The ionization constants of nine basic drugs ethylmorphine, thebaine, codeine, levorphanol, dihydrocodeine, cocaine, alprenolol, propranolol and . methamphetamine in methanol were determined from the dependence of their Ž . mobilities on the pH* of the background electrolyte BGE , based on a conventional pH* scale. Mobilities in the BGEs with acetate as counter ion were seemingly too low, an effect that was related to ion pair formation of the cationic analytes with acetate. After numerical correction of this effect the application of the Henderson᎐Hasselbalch equation enabled the calculation of the p K * values, a which were found to be between 9.3 and 11.2. These p K * values are only 1 to 2.5 a p K units higher than in pure water, which is in marked contrast to the changes observable for neutral acids.

No abstract

Potassium persulfate was compared with hydrogen peroxide as oxidant in pressurized hot water. Oxidant (in excess) and organic model pollutants (phenol, 2,3-dichlorophenol, and m-cresol, c ) 0.3-0.5 mM each) were introduced to the reaction capillary with and without preheating. Reaction time was 4-57 s, temperature 80-400 °C, and pressure 220-310 bar. Without preheating, potassium persulfate was clearly more efficient than hydrogen peroxide in oxidizing the model compounds: for example, with potassium persulfate, removal percentages close to 100 were obtained in 55 s at 110 °C, whereas with hydrogen peroxide the required temperature to obtain similar results in any reaction time was nearly 300 °C. Total organic carbon was removed more effectively by potassium persulfate under mild conditions. Overall, oxidation efficiencies were decreased when capillaries were preheated, especially with potassium persulfate as oxidant. Corrosion, measured as Ni concentration of the effluent, was more severe with potassium persulfate than hydrogen peroxide.