0171] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.984 2.547 2.547 2.984 Retention time of internal standard, min 3.833 3.831 3.831 3.833

[0172] It can be seen from Table 19 that when no alkaline reagent is added in the determination step, under the same chromatographic operating conditions, the retention times of diethyl aminoethyl hexanoate in the sample solution are 2.547 min and 2.547 min respectively; the retention time of diethyl aminoethyl hexanoate in the standard sample solution is 2.984 min. The relative differences are 15.80% and 15.80% respectively; both are greater than 1.5%. The retention time of diethyl aminoethyl hexanoate in the sample solution has a large deviation; it does not meet the qualified requirements. The peak areas of diethyl aminoethyl hexanoate and the internal standard are shown in Table 20.

[0173] Table 20 Peak Areas of Diethyl Aminoethyl Hexanoate and Internal Standard

[0174] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1180.76 - - 1182.83 Peak area of internal standard 1141.53 1154.69 1156.07 1138.61 Ratio of peak area of DA-6 to peak area of internal standard 1.0344 - - 1.0388

[0175] It can be seen from Table 20 that the peak shape of diethyl aminoethyl hexanoate in the sample solution is very poor and the tailing is serious, so the integration of the peak area cannot be accurately carried out.

[0176] Since the peak area of diethyl aminoethyl hexanoate cannot be accurately calculated, the detection result of the mass fraction of diethyl aminoethyl hexanoate is unqualified.

[0177] Adjust the pH of the sample solution in Comparative Example 2 to 3.6

[0178] The detection method of diethyl aminoethyl hexanoate in the aqueous solution of diethyl aminoethyl hexanoate·ethephon in the comparative example includes the following steps:

[0179] (1) Preparation of the sample solution:

[0180] Weigh a 30% aqueous solution of diethyl aminoethyl hexanoate·ethephon sample containing about 0.05 g of diethyl aminoethyl hexanoate (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 0.5 mL of monoethylamine respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h and adjust the pH of the sample solution to 3.6. The preparation of the standard sample solution is the same as that in Example 1.

[0181] (2) Carry out gas chromatography testing according to the method in Example 1.

[0182] The chromatograms of the first standard sample solution, the first sample solution, the second sample solution, and the second standard sample solution in this comparative example are as Figure 11 shown. The retention times of different injection solutions are shown in Table 21.

[0183] Table 21 Retention Times of Diethyl Aminoethyl Hexanoate and Internal Standard

[0184] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Retention time of DA-6, min 2.983 3.077 3.077 2.983 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0185] It can be seen from Table 21 that when 0.5 mL of monoethylamine is added in the determination step and the pH of the sample solution is adjusted to 3.6, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 3.077 min and 3.077 min respectively; the retention time of DA-6 in the standard solution is 2.983 min. The relative differences are 3.10% and 3.10% respectively, both greater than 1.5%. The retention time of DA-6 in the sample solution has a large deviation and the peak shape is very poor, not meeting the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 22.

[0186] Table 22 Peak Areas of DA-6 and the Internal Standard

[0187] Standard sample solution 1 Test sample solution 1 Test sample solution 2 Standard sample solution 2 Peak area of DA-6 1181.12 - - 1179.34 Peak area of internal standard 1140.45 1152.36 1149.98 1139.78 Ratio of the peak area of DA-6 to that of internal standard 1.0357 - - 1.0347

[0188] It can be seen from Table 22 that the peak shape of DA-6 in the sample solution is very poor and it is no longer possible to accurately integrate the peak area.

[0189] Since the peak area of DA-6 cannot be accurately calculated, the test result of the mass fraction of DA-6 is unqualified.

[0190] The pH of the sample solution in Comparative Example 3 was adjusted to 9.5

[0191] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of the comparative example includes the following steps:

[0192] (1) Preparation of the sample solution:

[0193] Weigh a 30% DA-6·ethephon soluble concentrate sample containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 6 mL of triethanolamine respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h and adjust the pH of the sample solution to 9.5. The preparation of the standard solution is the same as that in Example 1.

[0194] (2) Perform gas chromatography testing according to the method in Example 1.

