Question

help needed with this problem set

Refer to the HPLC chromatograms below for a 5-component mixture of organic acids for the following questions. The specific HPLC parameters for chromatogram A (top) are described in the figure title and the insert. You only need the lecture notes and/or your personal experience to answer those questions. Mobile phase: 30 % MeCN, 70 % TFA, 0.1 M (pH 2.0) low rate: 1.0 mL/min 2Benzok Acid Maleic Aci 1. (a) Which component has the strongest affinity for the stationary phase? Why? (b) What HPLC separation mode is used? Explain. 2. What elution mode is used for chromatogram A? Explain. 3. Discuss three factors that contributed broadened peak #5 in chromatogram A. 4. Using the experimental conditions and column information provided for chromatogram A, describe how each of the following changes in experimental conditions will affect the retention time of component 5. Specifically, will tR increase, decrease or not change at all? Justify your answer. a) Increasing the column temperature to 45 °C. Explain. b) Changing to an almost identical column but with smaller particle size. Explain c) Decreasing the mobile phase flow rate to 0.5 mL/min. Explain.

Answer 1

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