Simultaneous determination of three species with a single-injection step using batch injection analysis with multiple pulse amperometric detection

In this work, the possibility of simultaneous determination of three compounds with a single-injection step using batch injection analysis with multiple pulse amperometric detection (BIA–MPA) is demonstrated for the first time. A sequence of three potential pulses (+1.25V, +1.60V, and +1.80V) was applied with the acquisition of three separate amperograms. 8-Chlorotheophylline was detected selectively at +1.25V, both 8-chlorotheophylline and pyridoxine at +1.60V and 8-chlorotheophylline, pyridoxine, and diphenhydramine at +1.80V. Subtraction between the currents detected at the three amperograms (with the help of correction factors) was used for the selective determination of pyridoxine and diphenhydramine. The proposed method is simple, inexpensive, fast (60injectionsh−1), and present selectivity for the determination of the three compounds in pharmaceutical samples, with results similar to those obtained by HPLC (95% confidence level). [Display omitted] •Three species were simultaneously determined for the first time by BIA-MPA.•This method is simple, fast (60injectionsh−1) and cost-effective.•The proposed method presents advantages if compared to separation techniques.•The samples solutions were directly injected into the BIA–MPA system.