[0195] The chromatograms of Standard Solution 1, Sample Solution 1, Sample Solution 2, and Standard Solution 2 of this comparative example are as Figure 12 shown. The retention times of different injection solutions are shown in Table 23.

[0196] Table 23 Retention Times of DA-6 and the Internal Standard

[0197] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Retention time of DA-6, min 2.983 3.331 3.331 2.983 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0198] It can be seen from Table 23 that when 6 mL of triethanolamine is added in the determination step and the pH of the sample solution is adjusted to 9.5, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 3.331 min and 3.331 min respectively; the retention time of DA-6 in the standard solution is 2.983 min. The relative differences are 11.02% and 11.02% respectively, both greater than 1.5%. The retention time of DA-6 in the sample solution has a large deviation and the peak shape is very poor, not meeting the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 24.

[0199] Table 24 Peak Areas of DA-6 and the Internal Standard

[0200] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Peak area of DA-6 1180.36 - - 1179.68 Peak area of internal standard 1142.39 1149.98 1151.12 1141.57 Ratio of the peak area of DA-6 to that of internal standard 1.0332 - - 1.0334

[0201] It can be seen from Table 24 that the peak shape of DA-6 in the sample solution is very poor and it is no longer possible to accurately integrate the peak area.

[0202] Since it is impossible to accurately calculate the peak area of DA-6, the test result of the mass fraction of DA-6 is unqualified.

[0203] II. Detection Examples of DA-6·Ethrel Soluble Concentrates with Other Specifications

[0204] Example 10 Detection of 10% DA-6·Ethrel (1% + 9%) Soluble Concentrate

[0205] The detection method of DA-6 in the DA-6·Ethrel soluble concentrate of this example will be described for the detection process of 10% DA-6·Ethrel (1% + 9%) soluble concentrate, including the following steps:

[0206] (1) Preparation of the sample solution: Weigh a sample of 10% DA-6·Ethrel soluble concentrate containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 1 mL of triethanolamine respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h and adjust the pH of the sample solution to 6.8. The preparation of the standard solution is the same as in Example 1.

[0207] (2) Perform gas chromatography testing according to the method in Example 1.

[0208] The chromatograms of the first standard solution, the first sample solution, the second sample solution, and the second standard solution in this example are as Figure 13 shown. The retention times of different injection solutions are shown in Table 25.

[0209] Table 25 Retention Times of DA-6 and the Internal Standard

[0210] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Retention time of DA-6, min 2.983 2.983 2.983 2.983 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0211] It can be obtained from Table 25 that when 1 mL of triethanolamine is added in the determination step and the pH of the sample solution is adjusted to 6.8, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the retention time of DA-6 in the standard solution is 2.983 min. The relative differences are 0% and 0% respectively; both are less than 1.5%. The retention time deviation of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 26.

[0212] Table 26 Peak Areas of DA-6 and the Internal Standard

[0213] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Peak area of DA-6 1182.47 1191.89 1198.12 1179.96 Peak area of internal standard 1141.46 1152.14 1151.36 1143.77 Ratio of the peak area of DA-6 to that of internal standard 1.0359 1.0345 1.0406 1.0316

[0214] It can be obtained from Table 26 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0215] The test result of 10% DA-6·ethephon (1% + 9%) soluble concentrate is 1.00%, which meets the qualified standard of the mass content of DA-6 (1.0 ± 0.15)%, and the test result is qualified.

[0216] Example 11 Detection of 20% DA-6·ethephon (8% + 12%) soluble concentrate

[0217] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of this example is described for the detection process of 20% DA-6·ethephon (8% + 12%) soluble concentrate, including the following steps:

[0218] (1) Preparation of the sample solution: Weigh a 20% DA-6·ethephon soluble concentrate sample containing about 0.05 g of DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 2 mL of diethylamine respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h and adjust the pH of the sample solution to 7.1. The preparation of the standard solution is the same as that in Example 1.

[0219] (2) Perform gas chromatography testing according to the method in Example 1.

[0220] The chromatograms of the first standard solution, the first sample solution, the second sample solution, and the second standard solution in this example are as Figure 14 shown. The retention times of different injection solutions are shown in Table 27.

