Question

Use the following data to construct a spread sheet to determine the peak area ratio of the analyte to the internal standard. Construct a calibration curve plotting the the peak ratio of the analyte to the internal standard versus the concentration. Determine the concentration of the unknown. Your spreadsheet needs to be turned in also. (12 pts) Percent analyte 0.01 0.04 0.12 0.22 0.54 unknown Peak Area 15 50.1 160 303 950 225 Internal standard area 25.1 30.2 26.7 22.4 35.8 23.9

Answer 1

The plot of the (peak area ratio of the analyte to the internal standard) versus the (concentration of the analyte) can be drawn as follows.

10 0.0 0.2 0.3 0.4 0.5 0.6 Percent analyte

The equation of the plot: Peak area of analyte/peak area of internal standard = 49.8876*Percent analyte + 0.35545

Now, the peak area of unknown/peak area of internal standard = 225/23.9 = 9.414

Now, 9.414 = 49.8876*Percent analyte + 0.35545

Therefore, the concentration of the unknown = 0.18%