A Photovoltaic Detection System for Flow Injection and Liquid Chromatography

Abstract

A photoionization system has been developed for flow injection and liquid chromatographic applications that employs photovoltaic rather than traditional photoconductive detection. This detection system utilizes an excimer laser at 248 nm (5.0 eV) to achieve one-photon excitation in alcoholic, aqueous, and ionic solutions. The photovoltaic response is reported for a variety of solutes including aliphatic and aromatic amines, aldehydes, ketones, carboxylic acids, and halogenated compounds. The photovoltaic method is characterized with respect to solute concentration and flow rate. The detection limit is 5 × 10(-)(6) M (2.3 ng) for aniline in methanol with a linear dynamic range greater than 2 orders of magnitude, which compares favorably to UV-visible absorbance detection. Photovoltaic detection is demonstrated for a series of substituted anilines and aldehydes separated by reversed-phase liquid chromatography.