Industrial Acetic Anhydride (Appendix B)

Appendix B

(Standard appendix)

Determination of Acetic Anhydride Content—Gas Chromatography

Summary of Method B1

The components in industrial acetic anhydride are separated on Apiezon M/graphitized carbon black column, detected by thermal conductivity detector, and quantified by normalization method

B2 reagents and materials

B2.

Hydrogen : purity ≥99.

B2.

B2.

B2.

B3 instrument

B3.

B3.

B3.

B3.

B3.

B3.

Fixative: Carrier=10:100

Method of applying fixative solution: Weigh 0.

B3.

Plug the outlet end of the chromatographic column (connected to the detector end) with glass wool, connect the vacuum pump, and connect the other end to the funnel, turn on the vacuum pump, and load the stationary phase under gentle vibration

B3.

Install the filled chromatographic column in the column box of the chromatograph, disconnect the detector from the exit end, and age at 150°C for more than 8 hours until the baseline is stable
.

B3.
5 sampler

Micro glass syringe: the capacity is 10uL, and the minimum graduation is 0.
2uL
.

B4 analysis steps

B4.
1 Chromatograph operating conditions

Adjust the instrument according to the following conditions, allow appropriate changes according to different instruments, and obtain a suitable degree of separation
.

B4.
1.
1 Gasification chamber temperature: 200℃
.

B4.
1.
2 Test room temperature: 150℃
.

B4.
1.
3 Oven temperature: 90℃
.

B4.
1.
4 Bridge current: 120mA
.

B4.
1.
5 Carrier gas flow rate: 50mL/min
.

B4.
1.
6 Injection volume: 1uL
.

B4.
2 Quantitative method

Area normalization method
.

B4.
3 test

Adjust the instrument according to the above regulations.
After the baseline is stable, use the sampler to inject the sample and calculate by the chromatographic data processor
.

B4.
4 Chromatogram and relative retention time

B4.
4.
1 Chromatogram (see Figure B1)

Figure B1 Chromatogram of industrial acetic anhydride

B4.
4.
2 Relative retention time

The relative retention time of each component on the chromatographic column (Apiesone M/graphitized carbon black) is shown in Table B1
.

Table B1 Relative retention time

Expression of B5 analysis results

The content of acetic anhydride X ₁ expressed in mass percentage is calculated according to formula (B1):

In the formula: A—the peak area of ​​acetic anhydride in the sample, mm ² ;

∑A _i — the sum of the peak areas of each impurity in the sample, mm ²
.

Take the arithmetic mean of the two parallel determination results as the determination result, and the difference between the two parallel determination results shall not exceed 0.
10%
.

B6 minimum detection volume

The minimum detection amount of acetic anhydride is 0.
07ug
.

Related Links: Industrial Acetic Anhydride (Appendix A)