Polar compounds were separated by HPLC using a bonded phase containing polar diol substituent [-CH(OH)CH,OH]. How would the retention times be affected if the eluent were changed from 70 vol.% to 30 vol.% of acetonitrile in water? Retention times will be unchanged. Retention times will be shorter Retention times will be longer D Changes in retention times are not sure.

Polar compounds were separated by HPLC using a bonded phase containing polar diol substituent [-CH(OH)CH,OH]. How would the retention times be affected if the eluent were changed from 70 vol.% to 30 vol.% of acetonitrile in water? Retention times will be unchanged. Retention times will be shorter Retention times will be longer D Changes in retention times are not sure.

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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You must separate three different compounds with reversed phase HPLC. Compound 1 is an acid (pKa = 4.3), compound 2 is neutral compounds and compound 3 is a base (pKa = 9.6). As eluent, use 30/70 (v / v)% methanol / pH 3.0 formic acid buffer. The retention time and the top width at the base of the top for the three components are presented below. You can assume the dead time to 1.2 minutes in your calculations.Compound Retention time [minutes] Peak width [seconds] 1 10.1 282 5.0 143 6.1 17a) Calculate the efficiency (number of theoretical bases) for component 1.b) Calculate the selectivity and resolution between components 1 and 2.c) When you increase the pH of your eluent to pH 6, how will the retention be affected (increase, decreaseor unchanged) for the different associations (1, 2 and 3) ?, justify your answer.d) How retention factors are generally affected by an increase in the proportion organicallymobile phase solvents for reversed phase HPLC separations ?, justify your…
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