Method for detecting content of phosphonitrilic chloride trimer

Abstract

The invention relates to a method for detecting the content of phosphonitrilic chloride trimer, which comprises the following steps: (1) adding a methanol solution of sodium methoxide into a sample to be detected for reaction, and fixing the volume after the reaction is finished; and (2) injecting the liquid obtained by volume metering in the step (1) into a high performance liquid chromatograph for testing, and recording a chromatogram. Aiming at the bottleneck that hexachlorocyclotriphosphazene is easy to hydrolyze and difficult to directly and accurately detect, an appropriate derivatization reagent is selected, a derivatization pretreatment step is adopted, and hexachlorocyclotriphosphazene is stably converted into hexamethoxy cyclotriphosphazene, so that a solid foundation is laid for subsequent liquid phase analysis. According to the method, the characteristic of unstable hydrolysis of phosphonitrilic chloride trimer can be avoided, the accuracy and repeatability of detection are remarkably improved, and the detector is simple and convenient to maintain; and the method can be well suitable for quantitative analysis of phosphonitrilic chloride trimer with different content levels.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of analytical techniques, in particular to a method for detecting the content of hexachlorocyclotriphosphazene. BACKGROUND

[0002] Hexachlorocyclotriphosphazene is an important phosphorus-containing heterocyclic compound, and its core applications are concentrated in flame-retardant materials, high polymer modification synthesis, etc. In the field of flame-retardant materials, hexachlorocyclotriphosphazene can be used as a key intermediate to synthesize organic phosphorus-nitrogen flame retardants, which are applied to plastics, rubbers, textiles, etc. In the field of high polymer modification synthesis, hexachlorocyclotriphosphazene can be polymerized as a monomer to generate polyphosphazene high polymer materials, which have the characteristics of high temperature resistance, weather resistance, good biocompatibility, etc., and are applied to special rubbers, medical materials, coatings, etc. Hexachlorocyclotriphosphazene can also be used to prepare catalysts, bactericides, special additives, etc., and has a small amount of application in electronic materials and chemical intermediate synthesis.

[0003] Since hexachlorocyclotriphosphazene does not contain C, the FID detector commonly configured for GC cannot detect the peak, and a nitrogen-phosphorus detector or an ECD detector needs to be configured, which is not as convenient to maintain as the FID detector. In addition, the dynamic linear range of GCMS is relatively narrow, and high-content samples need to be diluted multiple times, which is easy to introduce errors and has poor quantitative accuracy, so GCMS is not suitable for testing high-content hexachlorocyclotriphosphazene and is only suitable for qualitative or low-content detection. In addition, hexachlorocyclotriphosphazene is easy to deteriorate due to water absorption, and may undergo hydrolysis reaction when exposed to water for a long time, so it needs to be stored and used to avoid long-term contact with water-containing systems, and therefore hexachlorocyclotriphosphazene is not suitable for direct detection by liquid phase method.

[0004] In view of the above, it is urgent to find a method that is easy to maintain and can detect hexachlorocyclotriphosphazene of different contents. SUMMARY

[0005] The purpose of the present application is to provide a method for detecting the content of hexachlorocyclotriphosphazene, which can test hexachlorocyclotriphosphazene of different contents and significantly improve the accuracy and repeatability of the detection, and the detector is easy to maintain.

[0006] To achieve the purpose of the present application, the following technical solutions are adopted:

[0007] In the present application, the standard sample of hexamethoxycyclotriphosphazene is purchased, and the derivative material is determined to be hexamethoxycyclotriphosphazene by confirming that the peak position of the standard sample and the retention time of the derivative product are consistent.

[0008] The first purpose of the present application is to provide a method for detecting the content of hexachlorocyclotriphosphazene, which comprises the following steps:

[0009] (1) adding sodium methoxide in methanol solution to the sample to be tested for reaction, and then performing constant volume after the reaction is completed;

[0010] (2) The liquid obtained by constant volume in step (1) is injected into a high performance liquid chromatograph for testing, and the chromatogram is recorded.

