CN108008034B - Method for detecting purity of N, N, N' -trimethylethylenediamine by gas chromatography - Google Patents

Abstract

The invention discloses a method for detecting the purity of N, N, N' -trimethylethylenediamine by adopting a gas chromatography, which adopts DB-624 capillary chromatographic column for detection, adopts a peak area normalization method to calculate the purity, and sets the detection conditions as follows: the injection port temperature is 200-250 ℃, the detection port temperature is 250-300 ℃, the carrier gas is high-purity nitrogen, the fuel gas is hydrogen, the combustion-supporting gas is compressed air, the column flow is 1.0ml/min, split-flow injection is adopted, the split-flow ratio is 50:1, the detector is a hydrogen flame ionization detector, and the column temperature adopts program temperature rise. The gas chromatography detection method is stable, reliable, accurate, high in repeatability and stable in peak-out time and peak value of the material, and the quality of the N, N, N' -trimethylethylenediamine can be well controlled by the detection method.

Description

A method for detecting the purity of N,N,N'-trimethylethylenediamine by gas chromatography

technical field

The invention relates to the technical field of material purity analysis, in particular to a method for detecting the purity of N,N,N'-trimethylethylenediamine, and more particularly to the detection of N,N,N'-trimethylethylenediamine by gas chromatography Methods for the determination of the purity of diamines, unknown single and total impurities.

Background technique

N,N,N'-trimethylethylenediamine is the main source of more than a dozen products such as 4-chloro-2-methylbenzaldehyde, N-(2-dimethylaminoethyl)-N-methylformamide, etc. Production raw materials, when the impurity content of N,N,N'-trimethylethylenediamine is high, it will affect the quality of the produced products. Therefore, it is particularly important to establish a stable, reliable and accurate method for the purity detection of N,N,N'-trimethylethylenediamine.

Gas chromatography detection method has the advantages of high separation efficiency, fast analysis speed, low sample consumption, high detection sensitivity and good selectivity, so it has been widely used in petrochemical, medical and health, environmental monitoring, biochemistry, food testing and other fields. Applications.

At present, there is no relevant report on the purity detection method of N,N,N'-trimethylethylenediamine. In order to strengthen the quality control of N,N,N'-trimethylethylenediamine, it is necessary to establish a stable , Reliable and accurate N,N,N'-trimethylethylenediamine purity gas chromatography detection method for rapid analysis of N,N,N'-trimethylethylenediamine's purity, unknown single impurities and total miscellaneous.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a stable, reliable and accurate N,N,N'-trimethylethylenediamine purity gas chromatography detection method to rapidly analyze N,N,N'-trimethylethylenediamine The purity, unknown single and total impurities of diamine provide a simple, accurate, fast and reliable detection method for the industrial production of N,N,N'-trimethylethylenediamine.

The technical scheme adopted in the present invention is: a method for detecting the purity of N,N,N'-trimethylethylenediamine by gas chromatography, comprising the following steps:

1) Set the working conditions of the instrument: the temperature of the injection port is 200-250°C, the temperature of the detection port is 250-300°C, the carrier gas is high-purity nitrogen, the gas is hydrogen, the auxiliary gas is compressed air, and the column flow rate is 1.0ml/ min, using split injection;

2) Sample injection detection: Precisely measure 0.2 μl of the test sample N,N,N'-trimethylethylenediamine and inject it into a gas chromatograph, record the spectrum, analyze the spectrum, and calculate the purity.

Preferably, when injecting the sample, a micro-injector can be used to inject the sample.

The gas chromatography method of the present invention adopts a medium polarity gas chromatography column, detects with a hydrogen flame ionization detector, and uses retention time for qualitative determination and peak area for quantitative determination.

Preferably, when setting the working conditions of the instrument in step 1), the chromatographic column used is a DB-624 capillary chromatographic column, and the specification of the chromatographic column is 30m (length) * 320 μm (inner diameter) * 1.8 μm (filler particle size).

Preferably, when setting the working conditions of the instrument in step 1), the detector used is a hydrogen flame ionization detector. The hydrogen flame ionization detector has the advantages of simple structure, good stability, high sensitivity, rapid response and high sensitivity.

