Residual chromatography of ethylene oxideInspection Principle

At a certain temperature, extract epoxyethane from the sample with water and determine the epoxyethane content using headspace gas chromatography.

Residual chromatography of ethylene oxidecondition

Hydrogen flame analyzer:Sensitivity not less than2X 1 0-11g/s(Benzene, carbon disulfide)（CS2）[]

chromatographic column:The chromatographic column used should be able to completely separate impurities and ethylene oxide in the sample, and have a certain degree of water resistance. Chromatographic column optional

Temperature of various parts of the instrument:

a）gasification chamber200centigrade;

b）Testing Room250centigrade.

airflow rate:

a）nitrogen15m L/min-30m l-/min;

b）hydrogen30m L/min;

c）air300 mL/min

prepare, compound, formulate

Take external dry50mCapacity bottle, with additional capacity30m 1Water, add bottle stopper, weigh accurately.0.1 m gInject approximately with a syringe0. 6 mLEthylene oxide, without a bottle stopper, gently shake well, cover the bottle stopper, weigh, and the difference between the two weighings is the weight of ethylene oxide contained in the solution. Add water to the mark and dilute the solution to1 X 10-' g/LAs a standard storage solution.

Preparation of retention test

4.1The preparation of test samples should be carried out immediately after sampling, otherwise the test samples should be sealed in a metal container sealed with polytetrafluoroethylene for storage.

4.2Cut the sample into5 mmLong fragments, take2. 0 gPut it into the extraction container and add10 mLWater, Top Space40 mLThe pressure inside the container is at atmospheric pressure and is maintained in a constant temperature water bath60 Cscholar1'CMiddle placement20 min..

Retention inspection steps

5 .1Prepare with reserve solution1X10^-3g/L—1X10²g/LStandard solutions with six series of concentrations. Each take10mLpress4 .2square

Legal processing.

Quickly take samples from the balanced standard and sample in sequence using a glass syringe1mLUpper gas, injected into the sampler.Record the peak height of ethylene oxide（Or area）.

note1:Try to have one person operate in an analysis and use the same one1m Lglass syringe

note2:The syringe is preheated to the same temperature as the sample

note3:Pay attention to changes in the retention time of ethylene oxide each time to prevent gas leakage from the injection vaporization pad

note4:each sample（Including standard samples）Analyze three times in the shortest possible time, and two out of the three analyses must have results that do not differ by more than5%Otherwise, this sample should be reanalyzed.

5.2Draw the standard curve using the data measured by the standard sample（X:EOconcentration/（g/L）; Y:Peak height or area）.

5 .3Find the corresponding concentration of the sample from the standard curve. If the measured sample results are not within the range of the standard curve, the concentration of the standard solution should be changed to create a new standard curve.

Calculation of inspection results

The residual amount of ethylene oxide is expressed in terms of content or relative content.

According to the formula（H.1 ）Calculate the content of ethylene oxide in the sample:

W_EO= 5c₁·G

in the formula:

W_EO—Ethylene oxide content per unit product, measured in milligrams（mg）;

5c₁—The corresponding concentration of the test solution found on the standard curve, in grams per liter（g/L）;

G—The quality of a unit product, measured in grams（9）.

2According to the formula（H.2）Calculate the relative content of ethylene oxide in the sample:

C_EO= 5c_1*1 0 00

in the formula:

C_EO—Relative content of ethylene oxide in the product, measured in milligrams per kilogram（mg/kg）;

c_1—The corresponding concentration of the test solution found on the standard curve, in grams per liter（g/L）.

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