[0011] Specifically, the mass concentration of the sodium methoxide methanol solution is 5-15%; preferably, the mass concentration of the sodium methoxide methanol solution can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%, etc., but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0012] Preferably, the mass concentration of the sodium methoxide methanol solution is 9-11%; more preferably, the mass concentration of the sodium methoxide methanol solution is 9%, 10%, or 11%, etc., but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0013] Specifically, the reaction temperature is 25-40℃, and the reaction time is 30-60 min; preferably, the reaction temperature can be 25℃, 30℃, 35℃, 40℃, or 45℃, etc., and the reaction time can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min, etc., but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0014] Preferably, the reaction temperature is 29-33℃, and the reaction time is 40-50 min; more preferably, the reaction temperature can be 29℃, 30℃, 31℃, 32℃, or 33℃, etc., and the reaction time can be 40 min, 45 min, or 50 min, etc., but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0015] Specifically, the reaction is a derivatization reaction, and the derivatization product is confirmed by retention time to be hexamethoxy cyclotriphosphazene, and a standard curve of hexamethoxy cyclotriphosphazene is established.

[0016] Specifically, the method can be applied to detect samples with a linear range of hexachlorocyclotriphosphazene of 0.0005 mg / mL-1.2 mg / mL.

[0017] Specifically, the chromatographic conditions of the test are as follows:

[0018] Chromatographic column: C18 chromatographic column, length 250 mm, inner diameter 4.6 mm, filler particle size 5 μm;

[0019] Flow rate: 0.9-1.1 mL / min;

[0020] Column temperature: 35-45℃;

[0021] Injection volume: 5-10 μL;

[0022] Detection wavelength: 210 nm;

[0023] Mobile phase A: water;

[0024] Mobile phase B: ACN.

[0025] Preferably, the mobile phase adopts an elution mode of isocratic elution;

[0026] Preferably, the isocratic elution time is 15 min.

[0027] Preferably, the volume ratio of the mobile phase A to the mobile phase B is 20: (78-82); more preferably, the volume ratio of the mobile phase A to the mobile phase B can be 20:78, 20:79, 20:80, 20:81 or 20:82, etc., but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The present application aims at the bottleneck of easy hydrolysis and difficult direct and accurate detection of hexachlorocyclotriphosphazene, selects a suitable derivatization reagent and adopts a pretreatment step of derivatization, and converts the hexachlorocyclotriphosphazene into hexamethoxycyclotriphosphazene, thereby laying a solid foundation for subsequent liquid analysis. The present application not only can effectively avoid the unstable characteristics of hexachlorocyclotriphosphazene hydrolysis, significantly improve the accuracy and repeatability of detection, and is simple to maintain the detector; but also can be well applied to the quantitative analysis of hexachlorocyclotriphosphazene at different content levels. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the chromatogram of the blank derivatization reagent in Example 1;

[0031] Figure 2 is the chromatogram of the non-derivatized hexachlorocyclotriphosphazene sample solution in Example 1;

[0032] Figure 3 is the chromatogram of the liquid obtained by constant volume after derivatization in step (1) in Example 1; DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations on the present application.

[0034] To confirm the feasibility and stability of the experiment of hexachlorocyclotriphosphazene derivative into hexamethoxycyclotriphosphazene, and to ensure the reliability of the content determination results of hexachlorocyclotriphosphazene derivative, the above chromatographic conditions are verified for specificity, linearity, solution stability, accuracy (recovery), detection limit and quantification limit.

[0035] Example 1

[0036] The present embodiment provides a method for detecting the content of hexachlorocyclotriphosphazene, which performs specificity test, including the following steps:

[0037] (1) Take 20 mg of the sample to be tested into a 20 mL volumetric flask, add 10 mL of 10% sodium methoxide methanol solution to the sample to be tested, and react at 30°C for 45 min. After the reaction is completed, add anhydrous methanol to make up the volume;

[0038] (2) The blank derivative reagent (10% sodium methoxide methanol solution), the non-derivatized hexachlorocyclotriphosphazene sample solution, and the liquid obtained after derivatization and constant volume in step (1) are filtered through a 0.45 μm filter head respectively, and then injected into a high performance liquid chromatograph for testing. The chromatographic conditions are as follows: chromatographic column: C18 chromatographic column (5 μm, 250 mm*4.6 mm); flow rate: 1.0 mL / min; column temperature: 40°C; injection volume: 10 μL; detection wavelength: 210 nm; mobile phase A: water; mobile phase B: acetonitrile; the volume ratio of mobile phase A to mobile phase B is 20:80, and the mobile phase is eluted isocratically with an elution time of 15 min; record the chromatogram, wherein the conversion rate of the liquid obtained after derivatization and constant volume in step (1) is 100%; and the retention time of the derivatized product is 5.20 min, as shown in the following figure. Figures 1-3

