Page 146 - Applied Pharmacognosy
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Mobile Phase Selection
Guidelines for Setting Mobile Phase Conditions
❑ If the sample is cationic i.e. basic: ion pair reagent should be
used.
Representative Ion Pair Reagents
Basic Substance Acidic Substance
❑ Alkyl sulfonates such as: ❑ Tetra-n-butylammonium
➢ Pentanesulfonic acid sodium salt (C5). hydroxide (TBA).
➢ Hexanesulfonic acid sodium salt (C6). ❑ Alkylamines.
➢ Heptanesulfonic acid sodium salt (C7). UV inactive
➢ Octanesulfonic acid sodium salt (C8).
❑ Perchlorate. 5 to 50 mmol/L
The retention strength increases with the length of alkyl cha14in5 .
