Simultaneous On-Line Characterization of Small Organic Molecules Derived from Combinatorial Libraries for Identity, Quantity, and Purity by Reversed-Phase HPLC with Chemiluminescent Nitrogen, UV, and Mass Spectrometric Detection

Abstract

In the ongoing quest for ever more rapid techniques to quantify small organic molecules, we have evaluated a chemiluminescent nitrogen detector (CLND) as a universal quantitation tool for nitrogen-containing molecules. By flow injection analysis (FIA) and in conjunction with reversed-phase (RP) chromatography using gradient elution, the CLND produced a linear response from 25 to 6400 pmol of nitrogen that was equivalent for a set of chemically and structurally diverse compounds. Over the entire linear range, the absolute response exhibited an average error of approximately ±10% among the compounds. In addition, the response was independent of mobile-phase composition. These results demonstrate that the CLND can be used with FIA or on-line with RP-HPLC for rapid and accurate quantitation down to low-picomole levels, using a single external standard. We also used the CLND in combination with a UV detector and a mass spectrometer (MS) during RP-HPLC (LC/UV/N/MS) to characterize several samples containing sma...