[0221] Table 27 Retention Times of DA-6 and the Internal Standard

[0222] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Retention time of DA-6, min 2.983 2.983 2.983 2.983 Retention time of internal standard, min 3.833 3.832 3.832 3.833

[0223] It can be seen from Table 27 that when 2 mL of diethylamine is added in the determination step and the pH of the sample solution is adjusted to 7.1, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.983 min and 2.983 min respectively; the retention time of DA-6 in the standard solution is 2.983 min. The relative differences are 0% and 0% respectively; both are less than 1.5%. The retention time shift of DA-6 in the sample solution meets the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 28.

[0224] Table 28 Peak Areas of DA-6 and the Internal Standard

[0225] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Peak area of DA-6 1178.97 1195.46 1197.56 1179.89 Peak area of internal standard 1142.37 1150.27 1149.98 1140.68 Ratio of the peak area of DA-6 to that of internal standard 1.0320 1.0393 1.0414 1.0344

[0226] It can be seen from Table 28 that the reproducibility of the peak area of DA-6 in the sample solution is good.

[0227] The detection result of the mass fraction of DA-6 in 20% DA-6·ethephon (8% + 12%) soluble concentrate is 8.05%, which meets the qualified standard of the mass content of DA-6 (8.0 ± 0.8)%, and the detection result is qualified.

[0228] For the sample solution of Comparative Example 4, the pH is adjusted to 10.0 (for the detection of 10% DA-6·ethephon soluble concentrate)

[0229] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of the comparative example includes the following steps:

[0230] (1) Preparation of the sample solution:

[0231] Weigh about 0.05 g of the 10% DA-6·ethephon soluble concentrate sample containing DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 6 mL of triethylamine respectively with a pipette, dilute to the mark with acetone, and shake well. Let it stand for 1 h and adjust the pH of the sample solution to 10.0. The preparation of the standard solution is the same as that in Example 1.

[0232] (2) Perform gas chromatography testing according to the method in Example 1.

[0233] The chromatograms of Standard Solution 1, Sample Solution 1, Sample Solution 2, and Standard Solution 2 of this comparative example are as Figure 15 shown. The retention times of different injection solutions are shown in Table 29.

[0234] Table 29 Retention Times of DA-6 and the Internal Standard

[0235] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Retention time of DA-6, min 2.983 2.839 2.839 2.983 Retention time of internal standard, min 3.832 3.833 3.833 3.832

[0236] It can be seen from Table 29 that when 6 mL of triethylamine is added in the determination step and the pH of the sample solution is adjusted to 10.0, under the same chromatographic operating conditions, the retention times of DA-6 in the sample solution are 2.839 min and 2.839 min respectively; the retention time of DA-6 in the standard solution is 2.983 min. The relative differences are 4.95% and 4.95% respectively; both are greater than 1.5%. The retention time of DA-6 in the sample solution has a large deviation; and the peak shape has serious tailing; it does not meet the qualified requirements. The peak areas of DA-6 and the internal standard are shown in Table 30.

[0237] Table 30 Peak Areas of DA-6 and the Internal Standard

[0238] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Peak area of DA-6 1179.34 - - 1183.12 Peak area of internal standard 1138.67 1152.14 1150.37 1141.39 Ratio of the peak area of DA-6 to that of internal standard 1.0357 - - 1.0365

[0239] It can be seen from Table 30 that the peak shape of DA-6 in the sample solution is very poor and it is no longer possible to accurately integrate the peak area.

[0240] Since the peak area of DA-6 cannot be accurately calculated, the test result of the mass fraction of DA-6 is unqualified.

[0241] For the sample solution of Comparative Example 5, the pH is adjusted to 4.8 (for the detection of 20% DA-6·ethephon soluble concentrate)

[0242] The detection method of DA-6 in the DA-6·ethephon soluble concentrate of the comparative example includes the following steps:

[0243] (1) Preparation of the sample solution:

[0244] Weigh about 0.05 g of the 20% DA-6·ethephon soluble concentrate sample containing DA-6 (accurate to 0.0001 g), place it in a 25 mL volumetric flask, add 10 mL of the internal standard solution and 0.8 mL of monoethanolamine respectively with a pipette, and make up to the mark with acetone, then shake well. Let it stand for 1 h and adjust the pH of the sample solution to 4.8. The preparation of the standard solution is the same as that in Example 1.

