Chromatofocusing of paracetamol-containing pharmaceuticals on reversed-phase sorbents

The chromatofocusing technique has been applied for the formation of ascending linear and quasilinear pH gradients within columns with reversed-phase sorbents Diasorb D-130-C₁₈ and Diasorb-100-CN-mono for the first time. It was found that the optimum composition of mobile phases was 25 mM KH₂PO₄ + 25% CH₃CN (pH 3.0) for the starting solution and 3.15 mM KH₂PO₄ + 25% CH₃CN (pH 6.8–7.0) for the eluent. Separation of components of Maxicold and Efferalgan-C pharmaceuticals has been carried out by the chromatofocusing technique on the Diasorb-100-CN-mono sorbent.