Preferably, when setting the working conditions of the instrument in step 1), the column temperature adopts programmed temperature rise, and the initial temperature is maintained at 48-52°C for 1-3min, raised to 118-125°C at 18-25°C/min, and then heated to 3-8°C. °C/min increased to 152-165 °C, maintained for 1-3 min, and finally increased to 210-225 °C at 3-6 °C/min.

More preferably, when setting the working conditions of the instrument in step 1), the column temperature adopts a programmed temperature rise, the initial temperature is maintained at 50 ° C for 2 min, raised to 120 ° C at 20 ° C/min, and then raised to 160 ° C at 5 ° C/min, and maintained. 2min, and finally to 220°C at 5°C/min.

Preferably, in step 1), the split ratio of split injection is 50:1.

Preferably, in step 2), the peak area normalization method is used to calculate the purity.

The beneficial effects of the present invention are:

The invention adopts the gas chromatography detection method to quickly analyze the purity, unknown single impurities and total impurities of N,N,N'-trimethylethylenediamine. The gas chromatography detection method is stable, reliable, accurate, and has high repeatability. The peak time and peak value are stable, and the quality of N,N,N'-trimethylethylenediamine can be well controlled by this detection method.

Description of drawings

Fig. 1 is the gas-phase spectrum of N,N,N'-trimethylethylenediamine that embodiment 1 detects;

Fig. 2 is the gas phase spectrum of N,N,N'-trimethylethylenediamine that embodiment 2 detects;

Fig. 3 is the gas phase spectrum of N,N,N'-trimethylethylenediamine detected in Example 3.

Detailed ways

Take 3 batches of N,N,N'-trimethylethylenediamine products produced by the same production specification, and detect them according to the detection method described in Example 1-3. and total miscellaneous calculations.

Example 1

A method for detecting the purity of N,N,N'-trimethylethylenediamine by gas chromatography, comprising the following steps:

1) Set the working conditions of the instrument: the temperature of the injection port is 200 °C, the temperature of the detection port is 250 °C, the carrier gas is high-purity nitrogen, the fuel gas is hydrogen, the auxiliary gas is compressed air, the column flow rate is 1.0ml/min, and the split flow is adopted. For sample injection, the split ratio of split injection is 50:1; the chromatographic column used is a DB-624 chromatographic column, the size of the chromatographic column is 30m*320μm*1.8μm, and the detector used is a hydrogen flame ionization detector , the column temperature adopts programmed temperature rise, the initial temperature is maintained at 48°C for 1min, increased to 118°C at 18°C/min, then increased to 152°C at 3°C/min, maintained for 3min, and finally increased to 210°C at 3°C/min;

2) Sample injection detection: Precisely measure 0.2 μl of the test sample N,N,N'-trimethylethylenediamine and inject it into a gas chromatograph, record the spectrum, analyze the spectrum, and calculate the purity by the peak area normalization method.

The gas spectrum of the obtained N,N,N'-trimethylethylenediamine is shown in Figure 1. The purity, unknown mono-mixture and total of the detected N,N,N'-trimethylethylenediamine are obtained. Miscellaneous as shown in Table 1.

Example 2

A method for detecting the purity of N,N,N'-trimethylethylenediamine by gas chromatography, comprising the following steps:

1) Set the working conditions of the instrument: the temperature of the injection port is 220 °C, the temperature of the detection port is 280 °C, the carrier gas is high-purity nitrogen, the fuel gas is hydrogen, the auxiliary gas is compressed air, the column flow rate is 1.0ml/min, and the split flow is adopted. For sample injection, the split ratio of split injection is 50:1; the chromatographic column used is a DB-624 chromatographic column, the size of the chromatographic column is 30m*320μm*1.8μm, and the detector used is a hydrogen flame ionization detector , the column temperature adopts programmed temperature rise, the initial temperature is maintained at 50 °C for 2 min, increased to 120 °C at 20 °C/min, then increased to 160 °C at 5 °C/min, maintained for 2 min, and finally increased to 220 °C at 5 °C/min;

2) Sample injection detection: Precisely measure 0.2 μl of the test sample N,N,N'-trimethylethylenediamine and inject it into a gas chromatograph, record the spectrum, analyze the spectrum, and calculate the purity by the peak area normalization method.