[0039] The results show that the blank derivative reagent has no interference, the peak retention time of the non-derivatized hexachlorocyclotriphosphazene sample solution is 3.58 min, and the peak retention time of the derivatized product is 5.20 min, with a separation degree ≥1.5 and no mutual interference, indicating that the method has good specificity. At the same time, the derivatized product is confirmed to be hexamethoxycyclotriphosphazene according to its peak retention time compared with the standard sample.

[0040] Example 2

[0041] The present embodiment provides a method for detecting the content of hexachlorocyclotriphosphazene, which performs linearity verification, including the following steps, first, the configuration of linear solution:

[0042]

[0043] ​Take a certain mass of hexamethoxycyclotriphosphazene reference substance into a 50 mL volumetric flask, add an appropriate amount of methanol, ultrasonic until completely dissolved, then dilute to the mark with methanol, shake well, detect by the chromatographic conditions of Example 1, and draw a standard curve with concentration (x) as the abscissa and peak area (y) as the ordinate. The standard curve equation is y = 2.635x - 0.278, the linear correlation coefficient R = 0.9995, and the results show that the linear relationship is good in the concentration range of 0.8-1.2 mg / mL, which can be used for content calculation. 2 The limit of quantification concentration in Example 5 is 0.0005 mg / mL, and the experimental results show that the linear curve is still applicable. Therefore, the linear relationship is good in the concentration range of LOQ-1.2 mg / mL, which can be used for content calculation.

[0044] Example 3

[0045] This example provides a method for detecting the content of hexachlorocyclotriphosphazene. The following tests the stability of the solution, specifically as follows: take 20 mg of hexachlorocyclotriphosphazene standard into a 20 mL volumetric flask, add 10 mL of 10% sodium methoxide methanol solution, place in a 30°C constant temperature water bath for 45 min, cool, then dilute to the mark with anhydrous ethanol, filter through a 0.45 μm filter head, inject, and detect by the chromatographic conditions of Example 1 to record the chromatogram.

[0046] Time (h) Retention time (min) Peak area 0 4.65 280.452 1 4.65 280.736 2 4.64 281.625 4 4.67 281.236 8 4.65 281.425 12 4.64 282.337 16 4.63 282.782 20 4.65 282.463 24 4.64 283.551 Mean 4.65 281.845 RSD (%) 0.23 0.34

[0047] The results show that within 24 h, the RSD of the retention time of the derivative hexamethoxycyclotriphosphazene is 0.23%, and the RSD of the peak area is 0.34%. Therefore, the derivatization condition is stable and feasible, the conversion rate is stable, and the derivative is stable within 24 h.

[0048] Example 4

[0049] This example provides a method for detecting the content of hexachlorocyclotriphosphazene. The following tests the repeatability, specifically as follows:

[0050] Prepare the linear sample solution according to Example 2, draw the standard curve, weigh 6 portions of 20 mg hexachlorocyclotriphosphazene sample into 20 mL volumetric flasks, perform derivatization experiments according to Example 3, inject to record the chromatogram, and calculate the content of the derivative hexamethoxycyclotriphosphazene by external standard method.

[0051] Determination results:

[0052]

[0053] The results show that the RSD value of the content determination results of the 6 parallel samples is less than 2%, and the method has good repeatability.

[0054] Example 5

[0055] The present embodiment provides a detection method for the content of hexachlorocyclotriphosphazene. The following tests the detection limit and the quantitative limit, specifically as follows:

[0056] The 1.0 mg / mL hexamethoxy cyclotriphosphazene standard solution is gradually diluted, and detected according to the chromatographic conditions of Example 1. The detection limit (LOD) is 0.0002 mg / mL calculated by the signal-to-noise ratio (S / N) = 3, and the quantitative limit (LOQ) is 0.0005 mg / mL calculated by S / N = 10, both of which are far lower than the conventional content determination concentration (0.1-1.0 mg / mL), meeting the needs of trace content determination.

