Development of a Novel Versatile Method for Determination of two Antihistamines in Association with Naphazoline Using Cathodically Pretreated Boron‐doped Diamond Electrode

Abstract

AbstractAntihistamines such as pheniramine (PHN) or chlorpheniramine (CPH) are commonly associated with naphazoline (NPZ) in eye drops and nasal decongestants. In this work, a batch‐injection analysis system with multiple pulse amperometric (BIA‐MPA) detection has been applied for the first time for fast simultaneous determination of naphazoline (NPZ) and pheniramine (PHN) or NPZ and chlorpheniramine (CPH). PHN or CPH was selectively detected at +1.1 V and both PHN and NPZ or CPH and NPZ were detected at +1.3 V using boron doped diamond (BDD) as working electrode and Britton‐Robinson (BR) buffer (pH=10.0) as supporting electrolyte. The current of NPZ can then be obtained by subtraction of the currents detected at both potential pulses and applying a correction factor (CF). The proposed method presented good intra‐day repeatability (RSD between 0.7 and 3.2 % for PHN; 0.7 and 2.1 % for CPH; 1.5 and 4.0 % for NPZ; n=20), high analytical frequency (>80 injections h−1), and limits of detection of 0.64, 0.47 and 0.11 μmol L−1 for PHN, CPH and NPZ, respectively. The results obtained with the proposed method are in agreement with those obtained by HPLC (95 % confidence level).