[0245] (2) Carry out gas chromatography testing according to the method in Example 1.

[0246] The chromatograms of Standard Solution 1, Sample Solution 1, Sample Solution 2, and Standard Solution 2 of this comparative example are as Figure 16 shown. The retention times of different injection solutions are shown in Table 31.

[0247] Table 31 Retention Times of DA-6 and the Internal Standard

[0248] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Retention time of DA-6, min 2.983 3.292 3.292 2.983 Retention time of internal standard, min 3.832 3.832 3.832 3.832

[0249] It can be seen from Table 31 that when 0.8 mL of monoethanolamine is added in the determination step and the pH of the sample solution is adjusted to 4.8, under the same chromatographic operating conditions, the retention times of diethyl aminoethyl hexanoate in the sample solution are 3.292 min and 3.292 min respectively; the retention time of diethyl aminoethyl hexanoate in the standard solution is 2.983 min. The relative differences are 9.85% and 9.85% respectively; both are greater than 1.5%. The retention time of diethyl aminoethyl hexanoate in the sample solution has a large deviation; and the peak shape has serious tailing; it does not meet the qualified requirements. The peak areas of diethyl aminoethyl hexanoate and the internal standard are shown in Table 32.

[0250] Table 32 Peak Areas of Diethyl Aminoethyl Hexanoate and the Internal Standard

[0251] Standard solution 1 Sample solution 1 Sample solution 2 Standard solution 2 Peak area of DA-6 1181.26 - - 1180.96 Peak area of internal standard 1140.45 1151.91 1149.57 1141.67 Ratio of the peak area of DA-6 to that of internal standard 1.0358 - - 1.0344

[0252] It can be seen from Table 32 that the peak shape of diethyl aminoethyl hexanoate in the sample solution is very poor and it is no longer possible to accurately integrate the peak area.

[0253] Since the peak area of diethyl aminoethyl hexanoate cannot be accurately calculated, the test result of the mass fraction of diethyl aminoethyl hexanoate is unqualified.

Claims

1. A method for detecting diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate·ethephon soluble concentrate, characterized in that, It includes the following steps: Add a basic reagent to the DA-6·ethephon soluble concentrate and mix to obtain a test solution with a pH of 6-8. Determine the DA-6 content in the test solution using gas chromatography.

2. The detection method of diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate · ethephon soluble concentrate according to claim 1, characterized in that The basic reagent is selected from one of monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, and aqueous calcium hydroxide solution.

3. The detection method of diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate·ethephon soluble concentrate as claimed in claim 2, wherein For the DA-6·ethephon soluble concentrate containing 0.05 g of DA-6, the dosage of the basic reagent is 1-4 mL. Among them, the mass fraction of the aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, and aqueous calcium hydroxide solution is 0.5-2%.

4. The detection method of diethyl aminoethyl hexanoate in the soluble solution of diethyl aminoethyl hexanoate and ethephon as claimed in claim 1, characterized in that When preparing the test solution, mix the DA-6·ethephon soluble concentrate, basic reagent, and internal standard solution, make up the volume with acetone and then let it stand. After standing, the test solution is obtained.

5. The detection method of diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate · ethephon soluble concentrate according to claim 4, characterized in that, The standing time is at least 1 h.

6. The detection method of diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate · ethephon soluble concentrate as described in claim 1, characterized in that The DA-6·ethephon soluble concentrate is a 10-30% DA-6·ethephon soluble concentrate, where the mass content of DA-6 is 1-8%, the mass content of ethephon is 9-27%, and the pH < 3.

0.

7. The detection method of diethyl aminoethyl hexanoate in the diethyl aminoethyl hexanoate·ethephon soluble concentrate according to claim 1, characterized in that, The gas chromatography uses a capillary column packed with methyl polysiloxane containing 5% phenyl and a hydrogen flame ionization detector; the initial column temperature is 160 °C, held for 2 min, then heated at a rate of 30 °C / min to 280 °C and held for 5 min.

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