Fast BIA-amperometric determination of isoniazid in tablets

This paper proposes a new, fast and precise method to analyze isoniazid based on the electrochemical oxidation of the analyte at a glassy carbon electrode in 0.1 M NaOH. The quantification was performed utilizing amperometry associated with batch injection analysis (BIA) technique. Fast sequential analysis (60 determinations h−1) in an unusually wide linear dynamic range (from 2.5 × 10−8 to 1.0 × 10−3 M), with high sensitivity and low limits of detection (4.1 × 10−9 M) and quantification (1.4 × 10−8 M), was achieved. Such characteristics allied to a good repeatability of the current responses (relative standard deviation of 0.79% for 30 measurements), were explored for the specific determination of isoniazid in isoniazid–rifampin tablet.