Sub-Minute Method for Determination of Naphazoline in the Presence of Diphenhydramine, Pheniramine or Chlorpheniramine by Capillary Electrophoresis

This paper presents a simple and low-cost capillary electrophoresis method for ultra-fast simultaneous determination of naphazoline (NPZ) and one of the following active ingredients: diphenhydramine (DIP), pheniramine (PHEN) or chlorpheniramine (CPHEN). The proposed method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) equipped with a short length capillary column (10 cm). One sample can be analyzed every 35 s (ca. 100 injections per hour) with resolutions between peaks greater than 1.4. The optimized background electrolyte (BGE) was composed by 20 mmol L-1 histidine and 10 mmol L-1 3,4-dimethoxycinnamic acid (pH = 9.5, adjusted with NaOH). Limits of detection were 25 µmol L-1 for NPZ, DIP, and PHEN and 13 µmol L-1 for CPHEN. The results obtained with the developed procedure were compared to those obtained by high-performance liquid chromatography (HPLC) and no statistically significant differences were observed (95% confidence level).