Determination of Oxygen in Gas Phase on Industrial Butadiene Liquid (2)

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Use a stainless steel capillary tube to connect the following components in order: the exit of the vaporization chamber of the chromatograph, the pre-separation column, the backflushing device, the separation column, and the entrance of the chromatograph thermal conductivity pool

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Figure 1 Flow chart of gas chromatography instrument

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According to the operating instructions of the instrument, age the chromatographic column in the chromatograph.

Table 1 Recommended typical operating conditions

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Under the recommended operating conditions, use a gas sampling valve to inject a standard sample (3.

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Take a sample with the same volume as the standard sample and inject it into the chromatograph with a gas sampling valve, measure and record the peak area of ​​oxygen in the sample, and compare it with the standard sample

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The oxygen content in the sample is calculated according to formula (1):

Where:

p _i —the oxygen content in the sample, the unit is milliliters per cubic meter (mL/m3);

P _E —The oxygen content of the standard sample, the unit is milliliters per cubic meter (mL/m3);

A _i —the corresponding peak area of ​​oxygen in the sample;

A _E —the area of ​​the corresponding peak of oxygen in the standard sample,

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Figure 2 Typical chromatogram

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The oxygen content in the sample is expressed as the arithmetic mean of the two repeated measurements, rounded to the nearest 1mL/m ³ according to GB/T8170

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7 Repeatability limit

In the same laboratory, the 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 in a short period of time should not exceed the repetition of Table 2.
The limit (r) is based on the premise that the repeatability limit (r) does not exceed 5%
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Table 2 Repeatability of oxygen content in samples analyzed by gas chromatography