A stock solution of each amine was prepared at a final concentration
of 1 mg/mL in 0.1 N HCl and further diluted with 0.1 N HCl to
obtain working solutions in the range 0.1e10.0 mg/mL; for synephrine
only the range was 5.0e125.0 mg/mL. All solutions were
stored at 20 C until use.
to btain working solutions