Determination of acrylonitrile peroxide content for industrial use. Spectrophotometric method (4)

7.

Use a pipette to transfer 0.

Where:

PD— The exact concentration of hydrogen peroxide standard solution D, in micrograms per milliliter (ug/mL);

P—Accurate concentration PA or pC of hydrogen peroxide stock solution A or solution C, in milligrams per milliliter (mg/mL);

0.

50.

7.

7.

Table 1 The amount of acetic anhydride and hydrogen peroxide standard solution added when preparing the calibration curve

7.

Where:

w— The mass fraction of hydrogen peroxide contained in each point in the calibration curve, in milligrams per kilogram (mg/kg);

P _D — the exact concentration of solution D, in micrograms per milliliter (pg/mL);

Vi—the volume of the pipetted solution D, in milliliters (mL);

P—The density of acrylonitrile at the time of sampling, in grams per milliliter (g/mL);

25.

7.

Note: Before adding potassium iodide , the Erlenmeyer flask should be protected from light with aluminum foil or a colored Erlenmeyer flask should be lighted and timed from the time when potassium iodide was added to the Erlenmeyer flask.

7.

7.

8 Measurement of sample

8.

Note 1: When the peroxide content in the sample exceeds 0.

Note 2: Acetic anhydride can absorb the moisture in acrylonitrile and keep the sample solution acidic

8.
2 At the same time, follow step 8.
1 and do a blank test with peroxide-free acrylonitrile (5.
15)
.

8.
3 According to the net absorbance of the sample (the absorbance of the actual test sample minus the absorbance of the blank solution), check the content of peroxide (as H2O2) in the acrylonitrile sample on the calibration curve, in milligrams per kilogram (mg /kg)
.

9 Expression of analysis results

Take the arithmetic average of the results of two repeated determinations to express the results, and round off according to the provisions of GB/T8170 to the nearest 0.
01 mg/kg
.

10 Repeatability

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 in a short period of time is not greater than the average value.
20%, on the premise that it does not exceed 5% if it is greater than 20% of its average value
.

11 Report

The report should include the following:

a) all information relating to the sample, such as sample name, batch number, sampling sites, sampling date, sampling time
.

b) Number of this part
.

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 Acrylonitrile Peroxide Content for Industrial Use Spectrophotometry (3)