Spring, 2012 Homework Set 3
Set 3.1 - Complete for quiz on May 2
Harris Text Ch. 21: 5, 10, 13a-b, e, 24, 28 + Ch. 22: 2, 7a, 17, 19
1. Using the information in Tables 21-1 and 21-2, determine the ratio of the M+1/M, and M+2/M peaks for C6H14SO2. To make this problem easier, you do not need to consider contributions from 2H or 17O atoms in any calculations.
2. A peptide in a liquid sample is analyzed using electrospray ionization mass spectrometry in the positive mode. The largest peaks are observed at 640.3, 427.0, and 320.8 Daltons. (15 pts)
a) What is the molecular mass of the most common isotope of the peptide?
b) What charge is associated with each of the above peaks?
c) Predict the location of one other likely observable peak and indicate its source.
Set 3.2 – Complete May 16th; no quiz
Harris Text Ch. 22: 22, 24, 26, 28, 31, 32, 38, 42, 43, Ch. 23: 3a, 5, 17, 20; Ch. 24: 1a, 4, 15
Additional Problem 1. Refer to the following chromatogram which shows the separation of 4 sugars using normal phase HPLC (more polar stationary phase – less polar mobile phase) with a 4.6 x 250 mm column. Compound names, retention times, and widths at the baseline, are given in the box within the chromatogram figure.
a) Calculate the retention factor (k) of fucose (the first major peak).
b) Calculate N and H (in mm/plate) using the glucose peak.
c) Calculate the resolution (RS) and the separation factor (α) between galactose and glucose.
d) Methylglucopyranoside can be made from glucose by replacing one of the hydroxy groups with a methoxy group (on the number 1 carbon). Predict whether you would expect methylglucopyranoside to be eluted before or after glucose. Explain your prediction in terms of polarity considerations.