Ammonium hydrogencarbonate, an excellent buffer for the analysis of basic drugs by liquid chromatography-mass spectrometry at high pH

Ammonium hydrogencarbonate buffer has been found to be especially useful for high-pH HPLC analysis of samples from both combinatorial and medicinal chemistry sources. Satisfactory results were obtained by the standard diode array, evaporative light-scattering, and MS detection by using this buffer at a concentration of 10 mM. From a practical standpoint, ammonium hydrogencarbonate is an ideal buffer for chromatographers since it provides excellent chromatographic behaviour and reproducible separation. In addition to this, its volatility makes it an essential tool for rapid LC-MS product identification. Ammonium hydrogencarbonate was tested for a number of drug-like compounds analysed as mixtures, and data obtained were compared to those from the classical and MS-friendly buffers widely used by chromatographers: trifluoroacetic and formic acids. The results of this study revealed the suitability of this buffer for routine HPLC application in research laboratories. (C) 2002 Elsevier Science B.V. All rights reserved.