The amount of caffeine in an analgesic tablet was determined by HPLC using a normal calibration curve. Standard solutions of caffeine were prepared and analyzed using a 10-uL fixed-volume injection loop. Results for the standards are summarized in the following table. Concentration of Standards Signal (arbitrary units) (ppm) 50.0 8354 100.0 16925 150.0 25218 200.0 33584 250.0 42002 The sample was prepared by placing a single analgesic tablet in a small beaker and adding 10 mL of methanol. After allowing the sample to dissolve, the contents of the beaker, including the insoluble binder, were quantitatively transferred to a 25-mL volumetric flask and diluted to volume with methanol. The sample was then filtered, and a 1.00-mL aliquot was transferred to a 10-mL volumetric flask and diluted to volume with methanol. When analyzed by HPLC, the signal for the caffeine was found to be 21469. Report the number of milligrams of caffeine in the analgesic tablet.

The amount of caffeine in an analgesic tablet was determined by HPLC using a normal calibration curve. Standard solutions of caffeine were prepared and analyzed using a 10-uL fixed-volume injection loop. Results for the standards are summarized in the following table. Concentration of Standards Signal (arbitrary units) (ppm) 50.0 8354 100.0 16925 150.0 25218 200.0 33584 250.0 42002 The sample was prepared by placing a single analgesic tablet in a small beaker and adding 10 mL of methanol. After allowing the sample to dissolve, the contents of the beaker, including the insoluble binder, were quantitatively transferred to a 25-mL volumetric flask and diluted to volume with methanol. The sample was then filtered, and a 1.00-mL aliquot was transferred to a 10-mL volumetric flask and diluted to volume with methanol. When analyzed by HPLC, the signal for the caffeine was found to be 21469. Report the number of milligrams of caffeine in the analgesic tablet.

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter33: Automated Methods Of Analysis

Section: Chapter Questions

Problem 33.8QAP

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