Photothermal refraction as a microbore liquid chromatography detector in femtomole amino acid determination

Modern analytical thermooptical spectroscopy

“…Most studies performed by thermal lens spectrometry coupled with HPLC were devoted to analysis of organic compounds. A combination of HPLC with the thermal lens detection was used to detect amino acids, 108,474 nitro derivatives of aromatic compounds, 378,514,515 catecholamines 478,479 and carotenoids ( Refs 408,475,511). Thermal lens spectrometry, photothermal refraction spectrometry and other thermooptical methods are employed for constructing detectors for chromatographic analysis of organic compounds.…”

Attomole amino acid determination by capillary zone electrophoresis with thermooptical absorbance detection

“…This research group has been interested in the detection of DABSYL amino acids since 1985 (11)(12)(13). The fortuitous overlap of the absorbance spectrum of the derivatives with the 442-nm line of the helium-cadmium laser and the 457.9-nm line of the argon ion laser proved useful in the development of thermooptical detection.…”

Subfemtomole detection limit for amino acid determination with laser-induced crossed-beam thermal lens detection

“…The crossed-beam thermal lens is designed to probe small volume samples (8)(9)(10)(11)(12)(13)(14)(15). Here, the pump and probe beams are tightly focused, cross at right angles, and are coplanar.…”

“…The high spatial resolution and excellent sensitivity of the crossed-beam thermal lens detector are matched to the requirements of capillary chromatography. Subpicomole amounts of five dinitrophenylhydrazones have been separated with a 250-/tm diameter chromatographic column and detected 0003-2700/87/0359-2803Í01.50/0 by using a 2-mW pump laser (15). Since the sensitivity of the detector increases linearly with pump laser power, smaller amounts of analyte may be detected with a higher power laser.…”