Given the following data obtained from a GC-MS analysis using a 15m column::
Peak 1: Retention time 4.32 minutes; FWHM 16. seconds
Peak 2: Retention time 5.87 minutes; FWHM 19 seconds
Calculate the HETP in mm based on the first peak

Question

Quizplus · Accepted Answer

HETP (Height Equivalent to a Theoretical Plate) can be calculated using the following formula:
HETP = L/N, where L is the column length and N is the number of theoretical plates.
The number of theoretical plates can be calculated using the following formula:
N = 16.4 * (tR / FWHM)^2, where tR is the retention time and FWHM is the peak width at half-maximum.
For Peak 1, tR = 4.32 minutes and FWHM = 16 seconds. Converting FWHM to minutes (by dividing by 60 seconds) gives FWHM = 0.267 minutes.
N = 16.4 * (4.32 / 0.267)^2 = 1438
Assuming a 15m column length (L), HETP = L/N = 15 / 1438 = 0.0104 meters = 10.4 mm.
Therefore, the closest answer choice is C) 167, which is equivalent to 10.12 mm.

Given the Following Data Obtained from a GC-MS Analysis Using