Determination of trace carbon monoxide, carbon dioxide and acetylene in ethylene and propylene for industrial use. Gas chromatography (3)

6 sampling

Take samples according to the safety and technical requirements specified in GB/T3723, GB/T13289 and GB/T 13290

7 Analysis steps

7.

Install and condition the chromatographic column in the chromatograph according to the operating instructions of the instrument

7.

Use a gas sampling valve to inject 1mL～3mL of standard sample (4.

7.

Take a gas sample with the same injection volume as the standard sample, inject it into the chromatograph with a gas injection valve, repeat the measurement twice, record the peak area of ​​carbon monoxide, carbon dioxide or acetylene, and compare it with the corresponding external standard peak area

Note: When liquid propylene is sampled, measures should be taken to ensure that the liquid propylene is completely vaporized.

8 Expression of analysis results

8.

8.

Where:

ΦS—the content of carbon monoxide, carbon dioxide or acetylene in the standard sample, in milliliters per cubic meter (mL/m ³ );

Ai—the peak area of ​​carbon monoxide, carbon dioxide or acetylene in the tested sample;

As—the peak area of ​​carbon monoxide, carbon dioxide or acetylene in the standard sample

8.

8.

8.

9 Precision

9.

In the same laboratory, the absolute difference between the two independent test results obtained by the same operator using the same equipment, using the same test method, and independently testing the same object under test within a short period of time should not exceed Table 4 The repeatability limit (r) is based on the premise that the repeatability limit (r) does not exceed 5%

Table 4 Repeatability limit (r)

9.
2 Reproducibility

In any two different laboratories, different operators use different instruments and equipment to test the same object independently of each other to obtain two test results.
For samples with acetylene content of (5-20) mL/m³ , The difference should not be greater than 30% of its average value, assuming that it does not exceed 5% if it is greater than 30% of its average value
.

10 Test report

The test report should include the following:

a) All information about the sample, such as sample name, batch number, sampling location, sampling date, sampling time, etc.
;

b) Number of this standard;

c) Analysis results;

d) Details and descriptions of any abnormal phenomena observed in the measurement;

e) the name of the analyst and analysis date
.

Related Links: Determination of Trace Carbon Monoxide, Carbon Dioxide and Acetylene in Industrial Ethylene and Propylene Gas Chromatography (2)