94. Решение задачки по химии №009 428

To determine the content of α-tocopheryl acetate in the analyzed solution by capillary GLC using an internal standard, squalane, we first prepared 5 model mixtures - solutions with different specified mass ratio mst / m of squalane mst and α-tocopheryl acetate m, chromatographed samples of these solutions, measured the ratio Sst /S peak areas of squalane Sst and α-tocopheryl acetate S and obtained the following results.
mst/m 0.172 0.232 0.262 0.301 0.326
Sst/S 0.224 0.300 0.342 0.388 0.419
Then, under the same conditions, a sample of the analyzed solution containing an unknown mass mx of α-tocopheric acetate and a known mass mst of squalane was chromatographed, the ratio of the peak areas of the internal standard and α-tocopheryl acetate Sst/Sx=0.285 was measured.
Calculate from the data given in the table the average value of the correction factor k in the equation:

The standard deviation s of the mean (with sample size n=5 and confidence probability P=0.95) and the mass mx of α-tocopheric acetate in the analyzed solution, if the mass of squalane in the analyzed solution from which the sample was taken for analysis, was mst=10 mg.
Answer: k=1.295; s=0, 0200; mx=45.44 mg.

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