Effect of pH on charcoal adsorption of lidocaine, methadone, pilocarpine, and procaine.
The charcoal adsorption from aqueous solution of four weak bases (lidocaine, methadone, pilocarpine, and procaine) was studied at a variety of pH values representing large differences in percent ionization. The measure of charcoal adsorption used was percent of the ligand adsorbed (constant starting ligand concentrations of 3 X 10(-4) M) by a variety of quantities of charcoal ranging from 3 to 30 mg per 10 mL of mixture. In addition, moles of ligand adsorbed/gram of charcoal values were calculated. The data indicated that for a given ligand, charcoal adsorption was statistically the same (p = 0.05) at all pH values. It is concluded that the generalization for weak bases that charcoal adsorption increases with increasing pH may not be universally valid.
D000327:Adsorption; D002606:Charcoal; D006863:Hydrogen-Ion Concentration; D008012:Lidocaine / Q000302:isolation & purification*; D008691:Methadone / Q000302:isolation & purification*; D010862:Pilocarpine / Q000302:isolation & purification*; D011343:Procaine / Q000302:isolation & purification*
D010862:Pilocarpine; D002606:Charcoal; D011343:Procaine; D008012:Lidocaine; D008691:Methadone