Trace analysis of organic compounds by high-performance liquid chromatography with photoionization detection

Photoionization detection (PID) has now been successfully interfaced with modern high-performance liquid chromatography (HPLC) to provide a new "hyphenated" technique, HPLC-PID. This method is compatible with reversed-phase HPLC solvents and conditions, as well as with certain organic solvents used in normal-phase liquid chromatography. The HPLC-PID interface consists of a variable-ratio eluent splitter, operated inside a heated oven, which vaporizes both analytes and mobile phase prior to introduction into the detector. Depending on the energy (eV) of the photoionization detector lamp, most of the solvents commonly used in reversed-phase liquid chromatography are compatible with long-term, on-line, real-time, continuous photoionization detector operation. Virtually all organic classes now detectable by gas chromatography-PID can also be detected by HPLC-PID, but with somewhat poorer detection limits. In certain instances, minimum detection limits are in the 5-500 ng/injection range. The HPLC-PID system appears ideal for aromatic or aliphatic amines, substituted hydrocarbons, and certain other classes of organic compounds. Various applications of HPLC-PID, under reversed-phase conditions are illustrated and discussed.