Question

The chromatogram shows the separation of components in an over-the-counter pain reliever. Calculate the number of theoretical plates, N, for the peaks of caffeine and benzoic acid. caffeine: N = 4751 plates 02 10 12 14 16 benzoic acid: N = 1. 8 min 6063 plates Peak Calculate the resolution, R, between caffeine and benzoic acid. 2 3 4 Component acetaminophen caffeine benzoic acid aspirin tr (min) 3.97 6.15 9.73 14.8 W1/2 (min) 0.12 0.21 0.35 0.73 R=1.77 R= 7.77

Answer 1

Column efficiency, indicated as the number of theoretical plates per column, is calculated as N = 5.54 (t_R / w_0.5)² where t_R is the retention time of the analyte of interest and w_0.5 the width of the peak at half height.

Answes ne. theovetial plates N N 16 S.54 coffers cO.21 xg.c) NS.SH =5.54 0.21 S.S4 x 857.653 Neaffeine 47S1 tr 9.73 w 0.35 for bengeie aufel 9-73 SS4 0- .42.8 S.S4X732.84 4281.5 p(ates Birgo ul 42 82 Resolution, R betuse an Caffene andl hengelt aud for Caffeine 2fer bengoie acil R = 1.7 X6.S Moro) put the ualuu Ph e .73-6.15) 17 X0.s(0.21t0.3) 3.s8 1-7Y0SXO-S6 8.58 0.46 7.521 R S So, Rercution A