Question: Retention factors for three solutes separated on a C8 nonpolar stationary phase are listed in the table on the next page. Eluent was a 70:30

Retention factors for three solutes separated on a C8 nonpolar stationary phase are listed in the table on the next page. Eluent was a 70:30 (vol/vol) mixture of 50 mM citrate buffer (adjusted to pH with NH3) plus methanol. Draw the dominant species of each compound at each pH in the table and explain the behavior of the retention factors.

Retention factor Analyte Acetophenone Salicylic acid Nicotine pH 3 4.21 2.97 0.00 pH 5 4.28 0.65 0.13 pH 7 4.37 0.62 3.11 CO,H CH3 Salicylic acic Nicotine pK1 3.15 pK2 7.85 pK 2.97

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