Derivative spectrophotometric determination of quinine, adenine and metoclopramide hydrochloride in their binary mixture using zero–crossing technique

A first–derivative spectrophotometric procedure has been applied for the simultaneous quantification of quinine–adenine or quinine–metoclopramide hydrochloride in their mixes using “zero–crossing” measuring approach. The first–derivative spectra of quinine and adenine allowed the determination of quinine (1.5–17.9 µg/mL) in the presence of 4.3 µg/mL of adenine, and adenine (5.4–27.0 µg/mL) in presence of 9.0 µg/mL of quinine. In the binary mixture of quinine–metoclopramide hydrochloride, the first–derivative spectra of quinine and metoclopramide hydrochloride allowed the determination of quinine (11.95–95.62 µg/mL) in presence of 5.4 µg/mL of metoclopramide hydrochloride, and metoclopramide hydrochloride (1.34–21.52 µg/mL) in existence of 29.88 µg/mL of quinine. A statistical scrutiny of the provided practical data was used to perform a critical assessment of the recommended approaches