Laser-Based Photoacoustic Densitometer for Two-Dimensional Scanning of Thin-Layer Chromatographic Plates

Abstract

Laser-based photoacoustic densitometry was applied to two-dimensional analysis in thin-layer chromatography. An acousto-optic device was used to provide both intensity modulation and a rastering scan. The spatial resolution is 25 × 60 spots for an area of 25 × 50 mm on the thin-layer chromatographic plate. Three detection modes, normal modulation, resonant modulation, and unmodulated rapid scan modes were compared. Detection limits in the most sensitive mode and in the fastest mode are 350 pg with scan time of 153 s and 6.9 ng with scan time of 1.5 s, respectively.