Design and evaluation of a multi-detection system composed of ultraviolet, evaporative light scattering and inductively coupled plasma mass spectrometry detection for the analysis of pharmaceuticals by liquid chromatography

摘要

Reversed-phase liquid chromatography was coupled to a multi-detection system composed of ultraviolet (UV) detection, evaporative laser scattering detection (ELSD) and inductively coupled plasma mass spectrometry (ICP-MS). By applying the principle of post-column solvent compensation, the organic modifier content was kept constant in ELSD and ICP-MS under gradient elution. Chlorine (Cl-35), bromine (Br-79 and Br-81) and sulfur (S-34) were monitored in several pharmaceutical compounds. The limit of quantitation (LOQ) was 80 ng/rnL for chlorine (chlorpropamide) and 2 ng/mL for bromine (bromazepam). Calibration graphs were linear from 1.0 mu g/mL to 100 mu g/mL for chlorpropamide (r(2) 0.990) and from 10 ng/mL to 500 ng/mL for bromazeparn (r(2) 0.996). The low LOQ value for bromine allows to quantify bromine in pharmaceutical samples below the 0.05% level of the active pharmaceutical ingredient. (C) 2008 Elsevier B.V. All rights reserved.