Ion chromatography (IC) with upstream inline coupled-column matrix elimination (CCME) can be used to detect sub-ppb concentrations of low-molecular-weight amines in the presence of cationic drugs.
In contrast to direct-injection IC, where the late elution of strongly retained drugs requires eluents with added acetonitrile, the CCME technique uses two pre-concentration columns in series.
In an inverse matrix elimination step, cationic drug and target amines are trapped on a high-capacity and a very-high-capacity pre-concentration column, respectively.
During amine determination, a rinsing solution flushes the drug to waste.
This shortens the analysis time and improves sensitivity as well as selectivity.
Besides the determination of monomethylamine in Nebivolol hydrochloride, the CCME technique is a promising tool for detecting further low-molecular-weight amines in a wide range of drugs.