The gas chromatogram of the obtained N,N,N'-trimethylethylenediamine is shown in Figure 2. The purity, unknown mono-mixture and total amount of the detected N,N,N'-trimethylethylenediamine are obtained. Miscellaneous as shown in Table 1.

Example 3

A method for detecting the purity of N,N,N'-trimethylethylenediamine by gas chromatography, comprising the following steps:

1) Set the working conditions of the instrument: the temperature of the injection port is 250 °C, the temperature of the detection port is 300 °C, the carrier gas is high-purity nitrogen, the fuel gas is hydrogen, the auxiliary gas is compressed air, the column flow rate is 1.0ml/min, and the split flow is adopted. For sample injection, the split ratio of split injection is 50:1; the chromatographic column used is a DB-624 chromatographic column, the size of the chromatographic column is 30m*320μm*1.8μm, and the detector used is a hydrogen flame ionization detector , the column temperature adopts programmed temperature rise, the initial temperature is maintained at 52 °C for 2 min, increased to 125 °C at 22 °C/min, then increased to 162 °C at 6 °C/min, maintained for 2 min, and finally increased to 225 °C at 6 °C/min;

2) Sample injection detection: Precisely measure 0.2 μl of the test sample N,N,N'-trimethylethylenediamine and inject it into a gas chromatograph, record the spectrum, analyze the spectrum, and calculate the purity by the peak area normalization method.

The gas spectrum of the obtained N,N,N'-trimethylethylenediamine is shown in Figure 3. The purity, unknown mono-mixture and total amount of the detected N,N,N'-trimethylethylenediamine are obtained. Miscellaneous as shown in Table 1.

The purity, unknown single impurity and total impurity obtained by the detection of table 1 embodiment 1-3

purity unknown complex total miscellaneous Example 1 98.2% 0.87% 1.8% Example 2 98.1% 0.95% 1.9% Example 3 98.9% 0.72% 1.1%

The gas chromatographic detection method is stable, reliable, accurate, and has high repeatability. The peak time and peak value of the material are stable, and the detection can be performed in about 20 minutes. The detection method can well control N,N,N'-trimethylamine quality of ethylenediamine.

Claims (5)

1. a method that adopts gas chromatography to detect N,N,N'-trimethylethylenediamine purity, is characterized in that, comprises the following steps: 1) Set the working conditions of the instrument: the temperature of the injection port is 200-250°C, the temperature of the detection port is 250-300°C, the carrier gas is high-purity nitrogen, the fuel gas is hydrogen, the auxiliary gas is compressed air, and the column flow rate is 1.0mL/ min, using split injection; 2) Sample injection detection: Precisely measure 0.2 μl of the test sample N,N,N'-trimethylethylenediamine and inject it into a gas chromatograph, record the spectrum, analyze the spectrum, and calculate the purity; When setting the working conditions of the instrument in step 1), the chromatographic column used is a DB-624 chromatographic column, and the specification of the chromatographic column is 30m*320μm*1.8μm; When setting the working conditions of the instrument in step 1), the column temperature adopts a programmed temperature rise, the initial temperature is 48-52 °C and maintained for 1-3min, and the temperature is increased to 118-125 °C at 18-25 °C/min, and then at 3-8 °C/min. Raised to 152-165°C, maintained for 1-3 min, and finally ramped to 210-225°C at 3-6°C/min. 2. adopt gas chromatography according to claim 1 to detect the method for N,N,N'-trimethylethylenediamine purity, it is characterised in that in step 1) when setting instrument operating conditions, the detector adopted It is a hydrogen flame ionization detector. 3. the method for adopting gas chromatography to detect the purity of N,N,N'-trimethylethylenediamine according to claim 1, is characterized in that, when setting instrument working condition in step 1), column temperature adopts program The temperature was increased, the initial temperature was maintained at 50 °C for 2 min, increased to 120 °C at 20 °C/min, then increased to 160 °C at 5 °C/min, maintained for 2 min, and finally increased to 220 °C at 5 °C/min. 4. the method that adopts gas chromatography to detect the purity of N,N,N'-trimethylethylenediamine according to claim 1, is characterized in that, in step 1), the split ratio of split injection is 50:1 . 5. the method for adopting gas chromatography to detect the purity of N,N,N'-trimethylethylenediamine according to claim 1, is characterized in that, in step 2), adopt peak area normalization method to calculate purity.

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