Question

(3) During the separation of two steroids by HPLC on a C18 column, a student reported the following elution times with a certain % acetonitrile/water mobile phase (uracil was added to the steroid mixture) tm (uracil) 1.2 min t, (steroid1) 4.55 min t, (steroid2) 6.55 min base width, w (steroid 1) 0.56 min base width, w (steroid 2) 0.79 min a. Sketch the chromatogram to illustrate the above separation. Label the peaks and the x- and y-axis. Calculate the resolution of the two steroid peaks b. Calculate the retention factor of steroid 2 c. d. Why is the retention time of uracil referred to as tm and those of the steroids referred to as tr? What does tm refer to?

Answer 1

tn ww Revelemtien tirme = 4' 55min : tr 6.55 min bare twidtbtevoid A)- ,aidth tenoid 2) 0.Skmm W s 6.79mm = :2mn tm tm umaci ) Resaluton of teroid peat (t-tr WI +Wh S 0-79) 2 96 I25 fartor of teraid 2 () Retanti e tn- tm K 6.5S-12 : 4458 T2 Her o ,uraeil h cai duy ed an mew Aetained peeien barane uracil Polas than ndavajd. h mehe Cinee tPLe his m mature entain C18 an stah onany , Straidn a mes auith ral. Sa, athuti'gn 'brme 0 uraul n mimimum w dered mon Aatained apeln Aatamed thm in Aatentm bime dtmerAatain gd aps in y attahed t Aetent'on bane ot Betector Aabene-