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4.
4.
4.
4.
4.
A.
b Fixative: polyethylene glycol 1500;
c.
d.
Column 1 carrier·fixed solution=100:12;
Column 2 carrier: fixative=100:3
4.
a.
According to the packing ratio of column 1 and column 2, accurately weigh the required fixing solution into a 400mL beaker, add chloroform equivalent to 1.
b.
When installing the filled chromatographic column on the chromatograph, one end of the detector should be temporarily disconnected, and nitrogen gas should be used for aging at 140~150℃ for 6~8h
c.
For the peak sequence and typical chromatogram of impurities in dichloroethane , see Appendix A (reference)
Resolution: The resolution of a pair of difficult-to-separate substances is R>1
.
4.
1.
4 Determination of correction factor
Use a known pure substance to prepare a mixture similar to the impurity composition of the sample for the test, and then calculate the relative mass correction factor under the standard specified conditions according to the components in the prepared sample, see Appendix B (reference)
.
4.
1.
5 Analysis steps
a.
Adjust the instrument, adjust the instrument according to the following reference conditions
.
Vaporization chamber temperature: 150℃;
The temperature of the testing room: 140℃;
Oven temperature: 80℃;
Ammonia flow rate: 20mL/min;
Hydrogen flow rate: 45mL/min;
Air flow rate: 350mL/min;
Injection volume: 0.
4uL
.
b.
Quantitative method: internal standard method
.
c.
Quantitative determination: Weigh 5-6g sample, according to the mass percentage of impurities in the product: Use a micro syringe to draw 2uL of benzene (low boiling internal standard substance) and 10uL of dodecane (high boiling internal standard substance) to obtain Mix and shake the mixture, analyze according to the specified conditions, and measure the peak area of the internal standard substance and each impurity component for calculation
.
Related links: Industrial 1.
2-Dichloroethane (1)