Photoacoustic Densitometry by Fast Laser Beam Scanning

Abstract

A photoacoustic densitometry technique by laser beam scanning is described. The laser beam was scanned on the photoacoustic cell without chopping or modulation. The photoacoustic signals generated by fast laser beam scanning were converted from analogue to digital data and then processed by a microcomputer. The signal intensity from the sample increased concomitantly with decrease in the scanning speed. The chromatogram obtained by this method, i.e. the waveform of the signal, was different in shape from that of the conventional photoacoustic densitometer. The reproducibility of measurement for 0.03 to 0.25μg Malachite Green was 1.7-4.5% (RSD).