[0057] Example 6

[0058] The present embodiment provides a detection method for the content of hexachlorocyclotriphosphazene. The following tests the accuracy, specifically as follows:

[0059] Prepare four concentrations of hexachlorocyclotriphosphazene derivative (hexamethoxy cyclotriphosphazene) standard solution, LOQ (0.0005 mg / mL), low (0.002 mg / mL), medium (1.0 mg / L), and high (1.2 mg / mL), respectively, for recovery rate test. According to the linear standard curve of hexamethoxy cyclotriphosphazene, the content of hexamethoxy cyclotriphosphazene in the sample solution is calculated by external standard method, and the recovery rate is calculated by comparing with the theoretical content.

[0060] The determination results are as follows:

[0061]

[0062] The results show that the recovery rate is between 99.00% and 99.95%, and the RSD is less than 2%, indicating that the method has good accuracy.

[0063] Example 7

[0064] The present embodiment provides a detection method for the content of hexachlorocyclotriphosphazene, which is basically the same as Example 1, except that in step (1), 10 mL of methanol solution of 5% sodium methoxide is added to the sample to be tested, and the conversion rate is 97.5%.

[0065] (The following examples and comparative examples do not repeat the comparison of blank derivative reagent (10% methanol solution of sodium methoxide) and non-derivatized hexachlorocyclotriphosphazene sample solution)

[0066] Example 8

[0067] The present embodiment provides a detection method for the content of hexachlorocyclotriphosphazene, which is basically the same as Example 1, except that in step (1), 10 mL of methanol solution of 15% sodium methoxide is added to the sample to be tested, and the conversion rate is 98.0%.

[0068] Example 9

[0069] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), 10 mL of a methanol solution of sodium methoxide with a mass concentration of 9% is added to the sample to be tested, and the conversion rate is 98.9%.

[0070] Example 10

[0071] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), 10 mL of a methanol solution of sodium methoxide with a mass concentration of 11% is added to the sample to be tested, and the conversion rate is 99.2%.

[0072] Example 11

[0073] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 25°C for 45 min, and the final chromatogram shows a conversion rate of 98.7%.

[0074] Example 12

[0075] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 40°C for 45 min, and the final chromatogram shows a conversion rate of 98.5%.

[0076] Example 13

[0077] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 29°C for 45 min, and the final chromatogram shows a conversion rate of 99.2%.

[0078] Example 14

[0079] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 33°C for 45 min, and the final chromatogram shows a conversion rate of 99.5%.

[0080] Example 15

[0081] This example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 30°C for 30 min, and the final chromatogram shows a conversion rate of 97.4%.

[0082] Example 16

[0083] The present example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 30°C for 60 min. The final chromatogram shows that the conversion rate is 96.5%.

[0084] Example 17

[0085] The present example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 30°C for 40 min. The final chromatogram shows that the conversion rate is 99.1%.

[0086] Example 18

[0087] The present example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (1), the reaction is carried out at 30°C for 50 min. The final chromatogram shows that the conversion rate is 98.0%.

[0088] Example 19

[0089] The present example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (2), the chromatographic conditions are changed as follows: chromatographic column: C18 chromatographic column (5 μm, 250 mm*4.6 mm); flow rate: 0.9 mL / min; column temperature: 35°C; injection volume: 5 uL; detection wavelength: 210 nm; mobile phase A: water; mobile phase B: acetonitrile; the volume ratio of mobile phase A to mobile phase B is 20:78, and the mobile phase is eluted isocratically for 15 min; record the chromatogram, which shows that the conversion rate is 100%.

[0090] Example 20

[0091] The present example provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of Example 1, except that in step (2), the chromatographic conditions are changed as follows: chromatographic column: C18 chromatographic column (5 μm, 250 mm*4.6 mm); flow rate: 1.1 mL / min; column temperature: 45°C; injection volume: 8 uL; detection wavelength: 210 nm; mobile phase A: water; mobile phase B: acetonitrile; the volume ratio of mobile phase A to mobile phase B is 20:82, and the mobile phase is eluted isocratically for 15 min; record the chromatogram, which shows that the conversion rate is 100%.

