Micellar Electrokinetic Chromatography Homework Questions

(Stephanie and Diana’s Topic)

1. Find the analyte migration time if the retention factor is 3.0, the EOF marker migration time is 2.4 min, and the micelle marker migration time is 7.2 min.

            t_r = (1 + k)t_o/[1 + (t_o/t_mc)k] = (1 + 3)2.4 min/[1 + (2.4/7.2)3] = 9.6 min/2 = 4.8 min

2. If the optimum retention factor for maximum resolution is 2.0, and the EOF marker migration time is 1.7 min, what is the micelle marker migration time?

k_optimum = (t_mc/t_o)^0.5 or t_mc = k_optimum²*t_o = 4(1.7 min) = 6.8 min

3. What is the most common surfactant used in MEKC?

sodium dodecylsulfate

4. Which direction is the electroosmotic flow when the inner capillary surface is negatively charged and the buffer system is set to pH 8?

Toward the anode.