Detection of airborne cocaine and heroin by high-throughput liquid-absorption preconcentration and liquid chromatography-electrochemical detection.

A high-throughput liquid-absorption preconcentrator (HTLAP) for rapid and/or ultrasensitive detection and analysis of trace contaminants samples air at a rate of 600-700 l/min and collects analytes from vapors or aerosols at an efficiency of 40-60% into a small volume of liquid absorbent dripping at a rate of 0.1-2 ml/min. These features combine to reduce the lower detection limit (LDL) of available analytical instrumentation by a factor of > 1000 and/or to permit faster sampling and far more rapid on-site air monitoring than were previously practicable. LDLs of ca. 1:10(13) (v/v) of alkaloids have been achieved with LC and electrochemical detection. The HTLAP is directly adaptable to most liquid-phase analyzers. The small rate of liquid collection is also compatible with available interfaces to mass spectrometers. Moreover, the HTLAP permits detection and quantitation of polar or highly reactive compounds that cannot be readily analyzed by conventional preconcentration and GC.