Liquid-chromatographic fractions, detection

Queiroz, E.F. et al., On-line identification of the antifungal constituents of Erythrina vogelii by liquid chromatography with tandem mass spectrometry, ultraviolet absorbance detection and nuclear magnetic resonance spectrometry combined with liquid chromatographic micro-fractionation, J. Chromatogr. A, 972, 123, 2002. 

Tentative confirmation of suspected liquid chromatographic peaks has been achieved in the analysis of carazolol and seven sedatives in swine kidney, by using photodiode-array detection in the wavelengUi range of 220-320 nm. It was reported (526) that further identification could be made possible if the corresponding fractions of the eluate were submitted off-line to two-dimensional thin-layer chromatography. 

R. F. Roberts and M. J. Fields, Monitoring radioactive compounds in high-performance liquid chromatographic eluates fraction collection versus on-line detection, J. Chromatogr., 342 25 (1985). 

The experiment was initiated by introducing nitrogen gas from the gas feed line at the head of the rotating column. Then, a 2.5-L volume of the BC solution was continuously introduced into the coil from the sample feed line at 1.5 mL/min. The hydrophobic components produced a thick foam which was carried with the gas stream and collected from the foam collection line at the tail other components stayed in the liquid stream and eluted from the liquid collection line at the head. High-performance liquid chromatographic analysis of the foam fraction revealed that the degree of enrichment increased with the hydrophobidty of the components. These results clearly indicate that the present method will be quite effective for the detection and isolation of small amounts of natural products present in a large volume of aqueous solution. 

Monitoring a liquid chromatographic effluent by means of an immunoassay provides sensitive and se-leetive deteetion in combination with the separation of eross-reaetive compounds [1,2]. When implementing the immunoassay as a postcolumn reaction detection system after liquid chromatography, it is frequently referred to as immunodetection [3,4]. Automation and assay speed are the main advantages of immunodetection over off-line eoupling of immunoassays to liquid ehromatography by means of fraction collection [5,6]. 

Most of the methods described for spirolides have been developed for rapid monitoring of these toxins in phytoplankton or shellfish matrices. Due to mass selectivity, a baseline separation of the different spirolides is not achieved in most cases. For research and toxin profiling purposes, a comprehensive separation method for a vast suite of spirolides may be of interest. Recently, several isobaric spirolides, which coelute and thus remain unidentified under standard chromatographic conditions, were detected (Krock et al., unpublished data). Only the attempt at a baseline-separation of all compounds revealed these variants. This was achieved by the following liquid chromatographic conditions for fractionation of spirolides ... 

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