[0092] Comparative Example 1

[0093] The comparative example 1 provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of the example 1, except that in step (1), 10 mL of a t-butanol solution of sodium t-butoxide with a mass concentration of 10% is added to the sample to be tested, and the conversion rate is only 70.0%, and the peak area of the product changes by about 10% within 24 h.

[0094] Comparative example 2

[0095] The comparative example 1 provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of the example 1, except that in step (1), 10 mL of a t-butanol solution of sodium t-butoxide with a mass concentration of 10% is added to the sample to be tested, and the conversion rate is only 70.0%, and the peak area of the product changes by about 10% within 24 h.

[0096] Comparative example 3

[0097] The comparative example 1 provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of the example 1, except that in step (1), 10 mL of a t-butanol solution of sodium t-butoxide with a mass concentration of 10% is added to the sample to be tested, and the conversion rate is only 70.0%, and the peak area of the product changes by about 10% within 24 h.

[0098] Comparative example 4

[0099] The comparative example 1 provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of the example 1, except that in step (1), 10 mL of a t-butanol solution of sodium t-butoxide with a mass concentration of 10% is added to the sample to be tested, and the conversion rate is only 70.0%, and the peak area of the product changes by about 10% within 24 h.

[0100] Comparative example 5

[0101] The comparative example 1 provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of the example 1, except that in step (1), 10 mL of a t-butanol solution of sodium t-butoxide with a mass concentration of 10% is added to the sample to be tested, and the conversion rate is only 70.0%, and the peak area of the product changes by about 10% within 24 h.

[0102] Comparative example 6

[0103] The comparative example 1 provides a method for detecting the content of hexachlorocyclotriphosphazene, which is basically the same as that of the example 1, except that in step (1), 10 mL of a t-butanol solution of sodium t-butoxide with a mass concentration of 10% is added to the sample to be tested, and the conversion rate is only 70.0%, and the peak area of the product changes by about 10% within 24 h.

[0104] Comparative example 7

[0105] The comparative example 2 provides a detection method of hexachlorocyclotriphosphazene content, which is basically the same as the example 1, except that in step (1), the reaction is carried out at 30°C for 15 min, and the final chromatogram shows that the reaction is not complete, and the conversion rate is only 90.0%.

[0106] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. It should be understood by those skilled in the art that any change or replacement within the technical range disclosed by the present application can be easily thought out by those skilled in the art, and falls within the protection scope and disclosure range of the present application.

Claims

1. A method for the determination of the hexachlorocyclotriphosphazene content, characterized in that, It comprises the following steps: (1) adding sodium methoxide methanol solution into the sample to be tested to react, and then constant volume is performed after the reaction is completed; (2) injecting the liquid obtained by constant volume in step (1) into a high performance liquid chromatograph to test, and recording a chromatogram.

2. The method of claim 1, wherein, The mass concentration of the sodium methoxide methanol solution is 5-15%.

3. The method of claim 2, wherein, The mass concentration of the sodium methoxide methanol solution is 9-11%.

4. The method of claim 1, wherein, The temperature of the reaction is 25-40℃, and the reaction time is 30-60 min.

5. The method of claim 4, wherein, The temperature of the reaction is 29-33℃, and the reaction time is 40-50 min.

6. The method of claim 1, wherein, The reaction is a derivatization reaction, and the derivatization product is confirmed as hexamethoxy cyclotriphosphazene by retention time, and a standard curve of hexamethoxy cyclotriphosphazene is established.

7. The method of claim 1, wherein, The method can be applied to detect samples with a linear range of hexachlorocyclotriphosphazene of 0.0005 mg / mL-1.2 mg / mL.

8. The method of claim 1, wherein, The chromatographic conditions of the test are as follows: A C18 chromatographic column with a length of 250 mm, an inner diameter of 4.6 mm, and a filler particle size of 5 μm is used; The flow rate is 0.9-1.1 mL / min; The column temperature is 35-45℃; The injection volume is 5-10 μL; The detection wavelength is 210 nm; The mobile phase A is water; The mobile phase B is ACN.

9. The method of claim 8, wherein, The mobile phase uses isocratic elution elution mode; Preferably, the isocratic elution time is 15 min.

10. The method of claim 8, wherein, The volume ratio of the mobile phase A to the mobile phase B is 20:(78-82).

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