Cetyl Alcohol (4)

4.

4.

4.

a.

b.

c.

4.

a.

b.

c.

4.

4.

Detector: hydrogen flame ionization detector, the lowest detection concentration is 0.

4.

a.

b.

c.
Filling method: plug the outlet end of the chromatographic column (connected to the detector) with a little glass wool, draw a vacuum from the outlet end, and fill it with about 20g of stationary phase under gentle vibration, fill it evenly and tightly, and then use a glass wool plug Good
.

d.
Aging of the chromatographic column: Put the filled column into the column box of the chromatograph.
After checking the air tightness, pass nitrogen and gradually increase the temperature to 210°C and age at 210°C for more than 8 hours until the baseline is stable
.

4.
7.
2.
3 Injector

Micro glass syringe
.

4.
7.
2.
4 Chromatographic data processor

Recorder or integrator
.

4.
7.
3 Analysis steps

4.
7.
3.
1 Adjust the instrument Adjust the instrument according to the following reference conditions

a.
Vaporization chamber temperature: 250～300℃;

b.
Testing room temperature: 250～300℃:

c.
Oven temperature: 180～200℃;

d.
Nitrogen flow rate: 25mL/min～30mL/min;

e.
Hydrogen flow rate: 25mL/min～30mL/min;

f.
Air flow rate: 400mL/min;

g.
Sample dilution: sample+solvent=1+5;

h.
Injection volume: 0.
02uL～0.
1uL
.

4.
7.
3.
2 Quantitative method

Modified area normalization method
.

4.
7.
3.
3 Test

Adjust the instrument according to the above reference conditions.
After the baseline is stable, use a micro glass syringe to inject the sample, and use the chromatogram recorder or integrator to process and calculate the data according to the corrected area normalization method
.

4.
7.
4 Calculation of analysis results

4.
7.
4.
1 Calculate according to formula (4) for each component X _i (%):

In the formula: x _i — the content of component i, when X _i is _Xc16 , it represents the purity of cetyl alcohol , and when X _i is X _RH , it represents the content of alkane;

A _i —corresponding to the chromatographic peak area of ​​component i;

f—The chromatographic peak quantitative correction factor corresponding to component i
.

4.
7.
4.
2 Quantitative correction factor: Measured with chromatographically pure known samples, calculated according to formula (5):

In the formula: f _w -weight correction factor;

A _i , W _i , A _s , W _s -are the peak area and weight of the analyte and the known chromatographically pure standard, respectively
.

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.
5%
.

Figure 2 C16 alcohol chromatogram